Adipocyte NCoR knockout decreases PPARγ phosphorylation and enhances PPARγ activity and insulin sensitivity.

Insulin resistance, tissue inflammation, and adipose tissue dysfunction are features of obesity and Type 2 diabetes. We generated adipocyte-specific Nuclear Receptor Corepressor (NCoR) knockout (AKO) mice to investigate the function of NCoR in adipocyte biology, glucose and insulin homeostasis. Despite increased obesity, glucose tolerance was improved in AKO mice, and clamp studies demonstrated enhanced insulin sensitivity in liver, muscle, and fat. Adipose tissue macrophage infiltration and inflammation were also decreased. PPARγ response genes were upregulated in adipose tissue from AKO mice and CDK5-mediated PPARγ ser-273 phosphorylation was reduced, creating a constitutively active PPARγ state. This identifies NCoR as an adaptor protein that enhances the ability of CDK5 to associate with and phosphorylate PPARγ. The dominant function of adipocyte NCoR is to transrepress PPARγ and promote PPARγ ser-273 phosphorylation, such that NCoR deletion leads to adipogenesis, reduced inflammation, and enhanced systemic insulin sensitivity, phenocopying the TZD-treated state.

GPR120 is an omega-3 fatty acid receptor mediating potent anti-inflammatory and insulin-sensitizing effects.

Omega-3 fatty acids (omega-3 FAs), DHA and EPA, exert anti-inflammatory effects, but the mechanisms are poorly understood. Here, we show that the G protein-coupled receptor 120 (GPR120) functions as an omega-3 FA receptor/sensor. Stimulation of GPR120 with omega-3 FAs or a chemical agonist causes broad anti-inflammatory effects in monocytic RAW 264.7 cells and in primary intraperitoneal macrophages. All of these effects are abrogated by GPR120 knockdown. Since chronic macrophage-mediated tissue inflammation is a key mechanism for insulin resistance in obesity, we fed obese WT and GPR120 knockout mice a high-fat diet with or without omega-3 FA supplementation. The omega-3 FA treatment inhibited inflammation and enhanced systemic insulin sensitivity in WT mice, but was without effect in GPR120 knockout mice. In conclusion, GPR120 is a functional omega-3 FA receptor/sensor and mediates potent insulin sensitizing and antidiabetic effects in vivo by repressing macrophage-induced tissue inflammation.

Opposite impact of Methylene tetrahydrofolate reductase C677T and Methylene tetrahydrofolate reductase A1298C gene polymorphisms on systemic inflammation.

BACKGROUND: Methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms have been found to be related with many diseases. Systemic inflammation is now considered as a major predisposition factor for diseases including diabetes mellitus (DM), coronary arterial disease (CAD), stroke, and cancer. This study aimed to investigate whether systemic inflammation is a possible underlying pathogenesis for MTHFR gene polymorphism-related disease. METHODS: A total of 292 patients were enrolled, and single nucleotide polymorphisms for MTHFR C667T and A1298C were genotyped. Systemic inflammation markers, neutrophil-to-lymphocyte ratio (NLR), and platelet-to-lymphocyte ratio (PLR) were collected. RESULTS: In our study population, MTHFR 677 variants had significant higher NLR level than MTHFR 677 wild type (3.77 ± 0.26 vs 3.06 ± 0.18, P = .028). Logistic regression analysis showed that MTHFR 677 variants were significantly associated with increased NLR level. MTHFR 1298 variants showed the opposite effects which tended to have lower level of NLR (3.21 ± 0.16 vs 3.79 ± 0.34, P = .087) and PLR (137.0 ± 4.8 vs 157.7 ± 9.4, P = .052) than MTHFR 1298 wild type. General linear model showed that there was no statistically significant interaction between MTHFR C667T and A1298C gene polymorphism on NLR or PLR. CONCLUSIONS: This study indicates that MTHFR C677T and MTHFR A1298C gene polymorphisms have opposite effect on systemic inflammation, and systemic inflammation may contribute to the pathogenesis for diseases associated with MTHFR C667T gene polymorphism.

Linkage disequilibrium between the CYP2C19*2,*17 and CYP2C9*1 alleles and impact of VKORC1, CYP2C9, CYP2C19 gene polymorphisms and gene-gene interactions on warfarin therapy.

