Progression-free and overall survival in ovarian cancer patients treated with CVac, a mucin 1 dendritic cell therapy in a randomized phase 2 trial.

BACKGROUND: CAN-003 was a randomized, open-label, Phase 2 trial evaluating the safety, efficacy and immune outcomes of CVac, a mucin 1 targeted-dendritic cell (DC) treatment as a maintenance therapy to patients with epithelial ovarian cancer (EOC). METHODS: Patients (n = 56) in first (CR1) or second clinical remission (CR2) were randomized (1:1) to standard of care (SOC) observation or CVac maintenance treatment. Ten doses were administered over 56 weeks. Both groups were followed for progression-free survival (PFS) and overall survival (OS). RESULTS: Fifty-six patients were randomized: 27 to SOC and 29 to CVac. Therapy was safe with only seven patients with Grade 3-4 treatment-emergent adverse events. A variable but measurable mucin 1 T cell-specific response was induced in all CVac-treated and some standard of care (SOC) patients. Progression free survival (PFS) was not significantly longer in the treated group compared to SOC group (13 vs. 9 months, p = 0.36, hazard ratio [HR] = 0.73). Analysis by remission status showed in the CR1 subgroup a median PFS of 18 months (SOC) vs. 13 months (CVac); p = 0.69 (HR = 1.18; CI 0.52-2.71). However CR2 patients showed a longer median PFS in the CVac-treated group (median PFS not yet reached, >13 vs. 5 months; p = 0.04, HR = 0.32 CI). OS for CR2 patients at 42 months of follow-up showed a difference of 26 months for SOC vs. > 42 months for CVac-treated (as median OS had not been reached; HR = 0.17 (CI 0.02-1.4) with a p = 0.07). CONCLUSIONS: CVac, a mucin 1-dendritic cell maintenance treatment was safe and well tolerated in ovarian cancer patients. A variable but observed CVac-derived, mucin 1-specific T cell response was measured. Notably, CR2 patients showed an improved PFS and lengthened OS. Further studies in CR2 ovarian cancer patients are warranted (NCT01068509). TRIAL REGISTRATION: NCT01068509. Study Initiation Date (first patient screened): 20 July 2010. Study Completion Date (last patient observation): 20 August 2013, the last patient observation for progression-free survival; 29 April 2015, the last patient was documented regarding overall survival.

Insulin-like growth factor-binding proteins (IGFBPs) and their regulatory dynamics.

The IGFBPs are a family of homologous proteins that have co-evolved with the IGFs and that confer upon the IGF regulatory system both functional and tissue specificity. IGFBPs are not merely carrier proteins for IGFs, but hold a central position in IGF ligand-receptor interactions through influences on both the bioavailability and distribution of IGFs in the extracellular environment. In addition, IGFBPs appear to have intrinsic biological activity independent of IGFs. The current status of research on IGFBPs is reviewed herein. Following a brief introduction to the entire IGF/IGFBP system, separate sections for each of the six cloned mammalian IGFBPs, the most extensive for IGFBP3, cover selected topics that emphasize the dynamics of IGFBPs--that is, their regulation in cells, their functionally important post-translational modifications, and their interactions in the cellular microenvironment--and how these dynamics influence physiological function.

Administration of growth hormone (GH), but not insulin-like growth factor-I (IGF-I), by continuous infusion can induce the formation of the 150-kilodalton IGF-binding protein-3 complex in GH-deficient rats.

In the adult circulation, 70-90% of the serum insulin-like growth factors (IGFs) are carried by IGF-binding protein-3 (IGFBP-3), which exists as part of a 150-kilodalton (kDa) ternary complex including IGF and an acid-labile subunit (ALS). We have examined the hormonal regulation and molecular distribution of IGFBP-3 in the circulation of a uniquely GH-deficient (GHD) rat model. For 7 days, GHD rats were given GH by either twice daily injections (1 mg/kg) or continuous infusion (2.4 mg/kg.day) or IGF-I by continuous infusion (1.4 mg/kg.day). Each day, weight and feed and water intake were monitored, and on day 7, liver, kidney, spleen, heart, and lung were weighted, and sera were collected. Serum IGF-I was analyzed by immunoassay, and the molecular distribution of the IGFBPs was determined by neutral size-exclusion chromatography combined with Western ligand blot and Western immunoblot. The GHD rats were 40-60% lighter than their normal littermates, and all organs examined were proportionately smaller. Serum IGF-I and IGFBP-3 levels were less than 10% of those in normal rats. Incubation of serum from GHD rats with [125I]IGF-II showed that radiolabel was incorporated only into a 44-kDa IGFBP region that contained the smaller IGFBPs. IGFBP-3 eluted around 60 kDa. No 150-kDa IGFBP region was detected. The administration of GH or IGF-I to GHD rats resulted in significant increases in weight gained, although food and water intake remained unaltered. Weight gain was observed in all three treatments groups. Both GH treatment regimens significantly increased liver, spleen, and lung weight, whereas IGF-I therapy increased spleen, kidney, and heart. Administration of GH twice daily did not increase serum IGF-I or IGFBP-3 concentrations, and the molecular distribution of IGFBP-3 remained unchanged. In contrast, continuous infusion of GH resulted in 5-fold increases in serum IGF-I and increases in IGFBP-3 levels. Size-exclusion chromatography combined with Western ligand blot analysis revealed that radioligand was incorporated into 150- and 60-kDa regions, and that IGFBP-3 was detectable in both regions. Thus, GH infusion was able to induce formation of the 150-kDa ternary complex by increasing circulating levels of IGF-I, IGFBP-3, and presumably ALS. Administration of IGF-I also increased serum IGF-I and IGFBP-3 levels, although the increase in IGFBP-3 was only in the 60-kDa region of the chromatograph, suggesting that IGF-I can induce neither ALS nor formation of the 150-kDa complex.(ABSTRACT TRUNCATED AT 400 WORDS)

Direct administration of insulin-like growth factor to fetal rhesus monkeys (Macaca mulatta).

