The dipeptidyl peptidase-4 inhibitor linagliptin lowers postprandial glucose and improves measures of ß-cell function in type 2 diabetes.

Progressive deterioration of pancreatic ß-cell function in patients with type 2 diabetes mellitus (T2DM) contributes to worsening of hyperglycaemia. To investigate the effects of the dipeptidyl peptidase-4 inhibitor linagliptin on ß-cell function parameters, a pooled analysis of six randomized, 24-week, placebo-controlled, phase 3 trials of 5 mg of linagliptin daily was performed in 2701 patients with T2DM (linagliptin, n = 1905; placebo, n = 796). At week 24, observed improvements in HbA1c, fasting plasma glucose, and 2-h postprandial glucose were significantly greater for linagliptin than placebo (all p < 0.0001). Homeostasis model assessment (HOMA)-%ß, as a surrogate marker of fasting ß-cell function, was significantly improved with linagliptin, and did not change with placebo (placebo-adjusted mean ± s.e. change for linagliptin: 16.5 ± 4.6 (mU/l)/(mmol/l); p = 0.0003). Further study is required to determine if the significant improvement in HOMA-%ß with linagliptin will translate into long-term improvements in ß-cell function.

The effect of initial therapy with the fixed-dose combination of sitagliptin and metformin compared with metformin monotherapy in patients with type 2 diabetes mellitus.

AIMS: This study was conducted to compare the glycaemic efficacy and safety of initial combination therapy with the fixed-dose combination of sitagliptin and metformin versus metformin monotherapy in drug-naive patients with type 2 diabetes. METHODS: This double-blind study (18-week Phase A and 26-week Phase B) randomized 1250 drug-naÏve patients with type 2 diabetes [mean baseline haemoglobin A1c (HbA1c) 9.9%] to sitagliptin/metformin 50/500 mg bid or metformin 500 mg bid (uptitrated over 4 weeks to achieve maximum doses of sitagliptin/metformin 50/1000 mg bid or metformin 1000 bid). Results of the primary efficacy endpoint (mean HbA1c reductions from baseline at the end of Phase A) are reported herein. RESULTS: At week 18, mean change from baseline HbA1c was -2.4% for sitagliptin/metformin FDC and -1.8% for metformin monotherapy (p < 0.001); more patients treated with sitagliptin/metformin FDC had an HbA1c value <7% (p < 0.001) versus metformin monotherapy. Changes in fasting plasma glucose were significantly greater with sitagliptin/metformin FDC (-3.8 mmol/l) versus metformin monotherapy (-3.0 mmol/l; p < 0.001). Homeostasis model assessment of ß-cell function (HOMA-ß) and fasting proinsulin/insulin ratio were significantly improved with sitagliptin/metformin FDC versus metformin monotherapy. Baseline body weight was reduced by 1.6 kg in each group. Both treatments were generally well tolerated with a low and similar incidence of hypoglycaemia. Abdominal pain (1.1 and 3.9%; p = 0.002) and diarrhoea (12.0 and 16.6%; p = 0.021) occurred significantly less with sitagliptin/metformin FDC versus metformin monotherapy; the incidence of nausea and vomiting was similar in both groups. CONCLUSION: Compared with metformin monotherapy, initial treatment with sitagliptin/metformin FDC provided superior glycaemic improvement with a similar degree of weight loss and lower incidences of abdominal pain and diarrhoea.

Efficacy and safety of treatment with sitagliptin or glimepiride in patients with type 2 diabetes inadequately controlled on metformin monotherapy: a randomized, double-blind, non-inferiority trial.

