Clinical inertia is the enemy of therapeutic success in the management of diabetes and its complications: a narrative literature review.

Diabetes mellitus is a chronic disease characterized by high social, economic and health burden, mostly due to the high incidence and morbidity of diabetes complications. Numerous studies have shown that optimizing metabolic control may reduce the risk of micro and macrovascular complications related to the disease, and the algorithms suggest that an appropriate and timely step of care intensification should be proposed after 3 months from the failure to achieve metabolic goals. Nonetheless, many population studies show that glycemic control in diabetic patients is often inadequate. The phenomenon of clinical inertia in diabetology, defined as the failure to start a therapy or its intensification/de-intensification when appropriate, has been studied for almost 20 years, and it is not limited to diabetes care, but also affects other specialties. In the present manuscript, we have documented the issue of inertia in its complexity, assessing its dimensions, its epidemiological weight, and its burden over the effectiveness of care. Our main goal is the identification of the causes of clinical inertia in diabetology, and the quantification of its social and health-related consequences through the adoption of appropriate indicators, in an effort to advance possible solutions and proposals to fight and possibly overcome clinical inertia, thus improving health outcomes and quality of care.

Predictors of treatment response to liraglutide in type 2 diabetes in a real-world setting.

AIMS: There is an unmet need among healthcare providers to identify subgroups of patients with type 2 diabetes who are most likely to respond to treatment. METHODS: Data were taken from electronic medical records of participants of an observational, retrospective study in Italy. We used logistic regression models to assess the odds of achieving glycated haemoglobin (HbA1c) reduction ≥ 1.0% point after 12-month treatment with liraglutide (primary endpoint), according to various patient-related factors. RECursive Partitioning and AMalgamation (RECPAM) analysis was used to identify distinct homogeneous patient subgroups with different odds of achieving the primary endpoint. RESULTS: Data from 1325 patients were included, of which 577 (43.5%) achieved HbA1c reduction ≥ 1.0% point (10.9 mmol/mol) after 12 months. Logistic regression showed that for each additional 1% HbA1c at baseline, the odds of reaching this endpoint were increased 3.5 times (95% CI: 2.90-4.32). By use of RECPAM analysis, five distinct responder subgroups were identified, with baseline HbA1c and diabetes duration as the two splitting variables. Patients in the most poorly controlled subgroup (RECPAM Class 1, mean baseline HbA1c > 9.1% [76 mmol/mol]) had a 28-fold higher odds of reaching the endpoint versus patients in the best-controlled group (mean baseline HbA1c ≤ 7.5% [58 mmol/mol]). Mean HbA1c reduction from baseline was as large as - 2.2% (24 mol/mol) in the former versus - 0.1% (1.1 mmol/mol) in the latter. Mean weight reduction ranged from 2.5 to 4.3 kg across RECPAM subgroups. CONCLUSIONS: Glycaemic response to liraglutide is largely driven by baseline HbA1c levels and, to a lesser extent, by diabetes duration.

Long-term effectiveness and safety of liraglutide in clinical practice.