A potential treatment for the amelioration of fetal growth failure is insulin-like growth factor-I (IGF-I). To address concerns of safety and efficacy, IGF-I (80 microg/kg; GroPep Pty.) was administered i.p. to healthy rhesus monkey fetuses via ultrasound guidance every other day between gestational days (GD) 110-120 and 130-140 (third trimester; term = approximately GD 165 +/- 10; n = 6). Pregnancies were monitored sonographically, and fetal/maternal blood samples were collected for complete blood counts, immunophenotyping, and biochemical analyses. Blood samples, external measures of the fetus and newborn, and tissue and organ weights were collected at fetal necropsy (GD 150; n = 2) or at term delivery of neonates (GD 160; n = 4). The results of these investigations have shown no evidence of hypoglycemia in the fetus or dam during the course of treatment. Circulating concentrations of fetal, but not maternal, IGF-I increased with treatment (approximately 80 to approximately 1015 ng/ml), and there was no evidence of a change in serum IGF-II or an increase in IGF binding protein-3 compared with historical control values. Fetal lymphocytes and select red cell parameters increased, and a significant elevation in circulating B cells and CD4/CD8 ratios in fetal lymph nodes was shown. Although no changes were detected in body weights, increases in thymic, splenic, and kidney weights and small intestine lengths occurred. Thus, administration of IGF-I to the fetal monkey is safe and results in 1) transient increases in circulating IGF-I, 2) a significant effect on fetal hematopoietic and lymphoid tissues, and 3) an increase in select fetal organ weights and measures. These data suggest that IGF-I may represent a potential candidate for therapeutic treatment of growth-compromised human fetuses in utero.

Insulin-like growth factor binding proteins in sera of pregnant nonhuman primates.

Insulin-like growth factors (IGFs) are mitogenic peptides that are important for fetal and maternal tissue growth during pregnancy. They circulate complexed primarily with a serum binding protein, IGFBP-3, which regulates the availability of the IGFs to their target tissues. We previously reported that in pregnant women, serum IGFBP-3 levels, assessed by Western ligand blotting, decline markedly beginning at 6 weeks gestation due to a circulating protease that cleaves IGFBP-3 into a 29-kilodalton (kDa) protein and lower mol wt (M(r)) fragments. In the current study, we compared IGFBP profiles, IGFBP-3 and IGFBP-1 levels, and IGFBP protease activities in sera from pregnant and nonpregnant women, baboons, and rhesus monkeys, using Western ligand blotting, IGFBP-specific immunoassays, IGFBP-3 protease assay, and zymographic gel electrophoresis. Serum IGFBP profiles in nonpregnant human and nonhuman primates were similar and were not cycle-dependent. IGFBP-3 (37-43 kDa), IGFBP-2 (31 kDa), and IGFBP-1 (28 kDa) were identified in all three species using IGFBP-specific human antisera. A 24-kDa IGFBP was also present and is believed to be IGFBP-4. Serum IGFBP-1 levels increased throughout gestation in human and nonhuman primates. Serum IGFBP-2 and putative IGFBP-4 were barely detectable in all three species from midgestation to term, but increased several days postpartum. In contrast, serum IGFBP-3 profiles differed markedly between species during gestation. Rather than the decrease seen in human pregnancy serum, there was an increase in circulating IGFBP-3 levels in nonhuman primates. Furthermore, for both baboon and rhesus monkey, the M(r) of serum IGFBP-3 was about 2 kDa greater in pregnant than in nonpregnant animals, and deglycosylation studies suggested that the higher M(r) forms may be alternatively glycosylated or may have a unique primary structure. As in nonpregnant women, serum IGFBP-3 protease activity was absent in nonpregnant and pregnant baboons. However, rhesus monkey serum contained a calcium-dependent protease that cleaved recombinant human IGFBP-3 into unique fragments, compared to the human pregnancy enzyme. Unlike human pregnancy serum, which proteolyzes IGFBP-3, in human nonpregnancy serum, rhesus serum incubated under similar conditions did not result in proteolysis of rhesus IGFBP-3, suggesting that the IGFBP-3 protease in human pregnancy serum is not present in the circulation of the rhesus monkey. To assess proteolytic activity in these sera, zymographic polyacrylamide gel analysis, using gelatin as a substrate, was performed. A minor band of proteolytic activity (72 kDa) was observed in all three species throughout gestation.(ABSTRACT TRUNCATED AT 400 WORDS)

The mouse intraovarian insulin-like growth factor I system: departures from the rat paradigm.