AIM: to evaluate the efficacy and safety of adding sitagliptin or glimepiride to the treatment regimen of patients with type 2 diabetes mellitus and inadequate glycaemic control on metformin monotherapy. METHODS: patients with type 2 diabetes and an HbA(1c) of 6.5-9.0% while on a stable dose of metformin (≥ 1500 mg/day) combined with diet and exercise for at least 12 weeks were randomized in a double-blind manner to receive either sitagliptin 100 mg daily (N = 516) or glimepiride (starting dose 1 mg/day and up-titrated, based upon patient's self-monitoring of blood glucose results, to a maximum dose of up to 6 mg/day) (N = 519) for 30 weeks. The primary analysis assessed whether sitagliptin is non-inferior to glimepiride in reducing HbA(1c) at week 30 (based on the criterion of having an upper bound of the 95% CI less than the prespecified non-inferiority bound of 0.4%). RESULTS: the mean baseline HbA(1c) was 7.5% in both the sitagliptin group (n = 443) and the glimepiride group (n = 436). After 30 weeks, the least squares (LS) mean change in HbA(1c) from baseline was -0.47% with sitagliptin and -0.54% with glimepiride, with a between-group difference (95% CI) of 0.07% (-0.03, 0.16). This result met the prespecified criterion for declaring non-inferiority. The percentages of patients with an HbA(1c) < 7.0% at week 30 were 52 and 60% in the sitagliptin and glimepiride groups, respectively. The LS mean change in fasting plasma glucose from baseline (95% CI) was -0.8 mmol/l (-1.0, -0.6) with sitagliptin and -1.0 mmol/l (-1.2, -0.8) with glimepiride, for a between-group difference (95% CI) of 0.2 mmol/l (-0.1, 0.4). The percentages of patients for whom hypoglycaemia was reported were 7% in the sitagliptin group and 22% in the glimepiride group (percentage-point difference = -15, p < 0.001). Relative to baseline, sitagliptin was associated with a mean weight loss (-0.8 kg), whereas glimepiride was associated with a mean weight gain (1.2 kg), yielding a between-group difference of -2.0 kg (p < 0.001). CONCLUSIONS: in patients with type 2 diabetes and inadequate glycaemic control on metformin monotherapy, the addition of sitagliptin or glimepiride led to similar improvement in glycaemic control after 30 weeks. Sitagliptin was generally well tolerated. Compared to treatment with glimepiride, treatment with sitagliptin was associated with a lower risk of hypoglycaemia and with weight loss versus weight gain (ClinicalTrials.gov: NCT00701090).

A treatment strategy implementing combination therapy with sitagliptin and metformin results in superior glycaemic control versus metformin monotherapy due to a low rate of addition of antihyperglycaemic agents.

AIMS: Combination therapy with sitagliptin and metformin has shown superior efficacy compared with metformin monotherapy. In this study, we compare two strategies: initial combination therapy with sitagliptin/metformin as a fixed-dose combination (FDC) and initial metformin monotherapy, with the option to add additional antihyperglycaemic agents (AHAs) in either treatment arm during the second phase of the study in order to reach adequate glycaemic control. METHODS: We evaluated the sitagliptin and metformin FDC compared with metformin monotherapy over 44 weeks in 1250 patients with type 2 diabetes mellitus in a two-part, double-blind, randomized, controlled clinical trial. The initial 18-week portion (Phase A) of this study in which additional AHAs were only allowed based on prespecified glycaemic criteria, has been previously reported. Here, we present results from the 26-week Phase B portion of the study during which double-blind study medication continued; however, unlike Phase A, during Phase B investigators were unmasked to results for haemoglobin A1C (HbA1c) and fasting plasma glucose (FPG) and directed to manage glycaemic control by adding incremental AHA(s) as deemed clinically appropriate. RESULTS: There were 1250 patients randomized in the study with 965 completing Phase A and continuing in Phase B. Among patients receiving sitagliptin/metformin FDC or metformin monotherapy, 8.8% and 16.7% received additional AHA therapy, respectively. Although glycaemic therapy in both groups was to have been managed to optimize HbA1c reductions with the option for investigators to supplement with additional AHAs during Phase B, patients randomized to initial therapy with sitagliptin/metformin FDC had larger reductions of HbA1c from baseline compared with patients randomized to initial metformin monotherapy [least squares (LS) mean change: -2.3% and -1.8% (p < 0.001 for difference) for sitagliptin/metformin FDC and metformin monotherapy groups, respectively]. A significantly larger reduction in FPG from baseline was observed in the sitagliptin/metformin FDC group compared with the metformin monotherapy group (p = 0.001). Significantly more patients in the sitagliptin/metformin FDC group had an HbA1c of less than 7.0% or less than 6.5% compared with those on metformin monotherapy. Both treatment strategies were generally well tolerated, with a low and similar incidence of hypoglycaemia in both groups and lower incidences of abdominal pain and diarrhoea in the sitagliptin/metformin FDC group compared with the metformin monotherapy group. CONCLUSIONS: A strategy initially implementing combination therapy with sitagliptin/metformin FDC was superior to a strategy initially implementing metformin monotherapy, even when accounting for the later addition of supplemental AHAs. Sitagliptin/metformin FDC was generally well tolerated.

Efficacy and safety of sitagliptin and the fixed-dose combination of sitagliptin and metformin vs. pioglitazone in drug-naïve patients with type 2 diabetes.

