Safety, pharmacokinetics and pharmacodynamics of BI 135585, a selective 11ß-hydroxysteroid dehydrogenase-1 (HSD1) inhibitor in humans: liver and adipose tissue 11ß-HSD1 inhibition after acute and multiple administrations over 2 weeks.

AIMS: To assess the safety and pharmacokinetic and pharmacodynamic characteristics of BI 135585, a selective 11ß-hydroxysteroid dehydrogenase-1 (11ß-HSD1) inhibitor, after single- and repeated-dose administration. METHODS: The single-dose study included open-label administration of 200 mg BI 135585 in healthy volunteers, while in the multiple-dose study, we carried out randomized, double-blind administration of 5-200 mg BI 135585 or placebo once daily over 14 days in patients with type 2 diabetes (T2DM). Assessments included 11ß-HSD1 inhibition in the liver (urinary tetrahydrocortisol (THF)/tetrahydrocotisone (THE) ratio) and in subcutaneous adipose tissue (AT) ex vivo and determination of hypothalamus-pituitary-adrenal (HPA) axis hormone levels. RESULTS: No major safety issues occurred with BI 135585 administration. The HPA axis was mildly activated with slightly increased, but still normal adrenocorticotropic hormone levels, increased total urinary corticoid excretion but unchanged plasma cortisol levels. After multiple doses of 5-200 mg BI 135585, exposure (area under the curve) increased dose-proportionally and half-life was 55-65 h. The urinary THF/THE ratio decreased, indicating liver 11ß-HSD1 inhibition. Median 11ß-HSD1 enzyme inhibition in the AT reached 90% after a single dose of BI 135585, but was low (31% or lower) after 14 days of continuous treatment. CONCLUSIONS: BI 135585 was safe and well tolerated over 14 days and can be dosed once daily. Future studies are required to clarify the therapeutic potential of BI 135585 in view of its effects on 11ß-HSD1 inhibition in AT after single and multiple doses. Enzyme inhibition in the AT was not adequately predicted by the urinary THF/THE ratio.

Neuronal overexpression of insulin receptor substrate 2 leads to increased fat mass, insulin resistance, and glucose intolerance during aging.

The insulin receptor substrates (IRS) are adapter proteins mediating insulin's and IGF1's intracellular effects. Recent data suggest that IRS2 in the central nervous system (CNS) is involved in regulating fuel metabolism as well as memory formation. The present study aims to specifically define the role of chronically increased IRS2-mediated signal transduction in the CNS. We generated transgenic mice overexpressing IRS2 specifically in neurons (nIRS2 (tg)) and analyzed these in respect to energy metabolism, learning, and memory. Western blot (WB) analysis of nIRS2 (tg) brain lysates revealed increased IRS2 downstream signaling. Histopathological investigation of nIRS2 (tg) mice proved unaltered brain development and structure. Interestingly, nIRS2 (tg) mice showed decreased voluntary locomotoric activity during dark phase accompanied with decreased energy expenditure (EE) leading to increased fat mass. Accordingly, nIRS2 (tg) mice develop insulin resistance and glucose intolerance during aging. Exploratory behavior, motor function as well as food and water intake were unchanged in nIRS2 (tg) mice. Surprisingly, increased IRS2-mediated signals did not change spatial working memory in the T-maze task. Since FoxO1 is a key mediator of IRS2-transmitted signals, we additionally generated mice expressing a dominant negative mutant of FoxO1 (FoxO1DN) specifically in neurons. This mutant mimics the effect of increased IRS2 signaling on FoxO-mediated transcription. Interestingly, the phenotype observed in nIRS2 (tg) mice was not present in FoxO1DN mice. Therefore, increased neuronal IRS2 signaling causes decreased locomotoric activity in the presence of unaltered exploratory behavior and motor coordination that might lead to increased fat mass, insulin resistance, and glucose intolerance during aging independent of FoxO1-mediated transcription.

Complete failure of insulin-transmitted signaling, but not obesity-induced insulin resistance, impairs respiratory chain function in muscle.