Although the rat intraovarian insulin-like growth factor I (IGF-I) system is well documented, the increasing availability of null mouse mutants for components of the IGF system necessitates characterization of the mouse model as well. Therefore, we undertook to define the components of the mouse intraovarian IGF-I system and to examine its operational characteristics. The cellular pattern of ovarian gene expression was comparable in the immature rat and mouse for IGF-I and the type I IGF receptor. In both species, IGF-I messenger RNA (mRNA) is selectively expressed by granulosa cells in growing, healthy appearing follicles. Type I IGF receptor mRNA was also concentrated in granulosa cells, but was uniformly expressed in all follicles large and small, healthy and atretic appearing alike. Cellular patterns of IGF-binding protein (IGFBP) gene expression were similar in mouse and rat, except in the case of IGFBP-2. IGFBP-2 mRNA was localized to the mouse granulosa cell, in contrast to its concentration in the rat thecal-interstitial compartment. This difference in IGFBP expression pattern was also noted in cultured mouse and rat granulosa cells. Although immunoreactive IGFBP-4 (24 and 28 kDa) and IGFBP-5 (29 kDa) were shared by both species, the cultured mouse granulosa cell also featured immunoreactive IGFBP-2 (30 kDa). The mouse paradigm further differed from its rat counterpart in that a maximal dose of FSH, previously shown to suppress the elaboration of rat granulosa cell-derived IGFBPs, was without effect. The addition of IGF-I proved stimulatory to the accumulation of the 28- to 29-kDa IGFBPs, as previously reported for the rat. However, IGF-I proved inhibitory to the accumulation of the 24-kDa IGFBP (presumptive nonglycosylated IGFBP-4); no consistent effect was reported for the rat model. Functional comparisons of mouse and rat ovarian cell cultures revealed qualitatively comparable FSH-stimulated steroidogenesis, disposition of radiolabeled pregnenolone, IGF-I-amplified FSH action, and IGFBP-mediated antigonadotropic activity. These findings indicate that the mouse intrafollicular IGF-I system differs from the rat paradigm in both the makeup and regulation of granulosa cell-derived IGFBPs as well as in the intensity and character of the steroidogenic process. Studies employing the mouse model must take into account these important distinctions relative to the more established rat paradigm.

Transcriptional and posttranscriptional regulation of intraovarian insulin-like growth factor-binding proteins by interleukin-1beta (IL-1beta): evidence for IL-1beta as an antiatretic principal.

Intraovarian interleukin-1 (IL-1), a putative intermediary in the ovulatory cascade, has recently been implicated as an antiatretic agent. Given the reported antigonadotropic and thus atretogenic potential of granulosa cell-derived insulin-like growth factor-binding proteins (IGFBPs), we evaluated the ability of IL-1beta to regulate ovarian IGFBP-4 and -5, the IGFBP species elaborated by the rat granulosa cell. Treatment of whole ovarian dispersates of immature rat origin with increasing concentrations of IL-1beta for 96 h resulted in substantial and significant time-dependent inhibition of IGFBP-4 and IGFBP-5 transcripts compared with that in untreated controls. The IL-1 effect proved relatively specific in that no significant alterations in IGFBP transcripts were observed in the presence of select ovarian agonists, including transforming growth factor-alpha, tumor necrosis factor-alpha, endothelin-1, hepatocyte growth factor, keratinocyte growth factor, or basic fibroblast growth factor. The inhibitory effect of IL-1beta on ovarian IGFBP-4 and -5 expression was almost completely reversed in the presence of IL-1 receptor antagonist, suggesting mediation via a specific IL-1 receptor. The addition of actinomycin D to IL-1beta-pretreated whole ovarian dispersates produced a pattern of (IGFBP-4 and -5) messenger RNA decay indistinguishable from that noted for the untreated control group. Medium conditioned by IL-1beta-treated (but not untreated) whole ovarian dispersates displayed a marked diminution in the relative content of the IGFBP-4 and IGFBP-5 proteins (24- and 28- to 29-kDa proteins, respectively). Medium conditioned by IL-1beta-treated (but not untreated) whole ovarian dispersates proteolyzed [125I]IGFBP-5 (but not IGFBP-4) into fragments with apparent molecular masses of 18 and 14 kDa, respectively. In conclusion, our present observations demonstrate the ability of IL-1 to 1) inhibit the steady state levels of transcripts corresponding to IGFBP-4 and -5 in a time-dependent, relatively specific, and receptor-mediated fashion; 2) suppress the accumulation of the corresponding IGFBP proteins; and 3) stimulate the activity of the IGFBP-5-directed (but not IGFBP-4) endopeptidase, a posttranscriptional phenomenon. Our findings also suggest, by inference, that the IL-1beta-mediated inhibition of IGFBP-4 and -5 transcripts is due in part to a decrease in the rate of transcription of the corresponding genes and not to a change in the stability of the relevant messenger RNAs. Consequently, the ability of IL-1 to influence ovarian IGFBP economy appears multifaceted, comprising both transcriptional and posttranscriptional effects. To the extent that IGFBP-4 and -5 constitute atretogenic agents, our present findings support the view that IL-1beta may play an antiatretic role in the context of ovarian physiology.

Measurement and characterization of insulin-like growth factor binding protein-3 in human biological fluids: discrepancies between radioimmunoassay and ligand blotting.