AIM: The efficacy and safety of sitagliptin (SITA) monotherapy and SITA/metformin (MET) vs. pioglitazone (PIO) were assessed in patients with type 2 diabetes and moderate-to-severe hyperglycaemia (A1C = 7.5-12.0%). METHODS: In an initial 12-week phase (Phase A), 492 patients were randomised 1 : 1 in a double-blind fashion to SITA (100 mg qd) or PIO (15 mg qd, up-titrated to 30 mg after 6 weeks). In Phase B (28 additional weeks), the SITA group was switched to SITA/MET (up-titrated to 50/1000 mg bid over 4 weeks) and the PIO group was up-titrated to 45 mg qd RESULTS: At the end of Phase A, mean changes from baseline were -1.0% and -0.9% for A1C; -26.6 mg/dl and -28.0 mg/dl for fasting plasma glucose; and -52.8 mg/dl and -50.1 mg/dl for 2-h post-meal glucose for SITA and PIO, respectively. At the end of Phase B, improvements in glycaemic parameters were greater with SITA/MET vs. PIO: -1.7% vs. -1.4% for A1C (p = 0.002); -45.8 mg/dl vs. -37.6 mg/dl for fasting plasma glucose (p = 0.03); -90.3 mg/dl vs. -69.1 mg/dl for 2-h postmeal glucose (p = 0.001); and 55.0% vs. 40.5% for patients with A1C < 7% (p = 0.004). A numerically higher incidence of gastrointestinal adverse events and a significantly lower incidence of oedema were observed with SITA/MET vs. PIO. The incidence of hypoglycaemia was similarly low in both groups. Body weight decreased with SITA/MET and increased with PIO (-1.1 kg vs. 3.4 kg; p < 0.001). CONCLUSION: Improvements in glycaemic control were greater with SITA/MET vs. PIO, with weight loss vs. weight gain. Both treatments were generally well tolerated.

A one-year study to assess the safety and efficacy of the CB1R inverse agonist taranabant in overweight and obese patients with type 2 diabetes.

AIM: To evaluate the efficacy and safety of taranabant in overweight and obese patients with type 2 diabetes mellitus (T2DM). METHODS: This was a multicenter, double-blind, randomized, placebo-controlled study in overweight and obese patients with T2DM (ages > or = 18 and < or = 75 years) with a BMI > or = 27 kg/m(2) and < or = 43 kg/m(2) and HbA1c > or =7.0 and < or = 10.0%, who were either not on an antihyperglycaemic agent or on a stable dose of metformin (> or = 1500 mg/day). After a 2-week placebo run-in, patients were randomized to placebo (N = 156) or taranabant 0.5-mg (N = 155), 1-mg (N = 157), or 2-mg (N = 155) once daily for 52 weeks. Primary efficacy endpoints were changes from baseline in body weight (BW) and HbA1c at Week 36, with results at Week 52 being key secondary endpoints. RESULTS: In the all-patients-treated population, using a last-observation-carried-forward analysis, reductions in BW were -2.5, -3.7, -4.5 and -5.1 kg at Week 36 and -2.4, -4.0, -4.6 and -5.3 kg at Week 52 in the placebo, 0.5-, 1- and 2-mg groups, respectively (all doses significant vs. placebo at both time points). The proportion of patients who lost > or = 5 and > or = 10% of their baseline BW was significantly greater in the 1- and 2-mg groups vs. placebo at Week 36 and all taranabant groups vs. placebo at Week 52. Reductions in HbA1c were -0.40, -0.47, -0.68 and -0.71% at Week 36 and -0.30, -0.43, -0.65 and -0.64% at Week 52, in the placebo, 0.5-, 1- and 2-mg groups, respectively (1- and 2-mg doses significant vs. placebo at both time points). After 52 weeks, the incidences of adverse experiences classified in the gastrointestinal (diarrhoea, nausea, vomiting), nervous system-related (dizziness, sensory-related), and psychiatric (irritability, depression-related) organ systems were numerically higher or statistically significantly higher in all taranabant groups compared with the placebo group. CONCLUSIONS: After 36 and 52 weeks, treatment with taranabant at the 1- and 2-mg doses led to clinically significant weight loss and improvement in glycaemic parameters in overweight and obese patients with T2DM that was associated with dose-related increases in adverse experiences. Based on these data and data from other Phase III clinical studies, it was determined that the overall safety and efficacy profile of taranabant did not support further development for the treatment of obesity.

Safety and efficacy of treatment with sitagliptin or glipizide in patients with type 2 diabetes inadequately controlled on metformin: a 2-year study.

