Multi-omics analysis identifies potential microbial and metabolite diagnostic biomarkers of bacterial vaginosis.

BACKGROUND: Bacterial vaginosis (BV) is a common clinical manifestation of a perturbed vaginal ecology associated with adverse sexual and reproductive health outcomes if left untreated. The existing diagnostic modalities are either cumbersome or require skilled expertise, warranting alternate tests. Application of machine-learning tools to heterogeneous and high-dimensional multi-omics datasets finds promising potential in data integration and may aid biomarker discovery. OBJECTIVES: The present study aimed to evaluate the potential of the microbiome and metabolome-derived biomarkers in BV diagnosis. Interpretable machine-learning algorithms were used to evaluate the utility of an integrated-omics-derived classification model. METHODS: Vaginal samples obtained from reproductive-age group women with (n = 40) and without BV (n = 40) were subjected to 16S rRNA amplicon sequencing and LC-MS-based metabolomics. The vaginal microbiome and metabolome were characterized, and machine-learning analysis was performed to build a classification model using biomarkers with the highest diagnostic accuracy. RESULTS: Microbiome-based diagnostic model exhibited a ROC-AUC (10-fold CV) of 0.84 ± 0.21 and accuracy of 0.79 ± 0.18, and important features were Aerococcus spp., Mycoplasma hominis, Sneathia spp., Lactobacillus spp., Prevotella spp., Gardnerella spp. and Fannyhessea vaginae. The metabolome-derived model displayed superior performance with a ROC-AUC of 0.97 ± 0.07 and an accuracy of 0.92 ± 0.08. Beta-leucine, methylimidazole acetaldehyde, dimethylethanolamine, L-arginine and beta cortol were among key predictive metabolites for BV. A predictive model combining both microbial and metabolite features exhibited a high ROC-AUC of 0.97 ± 0.07 and accuracy of 0.94 ± 0.08 with diagnostic performance only slightly superior to the metabolite-based model. CONCLUSION: Application of machine-learning tools to multi-omics datasets aid biomarker discovery with high predictive performance. Metabolome-derived classification models were observed to have superior diagnostic performance in predicting BV than microbiome-based biomarkers.

Vitamin D levels and insulin resistance in children born with severe growth restriction.

This study was designed to examine differences in serum 25(OH)D levels between small-for-gestational-age (SGA) and appropriate-for-gestational-age (AGA) prepubertal children in correlation with birth weight and indices of insulin resistance and ß-cell function. Sixty-five nonobese children were examined at age 5-7.5 years; 27 born SGA and 38 matched AGA. Body weight, height, BMI, and waist circumference were recorded and fasting serum levels of glucose, insulin, 25(OH)D, and parathyroid hormone (PTH) were measured. The homeostasis model assessment for insulin resistance (HOMA-IR) and the ß-cell function index (HOMA-ß%) were estimated. The mean level of 25(OH)D was higher in the SGA group (26.2±10 vs. 17.2±7 ng/ml, p<0.01) but that of PTH was no different. The insulin resistance and ß-cell function indices were higher in the SGA group: HOMA-IR 1.34±0.67 vs. 0.99±0.53, and HOMA-ß% 135±56 vs. 97±60 in the SGA and AGA groups, respectively. In the SGA group, 25(OH)D was correlated with HOMA-ß% but not with HOMA-IR or insulin. In multiple regression, in the total cohort 25(OH)D and HOMA-IR were independently negatively correlated with birth weight (ß= - 0.31, ß= - 0.36, p<0.05) respectively. In conclusion, at prepuberty severely in utero growth restricted children have increased birth weight dependent levels of 25(OH)D, which might exert a regulatory role on ß-cell function.

Serum insulin-like growth factor I (IGF-I), IGF-binding proteins-1 and -3, and postnatal growth of late preterm infants.