AIM: The rising adoption of liraglutide in clinical practice calls for an update on its long-term effectiveness and safety. The aims of this paper were to review characteristics of patients treated with liraglutide under routine clinical practice conditions, to describe therapeutic schemes, to assess the durability of liraglutide after two years of therapy, to evaluate changes in clinical parameters obtained after 20-24 months and to identify elective phenotype of patients that are able to respond better to this treatment. METHODS: One diabetes outpatient clinic in Italy systematically collected data of patients receiving liraglutide every four months during a two-year follow-up. Mean levels and changes vs. baseline of HbA1c, fasting blood glucose (FBG), body weight, body mass index, waist circumference, blood pressure and lipid profile were evaluated. Rate of treatment discontinuation and side effects were also investigated. RESULTS: Overall, 205 patients were analyzed. Liraglutide was prescribed as an add-on drug in 39% of patients and as a replacement in 61%. It was used both in patients with short (21% ≤5 years) and long (32% >15 years) diabetes duration and both in obese and non-obese individuals (38% BMI≤30 Kg/m2). Liraglutide was used within many different therapeutic schemes, also including insulin (20%). On average, HbA1c levels were reduced of 1% vs. baseline at each visit, but magnitude of reduction was inversely related to diabetes duration, i.e., to the preservation of beta-cell function. However, clinically relevant improvements of glycaemic control were obtained and sustained during two years in all subgroups of patients, despite of classes of diabetes duration, BMI and antidiabetic therapeutic regimen. Durability of effectiveness on body weight and waist circumference was also documented. Liraglutide treatment was also associated with a reduction of systolic blood pressure and improvement of lipid profile. Side effects, that occurred in 20% of patients during the first four months of treatment, decreased at 2% at 20 months. The rate of drop-out was 16.1% of the patients treated. CONCLUSION: The analysis of our clinical practice shows that treatment with liraglutide was safe, well tolerated and effective in reducing HbA1c, fasting blood glucose and body weight significantly, with positive effects on systolic blood pressure and lipid profile. Therefore, results of LEAD studies are substantially reproduced in the context of routine clinical practice. Even if the maximum effectiveness of liraglutide occurs in patients with short disease duration, preferably treated with metformin, also in patients with long duration of disease, treated with several drugs or in insulin therapy, the use of this GLP-1 analogue allows to obtain more than satisfactory results. Improvements in metabolic control and body weight are maintained after two years, suggesting durability and safety of liraglutide in the long run.

Incretin-based therapies in clinical practice: from efficacy to effectiveness. Focus on liraglutide.

AIM: Liraglutide is a GLP-1 analogue introduced in Italy in 2010; its efficacy and safety have been tested within the comprehensive "LEAD program". The aim of this paper was to evaluate whether and to what extent routine practice outcomes are consistent with research findings. METHODS: One diabetes outpatient clinic reviewed data of patients receiving incretin-based therapies. Differences in characteristics of patients treated with liraglutide, exenatide, or DPP-IV inhibitors were evaluated. The subgroups of patients treated with liraglutide, exenatide or DPP-IV inhibitors (sitagliptin, vildagliptin, saxagliptin) and followed for at least eight months were analyzed longitudinally. Hierarchical linear models for repeated measurements were applied to assess trends over time. RESULTS: Incretin-based treatments were prescribed to 312 patients (liraglutide: 130, exe-natide: 72, DPP-IV inhibitors: 110). Diabetes duration, HbA1c levels, and BMI were substantially higher in exenatide and liraglutide groups than in the DPP-IV inhibitors group. Liraglutide was often administered in combination with metformin alone, while exenatide was often added to two or more drugs. Overall, 20 (15.4%) liraglutide interruptions were recorded, especially due to nausea. Treatment drop out rate was higher in exenatide and DPP-IV inhibitors groups (in exenatide mostly for gastrointestinal side effects, in DPP-IV for inefficacy). After eight months, overall levels of HbA1c were reduced from 8.1±1.1 to 7.1±0.8 (P<0.0001) with liraglutide. Furthermore, fasting blood glucose was reduced by 37.9±6.2 mg/dL (P<0.0001), body weight by 4.1±0.5 kg (P<0.0001), systolic blood pressure by 8.9±2.7 mmHg (P<0.001), total cholesterol by 8.8±4.1 mg/dL (P=0.04), and triglycerides by 24.4±14.6 mg/dL (P=0.07). Patients who had their therapy replaced at baseline from exenatide or DPP-IV had a further reduction in HbA1c, FBG and body weight. CONCLUSION: Liraglutide is penetrating diabetes care with results strictly mimicking the promising beneficial effects found in the LEAD program.

Correlation between plasma transforming growth factor-beta 1 and second primary breast cancer in a chemoprevention trial.

The relationship between plasma transforming growth factor-beta 1 (TGF-beta 1) and second primary breast cancer was explored in a prevention trial of the synthetic retinoid fenretinide (N-(4-hydroxyphenyl)retinamide; 4-HPR). Plasma concentrations of TGF-beta 1 were measured by radioimmunoassay in plasma obtained at randomisation and after approximately 1 year of intervention in 28 women treated with 4-HPR and 27 untreated controls with stage I breast cancer. Baseline and 1 year growth factor concentrations were not significantly different between treated and control groups. After a median follow-up of 65 months, an increase in TGF-beta 1 over 1 year was the only significant, independent predictor of a shorter survival free from secondary primary breast cancer. Moreover, the change in TGF-beta 1 levels had a tendency to influence the treatment effect on second breast cancer incidence. Our data suggest that the role of plasma TGF-beta 1 as a surrogate endpoint of breast carcinogenesis should be assessed further.