Warfarin therapy is complicated by its large inter-individual and intra-individual variability. Both genetic and non-genetic factors can affect warfarin therapy. This study aims to investigate the allele distribution of VKORC1, CYP2C9 and CYP2C19, contribution of different allele variants and possible gene-gene interaction on warfarin therapy. Four hundreds and ninety-two patients were enrolled and single nucleotide polymorphisms for vitamin K epoxide reductase complex subunit 1 (VKORC1), cytochrome P450 CYP2C9 and cytochrome P450 CYP2C19 were genotyped. CYP2C9*1 allele is in complete linkage disequilibrium with CYP2C19*2 and CYP2C19*17 (D' = 1) in our study population. Patient with VKORC1-1639 G > A, CYP2C9*2 and CYP2C9*3 genetic variants need significant lower warfarin dose than patient with wild type allele of VKORC1 1639 G or CYP2C9*1. There is no significant differences between CYP2C19 allele variants for warfarin stable dose and INR > 5 event. Because of the complete linkage disequilibrium between CYP2C19*2,*17 and CYP2C9*1, patient with CYP2C19 *2/*2, *2/*17 and *17/*17 genotypes tend to have higher warfarin dose than patient with CYP2C19*1/*1 genotype. Stepwise regression analysis showed that VKORC1, CYP2C9, body mass index (BMI), age and gender were included as a factor significantly contributing to warfarin dose, whereas CYP2C19 did not contribute to warfarin dose. No statistically significant interaction between CYP2C9 and VKORC1 on warfarin dose and INR > 5 event was detected in univariate general linear model analysis. Our study suggests that polymorphic variants of VKORC1 and CYP2C9 affect warfarin dose independently, whereas CYP2C19 did not contribute to warfarin therapy.

FoxO1 regulates Tlr4 inflammatory pathway signalling in macrophages.

The macrophage-mediated inflammatory response is a key etiologic component of obesity-related tissue inflammation and insulin resistance. The transcriptional factor FoxO1 is a key regulator of cell metabolism, cell cycle and cell death. Its activity is tightly regulated by the phosphoinositide-3-kinase-AKT (PI3K-Akt) pathway, which leads to phosphorylation, cytoplasmic retention and inactivation of FoxO1. Here, we show that FoxO1 promotes inflammation by enhancing Tlr4-mediated signalling in mature macrophages. By means of chromatin immunoprecipitation (ChIP) combined with massively parallel sequencing (ChIP-Seq), we show that FoxO1 binds to multiple enhancer-like elements within the Tlr4 gene itself, as well as to sites in a number of Tlr4 signalling pathway genes. While FoxO1 potentiates Tlr4 signalling, activation of the latter induces AKT and subsequently inactivates FoxO1, establishing a self-limiting mechanism of inflammation. Given the central role of macrophage Tlr4 in transducing extrinsic proinflammatory signals, the novel functions for FoxO1 in macrophages as a transcriptional regulator of the Tlr4 gene and its inflammatory pathway, highlights FoxO1 as a key molecular adaptor integrating inflammatory responses in the context of obesity and insulin resistance.

Zoledronic acid for hip fracture during initial hospitalization.

Inpatient zoledronic acid (IP-ZA) administered during the initial fracture hospitalization significantly improves the osteoporosis treatment rate. Clinical outcomes of IP-ZA after hip fracture remain uncertain. Here we report a cohort study that emulated a randomized controlled trial using real-world data and evaluated the risk of all-cause-mortality and radiologically confirmed subsequent new fractures among patients hospitalized for a hip fracture who had received IP-ZA as compared with propensity-matched controls. A total of 654 patients who had received IP-ZA and 6877 controls (for whom anti-osteoporosis treatment was indicated but no IP-ZA started during index hospitalization) were included in the study. The primary cohort comprised 652 IP-ZA patients (IP-ZA group) and 1926 matched controls (untreated group), with 71.7% female 92.1% White participants, with a mean age of 80.9 years. Cumulative all-cause mortality over the 24-month follow-up for the IP-ZA group was 12.3% and 20.7% for the untreated group (hazard ratio [HR], 0.62; 95% CI, 0.49-0.78, p < .001). A total of 585 (89.7%) patients in IP-ZA group received only a single dose of ZA during the 24 months, and the death rate of this single dose group was 13.3%, which was significantly lower than that of the untreated group (HR, 0.70; 95% CI, 0.55-0.89, p = .003). Rates of radiologically confirmed cumulative subsequent new vertebral fractures were 2.0% in the IP-ZA group and 5.4% in the untreated group (HR, 0.40; 95% CI, 0.22-0.71, p = .001). A similarly lower rate of new vertebral fractures was seen in the single dose subgroup (1.9% vs 5.4%; HR, 0.44; 95% 0.24-0.82, p = .008). IP-ZA, administered during the initial hospitalization for hip fracture, was associated with lower all-cause-mortality and risk of radiologically confirmed subsequent new vertebral fractures, and thus offers a mechanism to narrow the treatment gap in patients having sustained a hip fragility fracture.