The role of mitochondrial dysfunction in the development of insulin resistance and type 2 diabetes remains controversial. In order to specifically define the relationship between insulin receptor (InsR) signaling, insulin resistance, hyperglycemia, hyperlipidemia and mitochondrial function, we analyzed mitochondrial performance of insulin-sensitive, slow-oxidative muscle in four different mouse models. In obese but normoglycemic ob/ob mice as well as in obese but diabetic mice under high-fat diet, mitochondrial performance remained unchanged even though intramyocellular diacylglycerols (DAGs), triacylglycerols (TAGs), and ceramides accumulated. In contrast, in muscle-specific InsR knockout (MIRKO) and streptozotocin (STZ)-treated hypoinsulinemic, hyperglycemic mice, levels of mitochondrial respiratory chain complexes and mitochondrial function were markedly reduced. In STZ, but not in MIRKO mice, this was caused by reduced transcription of mitochondrial genes mediated via decreased PGC-1α expression. We conclude that mitochondrial dysfunction is not causally involved in the pathogenesis of obesity-associated insulin resistance under normoglycemic conditions. However, obesity-associated type 2 diabetes and accumulation of DAGs or TAGs is not associated with impaired mitochondrial function. In contrast, chronic hypoinsulinemia and hyperglycemia as seen in STZ-treated mice as well as InsR deficiency in muscle of MIRKO mice lead to mitochondrial dysfunction. We postulate that decreased mitochondrial mass and/or performance in skeletal muscle of non-diabetic, obese or type 2 diabetic, obese patients observed in clinical studies must be explained by genetic predisposition, physical inactivity, or other still unknown factors.

Neuron-specific deletion of a single copy of the insulin-like growth factor-1 receptor gene reduces fat accumulation during aging.

Insulin, insulin-like growth factor-1 (IGF-1), and leptin signaling have been proposed to play an important role in regulating energy homeostasis. In order to specifically address the role of neuronal IGF-1 receptor (IGF-1R) signaling for energy expenditure and metabolism we used conditional mutagenesis. Deletion of one copy of the IGF-1R specifically in post-mitotic neurons (nIGF-1R(+/-) ) does not result in growth retardation or skeletal abnormalities. Interestingly, male nIGF-1R(+/-) mice accumulate less fat mass during aging accompanied with decreased leptin levels compared to wild-type littermates. Furthermore, male nIGF-1R(+/-) mice present with increased locomotor activity and energy expenditure. In contrast, female nIGF-1R(+/-) mice remained nearly unaffected. Circadian pattern of locomotor activity and energy expenditure as well as food and water intake did not change. Consistent with increased locomotor activity, the respiratory quotient was shifted to increased fat oxidation in nIGF-1R(+/-) mice. Surprisingly, serum IGF-1 and IGF-1 binding protein 3 (IGF-BP3) concentrations were decreased in nIGF-1R(+/-) mice despite the presence of normal pituitaries suggesting a functional feedback mechanism via neuronal IGF-1Rs, which regulate serum IGF-1 levels. Thus, we show that neuron-specific IGF-1R deletion in male mice decreases body fat accumulation and increases energy expenditure during aging.

Dipeptidyl-peptidase 4 and attractin expression is increased in circulating blood monocytes of obese human subjects.

Dipeptidyl-peptidase (DPP)-4, which catalizes the degradation of the insulinotropic incretin glucagon-like-peptide (GLP)-1, and the DPP-4 like enzyme attractin are involved in activation of T-lymphocytes and monocytes. Recently, it has been demonstrated, that the risk for certain infections is increased in type 2 diabetic patients under DPP-4 inhibitor treatment. The aim of the present study was to examine the expression of DPP-4 and attractin in circulating blood monocytes of obese and type 2 diabetic subjects. Monocytes were isolated by CD14-antibody based magnetic cell sorting from blood samples of 17 lean controls, 20 obese, non-diabetic subjects and 19 obese patients with type 2 diabetes. FACS analysis was performed to test purity of the cell preparations. Expression was measured by multiplex RT-PCR on RNA-level. DPP-4 and attractin were detectable in human circulating monocytes with attractin being expressed at higher levels compared to DPP-4. Both enzymes were significantly higher expressed in circulating blood monocytes of obese subjects compared to lean controls. In contrast, type 2 diabetes did not significantly affect expression levels. Finally, neither DPP-4 nor attractin expression was altered by sitagliptin or insulin treatment. In conclusion, our data demonstrate, that expressions of DPP-4 and attractin in circulating blood monocytes of human subjects are influenced by metabolic abnormalities with obesity being an important factor.