Late preterm infants may have impaired early growth. The role of circulating insulin-like growth factors (IGFs) in the regulation of postnatal growth of these infants is unclear. The aim of the study was to investigate prospectively the serum levels of IGFs during the first year of life in late preterm infants and their association with birth weight and early postnatal growth. The study was conducted on 112 infants, born appropriate for gestational age (GA) at GA 32-36 weeks. Serum levels of IGF-I and IGF-binding proteins (IGFBP) -1 and -3, and anthropometric measurements were recorded at the chronological age of 2 and 6 weeks, and 3, 6, 9, and 12 months. The mean levels of both IGF-I and IGFBP-3 were found to be lower at 2 and 6 weeks, 82±44, 100±31 ng/ml, and 1.7±0.8, 2.1±1 µg/ml, respectively, but then rose and remained stable between 3 and 12 months. The levels of IGFBP-1 were lower at the 3 first study points and increased gradually thereafter. Birth weight correlated positively with the level IGF-I at 2 and 6 weeks (R=0.35, 0.37; p<0.01), but negatively at 12 months (R= - 0.34; p<0.01), independent of other factors. At all study points up to 6 months, the level of IGF-I was higher in infants who showed more rapid growth in either body weight or crown heel length. In late preterm infants, the serum IGF-I level is closely related to early accelerated growth. Its diverse associations with birth weight may imply a regulatory effect on regression of growth towards the mean.

Visfatin levels in prepubertal children born small or large for gestational age.

Children born small (SGA) or large (LGA) for gestational age are prone to develop insulin resistance (IR) during childhood. Visfatin, a hormone with insulin-mimetic actions, has been associated with IR. This study was designed to examine whether serum level of visfatin is correlated with metabolic indices of IR, in prepuberty in association with the intrauterine growth pattern. The following parameters were evaluated at a mean age of 6.5±1.2 years in 155 prepubertal children born appropriate for the gestational age (AGA) (n=63), or SGA (n=42), or LGA (n=50): serum levels of visfatin, adiponectin, leptin, fasting glucose (G(F)) and insulin (I(F)), the homeostasis model assessment IR index (HOMA-IR), plasma lipids, anthropometric indices at birth and the time of evaluation, and obesity indices [waist circumference (WC), body mass index (BMI) and skinfold thickness]. The mean serum level of visfatin was lower in the SGA than in the AGA and the LGA children (9±5.2 vs. 11.8±5.1 and 12.7±5.6 ng/ml, respectively, p<0.01). Girls had lower visfatin levels than boys (10.4±4.3 ng/ml vs. 12.5±6.7 ng/ml, p<0.05). Visfatin was not correlated with IR indices. In multiple regression analysis visfatin level was positively correlated with birth weight z-score (t=2.56, beta=0.24, p<0.01) and crown to heel z-score (t=2.46, beta=0.22, p=0.014), independent of age, gender, maternal weight before pregnancy, maternal weight gain during pregnancy, BMI z-score, WC z-score, serum leptin and adiponectin, and HOMA-IR. In conclusion serum visfatin level was lower in prepubertal SGA children but not correlated with IR indices. Low birth weight was an independent predictor of visfatin level.

ANCA-stimulated neutrophils release BLyS and promote B cell survival: a clinically relevant cellular process.

OBJECTIVES: To determine a role for antineutrophil cytoplasmic antibody (ANCA)-activated neutrophils in promoting B cell survival through the release of B lymphocyte stimulator (BLyS). METHODS: Neutrophil BLyS expression was measured by flow cytometry. Concentrations of BLyS in cell supernatants and donor serum samples were measured by ELISA. Cell survival assays were carried out using an L3055 cell line and viability measured by flow cytometry. RESULTS: Tumour necrosis factor α and formyl-Met-Leu-Phe (fMLP) treatment of non-primed neutrophils and treatment of primed neutrophils with anti-PR3 ANCA IgG resulted in a significant increase in surface expression of BLyS within 30 min which returned to basal levels by 2 h. Supernatants from ANCA-stimulated neutrophils were shown to contain increased levels of BLyS and to promote the survival of the centroblast cell line L3055. Serum BLyS concentrations are increased in patients with active ANCA-associated systemic vasculitis and these levels are increased further following 1-3 months of treatment with rituximab. CONCLUSIONS: ANCA specifically causes the release of BLyS from activated neutrophils which can support B cell survival in vitro. The presence of serum BLyS in active disease and its increase following B cell depletion suggest it is an important factor in disease pathogenesis and may facilitate disease relapse.

Growth factors, adiponectin, leptin and body mass index in pre-pubertal children born large for gestational age.