Failure to increase insulin-like growth factor-I synthesis is involved in the mechanisms of growth retardation of children with inherited liver disorders.

OBJECTIVE: Growth retardation is a prominent secondary feature of chronic liver disease. We investigated the hypothalamic-pituitary-liver axis in six patients with inherited liver disease and growth failure. The objectives were to determine (1) whether there were any abnormalities in the GH/IGF-I/IGFBPs/GH binding protein (GHBP) axis, (2) whether any abnormalities were nutrition-dependent, and (3) whether recombinant human (rh) GH could be efficaciously and safely administered. MEASUREMENTS: The evaluation included two standard GH provocative tests, GHRH test, night-time GH secretion, GHBP; and IGF-I, IGFBP-3 and IGFBP-1 before and after 0.1 and 0.3 U/kg/day of rhGH given i.m., for 4 days. Two patients were enrolled for rhGH treatment. RESULTS: Quantitative nutritional assessment showed the patients' calorie and protein intake to be compatible with the recommended daily allowance in liver disease. The mean baseline GH level was higher in patients than in controls (8.4 +/- 3.8 vs 2.6 +/- 2.0 mU/l, P < 0.005) and the GH response to stimuli was normal; spontaneous GH secretion was apparently normal. The mean baseline IGF-I value in the patients was significantly below the mean of controls (31.6 +/- 16.4 vs 260 +/- 35.2 micrograms/l, P = 0.00001) and similar to that of children with GH-deficiency (40.8 +/- 18.4 micrograms/l). The mean peak IGF-I response after 0.1 U/kg/day of rhGH increased (84.9 +/- 28.2 micrograms/l, P = 0.009) but remained lower than the mean IGF-I response in GH-deficient patients and in controls (P = 0.00001). The mean peak IGF-I response after 0.3 U/kg/day (113.3 +/- 52.3 micrograms/l) was significantly higher than that after 0.1 U/kg/day (P = 0.002). The mean standard deviation score (SDS) peak for IGF-I response to 0.1 and 0.3 U/kg/day of rhGH decreased significantly from -1.7 to -1.0 (P = 0.02) and from -1.9 to -0.9 (P = 0.005), respectively. There was no difference between patients and controls in serum GHBP activity or in mean baseline IGFBP-3 and IGFBP-1 levels. IGFBP-3 levels did not change significantly in response to rhGH at either 0.1 or 0.3 U/kg/day, while IGFBP-1 significantly decreased after 0.3 U/kg/day (56.3 +/- 35.6 vs 45.9 +/- 33.1 micrograms/l, P = 0.04). A significant positive correlation was present between albumin and peak IGF-I responses to rhGH at the dose of 0.1 and 0.3 U/kg/day (R = 0.83, P = 0.03; R = 0.78, P = 0.03 respectively), as well as between height SDS and baseline or stimulated IGF-I after rhGH 0.1 U/kg/day (R = 0.81, P = 0.04; R = 0.88, P = 0.01 respectively). In the two patients treated with rhGH at 22-25 U/m2/week, the growth rate doubled in one and trebled in the other during the first year of treatment, and in both was maintained in the second year without acceleration of bone maturation or evidence of adverse effects. CONCLUSIONS: The underlying cause of growth retardation in patients with inherited liver disease seems to be a progressive failure to increase IGF-I synthesis (at the conventional rhGH dose) and the consequent lack of its growth-promoting effect. The moderate increase in baseline GH values, the greater IGF-I response to the higher rhGH dose and the improvement in growth rate following rhGH administration suggest at least a degree of sensitivity to rhGH which could be of therapeutic value.

Effects of sumatriptan on growth hormone releasing hormone-stimulated growth hormone secretion in acromegaly.

