Copper-catalysed selective hydroamination reactions of alkynes

The development of selective reactions that utilize easily available and abundant precursors for the efficient synthesis of amines is a long-standing goal of chemical research. Despite the centrality of amines in a number of important research areas, including medicinal chemistry, total synthesis and materials science, a general, selective and step-efficient synthesis of amines is still needed. Here, we describe a set of mild catalytic conditions utilizing a single copper-based catalyst that enables the direct preparation of three distinct and important amine classes (enamines, α-chiral branched alkylamines and linear alkylamines) from readily available alkyne starting materials with high levels of chemo-, regio- and stereoselectivity. This methodology was applied to the asymmetric synthesis of ​rivastigmine and the formal synthesis of several other pharmaceutical agents, including ​duloxetine, ​atomoxetine, ​fluoxetine and ​tolterodine.National Institutes of Health (U.S.) (GM58160

Metformin decreases the adipokine vaspin in overweight women with polycystic ovary syndrome concomitant with improvement in insulin sensitivity and a decrease in insulin resistance

OBJECTIVE-Polycystic ovary syndrome (PCOS) is associated with insulin resistance and obesity. Vaspin (visceral adipose tissue-derived serine protease inhibitor) levels increase with hyperinsulinemia and obesity. Currently, no data exists on vaspin in PCOS women. We therefore assessed mRNA and protein levels of vaspin, including circulating vaspin, from subcutaneous and omental adipose tissue of PCOS women and matched control subjects. Ex vivo regulation of adipose tissue vaspin and the effects of metformin treatment on circulating vaspin levels in PCOS subjects were also studied. RESEARCH DESIGN AND. METHODS-Real-time RT-PCR and Western blotting were used to assess mRNA and protein expression of vaspin. Serum vaspin was quantified by enzyme-linked immunosorbent assay. The effects of D-glucose, insulin, and gonadal and adrenal steroids on adipose tissue vaspin were analyzed ex vivo. RESULTS-There were significantly higher levels of circulating vaspin (P < 0.05), vaspin mRNA (P < 0.05), and protein (P < 0.05) in omental adipose tissue of PCOS women. Interestingly, in omental adipose tissue explants, glucose significantly increased vaspin protein levels and secretion into conditioned media (P < 0.001). Also, after 6 months of metformin treatment, there was a significant decrease in serum vaspin levels in PCOS women (P < 0.001). Furthermore, multivariate regression analysis revealed that following metformin therapy, changes in circulating glucose levels were predictive of changes in serum vaspin levels (P = 0.014). CONCLUSIONS-We report, for the first time, elevated serum and omental adipose tissue levels of vaspin in overweight PCOS women and ex vivo regulation of vaspin, predominantly by glucose. More importantly, metformin treatment decreases serum vaspin levels, a novel observation

Asymmetrical dimethylarginine, inflammatory and metabolic parameters in women with polycystic ovary syndrome before and after metformin treatment

Context: Insulin resistance plays a significant role in the pathogenesis of the polycystic ovary syndrome (PCOS) and represents a link to the unfavorable cardiovascular risk profile frequently found in affected patients. The endogenous nitric oxide synthase inhibitor asymmetrical dimethyl-L-arginine (ADMA) is associated with atherosclerosis and represents an independent marker for cardiovascular morbidity and mortality. Objective: We investigated ADMA levels among other cardiovascular, metabolic, and hormonal parameters in women with PCOS and the effects of metformin treatment on these parameters. Design: A cross-sectional study and clinical trial were performed. Patients and Participants: Women with PCOS (n = 83) compared with a control group of healthy women (n = 39) were studied. Interventions: In a subgroup of patients with PCOS (n = 21), the effect of metformin was assessed after 6 months of treatment. Main Outcome Measures: ADMA, intima media thickness (IMT), metabolic and hormonal parameters, and markers of inflammation were investigated. Results: ADMA levels were significantly higher in the PCOS group compared with controls (0.57 ± 0.15 vs. 0.50 ± 0.11; P = 0.024). Androgens, C-reactive protein, fasting C-peptide, area under the curve (AUC) insulin, AUC glucose, homeostatic assessment of insulin resistance, fasting insulin, glycosylated hemoglobin, cholesterol, low-density lipoprotein cholesterol, triglycerides, and IMT were significantly higher in women with PCOS compared with controls. In PCOS patients ADMA was found to be positively correlated with body mass index (BMI), waist to hip ratio, parameters of insulin sensitivity, hyperandrogenemia (free testosterone, free androgen index), and IMT. Treatment with metformin ameliorated hyperandrogenemia and decreased ADMA levels (0.53 ± 0.06 vs. 0.46 ± 0.09, P = 0.013). Decrease in ADMA levels subsequent to metformin treatment did not correlate with change in BMI or metabolic parameters. Conclusions: ADMA amd parameters of insulin sensitivity are elevated in women with PCOS and the degree of insulin resistance confers the greatest influence on ADMA level. Metformin treatment led to improvement of hormonal and metabolic parameters and decreased ADMA levels possibly independent of BMI and metabolic changes

