Early effects of metformin in women with polycystic ovary syndrome: a prospective randomized, double-blind, placebo-controlled trial

CONTEXT

Metformin is successfully used in the treatment of cycle disorders and anovulation in women with polycystic ovary syndrome (PCOS). No data of the exact point and the impact of insulin resistance (IR) on metformin's efficacy exist.

OBJECTIVE

The objective of the study was to evaluate the early potential effects of metformin treatment, their time of onset, and the role of IR on metformin's efficacy.

DESIGN

This was a prospective randomized, double-blind, placebo-controlled trial.

SETTING

The study was conducted at the University of Heidelberg, Heidelberg, Germany.

PATIENTS

The patient population was 45 oligo-/anovulatory PCOS women with typical ovaries.

INTERVENTIONS

Women were stratified for IR (32 of 13) and then randomly allocated to receive either metformin (n = 22) or placebo (n = 23) and were assessed before and every 4 wk within a treatment period of 12 wk.

MAIN OUTCOME MEASURES

Menstrual disturbance and markers of insulin metabolism were measured.

RESULTS

The main outcome criterion menstrual disturbance was successfully improved in the metformin-treated group, depending on IR (12 of 15 vs. three of 17), whereas women without IR (four of seven vs. four of six) had no significant amelioration of their menstrual irregularities (P < 0.05). Estradiol levels increased continuously only in the treatment group (P < 0.005), indicating an improvement of ovulatory function. Sixty-seven percent of metformin-treated women had at least one ovulation, compared with only 45% in the placebo group, shown by biphasic body temperature curves. Insulin sensitivity improved within 4 wk after beginning of metformin as shown by an increased area under the curve glucose to insulin ratio, compared with baseline (P < 0.005).

CONCLUSIONS

IR is a baseline predictor of clinical efficacy in metformin treatment in PCOS women measured by improved menstrual cyclicity and ovulatory function.

Migration rules: functional properties of naive and effector/memory-like regulatory T cell subsets

Suppressor T cells were first described in the early 1970s, but since the hypothetical soluble suppressor factor could not be identified on a molecular level and since appropriate cellular markers were lacking, the suppressor T cell concept vanished for a long time. The discovery by Sakaguchi and co-workers, that the adoptive transfer of CD25+CD4+ -depleted T cells induced several organ-specific autoimmune diseases in immunodeficient recipients, put the suppressor T cell model back into the focus of many immunologists. CD25+CD4+ T cells were named regulatory T cells (Treg) and since then have been intensively characterized by many groups. It has now been well documented in a variety of models that CD25+CD4+ Tregs, in addition to cell-intrinsic peripheral tolerance mechanisms such as anergy induction and peripheral deletion, play indispensable roles in the maintenance of natural self-tolerance, in averting autoimmune responses as well as in controlling inflammatory reactions. However, a number of fundamental questions concerning their origin, mechanism of action, and the sites of suppression remain elusive and are currently a matter of debate. Notably, the potential heterogeneity of Tregs with respect to phenotype and function deserves attention and is a major issue discussed in this review.

Neural driven angiogenesis by overexpression of nerve growth factor

Mechanisms regulating angiogenesis are crucial in adjusting tissue perfusion on metabolic demands. We demonstrate that overexpression of nerve growth factor (NGF) in brown adipose tissue (BAT) of NGF-transgenic mice elevates both mRNA and protein levels of vascular endothelial growth factor (VEGF) and VEGF-receptors. Increased vascular permeability, leukocyte-endothelial interactions (LEI), and tissue perfusion were measured using intravital microscopy. NGF-stimulation of adipocytes and endothelial cells elevates mRNA expression of VEGF and its receptors, an effect blocked by NGF neutralizing antibodies. These data suggest an activation of angiogenesis as a result of both: stimulation of adipozytes and direct mitogenic effects on endothelial cells. The increased nerve density associated with vessels strengthened our hypothesis that tissue perfusion is regulated by neural control of vessels and that the interaction between the NGF and VEGF systems is the critical driver for the activated angiogenic process. The interaction of VEGF- and NGF-systems gives new insights into neural control of organ vascularization and perfusion.