Sumatriptan (SU), a specific 5-HT1D receptor agonist, was recently shown to be able to increase growth hormone (GH) levels in normals, but not in acromegalics, while no effect was seen on prolactine (PRL). SU is also able to produce an increase in GH response to growth hormone releasing hormone (GHRH) in prepubertal children. In this study we investigated whether SU administration influences GHRH-induced GH secretion in 8 acromegalics, and 6 age-matched normal volunteers, as a control group. We evaluated the effects of SU (6 mg s.c.) or placebo (PL) administration on GHRH (1 microgram/kg bw i.v.)-induced GH and PRL secretion. After SU priming the GH response to GHRH did not changed in acromegalics, but significantly decreased in controls, in comparison with that observed after PL plus GHRH. In acromegalics, no difference in GH peak was seen after SU plus GHRH and PL plus GHRH, nor was any difference seen in AUC between tests. In controls, no difference was seen in GH peaks, while SU priming significantly (P < 0.03) decreased the AUC 90-120 min of GH after GHRH administration. In acromegalics, SU did not change the slight GHRH-induced increase in PRL levels. Our study documents that 5-HT1 D receptors do not interfere with GHRH-stimulated GH secretion in acromegalic subjects. In normals, SU is able to decrease GH response to GHRH, thus confirming that 5-HT1D receptors are able to modulate GH secretion in normals.

Hexarelin is a stronger GH-releasing peptide than GHRH in normal cycling women but not in anorexia nervosa.

Anorexia nervosa (AN) is a chronic disease in which an enhanced GH response to GHRH, a paradoxic increase after TRH and LHRH, and low IGF1 levels may be present according to the patient's clinical state. It is well known that the GH hypersecretory state commonly found in the "acute phase" of AN is restored with weight gain. The new synthetic hexapeptide, Hexarelin (HEX), which is chemically similar to GH-releasing peptide 6, has recently been shown to possess a stronger GH-releasing activity than GHRH in humans and to share a synergistic effect with GHRH when administered intravenously. Indeed, HEX shows a slight cortisol and PRL-releasing activity. The aim of the study was to evaluate the effect of i.v. administration of old (GHRH) and new (HEX) GH-releasing peptides on GH, PRL and cortisol secretion in 9 AN patients in the "recovery phase" of the disease, after partial but significant weight gain. For controls we studied 7 normal cycling women. No significant difference in GH secretion after GHRH was found between AN and controls. GHRH was not able to release cortisol or PRL either in AN or controls. HEX produced a significantly (p < 0.05) higher GH peak in controls than in AN, while GH AUC was slightly but not significantly higher. Indeed, only in controls, HEX was a stronger GH-releasing peptide than GHRH. These findings could be explained by the fact that, in AN, GH secretion is already stimulated both by reduced IGF1 levels and by increased GHRH/somatostatin ratio. As reported in the literature, the action of HEX action is only slightly influenced by variations in somatostatin tone. It therefore appears likely that the absolute or relative GHRH increase present in AN could partially mimic the unknown hypothalamic factor necessary for HEX action on the hypophisis and that, following a structural modification of pituitary HEX receptors, GHRH would become able to bind to HEX receptors on somatotropic cells. Consequently, the pituitary cells would already be over-activated and so unable to respond maximally to HEX stimulation. Indeed, in AN, GHRH might play a role of negative modulation in the control of HEX action. Finally, in our study HEX was able to produce a persistent PRL release in controls but not in AN, thus suggesting that its action could be partially dependent on the estrogen milieu, while it stimulated cortisol secretion only transiently in the patients studied.

Insulin-like growth factors (IGF-I and IGF-II) and IGF-binding protein-3 production by fibroblasts of patients with Turner's syndrome in culture.