Visfatin/PBEF/Nampt and resistin expressions in circulating blood monocytes are differentially related to obesity and type 2 diabetes in humans.

Low-grade inflammation is important in the development of obesity related pathologies such as insulin resistance and type 2 diabetes, and also cardiovascular disease. Visfatin/PBEF/Nampt and resistin are proinflammatory adipokines secreted from adipocytes, monocytes, and macrophages, and have been linked to atherosclerotic plaque formation, recently. The aim of the present study was to investigate if the expression of these molecules in circulating blood monocytes is altered in obese and/or type 2 diabetic human subjects. Monocytes were isolated by CD14-antibody based magnetic cell sorting from blood samples of 17 lean controls, 20 obese nondiabetic subjects, and 19 obese patients with type 2 diabetes. FACS analysis was performed to test purity of the cell preparations. Expression of the different adipokines was measured by multiplex real-time PCR on RNA-level. Visfatin/PBEF/Nampt was found to be very strongly expressed in monocytes, whereas resistin levels were significantly lower. Furthermore, visfatin/PBEF/Nampt expression was significantly upregulated in obese type 2 diabetic patients, whereas obese nondiabetics exhibited similar levels compared to lean controls, indicating that visfatin/PBEF/Nampt levels are related to type 2 diabetes rather than to obesity. In contrast, resistin expression displayed a different pattern being significantly increased in obese subjects compared to controls but not related to type 2 diabetes. These data suggest a differential role for these two proinflammatory adipokines in linking metabolic diseases to atherosclerosis with visfatin/PBEF/Nampt being more important in patients with type 2 diabetes and resistin in obese but nondiabetic human subjects.

Identification of a region in the human IRS2 promoter essential for stress induced transcription depending on SP1, NFI binding and ERK activation in HepG2 cells.

Recent studies have discovered changes in the insulin-/IGF1 signaling affecting glucose metabolism and the molecular pathogenesis of human hepatocellular cancer. Insulin/IGF1 receptor mediates its intracellular effects by recruitment of one out of the four different insulin receptor substrates (IRS). To investigate mechanisms of IRS2 expression, we analyzed transcriptional regulation of IRS2 in human HepG2 cells. We identified a region 688 bp upstream of the translation start codon responsible for approximately 90% of basal human IRS2 promoter activity in HepG2 cells, and confirmed binding of specificity protein 1 (also called Sp1 transcription factor, SP1) and nuclear factor 1 (NFI) in this region. Mutation of both SP1 and NFI binding sites or inhibition of extracellular signal regulated kinase (ERK) suppressed IRS2 promoter activity almost completely, revealing a major role of MAP kinases (MAPK) for IRS2 transcription. Activating this cascade with oxidative stress increased IRS2 promoter activity and endogenous IRS2 expression substantially. IRS2 promoter activity rose even more after additional inhibition of p38MAPK indicating an inhibitory effect of p38MAPK on ERK mediated IRS2 transcription. Activation of the MAPK pathway using interleukin 1, beta (IL1B) increased IRS2 promoter activity similar to oxidative stress. In contrast IL1B decreases and inhibition of the MAPK pathway increases IRS1 promoter activity revealing opposed effects of IL1B and ERK on the expression of different IRS proteins. In conclusion we discovered a specific region (-688 to -611 bp) in the IRS2 promoter essential for basal promoter activity and oxidative stress induced transcription depending on ERK activation and SP1 and NFI binding in human hepatocytes.