OBJECTIVE: To examine whether the IGF axis in pre-pubertal children born large for gestational age (LGA) differs from that of those born appropriate for gestational age (AGA). RESEARCH DESIGN AND METHODS: The study population consisted of 98 non-obese children aged 5.5-8 yr, of whom 37 were LGA, with birth weight (BW) > 90th percentile, and 61 AGA. The LGA children were subdivided into two subgroups, with BW 90th-97th percentile (no.=24) and BW > 97th percentile (no.=13), respectively. Total and free IGF-I, their binding proteins 1 and 3 (IGFBP-1 and IGFBP-3), leptin, adiponectin, fasting glucose (GF) and insulin (IF) were measured, and the homeostasis model assessment for insulin resistance (HOMA-IR index) was determined. RESULTS: IGF-I, free IGF-I and IGFBP-1 were similar in both groups. Both LGA subgroups had lower IGFBP-3 levels than the AGA group (2.34 ± 0.61 and 2.70 ± 0.90, respectively, vs 3.92 ± 1.1 µg/ml, p < 0.01). Adiponectin was higher in the 90th-97th percentile LGA subgroup than the AGA group (p<0.01). GF and IF were higher in the LGA group (86.5 ± 5.6 mg/dl, p < 0.01, and 5.84 ± 2.13 µU/ml, respectively, p < 0.05) than in the AGA group (82.6 ± 7.7 mg/dl and 4.62 ± 1.9 µU/ml, respectively), as was the HOMA-IR index (1.27 ± 0.60 vs 0.94 ± 0.43, p < 0.01). These three parameters were also found higher in the >97th percentile LGA subgroup. CONCLUSION: The IGF axis was not different in pre-pubertal children born LGA or AGA, with the exception of IGFBP-3, which was lower in the LGA children. In LGA pre-pubertal children the severity of intrauterine overgrowth was associated with the insulin resistance indices.

Changes in red cell phosphate metabolism of preterm and fullterm infants with perinatal problems during their first month of life.

The effects of perinatal problems on red cell phosphate metabolism were studied in two groups of infants (preterms B and fullterms D) during the first month of life. All infants started milk feeding from day three after birth. The results were compared to those of healthy preterms (A) and fullterms (C), respectively. Comparisons were also made between the preterm and fullterm groups B and D. The preterms with perinatal problems (B) showed a significant delay in catching up with the plasma and red cell inorganic phosphate (Pi) levels of controls (A) throughout the first month of life (p < 0.05). In parallel, the erythrocyte 2,3 diphosphoglycerate (2,3-DPG) concentrations of the sick preterms lagged significantly behind those of controls (p < 0.001); but the ATP levels were comparable between the two groups. The fullterms behaved slightly differently. No significant differences in plasma Pi (Pl Pi) and red cell 2,3-DPG were seen between the sick and healthy neonates during the month of study, while red cell Pi (RBC Pi) and ATP were found to be lower in the sick ones (p < 0.05). The fullterms with perinatal problems (D) had significantly higher Pl Pi (p < 0.05) and RBC Pi (p < 0.01) than preterms with problems (B) from the first week of life and continued in a similar pattern until the end of the month. Red cell 2,3-DPG concentrations were found to be significantly correlated with Pl Pi and RBC Pi in both preterm groups (p < 0.01) and in the sick fullterms (p < 0.001) during the time of the study. In the healthy fullterms 2,3-DPG was found to correlate only with red cell Pi (p < 0.05). Perinatal problems seem to affect Pi metabolism to a different degree in preterm and fullterm neonates in the first month of life.

Correlation of estrogen receptor beta gene polymorphisms with spinal bone mineral density in peri- and post-menopausal Greek women.