Reports indicate that in plasma insulin-like growth factor I (IGF-I) and IGF-binding protein-3 (IGFBP-3) are normal in patients with Turner's syndrome (TS). The aim of our study was to evaluate both the spontaneous and the stimulated synthesis of these peptides by mesenchymal cells obtained from skin biopsies of patients affected with TS. We compared the ability of fibroblasts from six TS patients with that of fibroblasts from six age-matched control (C) subjects to synthesize in vitro IGF-I, IGF-II, and IGFBP-3 under basal and GH-, estradiol (E2)-, or GH- plus E2-stimulated conditions. Furthermore, we evaluated IGF-I, IGF-II, and IGFBP-3 messenger ribonucleic acid (mRNA) expression in fibroblasts from TS and C subjects. Fibroblasts obtained from TS patients release into the medium significantly lower amounts of IGF-I and IGF-II than C fibroblasts (P = 0.0435 and 0.0318, respectively). In TS fibroblasts, GH and E2 are able to induce a similar increase, although not significant, of IGF-I secretion into the medium (163 +/- 75% and 112 +/- 41% of control values). On the contrary, in C fibroblasts, GH is more effective (275 +/- 61%; P = 0.0277) than E2 (75 +/- 46%). In both cell lines, GH and E2 do not significantly modify IGF-II release. Interestingly, the medium conditioned by fibroblasts from TS contains, under basal conditions, significantly higher amounts (273 +/- 79 ng/1 x 10(6) cells) of IGFBP-3 than that from control fibroblasts (67 +/- 19 ng/1 x 10(6) cells; P = 0.0191). GH exerts a stimulatory effect, although it is not statistically significant, on IGFBP-3 secretion, particularly in control fibroblasts. By contrast, the effect of E2 is inhibitory in all TS fibroblast cell lines, although it does not reach statistical significance (P = 0.067). In agreement with these data, a reduced mRNA expression of the genes encoding for IGF peptides was evident in TS fibroblasts, whereas no significant difference could be demonstrated for IGFBP-3 mRNA. The results suggest a reduced autocrine/paracrine action of IGFs in TS and indicate that skin fibroblast cultures can give information on the local responsiveness to the treatment.

Intrafollicular insulin-like growth factor-II levels in normally ovulating women and in patients with polycystic ovary syndrome.

OBJECTIVE: To investigate intrafollicular insulin-like growth factor II (IGF-II) in patients affected with polycystic ovary syndrome (PCOS) in comparison with normal women. DESIGN: Insulin-like growth factor-II was determined in 103 follicular fluids (FF) from normally ovulating women and in 102 FF from patients with PCOS. Ribonucleic acid was extracted from granulosa cells of follicles obtained from control and PCOS patients and from tissue from polycystic ovaries. SETTING: Procedures were performed in a university laboratory. PATIENTS: Twenty-nine normally ovulating women and 19 patients with PCOS underwent ovulation induction for IVF-ET with LH-releasing hormone (LH-RH) analog and gonadotropins. Eleven of them, 4 to 8 months later, underwent ovulation induction with approximately the same dosage of gonadotropins plus a standard dosage of GH. MAIN OUTCOME MEASURES: Intrafollicular IGF-II, IGF-I, epidermal growth factor (EGF), transforming growth factor beta 2, (TGF-beta 2), inhibin, and steroids were evaluated by appropriate RIA, immunoenzymatic assay (EIA), and ELISA assays. The expression of the gene encoding IGF-II was analyzed by Northern blot. RESULTS: Intrafollicular IGF-II was lower in PCOS than in controls. Accordingly, IGF-II messenger RNA expression was lower in PCO than in normal granulosa cells. Several differences in FF IGF-I, EGF, inhibin, and TGF-beta 2 concentrations were observed between PCOS and controls. CONCLUSIONS: Both IGF-II and IGF-I were reduced in PCOS, confirming a possible role of an IGF imbalance in the development of this disease.

Effect of the acid-labile subunit on the binding of insulin-like growth factor (IGF)-binding protein-3 to [125I]IGF-I.