The role of IGF-1 receptor and insulin receptor signaling for the pathogenesis of Alzheimer's disease: from model organisms to human disease.

In different clinical studies, an association of type 2 diabetes and Alzheimer's disease (AD) has been described. However, the underlying mechanisms are still unclear. One explanation could be that vascular complications of diabetes result in neurodegeneration. Alternatively, the mechanism might be directly related to insulin and insulin-like growth factor(IGF)-1 signaling, leading to the proposal that AD is a "brain-type diabetes". Furthermore, postmortem analyses of brains from patients with AD revealed a markedly downregulated expression of insulin receptor (IR), IGF-1 receptor (IGF-1R), insulin receptor substrate (IRS)-1 and IRS-2, and these changes progress with severity of neurodegeneration. These findings raise the question, whether this phenomenon is cause or consequence of neurodegeneration. Recently, Cohen and coworkers have show that knocking down DAF-2 in C. elegans, the homolog of the mammalian IR/IGF-1R, reduces beta-amyloid(Abeta)(1-42) toxicity. Cell based experiments suggest a specific role for the IGF 1/IRS-2 signaling pathway in regulating alpha-/beta-secretase activity. Moreover circulating IGF-1 might influence Abeta clearance from the brain by promoting Abeta transport over the blood brain barrier. Interestingly, brain specific deletion of IRS-2 increases life span, suggesting that long term neuronal IGF-1R signaling might be harmful. Taken together, the data from humans and different model organisms indicate a role of IR/IGF-1R signaling in Abeta metabolism, and clearance as well as longevity. Since more studies are needed to elucidate the impact of insulin and/or IGF-1 treatment in AD, the time to propose these hormones as a potential treatment option for AD has not come yet.

Comparison of long-acting testosterone undecanoate formulation versus testosterone enanthate on sexual function and mood in hypogonadal men.

OBJECTIVE: To compare the effects of two treatment modalities of testosterone on sexual functioning and mood. Design Forty men were randomized to receive either parenteral testosterone enanthate (TE) or long-acting parenteral testosterone undecanoate (TU) over a period of 30 weeks. Thereafter, 20 men who had received TU and 16 men who had received TE continued with TU and completed another 65 weeks to study longer-term effects of TU. METHODS: The following variables of sexual functioning were studied: sexual thoughts and fantasy, sexual interest and desire, satisfaction with sex life, number of erections and ejaculations per week, and number of spontaneous morning erections per week. Also variables related to mood were analyzed. RESULTS: Improvements in these variables were significant and were of a similar magnitude in the group treated with TU and TE for 30 weeks. Improvements were maintained at the same levels over a period of another 65 weeks when all men received TU. Effects on mood were recorded for 30 weeks, but were more difficult to establish in the study population. There were significant differences in baseline values between the two groups and scores showed wide s.d. CONCLUSIONS: Both TE and TU were effective in improving sexual functions in hypogonadal men. An advantage of TU over TE is its lower frequency of administration and its better tolerability and safety profile.

Comparison of a new long-acting testosterone undecanoate formulation vs testosterone enanthate for intramuscular androgen therapy in male hypogonadism.