Estrogens play a significant role in bone physiology. Their action is mainly exerted through their receptors. Estrogen receptor alpha (ERalpha) plays a major role in bone homeostasis and there is evidence suggesting that estrogen receptor beta (ERbeta) has also an effect on BMD. We investigated the possible effect of two ERbeta gene polymorphisms on spinal bone mineral density (BMD) and metabolic bone markers in Greek women. Spine BMD as well as biochemical bone markers were measured in 147 healthy peri- and post-menopausal women [mean age (S.D.) 54 (7.9) years]. Genotyping was performed for two restriction fragment length polymorphisms (RFLPs) of ERbeta gene, RsaI in exon 5 and AluI in exon 8. For each polymorphism studied the cohort was divided into two groups: the "wild-type" group (RR and AA, respectively) and the "carrier" group including subjects with at least one allele with the restriction site (Rr&rr and Aa&aa, respectively). The distribution of RsaI genotypes was RR: 91.2% (n = 134), Rr: 8.2% (n = 12), and rr: 0.6% (n = 1) and of AluI genotypes AA: 36.7% (n = 54), Aa: 57.2% (n = 84), and aa: 6.1% (n = 9). No linkage disequilibrium was found between the two polymorphic sites studied. Spine BMD did not differ significantly in the two groups of either polymorphism, after adjusting for age, weight, height, and years since menopause [mean BMD (S.D.) for RR 0.841 (0.17) g/cm(2) versus Rr&rr 0.798 (0.13) g/cm(2), p = 0.25, and mean BMD (S.D.) for AA 0.828 (0.16)g/cm(2) versus Aa&aa 0.848 (0.17) g/cm(2), p = 0.32]. No significant differences were noted in metabolic bone markers except for a marginal difference of RR versus Rr/rr in urinary hydroxyproline/creatinine ratio [median (IQR) 3.88 (6.04) micromol/mmol in RR versus 8.2 (4.32) micromol/mmol in Rr/rr, p = 0.05]. Furthermore, no interaction between the two polymorphisms on BMD was found. In conclusion, in a Greek female post-menopausal population, the two ERbeta gene polymorphisms were not associated with BMD, or metabolic bone markers.

CD40 ligand, Bcl-2, and Bcl-xL spare group I Burkitt lymphoma cells from CD77-directed killing via Verotoxin-1 B chain but fail to protect against the holotoxin.

Owing to its lineage and differentiation stage-restricted expression, CD77 has been mooted as a therapeutic target in Burkitt lymphoma (BL). The recognition that the globotriaosyl moiety of this neutral glycosphingolipid is a receptor for Escherichia coli-derived Verotoxin-1 (Shiga-Like Toxin-1) offers a potential delivery system for the attack. Here we show that CD77-expressing Group I BL cells which are normally susceptible to activation-induced death on binding Verotoxin-1 B chain are protected in the presence of CD40 ligand. Ectopic expression of either bcl-2 or bcl-xL also afforded resistance to the actions of the B chain. In total contrast, neither of the survival genes nor a CD40 signal - even when acting in concert - protected against killing mediated by the holotoxin. These findings indicate that while therapeutic modalities for CD77-expressing B cell tumors (which include follicular lymphoma) based on the use of Verotoxin-1 B chain might be compromised by the activation of endogenous or exogenous survival pathways, those exploiting the holotoxin should be left unscathed.

Identification and characterization of roundabout orthologs in zebrafish.

The Roundabout (Robo) family of receptors and their extracellular ligands, the Slit protein family, play important roles in repulsive axon guidance. First identified in Drosophila, Robo receptors form an evolutionarily conserved sub-family of the immunoglobulin (Ig) superfamily that are characterized by the presence of five Ig repeats and three fibronectin-type III repeats in the extracellular domain, a transmembrane domain, and a cytoplasmic domain with several conserved motifs that play important roles in Robo-mediated signaling (Cell 92 (1998) 205; Cell 101 (2000) 703). Robo family members have now been identified in C. elegans, Xenopus, rat, mouse, and human (Cell 92 (1998) 205; Cell 92 (1998) 217; Cell 96 (1999) 807; Dev. Biol. 207 (1999) 62). Furthermore, multiple robo genes have been described in Drosophila, rat, mouse and humans, raising the possibility of potential redundancy and diversity in robo gene function. As a first step in elucidating the role of Robo receptors during vertebrate development, we identified and characterized two Robo family members from zebrafish. We named these zebrafish genes robo1 and robo3, reflecting their amino acid sequence similarity to other vertebrate robo genes. Both genes are dynamically expressed in the developing nervous system in distinct patterns. robo3 is expressed during the first day of development in the hindbrain and spinal cord and is later expressed in the tectum and retina. robo1 nervous system expression appears later in development and is more restricted. Moreover, both genes are expressed in non-neuronal tissues consistent with additional roles for these genes during development.

Overexpression of ornithine decarboxylase in prostate cancer and prostatic fluid in humans.