OBJECTIVES: To evaluate the 2-year safety and efficacy of adding sitagliptin or glipizide to ongoing metformin in patients with type 2 diabetes. METHODS: Patients who were on a stable dose of metformin (> or = 1500 mg/day) for at least 8 weeks were randomised in a double-blind manner to receive either sitagliptin 100 mg q.d. (N = 588) or glipizide 5 mg/day (up-titrated up to 20 mg/day based upon prespecified glycaemic criteria) (N = 584). The efficacy analysis assessed the change in HbA(1c) from baseline using the per-protocol (PP) population. RESULTS: For the PP cohort, mean baseline HbA(1c) was 7.3% in both groups. After 2 years, the least squares (LS) mean change in HbA(1c) from baseline [95% confidence interval (CI)] was -0.54% (-0.64, -0.45) with sitagliptin (n = 248) and -0.51% (-0.60, -0.42) with glipizide (n = 256). The rise in HbA(1c) from week 24 to week 104 [i.e. coefficient of durability (COD)] was smaller with sitagliptin [COD (95% CI) 0.16%/year (0.10, 0.21)] compared with glipizide [0.26%/year (0.21, 0.31)]. The proportion of patients with an HbA(1c)< 7% was 63% and 59% with sitagliptin and glipizide, respectively. The beta-cell responsiveness to a meal challenge was maintained with sitagliptin and decreased with glipizide. The proportion of patients who reported hypoglycaemia was 5% with sitagliptin and 34% with glipizide [difference in proportions (95% CI) = -29% (-33, -25)]. Relative to baseline, sitagliptin was associated with weight loss (-1.6 kg) compared with weight gain (+0.7 kg) with glipizide. CONCLUSION: In patients with type 2 diabetes, adding sitagliptin to metformin monotherapy improved glycaemic control over 2 years, similar to the glucose-lowering efficacy observed with adding glipizide, but with greater durability and generally better maintenance of beta-cell function. Sitagliptin was generally well tolerated with a lower risk of hypoglycaemia and weight loss compared with weight gain observed with glipizide.

Concentration of transforming growth factor beta in human bone tissue: relationship to age, menopause, bone turnover, and bone volume.

Transforming growth factor beta (TGF-beta) is thought to play an important role in bone metabolism, but its relationship to human bone turnover and bone mass has not been examined yet. In this study, we measured the concentration of TGF-beta in 811 samples of male and female bone from four representative sites of the human skeleton and in the supernatants of 72 short-term human bone marrow cultures from the iliac crest. The concentrations of TGF-beta1 and TGF-beta2 in the bone matrix were positively correlated with histomorphometric indices of bone resorption and bone formation and with serum levels of osteocalcin and bone-specific alkaline phosphatase. We also observed a positive association between the release of TGF-beta in the bone marrow cultures and serum osteocalcin. Changes in the rate of cancellous or cortical bone remodeling with age or menopause were accompanied by corresponding changes in skeletal TGF-beta. In contrast, there was no significant relationship between the concentration of TGF-beta and bone volume at any skeletal site. In conclusion, our study supports the hypothesis that TGF-beta plays an important role in human bone remodeling, but fails to demonstrate an association between the skeletal concentration of TGF-beta and human bone mass.

Concentration of insulin-like growth factor (IGF)-I and -II in iliac crest bone matrix from pre- and postmenopausal women: relationship to age, menopause, bone turnover, bone volume, and circulating IGFs.

Insulin-like growth factor-I (IGF-I) and -II are important local regulators of bone metabolism, but their role as determinants of human bone mass is still unclear. In the present study, we analyzed the concentration of IGF-I and -II in the bone matrix of 533 human biopsies from the iliac crest that were obtained during surgery for early breast cancer. There was an inverse association of bone matrix IGF-I concentration with age that was unaffected by menopause. Bone matrix IGF-I was positively associated with histomorphometric and biochemical parameters of bone formation and bone resorption and with cancellous bone volume. Based on the estimates of the linear regression analysis, women with a bone matrix IGF-I concentration 2 SD above the mean had a 20% higher bone volume than women with a bone matrix IGF-I concentration 2 SD below the mean. In contrast, serum IGF-I was neither correlated with bone turnover nor with bone volume and was only weakly associated with bone matrix IGF-I when adjusted for the serum concentration of IGF binding protein-3. Bone matrix IGF-II was positively associated with the osteoblast surface, but in contrast to IGF-I, tended to be positively associated with age and was unrelated to cancellous bone volume. In summary, our study suggests the following. 1) The concentration of IGF-I in cancellous bone undergoes age-related decreases that are similar to those of circulating IGF-I. 2) Menopause has no effect on this age-related decline. 3) Physiological differences in bone matrix IGF-I are associated with differences in iliac crest cancellous bone volume. 4) Bone matrix IGF-I is a better predictor of cancellous bone volume than circulating IGF-I. 5) The role of IGF-II in human bone tissue is clearly distinct from that of IGF-I.