X-PERT: weight reduction with orlistat in obese subjects receiving a mildly or moderately reduced-energy diet: early response to treatment predicts weight maintenance

AIM

To determine the effect of two different levels of energy deficit on weight loss in obese patients treated with orlistat.

METHODS

Patients (n=430) were randomized in a 1-year, multicentre, open-label, parallel group study conducted at 23 hospital centres and university medical departments worldwide. Obese outpatients (body mass index 30--43 kg/m(2)) aged 18--70 years with a body weight of >or=90 kg and a waist circumference of >or=88 cm (women) or >or=102 cm (men) were treated with orlistat 120 mg three times daily plus a diet that provided an energy deficit of either 500 or 1,000 kcal/day for 1 year. Orlistat treatment was discontinued in patients who did not achieve >or=5% weight loss after assessment at 3 and 6 months. The primary outcome measure was change in body weight from baseline at week 52.

RESULTS

Reported mean difference in energy intake between the two groups (500-1,000 kcal/day deficit) at weeks 24 and 52 was actually 111 and 95 kcal/day respectively. Of the 430 patients involved in the study, 295 achieved >or=5% weight loss at both 3 and 6 months. In this population, at week 52, weight loss from baseline was similar for patients randomized to either the 500 or the 1,000 kcal/day deficit diet (-11.4 kg vs. -11.8 kg, respectively; p=0.778). After 12 months of treatment with orlistat, 84% (n=118/141) and 85% (n=131/154) of patients in the 500 and 1,000 kcal/day deficit groups, respectively, achieved >or=5% weight loss, and 50% (n=70/141) and 53% (n=82/154) of patients, respectively, achieved >or=10% weight loss. Patients in both the diet treatment groups showed similar significant improvements in blood pressure, lipid levels and waist circumference at week 52.

CONCLUSIONS

Treatment with orlistat was associated with a clinically beneficial weight loss, irrespective of the prescribed dietary energy restriction (-500 or -1000 kcal/day). Patients who achieved >or=5% weight loss at 3 months achieved long-term, clinically beneficial weight loss with orlistat plus either diet. Therefore, identifying patients who lose at least 5% weight after 3 months and who maintain this weight loss up to 6 months is a valuable treatment algorithm to select patients who will benefit most from orlistat treatment in combination with diet.

No association of the 94T/G polymorphism in the adiponectin gene with diabetic complications

AIM

This study examined a possible association of the T/G polymorphism at nucleotide 94 in the adiponectin gene with the prevalence of diabetic complications.

METHODS

The study was performed in 696 patients with type 1 diabetes and type 2 diabetes. Genotyping was performed by means of polymerase chain reaction and subsequent cleavage by using SmaI restriction endonuclease.

RESULTS

The 94G/G genotype was significantly more prevalent in patients with type 2 diabetes (2.2%) than in type 1 diabetics (0.0%) (p = 0.02), whereas no differences were found for frequencies of the 94T/T and the 94G/T genotypes, respectively. In patients with type 1 diabetes, 45 of 239 patients were heterozygous for the 94T/G polymorphism (carrier rate (CR): 18.8%; allele frequency (AF): 0.094). In type 2 diabetics, 71 of 457 patients were heterozygous and 10 patients were homozygous for the 94G/G genotype (CR: 17.7%; AF: 0.10). No association with diabetic nephropathy, diabetic neuropathy or diabetic retinopathy was found for either genotype in patients with type 1 and type 2 diabetes.

CONCLUSIONS

The 94T/G polymorphism in the adiponectin gene is not associated with diabetic complications. The significance of a higher prevalence of the G allele in type 2, compared to type 1 diabetes remains to be clarified.

Expression of the sodium iodide symporter in differentiated thyroid cancer: clinical evidence

AIM

Molecular analysis of the expression of the sodium iodide symporter (NIS) in 32 patients with differentiated thyroid cancer (DTC) and correlation with scintigraphic findings ((131)I,(123)I) in 19 (59.4%) of them.

PATIENTS, METHODS

NIS expression of 27 primary tumours, 13 lymphnodes and 18 distant metastases was determined by immunostaining using a murine monoclonal anti-NIS-antibody. NIS expression and radionuclide uptake of metastases were analysed by a semiquantitative visual score. Patients were divided into two subgroups: Group 1 (n = 8 patients): indirect correlation of radioiodine uptake (RIU) of subsequent metastases with NIS expression of 7 primary tumours and 3 metastases; Group 2 (n=11 patients): direct correlation of radionuclide uptake with NIS expression of 19 metastases which were excised after imaging.