Prostate cancer (PCA), the most commonly diagnosed cancer in males in the United States, is the second leading cause of cancer-related deaths of males in this country. Because of the poor success rate in the treatment of PCA, an intervention at an early stage may reduce the progression of small carcinoma to large metastatic lesion, thereby reducing PCA-related deaths. Concerted efforts are needed to establish mechanism-based approaches to develop: (a) the markers for early detection of the disease as well as toward monitoring the efficacy of treatment(s); and (b) novel chemopreventive strategies against PCA. Using unique samples of pair-matched benign and cancer tissue obtained from the same PCA patient, we showed that ornithine decarboxylase (ODC) activity is significantly (P < 0.001) elevated in PCA (1142 +/- 100; mean +/- SE) than in paired benign tissue (427 +/- 51; mean +/- SE). The immunoblot analysis also showed a significant elevation in the protein expression of ODC in the PCA tissues as compared with the paired benign tissue. Furthermore, our data showed that the ODC activity in the prostatic fluid obtained by a digital rectal massage from the patients with PCA (3847 +/- 162; mean +/- SE) was significantly higher than in the patients with benign prostatic hyperplasia (2742 +/- 167; mean +/- SE) or normal individuals (1244 +/- 67; mean +/- SE). This observation might be of significance because the prostatic fluid could be obtained noninvasively by digital rectal massage. We suggest that ODC could serve as a target for early detection of human PCA as well as for monitoring the efficacy of treatment(s). The development of ODC as a target for novel chemopreventive strategies against PCA is an intriguing possibility.

No effect of switching to high-dose rosuvastatin, add-on nicotinic acid, or add-on fenofibrate on serum vitamin D levels in patients with mixed dyslipidemia.

BACKGROUND: Low 25-hydroxy-vitamin D [25(OH)VitD] levels may represent a novel cardiovascular disease risk factor. Several statins may increase 25(OH)VitD concentration. The effect of other lipid-lowering drugs is unknown. AIM: To investigate whether switching to high-dose rosuvastatin, add-on-statin nicotinic acid or add-on-statin fenofibrate would alter 25(OH)VitD levels in patients with mixed dyslipidemia who are already on a conventional statin dose. METHODS: This is a prespecified analysis of a previously published study. Forty-four patients with mixed dyslipidemia not at treatment goal despite treatment with simvastatin 10-40 mg or atorvastatin 10-20 mg or rosuvastatin 5-10 mg were randomly allocated to switch to rosuvastatin 40 mg (n=17), add-on-statin extended release nicotinic acid (ER-NA)/laropiprant (LRPT) (1000/20 mg first four weeks and 2000/40 mg thereafter) (n=14), or add-on-statin micronized fenofibrate (200 mg) for three months. The endpoint for this analysis was between-group difference in changes in 25(OH)VitD levels. RESULTS: Serum 25(OH)VitD levels did not significantly change in any group. In the switch to the highest dose of rosuvastatin group and the add-on-statin ER-NA/LRPT group there was an insignificant decrease in 25(OH)VitD levels {-4.7% [from 16.8 (3.2-37) to 16.0 (7.9-51.6)] and -14.8% [from 12.8 (2.0-54.8) to 10.9 (2.4-34)], respectively]}, while in the add-on-statin fenofibrate group there was an insignificant increase [+13% (from 14.5 (1.0-42) to 16.4 (4.4-30.4) ng/mL)]. No significant difference between groups was found. CONCLUSION: In patients already on a conventional statin dose, neither switching to high-dose rosuvastatin (40 mg) nor add-on-statin ER-NA/LRPT or fenofibrate were associated with significant changes in 25(OH)VitD serum levels. Hippokratia 2015; 19 (2):136-140.

Cellular phosphate metabolism in patients receiving bisphosphonate therapy.

Patients with Paget's disease of bone were treated with oral disodium dihydrogen ethylidene-1-hydroxy-1,1-bisphosphonate (EHBP), a drug that is known to stimulate renal tubular reabsorption of orthophosphate (Pi). After 2 weeks of treatment, plasma Pi rose from 1.02 to 1.67 mmol/l. No increase in Pi was observed with the related drug, dichloromethylene bisphosphonate, which also reduces bone turnover in Paget's disease. Intravenous EHBP caused a more rapid increase in plasma Pi, but maximum hyperphosphatemia was not observed until 7-11 days after treatment commenced. It is therefore unlikely that this effect is due to an immediate action of EHBP on the luminal face of the renal brush border Pi transporter. After 2 weeks of oral EHBP, the increase in the Pi concentration in patients' erythrocytes was 31% compared with 64% in plasma. In blood platelets and leukocytes, negligible changes in cellular Pi occurred. The concentrations of 2,3-diphosphoglycerate, adenosine 5'-diphosphate (ADP) and adenosine 5'-triphosphate (ATP) were unaltered, indicating that these organic phosphates were not offsetting a potential change in cellular Pi. The decrease in erythrocyte/plasma distribution ratio for Pi was also observed in patients receiving intravenous EHBP. However, no change occurred in cell/plasma distribution of chloride, suggesting that this apparent regulation of cellular Pi did not arise from changes in erythrocyte membrane potential, pH, or water content.