Expression of Interleukin-6 (IL-6) and IL-6 receptor mRNA in human bone samples from pre- and postmenopausal women.

Interleukin-6 (IL-6) has been attributed to induction of osteoclastogenic-precursor cell proliferation and maturation. Estrogens suppress IL-6 production in stromal/osteoblastic cells in vitro. Conversely, estrogen withdrawal is associated with increased IL-6 production. IL-6 is therefore thought to be an important mediator of the increased bone resorption after menopause. However, evidence supporting a rise in the expression of IL-6 or the IL-6 receptor in human bone tissue with menopause is still lacking. To address this question, we established a 5'-nuclease assay to quantitate the expression of human IL-6 and the gp80 subunit of the IL-6 receptor in human bone samples. The number of mRNA copies was normalized to the number of copies of beta actin mRNA. Osteocalcin expression served as an independent control. The study population consisted of 169 women (mean age 52.4 +/- 11.6 years) who underwent surgery for early breast cancer. Serum IL-6 was measured by enzyme-linked immunosorbent assay, serum crosslaps as a marker of bone resorption were measured by electrochemiluminescent assay, and serum osteocalcin was measured by chemoluminescence assays. RNA expression of osteocalcin in bone tissue from early postmenopausal women was higher compared with premenopausal women. Local expression was positively associated with circulating osteocalcin and crosslaps concentrations. Postmenopausal women also had higher circulating IL-6 concentrations. In contrast, bone samples from postmenopausal women lacked an increased expression of either IL-6 or gp80 compared with bone samples from premenopausal women. In conclusion, we failed to detect local increases in IL-6 or IL-6 receptor expression in human bone tissue with menopause. If direct changes in the IL-6 system in bone tissue are involved in postmenopausal bone loss, these changes appear to be below the detection limit of our assay system.

Age-related changes in insulin-like growth factor I and II in human femoral cortical bone: lack of correlation with bone mass.

The concentration of insulin-like growth factor-I (IGF-I) in human cortical bone declines with age, but the relevance of this decline for cortical bone turnover and bone mass is unknown. In the present study, we simultaneously assessed the concentration of IGF-I and -II in cortical bone matrix and histomorphometric parameters of bone mass and bone turnover in 125 samples from the proximal human femur shaft. Bone width decreased by 27% and porosity increased by 100% in female cortical bone between the fourth and the ninth decade. Similar, but weaker, changes tended to occur in male cortical bone. The concentrations of both IGF species were correlated with the percentage of osteons undergoing bone remodeling. However, despite age-related decreases in both IGF species in men and in IGF-I in women, neither of the IGFs accounted for age-related or age-independent variability in cortical porosity or bone width. In conclusion, these data suggest that the local concentrations of IGF-I and -II are related to cortical bone turnover. In contrast, our study provides no evidence for a major role of bone matrix IGF-I and -II as determinants of cortical bone mass in elderly individuals. Whether other components of the IGF system may be stronger determinants of cortical bone loss remains to be determined.

Effects of triiodothyronine on the insulin-like growth factor system in primary human osteoblastic cells in vitro.

Thyroid hormone plays a major role in the regulation of bone metabolism but the mechanism by which this is accomplished is not clear. Interactions of thyroid hormone with the growth hormone/insulin-like growth factors (IGFs) axis suggest an alternate pathway of action for triiodothyronine (T(3)) on bone formation, besides direct effects. The present study investigates the influence of T(3) on IGF-1, IGF-2, IGF-1 receptor (IGF-1R), and IGF binding protein (IGFBP) transcripts, and on IGF-1 action in human osteoblastic cells (hOB) under serum-free culture conditions. No influence of T(3) on IGF-1, IGF-2, IGFBP-3, or IGFBP-4 mRNA levels in hOB was observed. However, T(3) at concentrations of 10(-8) mol/L and 10(-7) mol/L increased IGF-1R mRNA levels in a dose-dependent manner (p < 0.01) and enhanced IGFBP-5 mRNA levels at a concentration of 10(-7) mol/L (p < 0.05), as assessed by reverse transcriptase-polymerase chain reaction. Correspondingly, Scatchard analysis of [(125)I]-IGF-1 binding revealed that T(3) at 10(-7) mol/L increased the number of IGF-1 binding sites in hOB, with small changes in receptor affinity. In addition, a synergistic effect of T(3) and IGF-1 on hOB proliferation was found (p < 0.05). We conclude that IGF-1R and IGFBP-5 are thyroid hormone target genes in human osteoblasts, whereas IGF-1 mRNA expression itself appears not to be regulated by T(3) in hOB. However, T(3) stimulates IGF-1R mRNA expression as well as IGF-1 binding and IGF-1 induced cell proliferation in osteoblasts, thus suggesting thyroid hormone may potentiate the effect of IGF-1 at the receptor level. This may contribute to the positive effects of thyroid hormone on bone formation, which, in addition, may be modulated by increased IGFBP-5 expression.