RESULTS

49 of 58 specimens (84.5%) were NIS-positive. A preserved NIS-expression was found in 12 primary tumours and 8 of 10 (80%) synchrone and 6 of 7 (85.7%) metachrone metastases. Group 1 revealed a 100% positive predictive value (PPV) of a preserved NIS expression in the primary tumour regarding radioiodine uptake in metastases while a lack of NIS expression in the primary tumor did not reliable predict a loss of the metastases' ability to concentrate radioiodine. In group 2, only 11 of 19 (57.9%) specimens showed a concordant NIS expression and RIU whereas in the remaining 8 cases without visible RIU NIS expression was still present.

CONCLUSIONS

NIS expression of the primary tumour and metastases in DTC is usually well preserved. We found a positive correlation between NIS expression of the primary and metastatic tissue but could not identify such well correspondence between NIS expression and the RIU of subsequent metastases.

[Oral diabetes treatment. Which substance is indicated at which time?]

The prevalence of type 2 diabetes continues to show a clear upward trend in Germany. In earlier days it was considered the "harmless diabetes of old age," but has become increasingly recognized as a disease carrying a high risk of vascular sequelae as well as shortening the diabetic's remaining life expectancy if adequate therapy is not initiated. In addition to correcting hyperglycemia, treatment consists in effective management of concomitant risk factors such as hypertension, dyslipidemia, and adiposity resulting from faulty nutrition and lack of exercise. In the large majority of overweight type 2 diabetics, metformin is the oral antidiabetic agent of first choice provided the patient does not exhibit renal insufficiency, which represents the most important contraindication. This recommendation for monotherapy of overweight type 2 diabetics is supported by an endpoint study. In contrast, no equivalent evidence is available on any of the possible options for oral combination therapy.

Variants in the human beta 1-, beta 2-, and beta 3-adrenergic receptor genes are not associated with morbid obesity in children and adolescents

AIM

beta-adrenergic receptors (beta-ARs) are of key importance for the regulation of lipolysis and thermogenesis by catecholamines. Genetic defects in expression or function of beta(1)- beta(2)- and/or beta(3)-AR could affect energy homeostasis and predispose an individual towards the development of obesity. We therefore investigated the possible association of polymorphisms in the beta-adrenergic receptor genes with early onset obesity.

METHODS

Frequencies of the following variants were assessed in extremely obese children and healthy underweight controls: Gly/Ser in codon 49 and Arg/Gly in codon 389 of the beta(1)-AR, Arg/Gly in codon 16 and Gln/Glu in codon 27 of the beta(2)-AR, Trp/Arg in codon 64 of the beta(3)-AR.

RESULTS

The Ser49 allele in the beta(1)-AR gene was found at a frequency of 0.131 in obese and 0.136 in lean subjects (p = 0.835), while the Gly389 allele in the beta(1)-AR had a frequency of 0.319 in obese and 0.328 in lean subjects (p = 0.802). Gly16 in the beta(2)-AR was found with a frequency of 0.590 in obese and 0.611 in lean subjects (p = 0.591) and the Glu27 allele in the beta(2)-AR had a frequency of 0.380 in obese and 0.420 in lean subjects (p = 0.298).

CONCLUSION

We did not detect significant differences for allele and carrier frequencies of individual polymorphisms. Together with previously obtained data on genotype distribution of a beta(3)-AR variant in the same study group, no significant differences were found between obese and lean subjects for the distribution of individuals with variants in none, one, two or all three beta-ARs. Our data make it unlikely that polymorphisms in beta-ARs are involved in the pathogenesis of early onset obesity.

Tissue and serum levofloxacin concentrations in diabetic foot infection patients

OBJECTIVES

Levofloxacin has a high bioavailability and a broad antibacterial spectrum which covers the common pathogens found in acute and chronic diabetic foot infections. The purpose of our study was to determine the serum and tissue concentrations of levofloxacin when administered orally in patients with infected diabetic foot ulcers and to compare these values with microbiological findings.