Hip fracture is a serious complication of osteoporosis affecting approximately 300 000 Americans per year and is associated with a 20%-30% 1-year mortality rate. Most patients with hip fracture are elderly (average age, 80-81 years), with multiple underlying medical conditions and are often unable to timely attend post-hospitalization outpatient follow-up to initiate anti-osteoporosis treatment. As a result, only ~10% of post­hip fracture patients receive treatment for underlying osteoporosis. We have previously reported that zoledronic acid (ZA) administered during initial fracture hospitalization (IP-ZA) is safe and can effectively improve the osteoporosis treatment rate to 70%. The present study analyzed the clinical outcomes of 652 patients who had sustained hip fractures and were treated with IP-ZA and 1926 matched controls and revealed significantly reduced rates of all-cause mortality and vertebral compression fracture (VCF) during a 2-year follow-up period. Of note, nearly 90% of the treated patients received only a single dose of ZA (namely, IP-ZA), suggesting that, for most patients, the only opportunity to receive anti-osteoporosis treatment was during the index fracture hospitalization. Importantly, reduced mortality and VCF rates were readily seen in this single-dose group of patients. Our data suggest that IP-ZA is beneficial for osteoporotic hip fracture.

A Fracture Liaison Service to Address Vitamin D Deficiency for Patients Hospitalized for Osteoporotic Fracture.

Context: Addressing vitamin D deficiency (VDD) is important for fracture secondary prevention. Objectives: To explore the function of a fracture liaison service (FLS) to address VDD. Design Setting and Patients: An observational study of patients admitted to the Massachusetts General Hospital with fractures between January 1, 2016, and October 31, 2023, cared for by the FLS. Intervention: Ergocalciferol 50 000 international units (50ku-D2) oral daily for 3 to 7 days. Main Outcomes Measures: VDD prevalence. Efficacy of inpatient daily 50ku-D2 in raising serum 25-hydroxyvitamin D (25OHD) levels. Results: Of the 2951 consecutive patients, 724 (24.53%) had VDD (defined by 25OHD ≤ 19 ng/mL). Men (252/897, or 28.09%) were more likely than women (472/2054, or 22.98%) to have VDD (P = .003). VDD was seen in 41.79% (117/280), 24.41% (332/1360), and 20.98% (275/1311) of patients of aged ≤59, 60 to 79, and ≥80 years, respectively (P < .00001). Of the 1303 patients with hip fractures, 327 (25.09%) had VDD, which was associated with a longer length of stay (8.37 ± 7.35 vs 7.23 ± 4.78 days, P = .009) and higher trend of 30-day-readmission rate (13.63% vs 18.35%, P = .037). In a cohort of 32 patients with complete data, each dose of 50ku-D2 increased serum 25OHD by 3.62 ± 2.35 ng/mL without affecting serum calcium or creatinine levels. Conclusion: VDD was seen in nearly 25% of Massachusetts General Hospital FLS patients and more prevalent in male and younger patients. VDD was associated with longer length of stay and higher 30-day-readmission risk in patients with hip fracture. Daily 50ku-D2 appeared to be a practical way to quickly replete vitamin D in the inpatient setting.

Safety of Inpatient Zoledronic Acid in the Immediate Postfracture Setting.

CONTEXT: Zoledronic acid (ZA) administered during the initial hospitalization for a fragility fracture improves the osteoporosis pharmacotherapy rate. Distinguishing the safety profile of inpatient ZA (IP-ZA) in this context is crucial if this approach is to be widely adopted. OBJECTIVE: To study the acute safety profile of IP-ZA. METHODS: An observational study of patients admitted to the Massachusetts General Hospital with fragility fractures who were eligible to receive IP-ZA. Patients were treated with or without IP-ZA. Acetaminophen, either as a single pre-ZA dose or standing multiple-doses-per-day regimen for 48 hours or longer after ZA infusion, was also administered along with protocolized vitamin D and calcium supplementation. Changes in body temperature, serum creatinine, and serum calcium were measured. RESULTS: A total of 285 consecutive patients, meeting inclusion and exclusion criteria, are included in this analysis; 204 patients received IP-ZA. IP-ZA treatment was associated with a transient mean rise of body temperature of 0.31 °C on the day following its administration. Temperatures above 38 °C were seen in 15% of patients in the IP-ZA group and 4% in the nontreated group. Standing multiple-doses-per-day but not a single pre-ZA dose of acetaminophen effectively prevented this temperature increase. IP-ZA did not affect serum creatinine levels. Mean levels of serum total calcium and albumin-corrected calcium decreased by 0.54 mg/dL and 0.40 mg/dL, respectively, at their nadirs (Day 5). No patient experienced symptomatic hypocalcemia. CONCLUSION: IP-ZA along with standing multiple-doses-per-day acetaminophen, administered to patients in the immediate postfracture period, is not associated with significant acute adverse effects.