Bone minerals in beta-thalassemia minor.

Homozygous beta-thalassemia is a severe hereditary disorder associated with osteopenia. Recently it was suggested that thalassemia minor may be a risk factor for osteoporosis. The purpose of the present study was to investigate this suggestion. Bone mineral status was assessed in 22 premenopausal women and 21 men with beta-thalassemia minor. In vivo neutron activation analysis was applied to measure hand-bone phosphorus (HBP), single-photon absorptiometry to measure forearm bone mineral content (BMC), and dual-energy X-ray absorptiometry to measure spinal bone mineral density (BMD). Comparison of the HBP, BMC, and BMD values with those of sex- and age-matched healthy subjects without the beta-thalassemia trait failed to indicate a statistically significant difference for either sex group. Concerning the biochemical markers of bone metabolism that were studied (serum calcium, phosphate, alkaline phosphatase, osteocalcin, and parathyroid hormone, and 3-h fasting urine calcium-to-urine creatinine ratio) no difference was observed between the study subjects and matched controls. In conclusion, the present study showed that subjects with beta-thalassemia minor are not at risk for osteoporosis.

Release of clonal block in B cell chronic lymphocytic leukaemia by engagement of co-operative epitopes on CD40.

The clonal cells of patients with B-chronic lymphocytic leukaemia (B-CLL)--which essentially reside in a resting configuration--are characterised by a relative refractoriness to the normal signals for B cell growth and differentiation. Previously it has been shown that, using an in vitro culture system where CD40 is hyper-crosslinked by monoclonal antibody (mAb) held on CD32-transfected mouse L cells, the clonal block in B-CLL cells can be released with a resultant high rate of DNA synthesis ensuing. In the present study, we report that such release can be achieved purely with soluble reagents whereby co-operative epitopes on CD40 are targeted by the combined use of mAb and soluble recombinant CD40L. Substantial levels of DNA synthesis were induced under such conditions in 7/18 patients using CD40-targeted reagents alone and in 16/18 patients in the additional presence of interleukin 4. Possible extrapolation of these findings to novel therapeutic modalities could be envisaged.

Cancer prevention through sensible nutrition (commentary).

Because of the constant inflow of information and educational efforts by many organizations, public attention is increasingly focused in finding information about strategies for prevention of cancer. Because of the research efforts of the last twenty years it is now increasingly appreciated that changes in dietary habits may result in cancer incidence. In addition, the usefulness of dietary substances in affording prevention against the occurrence of cancer is increasingly recognized as one practical. approach in this direction. The general public through media efforts and through educational efforts by many organizations is becoming aware of the fact that certain dietary substances can increase the risk for cancer development whereas certain others can lower it. This awareness, most likely, will have practical implications in reducing cancer risk because unlike the carcinogenic environmental factors that are difficult to control, individuals can make decisions to modify their choice for the food and beverage they consume. This commentary deals with issues related to cancer prevention through sensible nutrition.

Growth hormone and insulin-like growth factor in non-uremic acidosis and uremic acidosis.

Growth retardation is a cardinal feature of children with renal tubular acidosis. This is reversible by correcting the non-uremic acidosis with alkali therapy. Sodium bicarbonate solutions or citrate solutions have been used for this purpose. However, the odious taste of these medications almost invariably causes medical noncompliance. The persistent and often profound metabolic acidosis from medical noncompliance, precipitates hypercalciuria and hypocitraturia, and increases the risk of nephrocalcinosis. The mechanism of the growth retardation in renal tubular acidosis is thought to be related to a blunting of anterior pituitary growth hormone secretion. In experimental metabolic acidosis, the growth hormone secretory pulse areas are reduced. Just as importantly, hepatic growth hormone receptor expression and IGF-I mRNA were blunted in metabolic acidosis. In uremia, growth retardation is secondary to a host of factors including metabolic acidosis, renal osteodystrophy, and the side effects of treatment such as corticosteroids, which compound the growth retardation. Growth hormone secretion by individual pituitary cells was stimulated by corticosteroids but, paradoxically, the total number of somatotropes was suppressed. In uremia, the secretion of growth hormone was not different from controls at any level of growth-hormone-releasing hormone challenges. Hepatic IGF-I mRNA was markedly reduced in uremic rats. Growth hormone receptor expression was significantly reduced in uremic acidotic rats. The growth hormone and IGF-I expression on the growth plate of the long bone of uremic rats was reduced. IGF-I immunoreactivity was present in both the hypertrophic and proliferative zones. The lack of growth of the proliferative zones suggested growth hormone and IGF-I resistance in uremic chondrocytes.