OBJECTIVE: To assess the efficacy and safety of a novel long-acting im testosterone undecanoate (TU) formulation in comparison with testosterone enanthate (TE). SUBJECTS AND METHODS: An open-label, randomized, prospective clinical trial in 40 hypogonadal men (baseline serum testosterone levels <5 nmol/l), randomly assigned to 250 mg TE/3 weeks (no.=20) or 1000 mg TU im every 6 to 9 weeks for 30 weeks (no.=20). Subsequently, 32/40 men continued the study for another 114 weeks, now receiving TU 1000 mg/12 weeks. RESULTS: TU and TE produced no statistically significant improvements in grip strength over the first 30 weeks, which only occurred after approximately 90 weeks when all subjects received TU. There were no changes in body mass index with TU and TE, neither in the follow-up period when all patients received TU. But ratios of waist to hip circumferences declined in the longer term. Total serum cholesterol, LDL cholesterol, and triglycerides declined over the first 30 weeks, while plasma HDL also declined. Plasma LDL decreased further under long-term TU therapy, while HDL then increased. Hemoglobin and hematocrit values significantly increased over the first 30 weeks in both treatment groups and then no further increase was observed. Levels did not exceed the upper limit of normal. In both treatment groups, serum prostate specific antigen levels rose slightly after 30 weeks, with no further increase over the first 12 months, remaining stable within the normal range. Plasma T before the following TU injection was above the lower limit of reference values. Four injections per year are adequate. CONCLUSIONS: Administration of TU every 12 weeks is at least as safe and efficacious for treatment of hypogonadal men as TE, with a substantially lower frequency of administration. Follow-up over 114 weeks, when all subjects received TU, showed an excellent profile of efficacy and safety.

A four-year efficacy and safety study of the long-acting parenteral testosterone undecanoate.

INTRODUCTION: This is a four-year follow-up of 25 men who received parenteral testosterone undecanoate (TU), 1000 mg every 12 weeks for at least four years. This study was a continuation of a 30-week study wherein the effects of TU had been compared to those of parenteral testosterone enanthate. METHODS & RESULTS: Plasma testosterone (T) trough values of the injection interval of 12 weeks): median 11.9 - 15.9 nmol/L (N 10.0-30.0). E2 and SHBG were stable. Body weight, BMI, waist-to-hip ratio remained stable. Total cholesterol, and triglycerides were unchanged but plasma LDL declined while HDL, after an initial reduction over the first 30 weeks, had increased significantly after three years. Leptin levels, bone mineral density, blood pressure, liver function tests, haemoglobin and haematocrit levels remained stable without values above the upper limit of normal. Over the first 12 months of the study there was an increase in prostate volume from 19.7 +/- 8.8 mL to 22.0 +/- 8.4 mL (p < 0.05) but thereafter volumes remained stable, paralleled by an increase in PSA from 0.67 +/- 0.38 microg/dL to 0.75 +/- 0.35 microg/dL (p < 0.05) without any further changes after 12 months. CONCLUSION: TU appears to be a stable and safe treatment modality of hypogonadal men.

Septo-optic dysplasia and growth hormone deficiency: accelerated pubertal maturation during GH therapy.

We report four patients (three male, one female) with septo-optic dysplasia and growth hormone deficiency. All had GH therapy for a period of four to eight years until reaching final height. In all four cases bone maturation during puberty was accelerated (1.4 to 1.9 "years"/year), resulting in a final height which was clearly below the predicted height. The progress of pubertal stages was very short in all patients. In three patients TSH and prolactin release after TRH stimulation were increased. These data support a hypothalamic original of the endocrine disorder. Insufficient GH release, even after repeated GHRH stimulation, is in contrast to this assumption. In one case there was a late manifestation of neurohormonal diabetes insipidus, which indicates the possibility of later disease progression. MR imaging of the brain demonstrated variable malformation of the septum pellucidum, chiasma and nervus opticus or the pituitary gland, respectively.

[Warfarin embryopathy in maternal coumarin therapy for protein S deficiency]. / Warfarin-Embryopathie bei mütterlicher Coumarin-Therapie wegen Protein-S-Mangels.

A case of Warfarin embryopathia is shown. The newborn, whose mother had been treated with Marcoumar (Phenprocoumon 3 mg/day) during the whole pregnancy because of a hereditary protein-S-deficiency showed the typical symptom of nasal hypoplasia. Coumarol derivates pass the placental membrane and are known as teratogenic. Recent retrospective and prospective studies show that the risk of fetal or embryonal teratogenic injury is about 25-30% if Coumarol derivates are given through the 6th to the 9th week of pregnancy. It is possible to nearly avoid those injuries when Heparin is used for anticoagulant therapy in this period and Coumarol itself is used in the lowest possible therapeutic dose.