Serum parathyroid hormone, but not menopausal status, is associated with the expression of osteoprotegerin and RANKL mRNA in human bone samples.

OBJECTIVE: Osteoprotegerin (OPG) and its ligand 'receptor activator of NF-kB ligand' (RANKL) are important regulators of bone metabolism. RANKL, expressed in osteoblasts, activates osteoclast differentiation and osteoclast function by binding the 'receptor activator of NF-kB' (RANK), expressed in ostoclast precursors and mature osteoclasts. The effect is prevented by OPG, a soluble receptor of RANKL. In vitro studies have suggested that estrogen stimulates OPG, whereas parathyroid hormone (PTH) inhibits OPG expression and stimulates the expression of RANKL. DESIGN: In the present study, we examined the relationship between the menopause, serum PTH and the expression of OPG and RANKL in human bone tissue in vivo. METHODS: To address this question, we established a 5'-nuclease assay to quantify the mRNA copies of human OPG and RANKL, normalized to the number of copies of beta-actin mRNA in 169 women (mean age: 52.4+/-11.6 years), who underwent surgery for early breast cancer. Intact serum PTH was measured by chemoluminescence in 61 women. RESULTS: We found no significant difference in the expression of OPG and RANKL between postmenopausal women and premenopausal women. Also, the ratio of RANKL to OPG was unchanged in relation to the menopausal status. Serum PTH was negatively associated with the expression of OPG (r=-0.33, P=0.01), but also, surprisingly, with the expression of RANKL (r=-0.28, P=0.03). CONCLUSION: We failed to observe the expected changes in the expression of OPG and RANKL in human bone samples at menopause. High in vivo levels of circulating PTH are accompanied by low levels of expression of the two transcripts in human bone tissue.

Influence of fluor salts, hormone replacement therapy and calcitonin on the concentration of insulin-like growth factor (IGF)-I, IGF-II and transforming growth factor-beta 1 in human iliac crest bone matrix from patients with primary osteoporosis.

OBJECTIVE: Data from cell culture experiments suggest that local growth factors (GFs) may mediate the effects of estrogens, calcitonin or fluor ions on the skeleton. To assess the in vivo relevance of the in vitro reports, the effect of fluor salts, hormone replacement therapy (HRT) and calcitonin on the concentrations of IGF-I, IGF-II and transforming growth factor (TGF)-beta 1 in bone matrix extracts from osteoporotic patients was evaluated. DESIGN: Iliac crest bone biopsies were obtained from 170 patients (76 men and 94 women) with primary osteoporosis aged 55.5+/-0.8 Years. METHODS: Bone matrix extraction was performed based on a guanidine-HCl/ethylendiamine-tetra-acetic acid method. RESULTS: In comparison with age- and body mass index (BMI)-matched controls, no influence of long-term therapy with fluor ions (n=41) or calcitonin (n=16) on the bone matrix concentration of GFs was noticed. Postmenopausal women with osteoporosis on HRT (n=39) had lower skeletal IGF-I but not IGF-II levels as compared with age- and BMI-matched non-users. However, the lower rate of bone turnover in women with HRT may account for this difference, since the significance was lost after adjustment for alkaline phosphatase. Likewise, a tendency for lower TGF-beta 1 levels was observed in HRT users as compared with non-users but was lost after adjustment for bone turnover. None of the therapies influenced the serum levels of GFs when patients receiving continuous therapy for at least 1 Year before bone biopsy were considered. CONCLUSIONS: Our data suggest no direct effect of fluor therapy on skeletal GFs levels. At the concentrations used, neither HRT nor calcitonin appeared to exert any significant influence on serum or bone matrix GF levels.

Leptin concentrations in serum from a randomly recruited sample of 50- to 80-year-old men and women: positive association with plasma insulin-like growth factors (IGFs) and IGF-binding protein-3 in lean, but not in obese, individuals.