The inability to detect insulin-like growth factor binding protein-3 (IGFBP-3) in some circumstances by Western ligand blot analysis has emphasized the need to characterize IGFBPs by both ligand binding and immunological techniques. In this study, we have: 1) characterized and quantified IGFBP-3 in nonpregnancy, pregnancy, and fetal cord serum, follicular, peritoneal, and amniotic fluid, seminal plasma, cerebrospinal fluid (CSF), and urine; 2) established a new IGFBP-3 RIA that detects both intact and fragments of IGFBP-3; 3) identified both intact and fragments of IGFBP-3 by Western immunoblot techniques; and 4) addressed the discordance between Western ligand blot analysis and RIA by assessing fluids for IGFBP proteolytic activity. All fluids examined, except pregnancy serum, CSF, and amniotic fluid, displayed a 44-34-kilodalton (kDa) IGFBP-3 doublet by Western ligand blot analysis. Western immunoblot analysis using specific IGFBP-3 antiserum showed a 44-34-kDa IGFBP-3 doublet and a 28-kDa fragment in nonpregnancy serum, fetal cord serum, follicular fluid, and peritoneal fluid. The immunoreactive 42-38-kDa doublet was faint in urine and seminal plasma. IGFBPs in CSF did not cross-react with IGFBP-3 antiserum. Pregnancy serum and amniotic fluid contained only the 28-kDa fragment when compared against equal volumes of nonpregnancy serum. With the development of an IGFBP-3 RIA, IGFBP-3 could be accurately measured; urine, CSF, and seminal plasma contained the lowest levels of IGFBP-3 at 27 +/- 3 ng/ml (mean +/- SEM), 110 +/- 26 ng/ml, and 209 +/- 56 ng/ml, respectively. In increasing concentration: fetal cord serum contained 753 +/- 101 ng/ml; peritoneal fluid, 1124 +/- 130 ng/ml; follicular fluid, 2356 +/- 211 ng/ml; nonpregnancy serum, 3556 +/- 508 ng/ml; pregnancy serum, 3718 +/- 842 ng/ml; and amniotic fluid, 5150 +/- 688 ng/ml. The measurable concentrations of IGFBP-3 in CSF and the high concentrations measured in pregnancy serum and amniotic fluid conflicted with Western blot analysis. Thus, fluids were assessed for IGFBP proteolytic activity by incubation with a source of IGFBP-3, either nonpregnancy serum or purified IGFBP-3. All fluids displayed some proteolytic activity with either assay. Fluids with little protease activity (nonpregnancy serum, follicular fluid, and urine) showed a close relationship between immunoassayable IGFBP-3 by RIA and IGFBP-3 band intensity by Western ligand blot. Fluids with high proteolytic activity (pregnancy serum, CSF, seminal plasma, peritoneal fluid, and amniotic fluid) gave discrepant IGFBP-3 values between RIA and Western ligand blot.(ABSTRACT TRUNCATED AT 400 WORDS)

Identification and characterization of insulin-like growth factors (IGFs), IGF-binding proteins (IGFBPs), and IGFBP proteases in human synovial fluid.

The insulin-like growth factors (IGFs) and IGF-binding proteins (IGFBPs) in human synovial fluid play an important role in maintaining articular cartilage metabolism. In this study we measured the concentrations of IGF-I, IGF-II, and IGFBP-3 in normal human synovial fluid by RIA and characterized the IGFBPs by Western ligand blot (WLB), Western immunoblot, and immunoprecipitation. We also extended the study and compared normal synovial fluid to synovial fluids from patients with osteoarthritis (OA) and rheumatoid arthritis (RA). The concentrations of IGF-I, IGF-II, and IGFBP-3 in normal synovial fluid were 19 +/- 3 (mean +/- SE), 194 +/- 14, and 349 +/- 65 ng/mL, respectively. In synovial fluid of patients with OA, IGF-I levels were elevated, whereas IGF-II was decreased, and the IGFBP-3 level was similar to the control value. In patients with RA, both IGF-I and IGFBP-3 were elevated, whereas IGF-II remained unchanged. WLB and immunoprecipitation of normal synovial fluid revealed IGFBP-1 (26-29 kDa), IGFBP-2 (32 kDa), IGFBP-3 (42- to 39-kDa doublet), and IGFBP-4 (24 kDa); the IGFBP-3 doublet was very faint. In RA synovial fluid, all IGFBPs were dramatically increased, whereas little change was seen in the synovial fluid of OA. Western immunoblot against IGFBP-3 revealed a prominent 30-kDa immunoreactive fragment of IGFBP-3 in synovial fluids of normal adults as well as in those of RA and OA patients. This was concurrent with detectable IGFBP-3 protease activity, which was characterized to be of the metallo- and serine protease family. Thus, in normal synovial fluid, there is a balance of circulating IGF, IGFBP, and proteases to modulate the bioactivity of IGF. In pathological states, the increased IGF-I concentrations were accompanied by an increase in IGFBP-I concentrations were accompanied by an increase in IGFBP-3 levels in synovial fluid. These findings suggest that alteration of the IGF and IGFBP axis in pathological states may be important for understanding the underlying pathophysiology of disordered articular growth and metabolism.

Concentrations of insulin-like growth factor (IGF)-binding protein-3 (IGFBP-3), IGF, and IGFBP-3 protease activity in cerebrospinal fluid of children with leukemia, central nervous system tumor, or meningitis.

Insulin-like growth factor-II (IGF-II) is the major IGF in human cerebrospinal fluid (CSF), whereas IGF-I is only detectable in trace amounts. The major IGFBPs in CSF are IGFBP-2 and IGFBP-4. Normally, IGFBP-3 is a minor component in CSF of healthy subjects, but may be increased in pathological states. We investigated IGF-I, IGF-II, and IGFBP-3 levels by specific RIAs in CSF from patients with central nervous system (CNS) tumor or leukemia and compared them with values in patients with meningitis. Further, as proteolysis of IGFBP-3 is part of the modulation of IGF activity, IGFBP-3 fragmentation was quantified by densitometric analysis of [125I]IGFBP-3 protease assays. We examined CSFs of 23 children with malignant CNS tumors, 18 children with leukemia, and 13 children with meningitis. The CSF from 38 children who received lumbar punctures to exclude meningitis was used to define the normal range for IGF-I, IGF-II, IGFBP-3, and IGFBP-3 protease activity in CSF. CNS tumor and leukemia patients had normal levels of IGF-I and IGF-II in CSF, whereas the IGF-II concentration in CSF of meningitis patients was elevated (P < 0.0001). Only 2 of 13 (15%) meningitis patients had elevation of CSF IGFBP-3 concentrations, despite high numbers of inflammatory cells. By comparison, elevated IGFBP-3 concentrations were found in the CSF of 16 of 23 (70%) CNS tumor patients and 6 of 7 (86%) CNS tumor patients with microscopically detectable malignant cells in CSF. Twelve of 13 (92%) patients with medulloblastoma or ependymoma and all 7 medulloblastoma/ependymoma patients with malignant cells in CSF had elevated IGFBP-3 concentrations. The IGFBP-3 protease activity in CSF was elevated in 15 of 16 (94%) patients with CNS tumors of high grade histological malignancy. Five of 6 patients (83%) with acute leukemia and microscopically detectable malignant cells in CSF at the time of diagnosis showed elevated IGFBP-3 concentrations, with normalization after chemotherapy. Leukemia patients without malignant cells in CSF had normal IGFBP-3 concentrations. We conclude that in CSF of children with highly malignant CNS tumor or CNS leukemia, IGFBP-3 is elevated. This phenomenon could be caused by disruption of the blood-CSF barrier and entry of IGFBP-3 from serum, although this appears unlikely, especially for CNS leukemia. More likely possibilities are 1) local production of IGFBP-3 by CNS tumor tissue and secretion into the CSF, or 2) local production of IGFBP-3 by malignant cells within the CSF.