PATIENTS AND METHODS

Ten outpatients with diabetes and ulcerations of the lower extremity were included. All patients received oral levofloxacin therapy at a dose of 500 mg once daily. Wound tissue and serum samples were collected and levofloxacin concentrations determined by HPLC with fluorescence detection. Additionally, microbiological cultures were performed from swabs and debrided wound tissue, both before and after treatment. MICs of levofloxacin for all bacterial isolates were determined using the Etest.

RESULTS

Following oral treatment with levofloxacin for an average of 10 +/- 3.8 days, all patients received debridement at the affected limbs. The levofloxacin concentrations in necrotic wound tissue were between 2.33-23.23 mg/kg and between 0.12-6.41 mg/L in serum. Tissue-to-serum ratios of levofloxacin concentrations for each patient were >1.0. The MIC values for all 17 initially isolated bacteria were < or = 2 mg/L. In half of our patients, fluoroquinolones were one of the few oral monotherapy options where the spectrum covered all initially isolated pathogens.

CONCLUSION

Our data showed good tissue penetration of levofloxacin in diabetic foot ulcers. In combination with adequate surgical debridement, levofloxacin seems well suited to the treatment of skin structure infections of diabetics caused by susceptible organisms.

Reduction of postprandial hyperglycemia in patients with type 2 diabetes reduces NF-kappaB activation in PBMCs

AIMS/HYPOTHESIS

Short-lasting hyperglycemia results in activation of the transcription factor NF-kappaB in peripheral blood mononuclear cells. We therefore studied whether the postprandial increase in glucose is sufficient to induce mononuclear NF-kappaB activation and whether blunting postprandial hyperglycemia with the alpha-glucosidase inhibitor acarbose reduces NF-kappaB activation.

METHODS

20 patients with type 2 diabetes were included in a double-blind randomized trial receiving 100 mg acarbose or placebo three times a day over a period of eight weeks. Peripheral blood mononuclear cells were isolated before and 120 minutes after a standardized breakfast. NF-kappaB binding activity was estimated by electrophoretic mobility shift assay and NF-kappaB-p65; translocation was determined by Western blot.

RESULTS

Eight weeks of treatment with acarbose significantly reduced postprandial hyperglycemia (p = 0.004 when compared to placebo), postprandial mononuclear NF-kappaB-binding activity (p = 0.045) and nuclear translocation of NF-kappaB-p65 (p = 0.02).

CONCLUSION

Reduction of postprandial glucose peak levels by acarbose reduces postprandial mononuclear NF-kappaB activation.

Therapeutic dose of HIV-1 protease inhibitor saquinavir does not permanently influence early insulin signaling

The introduction of HIV-1 protease inhibitor therapy has significantly improved the expectancy and quality of life for HIV-infected patients. Recent reports have highlighted the development of metabolic complications in patients taking protease inhibitors, including abnormalities in glucose metabolism such as impaired glucose tolerance and type 2 diabetes. The mechanisms by which protease inhibitors induce these metabolic syndromes are not well understood. The aim of this study was to determine whether treatment with the HIV-1 protease inhibitor, saquinavir, influences the early insulin signaling cascade in insulin-sensitive cell lines.

METHODS

Insulin-stimulated phosphorylation of insulin receptor (IR-beta), insulin receptor substrates (IRS-1 and IRS-2), association of phosphatidylinositol 3-kinase (PI 3-kinase), Ser 473-phosphorylation of Akt and Thr202/Tyr204-phosphorylated p44/42 MAP kinase in 3T3L1 adipocytes and FAO hepatoma cells incubated with increasing concentrations of saquinavir for 24, 36 hours, 2, 3 and 6 days were measured. Results. Phosphorylation of IR-beta, IRS-1 and IRS-2 was not permanently affected by incubation with therapeutic doses (2.5 microM) of saquinavir for 36 hours. After 24 hours we observed an increase of IR-beta and IRS-1 phosphorylation. However, this initial stimulation of IR-beta and IRS-1 phosphorylation was not permanent and did not result in an increased PI 3-kinase association. Phosphorylation of IRS-2 and MAP kinase as well as glucose transport activity was not altered by therapeutic doses. Doses of 10, 25 and 50 microM of saquinavir altered the early insulin signaling events in a dose-dependent manner. However, this effect was primarily due to the cytotoxic effect of higher saquinavir doses. Glucose transport activity was not significantly reduced in 3T3L1 cells treated with 2.5 microM saquinavir in comparison to the control cells stimulated with insulin.