OBJECTIVE: The GH/IGF axis is thought to play an important role in the regulation of body composition throughout life. Changes in body fat stores also affect the activity of the GH/IGF axis, but the mechanisms whereby body fat status is signaled to the GH/IGF axis are poorly understood. The newly discovered protein leptin is exclusively produced by adipocytes, and circulating concentrations of leptin closely reflect body fat stores. DESIGN: We here examined whether leptin might be associated with the activity of the GH/IGF axis in a population-based sample. PATIENTS AND METHODS: Circulating concentrations of leptin, IGF-I, IGF-II, and insulin-like growth factor-binding protein-3 (IGFBP-3) were measured in a population-based sample of 50- to 80-year-old men (n=217) and women (n=198) by specific RIA. RESULTS: All three IGF components were significantly positively correlated with leptin in lean women (body mass index (BMI) <25 kg/m2). IGF-II was also positively correlated with leptin in lean men, and positive correlation of leptin with IGF-I in lean men was of borderline statistical significance. In contrast, no correlation was observed in moderately overweight (BMI 25-30kg/m2) and obese individuals (BMI >30 kg/m2). CONCLUSION: Our study shows that serum leptin concentrations are significantly associated with circulating IGF components in lean elderly subjects. The precise mechanism of this interaction between leptin and the GH/IGF system remains to be determined.

The effects of triiodothyronine on human osteoblast-like cells metabolism and interactions with growth hormone.

The expression of thyroid hormones receptors in osteoblasts and osteoclasts has involved these cells as direct targets for triiodothyronine (T3), but thyroid hormones may also interact with other hormones or local growth factors to exert their actions on bone cells. Among these, growth hormone (GH) is recognised as participating in the acquisition and maintenance of bone mass and exerting stimulatory effects on human osteoblastic cells. The aim of this study was to investigate T3 effects on primary human adult osteoblast-like cells (HOB) as well as to test for possible interactions between T3 and GH on bone cell metabolism. Primary human bone cell cultures were obtained by outgrowth from trabecular bone fragments from the hip and knee. Dose-response studies demonstrated enhanced [3H]-thymidine incorporation for T3 at 10(-9), 10(-8), 10(-7) and 20(-7) M, with a maximal response of 162.81 +/- 12.97 % with T3 10(-8) M, compared to vehicle (p < 0.001). Time-course studies showed an increased osteoblast-like cell proliferation after 24 h, followed by a decrease of cell proliferation by 48 h and 72 h of culture, respectively, when compared to control cells, with a maximal response after 72 h (T3 10(-10) M: 45.21 +/- 6.97 %, p < 0.01). In addition, T3 markedly increased specific alkaline phosphatase (AP) activity in HOB (10(-10) M: 169.86 +/- 12.14 % vs. control, p < 0.001), but no significant influence on type I procollagen propeptide (PICP) production was observed. At 10(-9) - 10(-7) g/ml, GH significantly enhanced HOB proliferation (p < 0.001) however, GH effects were not dose-dependent. Triiodothyronine, at a high concentration (10(-7) M), stimulated GH-receptor (GHR) mRNA levels by 165.20 +/- 16.54 % after 24 h (p < 0.05). Correspondingly, a synergistic effect of T 3 with the same concentration and GH on cell proliferation in human adult osteoblast-like cells was found.

Concentration of insulin-like growth factor (IGF)-I in iliac crest bone matrix in premenopausal women with idiopathic osteoporosis.

Previous studies have shown a link between low serum insulin-like growth factor-I (IGF-I) and decreased bone mass of patients with osteoporosis. However, whether serum levels are representative for the growth factor concentration or activity available in human bone tissue is controversial. In the present study, IGF-I was assessed in serum and bone matrix extracts from the iliac crest in 19 eugonadal women with idiopathic osteoporosis and in 38 age-matched controls. In addition, the relationship between the skeletal levels of IGF-I and bone mineral density (BMD) or the susceptibility to osteoporotic fractures in women with osteoporosis was examined. Bone matrix extraction was performed based on a guanidine-HCL/ethylendiamine-tetraacetic acid (EDTA) method. No significant difference in both serum and bone matrix IGF-I levels between groups was observed. Serum IGF-I concentrations failed to be associated with bone matrix IGF-I levels in osteoporotic patients. However, in premenopausal women with idiopathic osteoporosis, skeletal IGF-I positively correlated with BMD at the lumbar spine (r = + 0.58, p = 0.01). In contrast, neither femoral neck BMD nor Ward's triangle BMD was associated with bone matrix IGF-I concentrations. A tendency towards lower levels of bone matrix IGF-I in subjects with vertebral fractures as compared to those without fractures was observed in age-adjusted analyses, however the difference failed to remain statistically significant after adjustment for bone mineral density. These data provide no clear evidence for low bone matrix IGF-I as a determinant factor of age-unrelated osteoporosis. However, low skeletal IGF-I concentrations may aggravate osteoporosis in these women.

Influence of glycoproteins B, C and D on the conversion of virus-to-cell attachment from heparin sensitivity to resistance.