Urinary insulin-like growth factors (IGF) and IGF-binding proteins in normal subjects, growth hormone deficiency, and renal disease.

Recent studies in our laboratories have shown that urine from healthy adults contains immunoreactive and intact insulin-like growth factor-binding protein-3 (IGFBP-3). The aim of this study was to assess urinary IGF-I, IGF-II, and IGFBP-3 in a cross-sectional study of healthy subjects, as well as characterize urinary IGFBPs (uIGFBps) in patients with GH deficiency (GHD) and renal disease, such as, Alport syndrome, immunoglobulin A nephropathy, focal segmental glomerulosclerosis, and systemic lupus erythematosus. Urinary concentrations of IGF-I and IGF-II in pooled spot morning urines of healthy subjects, measured by RIA, were low and relatively unaltered throughout age, when expressed as either nanograms per milliliter or nanograms per milligram creatinine. To determine the complement of IGFBPs in urine of healthy subjects, spot morning urine samples were subjected to Western ligand blot and immunoblot analysis. IGFBP-3 was detected at 40-50 kDa, possibly due to variable glycosylation of uIGFBP-3. In addition, a 32-kDa IGFBP-2 and smaller unclassified IGFBPs were detected. Unlike uIGFs, urinary concentrations of IGFBP-3 (uIGFBP-3; nanograms per milligram creatinine) were age-, but not sex-related. Levels of uIGFBP-3 ranged from 40-60 ng/mL in children between 4 and 10 yr of age. After 11 yr, immunoreactive uIGFBP-3 progressively declined, attaining a plateau after 26 yr of age to approximately 18 ng/mg creatinine. uIGFBP-3 did not correlate with uIGF levels. Regulation of IGFBP-3 in the urine of normal subjects and of renal disorders was examined by RIA, Western ligand blot (WLB), and protease assay. Intact uIGFBP-3 was consistently found in normal urine and little urinary protease was identified. In GHD patients, IGFBP-3 by WLB was low or undetectable, whereas RIA levels of uIGFBP-3 were normal or high, consistent with the presence of IGFBP-3 proteolytic activity. In Alport syndrome, both RIA measures and WLB analysis were high, as was the IGFBP-3 proteolytic activity. Patients with immunoglobulin A nephropathy, focal segmental glomerulosclerosis and systemic lupus erythematosus measured low-normal levels of IGFBP-3 by WLB and RIA, and displayed little protease activity. This study provides normative data concerning radioimmunoassayable levels of IGFBP-3 in urine. The presence of normal-elevated levels of uIGFBP-3 by RIA in GHD indicates that uIGFBP-3 levels are not under GH control and are unlikely to represent filtered serum IGFBP-3.(ABSTRACT TRUNCATED AT 400 WORDS)

The insulin-like growth factor system in human peritoneal fluid: its effects on endometrial stromal cells and its potential relevance to endometriosis.

Peritoneal fluid (PF) lines the abdomen and pelvis and is believed to contain growth factors that stimulate endometriosis, a benign gynecological condition associated with pelvic pain and infertility, in which endometrial cells proliferate and differentiate on the pelvic peritoneum, outside of their normal location within the uterus. In this study, we examined the insulin-like growth factor (IGF) system in seven paired samples of PF and serum from normally cycling women and examined the mitogenic potential of this fluid on cultured endometrial stromal cells. IGF-I, IGF-II, and IGF-binding protein-1 (IGFBP-1), -2, -3, and -4 were identified in PF by immunoassays. PF IGF levels, determined by RIA, were approximately 60% of paired serum levels, and PF levels of IGFBP-2 and IGFBP-3, determined by Western ligand blotting and RIA, respectively, were approximately half of their serum concentrations. IGFBP-4 was barely detectable by Western ligand blotting in PF, and levels of IGFBP-1, determined by immunoassay, were not appreciably different in PF and serum. Incubation of [125I]IGF-II with serum and PF and subsequent size-exclusion chromatography at neutral pH revealed approximately equal incorporation of radiolabel in the IGFBP regions of 150 and 44 kilodaltons (kDa) in serum and primarily in the 44-kDa region in PF. RIA of IGFBP-3 in the IGFBP regions of column effluent revealed that the majority of IGFBP-3 was in the 150-kDa region in both serum and PF, suggesting the presence of the ternary complex in PF. Western ligand blotting of column effluent samples revealed 37-/43-kDa IGFBP-3 primarily in the 150-kDa complex in serum and a marked reduction in the amount of the 37-/43-kDa IGFBP in PF. Western immunoblotting of column effluent with IGFBP-3 antiserum revealed immunoreactive IGFBP-3 forms of 37-43 kDa (major) and 28 kDa (minor) in serum and almost exclusively the 28-kDa band in PF, suggesting that IGFBP-3 in PF may be proteolytically processed. The presence of an IGFBP-3 protease was confirmed using [125I]IGFBP-3 as substrate and was not appreciably present in paired serum samples. Inhibitor profiles demonstrated that this protease is a metal-independent serine protease, and its approximate relative molecular mass was estimated to be 69 kDa, determined by size-exclusion chromatography. The mitogenic potential of IGF peptides and PF was assessed on cultured endometrial stromal cells to test the hypothesis that IGFs in PF may stimulate the growth of endometrium in the pelvic cavity, for example in the disorder of endometriosis.(ABSTRACT TRUNCATED AT 400 WORDS)

Regulation of extragonadal insulin-like growth factor-binding protein-3 by testosterone in oophorectomized women.