In normal subjects, the major form of circulating insulin-like growth factor (IGF) is the GH-dependent 150K complex. This complex is formed by the IGF peptide, the acid-stable binding protein IG-FBP-3, and the acid-labile subunit (ALS), which, although not binding IGF, appears to be necessary to reconstitute the complex in its natural form. The ALS was purified in our laboratory from human serum by ammonium sulfate precipitation, ion exchange chromatography using DEAE-Sephadex A-50, Concanavalin-A-Sepharose-4B chromatography, and two sequential gel filtrations by fast performance liquid chromatography. As demonstrated by gel permeation chromatography on fast performance liquid chromatography, incubation for 2 h at 20 C of this preparation with [125I]IGF-I and recombinant IGFBP-3 (rIGFBP-3) allows the reconstitution of a complex of about 150 kilodaltons. In these experimental conditions, the ALS is not only able to increase the mol wt of the complex, but also to greatly increase the amount of IGF-I bound; in the absence of ALS, radioactivity in the mol wt volume of the complexed forms was lower than that in the mol wt volume of the free form (percentage of total [125I]IGF-I: rIGFBP-3 alone, 15% and 44%; in the presence of ALS, 41% and 24%, respectively). In both charcoal and polyethylene glycol ligand binding assays, competitive binding curves for the displacement of [125I]IGF-I from rIGFBP-3 by increasing concentrations of unlabeled IGF-I showed an increased binding activity of rIGFBP-3 in the presence of ALS. The effect of ALS on rIGFBP-3-binding activity was dose dependent. These data show that the non-IGF-binding ALS subunit of the 150-kilodalton complex can play an important role in the regulation of IGF-I or IGF-II binding to rIGFBP-3 and, therefore, on the levels of free IGF peptide, possibly by inducing conformational changes in rIGFBP-3. In addition, ligand and immunoblot reveal that ALS and rIGFBP-3 are able to form a high mol wt complex in the absence of IGF peptide. On the basis of these data, ALS seems to have a more complex function than that of simply increasing the mol wt of the IGF-IGFBP-3 complex.

Effect of octreotide on circulating IGF-I chromatographic profile: evidence for an inhibitory action on the formation of the 150-kDa ternary complex.

OBJECTIVE: The increasing use in clinical practice of octreotide (a somatostatin analogue which inhibits the secretion of GH and other peptide hormones) led us to study the effects of this treatment on GH, insulin-like growth factors (IGF)-I and II and IGF-binding protein (IGFBP)-3, as well as on circulating IGFBP complexes in acromegalic patients. DESIGN: The circulating concentrations of GH, IGF-I, IGF-II and IGFBP-3 were measured in acromegalic patients before and after 3, 6, 9, and 12 months of treatment with octreotide (group I: n = 5), and compared with those found in a group of patients (group II) treated with bromocriptine (n = 3), cabergoline (n = 7) radiotherapy (n = 3) or surgical therapy (n = 2). In pools of serum obtained from patients treated with octreotide, dopaminergic drugs, surgery and radiation, before and after therapy, immunoreactive IGF-I and IGFBP-3 were also evaluated after Superdex 200 gel filtration in neutral conditions. RESULTS: Before treatment, the concentration of IGF-I and IGFBP-3 were above the normal range in all patients, while IGF-II levels were slightly reduced. After treatment with octreotide, IGF-I (P = 0.004), IGF-II (P = 0.02) and IGFBP-3 (P < 0.001) were significantly reduced as compared to basal levels. In subjects of group II, only IGF-I concentration was significantly reduced by the treatment (P = 0.02), and a negative correlation between IGF-I and IGF-II concentrations was found (r = -0.58, P < 0.0001). After gel filtration immunoreactive IGF-I and IGFBP-3 were found in the 150-kDa mol.wt. region in serum obtained from untreated patients and from treated patients of group II, while in the serum of octreotide-treated patients the IGF-I and IGFBP-3 peaks were shifted to the 60-kDa mol.wt. region, thus suggesting that the acid-labile subunit of the 150-kDa complex was drastically reduced. Since the GH concentrations in groups I and II were similar (M +/- SEM; 13.8 +/- 7.4 and 21.2 +/- 10.6 mU/l respectively), the marked reduction in acid-labile subunit in the octreotide treated patients can be explained by a direct inhibitory effect of somatostatin on the subunit. CONCLUSIONS: Octreotide exerts an inhibitory effect not only on IGF-I but also on IGF-II. The reduced formation of the 150-kDa complex probably causes an increased metabolic clearance rate of IGF peptides which can account for the reduced concentration of both IGFs after treatment with octreotide.

Functions and regulation of the acid-labile subunit of the 150 K complex.