Pancreatic beta-cell failure in obese mice with human-like CMP-Neu5Ac hydroxylase deficiency.

Type 2 diabetes is highly prevalent in human populations, particularly in obese individuals, and is characterized by progressive pancreatic ß-cell dysfunction and insulin resistance. Most mammals, including Old World primates, express two major kinds of sialic acids, N-acetylneuraminic acid (Neu5Ac) and N-glycolylneuraminic acid (Neu5Gc), typically found at the distal ends of glycoconjugate chains at the cell surface. Humans are uniquely unable to produce endogenous Neu5Gc due to an inactivating mutation in the CMP-Neu5Ac hydroxylase (CMAH) gene. The CMAH enzyme catalyzes the generation of CMP-Neu5Gc by the transfer of a single oxygen atom to the acyl group of CMP-Neu5Ac. Here, we show that mice bearing a human-like deletion of the Cmah gene exhibit fasting hyperglycemia and glucose intolerance following a high-fat diet. This phenotype is caused not by worsened insulin resistance but by compromised pancreatic ß-cell function associated with a 65% decrease in islet size and area and 50% decrease in islet number. Obese Cmah-null mice also show an ∼40% reduction in response to insulin secretagogues in vivo. These findings show that human evolution-like changes in sialic acid composition impair pancreatic ß-cell function and exacerbate glucose intolerance in mice. This may lend insight into the pathogenesis of type 2 diabetes in obese humans.

Inpatient Zoledronic Acid and Integrated Orthopedic and Fracture Liaison Services Improve Osteoporosis Treatment Rates.

CONTEXT: Fragility fractures increase risks for future fractures, morbidity, and mortality. Available pharmacotherapy for underlying osteoporosis is safe and effective but underused. OBJECTIVE: To improve pharmacotherapy rate representing secondary prevention of osteoporotic fractures. METHODS: This single-center, observational, follow-up study included patients with fragility fractures admitted to the Massachusetts General Hospital between February 2016 and December 2019. For patients admitted to the orthopedics service with fragility fracture, the Massachusetts General Hospital Fracture Liaison Service (FLS) was systematically consulted. Initial outpatient follow-up with FLS was established in conjunction with the orthopedic postoperative follow-up visit. Patients at risk for failing timely outpatient follow-up were administered zoledronic acid (ZA) during the index fracture hospitalization. The main outcome measures were percentage of patients with fragility fracture(s) started on pharmacotherapy for osteoporosis and average length of stay and 30-day readmission rate of patients treated with ZA. RESULTS: Compared with baseline (8-11%) and reference (5-20%) rates, integration of FLS to the orthopedics service, along with appropriate inpatient administration of ZA, increased the pharmacotherapy rate to 70% (412/589) among eligible patients with verified treatment status. Inpatient ZA administration neither affected the average length of stay nor 30-day readmission rate. Treatment status of 37.9% (471/1240) of the study patients remained unknown due to lack of or unknown follow-up. CONCLUSION: Integration of a FLS and orthopedics services along with inpatient ZA administration improved the osteoporosis pharmacotherapy rate among patients with fragility fracture(s) who often had obstacles for outpatient follow-up.

Exenatide, Metformin, or Both for Prediabetes in PCOS: A Randomized, Open-label, Parallel-group Controlled Study.