Study of growth hormone secretion and action in growth-retarded children with juvenile chronic arthritis (JCA).

The stimulated and spontaneous growth hormone (GH) secretion and the response to GH action were assessed in growth-retarded children with juvenile chronic arthritis (JCA), in order to determine the underlying mechanisms of growth retardation in such children. Six children (4 boys and 2 girls aged 10.7-13.8 years) with active JCA of systemic onset were included in the study which involved: (1) anthropometric measurements; (2) assessment of GH responses to insulin-induced hypoglycaemia and clonidine stimulation; (3) assessment of the nocturnal pulsatile GH secretion by measuring GH in blood samples obtained every 20 min from 20.00 to 08.00 h; and (4) the IGF-I generation test. As a control, the latter test was also performed in eight aged-matched children with physiological delay in puberty. Biosynthetic hGH (0.1 IU/kg BW) was administered s. c. for 4 days and blood samples were taken at baseline and the morning after the last GH injection for measurement of IGF-I and IGFBP-3. All six children with JCA were prepubertal and their growth velocity was <3 cm/year. The GH responses to both stimulation tests were normal (peak GH >20 mU/l). Analysis of the pulsatile GH secretion during the night revealed three-to-four GH pulses of normal amplitude (>20 mU/l). IGF-I (26.7+/-4.6 nmol/l, mean+/-SD) and IGFBP-3 (2.1+/-0.2 mg/l) levels were lower in the patients compared with the controls (43.0+/-3.7 nmol/l and 2.8+/-0.2 mg/l, respectively, P<0.01). Following stimulation with exogenous hGH, there was a significant increase in IGF-I and IGFBP-3 levels in the control group (85 and 73%, respectively), but only a small increase in the patients (31 and 14%). It appears that stimulated and spontaneous GH secretion is normal in children with active systemic JCA, but the response to endogenous and exogenous GH with regard to IGF-I and IGFBP-3 production is impaired, indicating a degree of GH insensitivity in such children.

Reduced serum insulin-like growth factor-1 (IGF-1) and IGF-binding protein-3 levels in adults with inflammatory bowel disease.

In the present study, the changes in circulating IGF-1 and its binding protein IGFBP-3 were determined in adult patients with active inflammatory bowel disease (IBD) in order to assess the effect of this inflammatory condition on the IGF system. IGF-1 and IGFBP-3, as well as interleukin-6 (IL-6) were measured in serum obtained from 22 consecutive newly diagnosed patients (mean age 41.3 years) with active IBD, including 10 patients with Crohn's disease (CD), and 12 with ulcerative colitis (UC). For comparison the same parameters were determined in 30 healthy volunteers matched for age, sex and Body Mass Index (BMI). Serum IGF-1 and IGFBP-3 levels were similar in the two subgroups of patients and the values from all patients were combined for comparison with those from the control group. The mean (+/- SD) serum IGF-1 concentration (178 +/- 91 ng/ml) in the patients with IBD was lower compared with that in the controls (227 +/- 79 ng/ml, P<0.035). Similarly, the mean IGFBP-3 concentration in the patients was lower than in the controls (1.6 +/- 0.6 ng/ml vs 3.2 +/- 0.7 ng/ml respectively, P<0.001), Serum IL-6 levels were higher in the patients compared with the controls (5.5 +/- 4.2 vs 0.65 +/- 0.11 pg/ml, P<0.0001). The reduced IGF-1 and IGFBP-3 levels in patients with active IBD suggest that this systemic inflammatory condition is associated with a degree of acquired GH resistance, possibly induced by inflammatory cytokines.