In normal subjects, the major form of circulating IGF is the GH-dependent 150 K complex. As demonstrated by gel-permeation chromatography, the acid-labile subunit (ALS) purified from human serum, incubated for 2 h at 20 degrees C with [125I]IGF-I and rIGFBP-3, is able to increase not only the molecular weight (mol. wt.) of the IGF-IGFBP-3 complex, but also the amount of IGF-I bound. In both charcoal and polyethylene glycol ligand binding assays, competitive binding curves for the displacement of [125I]IGF-I from rIGFBP-3 by increasing concentrations of unlabeled IGF-I showed an increased binding activity of rIGFBP-3 in the presence of ALS. The effect of ALS on rIGFBP-3 binding activity was dose dependent. In addition, ligand and immunoblot revealed that ALS and rIGFBP-3 are able to form a high mol. wt. complex in the absence of IGF peptide. On the basis of these data, ALS seems to have a more complex function than that of simply increasing the mol. wt of the IGF-IGFBP-3 complex. The regulation of ALS synthesis by rat hepatocytes in primary culture has also been evaluated by immunoblot. In agreement with the in vivo finding of an inhibitory effect of octreotide (a somatostatin analog) on the formation of the 150 K complex in acromegalic subjects, we could observe in vitro that octreotide produces a dose-dependent inhibition of ALS secretion into the hepatocyte conditioned medium. TGF-beta 1 was also inhibitory at high doses. On the contrary, we could not evidence any effect of IGF-I or IGF-II, while a small increase has been noted after incubation with T3.

Assessment of growth hormone insulin like growth factor-I axis in Down's syndrome.

As GH therapy has been reported to increase growth velocity in children with Down's syndrome (DS), we studied the GH-IGF-I axis in some DS patients affected by growth retardation without serious congenital malformation, malnutrition or pathological thyroid or adrenal function. IGF-I and IGF-II were evaluated in 39 patients in basal conditions. The patients were subsequently divided into two groups with respect to the IGF-I basal value: Group 1 (GR 1) consisting of patients with abnormally low basal IGF-I concentration as compared to age matched control subjects, group 2 (GR 2) consisting of patients with IGF-I in the normal range. In 6 GR 1 patients and 12 GR 2 patients we evaluated GH and IGF-I concentrations after stimulation with arginine (0.5 g/kg bw), and recombinant GH (4 IU im). In the same patients, GH radioreceptor assay and serum GH-binding protein were evaluated. In all patients IGF-II proved normal (534 +/- 23 ng/ml; mean +/- SE), while IGF-I was pathological in 36% of subjects. The cause of the defective IGF-I secretion in these patients does not seem to depend on an impaired GH axis, as no significant difference in arginine-stimulated GH peak values was seen between GR 1 (29.6 +/- 5.3 ng/ml) and GR 2 (15.1 +/- 2.24 ng/ml). IGF-I concentration evaluated 12, 24, and 48 h after arginine stimulation was significantly increased only in GR 2 patients (peak value: 0.95 +/- 0.1, p = 0.0003 vs baseline; GR 1: 0.34 +/- 0.05 U/ml).(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in autonomic nervous function over a 5-year period in non-insulin-dependent diabetic patients.

One hundred and eight non-insulin-dependent diabetic patients who had been tested for autonomic dysfunction in 1984/85 were re-evaluated 5 years later. Autonomic function was assessed by means of four cardiovascular tests (heart rate variation during deep breathing and standing, and blood pressure variation after standing and sustained handgrip). Eighteen subjects were lost to follow-up; in the 90 patients who completed the study, both the deep breathing and the handgrip test significantly worsened (respectively from 13.7 +/- 7.8 to 11.6 +/- 6.3 beats min-1 p < 0.01, and from 16.9 +/- 8.2 to 12.7 +/- 7.1 mmHg, p < 0.001), whereas both the 30:15 ratio and the variation of blood pressure on standing did not change. The impairment of a comprehensive evaluation score (from 2.5 +/- 1.7 to 3.0 +/- 1.5; p < 0.05) also confirmed the gradual deterioration of autonomic function over the study period.

The synthetic retinoid fenretinide lowers plasma insulin-like growth factor I levels in breast cancer patients.