Insulin-like growth factor (IGF)-binding protein-3 (IGFBP-3) is the principal carrier protein of IGF-I in the circulation. IGF-I has been postulated to play a role in the genesis and maintenance of the polycystic ovary syndrome. Regardless of the exact mechanism of action of IGF-I on ovarian steroidogenesis, alterations in the level of IGFBP-3 may play a significant role in regulating the concentration of IGF-I in hyperandrogenism. We have postulated that androgens reduce the circulating IGFBP-3 concentration through a mechanism similar to its suppression of the hepatic production of sex hormone-binding globulin (SHBG), thereby increasing bioavailable IGF-I and amplifying its impact on ovarian steroidogenesis. To test this hypothesis, we studied seven oophorectomized women (aged 39-51 yr; body mass, 20.9-35.8 kg/m2) during 3 weeks of testosterone (T) propionate administration (20 mg, three times weekly). All subjects were receiving 0.625 or 1.25 mg conjugated estrogens/day. Blood was sampled before (week 0), during (weeks 1-3), and after (week 4) T administration. Serum was assayed for total T, GH, and SHBG, and plasma was assessed for IGF-I, insulin (INS), and IGFBP-3. IGFBP-3 was measured by both RIA and Western ligand blotting; (expressed as a percentage of the control value). Circulating T increased from 1.51 +/- 1.06 to 30.8 +/- 13.8 mmol/L by week 2 (P < 0.001). During T administration, IGF-I increased (from 55 +/- 23 ng/mL at week 0 to 124 +/- 37 ng/mL at week 4; P < 0.05); INS did not change, with the exception of a higher fasting level 1 week after discontinuing therapy, and GH decreased (from 1.7 +/- 2.3 micrograms/L at week 0 to 0.4 +/- 0.4 microgram/L at week 4; P < 0.03), as did the circulating SHBG concentration (397 +/- 205 to 273 +/- 93 nmol/L by week 2; P < 0.01). IGFBP-3 levels determined by Western ligand blot were higher during the second and third weeks of T administration (265 +/- 28% and 218 +/- 43% of control values, respectively; P < 0.05) compared to that at week 0 (165 +/- 44% of control values). However, there was no difference in the circulating concentration of IGFBP-3, determined by RIA, at weeks 0, 1, 3, and 4 (3.59 +/- 0.35, 4.00 +/- 0.79, 3.48 +/- 0.56, and 3.65 +/- 0.52 microgram/mL, respectively).(ABSTRACT TRUNCATED AT 400 WORDS)

Adjunctive growth hormone during ovarian hyperstimulation increases levels of insulin-like growth factor binding proteins in follicular fluid: a randomized, placebo-controlled, cross-over study.

GH increases circulating insulin-like growth factor I (IGF-I), which can promote the growth and differentiated function of ovarian granulosa and theca cells. Reported studies of GH as an adjunct to menotropin stimulation in women, largely those with ovarian dysfunction, have not consistently shown a benefit of GH, despite increases in serum and follicular fluid IGF-I. We hypothesized that changes in intrafollicular IGF-binding proteins (IGFBPs), which can antagonize IGF actions on granulosa cells, may underlie the inconsistent effects of GH. In the present study of GH, administered in double-blind, placebo-controlled, cross-over fashion to regularly cycling women undergoing in vitro fertilization, we found that follicular fluid levels of IGFBP-1, -3, and -4 and serum levels of IGFBP-3, as well as follicular fluid and serum IGF-I, were significantly increased in the GH-treated cycles, when compared with the placebo cycle of the same patient. We suggest that the net increase in intrafollicular IGFBPs in GH cycles may mitigate the potential beneficial effect of increased IGF-I.

Two-year treatment of growth hormone (GH) receptor deficiency with recombinant insulin-like growth factor I in 22 children: comparison of two dosage levels and to GH-treated GH deficiency.

We have reported 1-yr results of a double blind, placebo-controlled trial of recombinant human insulin-like growth factor I (rhIGF-I) replacement in 16 children from the Ecuadorian GH receptor-deficient (GHRD) population. This report extends observations of rhIGF-I efficacy at two dosage levels [120 micrograms/kg BW twice daily (n = 15) and 80 micrograms/kg twice daily (n = 7)] over 2 yr, compares biochemical responses [serum IGF-I and IGF-binding protein-3 (IGFBP-3)] and their relationship to growth effects, and compares treatment effects of rhIGF-I in GHRD to rhGH in idiopathic GH deficiency (GHD). There were no baseline differences between the low and high dose groups for growth velocity (GV), bone age (BA), SD score for height, or percent mean body weight for height (MBWH). Over 2 yr of rhIGF-I treatment, there were no differences in GV or in changes in height SD score, height age (HA), or BA between the two groups; a subgroup of six subjects at the higher dose followed for a third year continued at the second year GV. The higher dose resulted in a greater change in percent MBWH. GV in yr 1 and 2 for the entire group and in yr 3 for a subgroup were greater for GH-treated GHD (n = 11). The GHD group showed a greater change in SD score for height and HA, but did not differ from the rhIGF-I-treated GHRD group in the change in BA (delta BA) or delta HA/delta BA over 2 yr. There was a greater change in percent MBWH in GHRD. There were no differences between dosage groups for serum IGF-I levels at baseline or the near-normal trough levels 12 h after rhIGF-I injection; these individual levels correlated with HA gain in yr 1 and 2. IGFBP-3 levels were markedly low, with no changes of significance with treatment. Comparable growth responses to the two dosage levels and the biochemical changes indicate a plateau effect at or below 80 micrograms/kg BW twice daily. The growth response and favorable trough levels of IGF-I despite the overall lack of increase in circulating IGFBP-3 levels suggest an alternative mechanism for sustaining IGF-I levels and avoiding rapid clearance of rhIGF-I. The greater increase in MBWH with treatment of GHRD than with treatment of GHD may reflect comparable effects on lean body mass without the lipolytic effects of GH in the GHRD subjects. The difference in growth response between rhIGF-I-treated GHRD and rhGH-treated GHD groups is consistent with the hypothesis that 20% or more of GH-influenced growth is due to the direct effects of GH on bone. Nonetheless, the comparable delta HA/delta BA suggests similar long term effects of replacement therapy in the two conditions.