Insulin and metformin regulate circulating and adipose tissue chemerin

OBJECTIVE-To assess chemerin levels and regulation in sera and adipose tissue from women with polycystic ovary syndrome (PCOS) and matched control subjects. RESEARCH DESIGN AND METHODS-Real-time RT-PCR and Western blotting were used to assess mRNA and protein expression of chemerin. Serum chemerin was measured by enzyme-linked immunosorbent assay. We investigated the in vivo effects of insulin on serum chemerin levels via a prolonged insulin-glucose infusion. Ex vivo effects of insulin, metformin, and steroid hormones on adipose tissue chemerin protein production and secretion into conditioned media were assessed by Western blotting and enzyme-linked immunosorbent assay, respectively. RESULTS-Serum chemerin, subcutaneous, and omental adipose tissue chemerin were significantly higher in women with PCOS (n = 14; P < 0.05, P < 0.01). Hyperinsulinemic induction in human subjects significantly increased serum chemerin levels (n = 6; P < 0.05, P < 0.01). In adipose tissue explants, insulin significantly increased (n = 6; P < 0.05, P < 0.01) whereas metformin significantly decreased (n = 6; P < 0.05, P < 0.01) chemerin protein production and secretion into conditioned media, respectively. After 6 months of metformin treatment, there was a significant decrease in serum chemerin (n = 21; P < 0.01). Importantly, changes in homeostasis model assessment-insulin resistance were predictive of changes in serum chemerin (P = 0.046). CONCLUSIONS-Serum and adipose tissue chemerin levels are increased in women with PCOS and are upregulated by insulin. Metformin treatment decreases serum chemerin in these women. Diabetes 58:1971-1977, 200

Symmetric dimethylarginine (SDMA) is raised in women with polycystic ovary syndrome: a pilot study

Polycystic ovary syndrome (PCOS) is associated with endothelial dysfunction, which may be caused by elevated levels of asymmetric dimethylarginine (ADMA). ADMA reduces nitric oxide production in diabetes mellitus, hypertension and renal failure. Symmetric dimethylarginine (SDMA) is a stereoisomer produced alongside ADMA, and has recently been described as a risk factor for cardiovascular events. In this cross-sectional study based in a teaching hospital, 16 women with PCOS were recruited alongside 15 healthy controls, and fasting venous blood samples were obtained. Renal function was measured, and ADMA and SDMA were analysed using a high-performance liquid chromatography method. After controlling for BMI, mean ADMA and SDMA levels in women with PCOS were higher than in controls (p = 0.036 and p = 0.030, respectively). Renal function was not different between the two groups (p = 0.152). Women with PCOS have raised levels of SDMA, a molecule implicated in endothelial dysfunction and long-term cardiovascular risk

Cardiovascular disease markers in women with polycystic ovary syndrome with emphasis on asymmetric dimethylarginine and homocysteine

<b>Background and Objectives :</b>Polycystic ovary syndrome (PCOS) is a disorder characterized by hyperandrogenism, ovulatory dysfunction, and polycystic ovaries. Little is known about cardiovascular risk factors in patients with PCOS. We investigated plasma markers of cardiovascular disease in Saudi women with PCOS, with an emphasis on asymmetric dimethylarginine (ADMA) and total homocysteine (tHcy). <b> Patients and Methods : </b>Fifty Saudi women with PCOS diagnosed by the Rotterdam criteria (mean age [SD] 30.2 [3.0] years) and 40 controls without PCOS (mean age 29.3 [2.5] years) had measyrements taken of clinical, metabolic, and hormonal parameters, including plasma ADMA, tHcy, lipoprotein (a) ([Lp(a)], and serum high sensitivity C-reactive protein (hs-CRP), nitric oxid, and fibrinogen. Insulin resistance was calculated by the homeostasis model assessment (HOMA-IR). <b> Results</b> : Women with PCOS had significantly higher fasting insulin, HOMA-IR, and luteinizing hormone (LH) levels than healthy controls (<i>P</i> &lt; .001). Lipid profile, free androgen index (FAI), ADMA, tHcy, hsCRP, and Lp(a) were significantly higher in women with PCOS compared with healthy controls (<i>P</i> &lt; .001). The women with PCOS had significantly lower nitric oxide and high-density lipoprotein cholesterol (HDL-C) levels compared with healthy controls (<i>P</i> &lt; .001). <b> Conclusion</b> : Our study revealed that Saudi women with PCOS had a significantly different levels of plasma markers of cardiovascular disease compared with normal controls. Therefore, clinicians who manage women with PCOS should follow up on these markers to reduce the risk of cardiovascular disease