CONCLUSION

Early insulin signaling cascade, essential for normal glucose metabolism, is not affected by therapeutic doses of saquinavir. The reduction of insulin-induced phosphorylation in higher concentrations is primarily related to cytotoxic effects. Other mechanisms than early insulin signaling must be primarily responsible for the metabolic alterations during saquinavir therapy.

A 63bp Deletion in the Promoter of RAGE Correlates with a Decreased Risk for Nephropathy in Patients with Type 2 Diabetes

Several polymorphisms have been identified in the RAGE-promoter region that might modulate the outcome of disease. Here we analyse the association of a 63bp deletion (delta63) spanning from bp - 407 to bp - 345 with diabetic nephropathy. The deletion was determined using the polymerase chain reaction (PCR) in a cross-sectional study with 1087 patients with type 1 diabetes (n = 559) and type 2 diabetes (n = 528). 475 patients with osteoporosis served as disease independent control. The prevalence of the heterozygous genotype did not significantly differ between the three groups (type 1: 2.15 %, type 2: 2.27 %, controls: 1.47 %), indicating that heterozygous delta63 is not related to the manifestation of diabetes. Homozygous carriers were not identified in this study. The heterozygous delta63 genotype, was associated with a reduced prevalence of diabetic nephropathy in patients with type 2 diabetes (OR = 0.06; 95 % CI: [0.05, 0.07]), but not in patients with type 1 (OR = 1.49; 95 % CI: [1.14, 1.94]). We conclude, that patients with type 2 diabetes and the 63bp deletion in the promoter of RAGE seem to be protected from diabetic nephropathy. The observed difference between type 1 and type 2 diabetes might point to diverse pathomechanisms of nephropathy in both types of diabetes.

Microflora reactive IL-10 producing regulatory T cells are present in the colon of IL-2 deficient mice but lack efficacious inhibition of IFN-gamma and TNF-alpha production

BACKGROUND

Inflammatory bowel disease in interleukin 2 (IL-2) deficient (IL-2(-/-)) mice is triggered by the intestinal microflora and mediated by CD4(+) T cells.

AIMS

To determine the characteristics of microflora specific intestinal T cells, including migration and cytokine production.

METHODS

Intestinal T cell populations and cytokine mRNA expression of specific pathogen free (SPF) and germ free (GF) IL-2(-/-) and IL-2(+/+) mice were compared by flow cytometry and reverse transcription-polymerase chain reaction. Cytokine production of intestinal mononuclear cells on stimulation with microflora antigens was assessed by ELISA. In vivo migration of T cells was assessed by adoptive transfer of (51)Cr labelled CD4(+)CD25(-)alpha beta(+) T cells. The ability of intestinal T cell lines to promote colitis was determined by adoptive transfer experiments.

RESULTS

SPF IL-2(-/-) mice produced higher interferon gamma (IFN-gamma) and tumour necrosis factor alpha mRNA levels than GF IL-2(-/-) mice, which was accompanied by an increased number of CD4(+)alpha beta T cells in the colon. Tracking of (51)Cr labelled and adoptively transferred T cells revealed an increased MAdCAM-1 dependent but VCAM-1 independent recruitment of these cells into the colon of SPF IL-2(-/-) mice. Colon lamina propria lymphocytes (LPL) from SPF IL-2(-/-) mice showed increased spontaneous IFN-gamma production in vitro. On stimulation with bacterial microflora antigens, intraepithelial lymphocytes and LPL did not produce IFN-gamma, but high quantities of IL-10, which did not suppress IFN-gamma production. Bacterial antigen specific cell lines established from colon LPL of SPF IL-2(-/-) mice with colitis showed a regulatory T cell-like cytokine profile and only marginally modulated the course of colitis and survival of IL-2(-/-) mice.

CONCLUSIONS

Our results suggest that microflora reactive regulatory T cells are present in the colon of SPF IL-2(-/-) mice. However, IL-10 produced by these cells did not significantly modulate a possible secondary proinflammatory CD4 Th1 cell population to produce IFN-gamma.