Insulin-like growth factor binding protein-I levels are strongly associated with insulin sensitivity and obesity in early pubertal children.

In conditions associated with insulin resistance, insulin-like growth factor binding protein-I (IGFBP-I) levels have been shown to correlate inversely with insulin levels. Puberty is associated with insulin resistance and thus provides a model for comparing the relationship of IGFBP-I to both insulin levels and measures of insulin sensitivity. Our study population consisted of 104 healthy pubertal children, age 9.8-14.6 yr. Each subject had his/her insulin sensitivity (Si) assessed by the modified minimal model of Bergman, which employs a frequently sampled i.v. glucose tolerance test. Results showed that IGFBP-I levels were significantly higher in boys than in pubertally matched girls (P < 0.01). There was a strong positive correlation between IGFBP-I levels and Si (r = 0.65, P < 0.0001) and a weaker negative correlation with fasting insulin levels (r = -0.38, P < 0.0001). An inverse relationship was also found between IGFBP-I levels and body mass index (r = -0.46, P < 0.0001) and with IGF-I levels (girls only, r = -0.41, P < 0.003). Consequently, insulin sensitivity, obesity, and IGF-I are important predictors of IGFBP-I levels in pubertal children. It is possible that insulin-mediated suppression of IGFBP-I in obese children may increase free IGF-I levels and thus contribute to somatic growth. The same mechanism may operate in pubertal children, where insulin resistance and growth acceleration occur simultaneously.

A randomized, double blind, placebo-controlled trial on safety and efficacy of recombinant human insulin-like growth factor-I in children with growth hormone receptor deficiency.

GH insensitivity due to GH receptor deficiency is a rare autosomal recessive condition, characterized by deletions or mutations of the GH receptor gene. Patients are refractory to both endogenous and exogenous GH, resulting in severe growth retardation. Therapy with recombinant human insulin-like growth factor-I (rhIGF-I) can bypass the defect in the GH receptor and potentially stimulate growth. We previously identified a genetically homogeneous group of patients in southern Ecuador, thus providing a patient base for a controlled clinical trial of rhIGF-I therapy. Seventeen prepubertal patients were entered in a randomized, double blind, placebo-controlled trial. Subjects received either a 12-month course of rhIGF-I (120 micrograms/kg, sc, daily) or 6 months of placebo followed by 6 months of rhIGF-I. Subjects receiving rhIGF-I showed a significant increase in growth rate, which was sustained over the 1-yr course of therapy (from 2.9 +/- 0.6 to 8.6 +/- 0.4 cm/yr). Incidents of hypoglycemia were equal in frequency in the placebo and rhIGF-I groups. One recipient of rhIGF-I developed papilledema, which resolved spontaneously. rhIGF-I therapy did not alter serum IGF-binding protein-3 concentrations. rhIGF-I treatment is effective in stimulating skeletal growth in GH receptor deficiency. Although the therapy proved to be safe, the potent metabolic actions of rhIGF-I and the persistently low levels of serum IGF carrier protein necessitate continued careful observation for side-effects.

Insulin-like growth factors and their binding proteins in the term and preterm human fetus and neonate with normal and extremes of intrauterine growth.

Insulin-like growth factors (IGFs), IGF-binding proteins (IGFBPs), and insulin are believed to be important in the regulation of fetal and neonatal growth. We previously reported that the profiles of IGFBPs in fetal cord serum (FCS) were dependent on the growth/metabolic status of the fetus. The goals of the current study were to examine the IGF system in FCS from term fetuses with normal growth, those with intrauterine growth retardation (IUGR), and those who were large for gestational age (LGA) and in FCS from normal weight preterm (25-37 weeks) and term fetuses in the neonatal period from the day of birth (day 0) until 7 days of age (day 7). Western ligand blotting (WLB) of term FCS revealed IGFBPs with mol wt of 43 and 38 kilodaltons (kDa; IGFBP-3), 34 kDa (IGFBP-2), 28 kDa (IGFBP-1 and glycosylated IGFBP-4), and 24 kDa (IGFBP-4). In IUGR FCS, there was a 50% decrease in IGFBP-3 detected by WLB, which was shown not to be due to an IGFBP-3 protease in IUGR sera. In LGA FCS, IGFBP-3 levels were elevated 2-fold by densitometric analysis of ligand blots. In normal term FCS, the following levels (+/- SE) were present: IGF-I, 76 +/- 16; IGF-II, 401 +/- 38; IGFBP-3, 700 +/- 112; IGFBP-1, 77 +/- 10 ng/mL; and insulin, 3.8 +/- 1.6 microU/mL. In IUGR FCS, IGF-I, IGF-II, and IGFBP-3 were significantly reduced, and IGFBP-1 was 7-fold higher than in FCS from normal weight fetuses. In LGA FCS, IGF-I, insulin, and IGFBP-3 were significantly increased, whereas IGFBP-1 was significantly decreased. During the neonatal period, IGF-I levels on day 0 were 4-fold higher in FCS from term (38-40 weeks) compared to preterm (25-31 weeks) newborns. FCS IGF-II levels did not change significantly on day 0 between 25-40 weeks gestation. In the first 7 days of postnatal life, IGF-I levels were unchanged in preterm newborns, whereas in term neonates, IGF-I levels decreased precipitously on day 1, remained low during the first 3 days of life, and returned to birth levels by the end of the first week. In contrast, IGF-II and IGFBP-3 levels did not significantly change during the first week of life in preterm or term newborns.(ABSTRACT TRUNCATED AT 400 WORDS)