We studied the effect of fenretinide [N-(4-hydroxyphenyl)retinamide (4-HPR)], a synthetic analogue of retinoic acid, on plasma insulin-like growth factor I (IGF-I) levels in a consecutive cohort of stage I breast cancer patients belonging to a randomized phase III trial of breast cancer chemoprevention. Thirty-two women receiving 4-HPR 200 mg/daily and 28 untreated controls entered the study. IGF-I levels were determined after acid-ethanol extraction, on plasma obtained at randomization and after a mean time of 10.8 +/- 0.3 months. At baseline, there was no difference in IGF-I levels between the two groups [152.9 +/- 9.4 versus 159.2 +/- 7.0 ng/ml in treated and control group (P = 0.59), respectively]. After follow-up time, while plasma IGF-I levels were unchanged in control patients (163.3 +/- 7.4 ng/ml; P = 0.5), they were significantly reduced to 134.6 +/- 8.1 ng/ml in the patients treated with 4-HPR (P = 0.003 and P = 0.011 versus baseline and control values, respectively). Multiple regression analysis showed that treatment was the only determinant of IGF-I decline. Moreover, the interaction between treatment and age was significant, in that the decrease of IGF-I levels induced by 4-HPR administration was much more pronounced in younger patients, while an age-related decline was observed in controls. We conclude that the synthetic retinoid 4-HPR lowers circulating IGF-I levels in early breast cancer patients. Although the importance of this observation for the clinical prevention of breast cancer remains to be established, it further substantiates the rationale of the combination of 4-HPR with tamoxifen, which is known to decrease IGF-I as well and to act synergistically with the retinoid in preclinical models.

In vivo and in vitro effect of growth hormone on estradiol secretion by human granulosa cells.

GH therapy increases the ovarian response to gonadotropin stimulation in women presenting with ovaries that are relatively resistant to conventional gonadotropin therapy. As it is not completely certain whether GH modulates the actions of FSH on granulosa cells directly or via insulin-like growth factor-I (IGF-I) production, we studied its effect on steroid release by human granulosa cells obtained from subjects affected by unexplained or male factor infertility. In all subjects, superovulation for in vitro fertilization/embryo transfer was induced by treatment with gonadotropins or GH plus gonadotropins combined. The effects of the different in vivo treatments were evaluated in the conditioned medium obtained after the first 24 h of incubation; granulosa cells from patients treated with GH released higher amounts of estradiol and progesterone into the medium than did granulosa cells from patients treated with gonadotropins alone. When the release of steroid due to the in vivo treatment was exhausted, cells were subjected to increasing concentrations of GH in the presence or absence of 200 nmol anti-IGF Sm 1.2 monoclonal antibody (MoAb) or the antitype I receptor alpha IR3 MoAb. The results revealed that GH stimulates estradiol production in a dose-dependent fashion, and the presence of the MoAbs drastically reduces the GH effect. These data demonstrate that the established stimulatory effect of GH on ovarian function is dependent not only on the increased levels of circulating IGF-I, but also on a direct effect of GH on granulosa cells, which seems to be mediated at least in part by the autocrine action of IGF, particularly IGF-II. In fact, chromatographic analysis of medium conditioned by human granulosa cells revealed that these cells clearly produce IGF-II and IGF-binding proteins and only small amounts of IGF-I. Since GH appears to be able to increase the in vitro effect of both IGF-I and IGF-II, we can hypothesize a sensitization of the granulosa cells to the IGF-II produced by the cells themselves, which acts through the IGF-I receptor.

[Is it possible to prevent andrological complications in the diabetic patient?]. / Si possono prevenire le complicanze andrologiche nel paziente diabetico?

Sexual impotence is the main andrological complication of diabetes mellitus and is the consequence of nervous, vascular and psychological factors which act either separately or in association. An attempt to prevent this complication will be successful if performed early before impotence has became irreversible. Neuropathy-induced impotence can be prevented by obtaining a good metabolic control of diabetes and/or by using some specific drugs such as gangliosides and aldose reductase inhibitors. The vascular causes of erectile failure can be prevented by reducing or removing associated risk factors such as smoking, hypertension, obesity, hypercholesterolemia, sedentariness and insulin-resistance. Finally, correct information and reassurance of the patient and his partner can prevent the negative role played by psychological factors on the sexual dysfunctions complained by the diabetic subject.