Glycoprotein C-negative (gC-) mutants of herpes simplex virus type 1 (HSV-1) derived from strains KOS and ANGpath were used to analyse the influence of soluble heparin on the phase of adsorption/attachment of HSV-1 to cells. A dose of 200 micrograms/ml heparin given 20 mins after infection of cells with the gC- positive (gC+) strains KOS and ANGpath at 4 degrees C reduced the adsorption of infective particles to 20-30% of the controls. A weaker heparin effect was observed with gC- mutants. However, also the gC- mutants exhibited a short heparin-sensitive phase. Mutations in amino acids of gB or gD at positions 854 or 25 and 27, respectively, did not alter the attachment capacities of these HSV mutants in the presence of heparin despite their peculiar fusion properties and resistance to soluble gD. We conclude that HSV-1 strains exhibit a heparin-resistant phase of attachment, which is determined by gC. Lack of gC delays the heparin-resistant attachment phase of HSV-1 to cells.

[Prevalence of thyroid gland dysfunctions in 50- to 80-year-old patients. An epidemiologic cross-sectional study in a southwestern community]. / Prävalenz von Schilddrüsenfunktionsstörungen bei 50- bis 80jährigen. Eine epidemiologische Querschnittsstudie in einer südwestdeutschen Gemeinde.

BACKGROUND: Thyroid dysfunctions in the elderly are common in iodine deficient Germany. However, the exact prevalence of hypo- and hyperthyroidism is unknown and differs according to the composition of the screened population. In this study we examined the prevalence of thyroid disorders in a population based sample of non-hospitalized elderly people living in a community in southwestern Germany. PATIENTS AND METHODS: In the context of an epidemiological study on the prevalence of osteoporosis and associated factors, 288 men and 271 women between the age of 50 and 80 years were screened for plasma levels of thyreotropin, free T3 and free T4. Participants received an interview on medical conditions including a history on thyroid disorders. RESULTS: 6.7% of the women and 1.7% of the men had a history of thyroid surgery. Manifest or treated hyperthyroidism was observed in 3.5% of the women (n = 10) and 0.7% of the men (n = 2). In 2 of 12 patients with manifest hyperthyroidism the condition was previously unknown. 70- to 80-year old women tended to have a higher prevalence of hyperthyroidism (6.3%) than 50- to 59-year old women (2.9%), or 60- to 69-year old women (3.4%). Subclinical hyperthyroidism was observed in 7.3% of the men (n = 21) and 5.9% of the women (n = 16). We observed no cases of over hypothyroidism in men but in 1.8% of the women (n = 5). Four of 5 manifest states of hypothyroidism were previously unknown. CONCLUSION: The prevalence of thyroid dysfunction in older women and men living in southwestern Germany is high. In view of the often nonspecific clinical symptoms of hypo- and hyperthyroidism in elderly individuals, thyroid disorders should be early included to the list of the differential diagnosis of clinical complaints in this age group.

Effect of glucocorticoid-, parathyroid- and thyroid hormones excess on human iliac crest bone matrix insulin-like growth factor (IGF)-I in patients with osteoporosis.

Insulin-like growth factor-I (IGF-I) is a well documented bone-active growth factor. Clinical studies reported that circulating hormones may affect serum IGF-I levels, with potential consequences on bone remodeling. However, no data on bone matrix concentrations of IGF-I in subjects with endocrine dysfunction is available in humans. Bone mineral density and cancellous bone matrix IGF-I levels were assessed in iliac crest biopsies from 38 patients with low bone mass related to glucocorticoid- (n=10), parathyroid- (n=14) or thyroid (n=14) hormones excess. Results were compared to those of sex- and age-matched patients with primary osteoporosis. Bone matrix extraction was performed based on a guanidine-chlorhidric acid/ethylendiamine-tetraacetic acid method. Long-term glucocorticoid therapy (> or =24 months) led to significantly lower cancellous bone matrix IGF-I levels in comparison to age-matched controls (p=0.03). Although higher trabecular bone IGF-I levels were seen in hyperparathyroid subjects, the difference was not significant in comparison to controls (p=0.24). Likewise, no difference was noticed in cancellous bone matrix IGF-I concentrations between subjects with low bone mass and sub-clinical or overt thyrotoxicosis and euthyroid controls. Neither parathyroid hormone (PTH) nor thyroxin (T (4)) concentrations were associated with bone matrix IGF-I levels. To conclude, our study documented that in vivo long-term corticotherapy is associated with low trabecular human bone matrix IGF-I. In contrast, no influence of increased circulating parathyroid- or thyroid hormones levels on human iliac crest skeletal IGF-I concentrations was observed.