A longitudinal analysis of maternal serum insulin-like growth factor I (IGF-I) and total and nonphosphorylated IGF-binding protein-1 in human pregnancies complicated by intrauterine growth restriction.

In cord blood and late gestation maternal serum, IGF-I is positively correlated with birth weight, whereas IGF-binding protein-1 (IGFBP-1) is inversely correlated with birth weight. Our goal was to determine whether maternal serum or amniotic fluid concentrations of IGF-I, IGFBP-1, or nonphosphorylated IGFBP-1 (npIGFBP-1) in early gestation predict later fetal growth abnormalities. Maternal serum was collected prospectively across gestation (5-40 wk) from 749 pregnant subjects. Amniotic fluid was collected after amniocentesis during wk 15-26 from 207 subjects. We compared median serum concentrations of IGF-I, IGFBP-1, and npIGFBP-1 in 38 subjects who delivered growth-restricted infants with the control group of 236 subjects with normal weight infants for each gestational age grouping, wk 5-12, 13-23, and 24-34. In the control group median IGF-I concentrations were 14.8, 11, and 15.6 nmol/liter for wk 5-12, 13-23, and 24-34, respectively, compared with 13.7, 14.3, and 10.6 nmol/liter in the intrauterine growth restriction (IUGR) group. Median IGFBP-1 concentrations were 8.5, 30.4, and 24.4 nmol/liter, respectively, in controls, compared with 11.4, 28.6, and 25.5 nmol/liter in the IUGR group. Median npIGFBP-1 concentrations were 6.9, 22, and 17.4 nmol/liter, respectively, in controls, compared with 5.0, 32.1, and 24.2 nmol/liter in the IUGR group. In the control group the median amniotic fluid IGFBP-1 level was 13,160 nmol/liter, and the median npIGFBP-1 level was 15,970 nmol/liter; in the IUGR group these levels were 13,440 and 18,440 nmol/liter, respectively. No clinically useful differences were found between the IUGR and control groups. Our results do not support the use of maternal serum IGF-I or IGFBP-1 or amniotic fluid IGFBP-1 or npIGFBP-1 early in gestation to predict later fetal growth restriction.

Characterization of a low molecular mass form of insulin-like growth factor binding protein-3 (17.7 kilodaltons) in urine and serum from healthy children and growth hormone (GH)-deficient patients: relationship with GH therapy.

The insulin-like growth factor binding proteins (IGFBPs) are the carriers for insulin-like growth factor (IGF0-I and IGF-II. IGFBP-3 is GH-dependent and circulates associated with IGFs and an acid-labile subunit to form a 150-kilodalton (kDa) complex. In human serum, two immunoreactive molecular weight forms of IGFBP-3 have been identified. In human urine, radioimmunoassayable levels of IGFBP-3 have been detected. The objectives of this study were to characterize the molecular weight forms of IGFBP-3 in urine and serum of healthy children and adults and in children with GH deficiency (GHD), to quantify the urinary molecular weight forms of IGFBP-3, and to evaluate the relationship of these forms with GH therapy. Urine and serum were obtained from 12 prepubertal children with GHD, before and after 6 months of GH therapy, from 30 prepubertal healthy children, and from 8 healthy adults. Western immunoblotting (WIB) with IGFBP-3 antiserum (alpha IG-FBP-3g1) showed that in urine the most representative IGFBP-3 was a 17.7-kDa form. The 17.7-kDa IGFBP-3 was high in urine of healthy children compared with healthy adults and was low in children with GHD but increased after GH therapy. Urinary IGFBP-3 immunoreactive profile was determined by neutral-size exclusion chromatography, followed by IGFBP-3 RIA analysis of the fractions. Urine showed a major peak of IGFBP-3 immunoreactivity around 17 kDa. The 17-kDa urinary IGFBP-3 chromatographic peak averaged 8461 +/- 367 ng/12 h.m2 of body surface in healthy children, 3415 +/- 739 in adults (P < 0.001), 2294 +/- 354 in children with GHD before GH therapy (P < 0.001), and 7940 +/- 1874 in children with GHD after GH therapy. Urinary IGFBP-3 was also measured by RIA in unfractionated urine; healthy children showed levels significantly higher (14575 +/- 460 ng/12 h.m2) than adults (7823 +/- 1083, P < 0.001) and higher than children with GHD before GH therapy (4710 +/- 703, P < 0.001). Again, however, immunoreactive IGFBP-3 increased after GH treatment (12294 +/- 3394). In the serum of the healthy children we characterized by specific IGFBP-3 WIB analysis, a 17.7-kDa immunoreactive form of IGFBP-3 that was absent in the serum of healthy adults and low in patients with GHD, increased during GH therapy. Serum samples were subjected to neutral-size exclusion chromatography and the fractions were analyzed by WIB.(ABSTRACT TRUNCATED AT 400 WORDS)