CONTEXT: Up to 40% of patients with polycystic ovary syndrome (PCOS) have prediabetes; an optimal pharmacotherapy regimen for diabetes prevention in PCOS is yet to be established. OBJECTIVE: To evaluate clinical efficacy of exenatide (EX), metformin (MET), or combination (COM) for prediabetes in PCOS. DESIGN: Randomized, open-label, parallel-group controlled trial. SETTING: Renji Hospital Affiliated to Shanghai Jiaotong University School of Medicine. PATIENTS: PCOS with prediabetes (fasting plasma glucose 5.6-6.9 mmol/L and/or 2 hour post glucose 7.8-11.0 mmol/L on oral glucose tolerance test [OGTT]). A total of 150 out of 183 eligible enrollees completed the study. INTERVENTION: EX (10-20µg daily), MET (1500-2000 mg daily), or COM (EX plus MET) for 12 weeks. MAIN OUTCOME MEASURES: Sustained remission rate of prediabetes (primary endpoint, a normal OGTT after 12 weeks of treatment followed by 12 weeks of washout on no drug treatment) along with anthropometric, hormonal, metabolic, and pancreatic ß-cell function parameters (secondary endpoints) and potential mechanisms were assessed. RESULTS: Impaired glucose tolerance was found the dominant prediabetes phenotype. Overall sustained prediabetes remission rate was 50.7%. Remission rate of COM group (64%, 32/50) or EX group (56%, 28/50) was significantly higher than that of the MET group (32%, 16/50) (P = .003 and .027, respectively). EX was associated with superior suppression of 2-hour glucose increment in OGTT. A 2-step hyperglycemic clamp study revealed that EX had led to higher postprandial insulin secretion than MET, potentially explaining the higher remission rate. CONCLUSIONS: Compared with MET monotherapy, EX or COM achieved higher rate of remission of prediabetes among PCOS patients by improving postprandial insulin secretion.

Glucocorticoids and thiazolidinediones interfere with adipocyte-mediated macrophage chemotaxis and recruitment.

The link between intra-abdominal adiposity and type II diabetes has been known for decades, and adipose tissue macrophage (ATM)-associated inflammation has recently been linked to insulin resistance. However, the mechanisms associated with ATM recruitment remain ill defined. Herein, we describe in vitro chemotaxis studies, in which adipocyte conditioned medium was used to stimulate macrophage migration. We demonstrate that tumor necrosis factor alpha and free fatty acids, key inflammatory stimuli involved in obesity-associated autocrine/paracrine inflammatory signaling, stimulate adipocyte expression and secretion of macrophage chemoattractants. Pharmacological studies showed that peroxisome proliferator-activated receptor gamma agonists and glucocorticoids potently inhibit adipocyte- induced recruitment of macrophages. This latter effect was mediated by the glucocorticoid receptor, which led to decreased chemokine secretion and expression. In vivo results were quite comparable; treatment of high fat diet-fed mice with dexamethasone prevented ATM accumulation in epididymal fat. This decrease in ATM was most pronounced for the proinflammatory F4/80(+), CD11b(+), CD11c(+) M-1-like ATM subset. Overall, our results elucidate a beneficial function of peroxisome proliferator-activated receptor gamma activation and glucocorticoid receptor/glucocorticoids in adipose tissue and indicate that pharmacologic prevention of ATM accumulation could be beneficial.

Complete Resolution of Sellar Metastasis in a Patient With NSCLC Treated With Osimertinib.

Non-small cell lung cancer with pituitary metastasis (NSCLC-PM) is a devastating disease; however, treatment is being revolutionized by a novel therapy targeting highly specific tumor signals, such as the mutation of epidermal growth factor receptors (EGFRs). Long-term management of hormonal defects in this population has become a unique neuroendocrine clinical challenge. We report the case of a 73-year-old female nonsmoker who was diagnosed with stage IV non-small cell lung cancer. The initial staging evaluation revealed a 7 × 11 × 21-mm sellar lesion abutting the optic chiasm and causing clinical hypopituitarism. The patient received three cycles of chemotherapy with carboplatin and pemetrexed, which was discontinued because of major cumulative side effects of myelosuppression and kidney disease. Eight months later, scans demonstrated evidence of disease progression. A repeated lung nodule biopsy revealed an EGFR exon 19 deletion mutation. EGFR-targeted therapy with osimertinib 80 mg daily was initiated. A complete resolution of the pituitary lesion was evident on a follow-up pituitary MRI 5 weeks later and was sustained 1 year after. However, the panhypopituitarism persisted. This is an illustrative case of NSCLC-PM with EGFR exon 19 deletion mutation, wherein osimertinib, a third-generation EGFR‒tyrosine kinase inhibitor, eradicated the sellar metastasis and prevented the need for radiotherapy. However, the neuroendocrine deficits persisted despite anatomic improvement.

Low Plasma Oxytocin Levels and Increased Psychopathology in Hypopituitary Men With Diabetes Insipidus.

CONTEXT: Oxytocin (OT) and vasopressin share anatomical pathways of synthesis and secretion, and patients with central diabetes insipidus (CDI) presumably are at risk for OT deficiency. However, an OT-deficient state in hypopituitary patients has not been established. OBJECTIVES: We hypothesized that men with CDI compared to patients with similar anterior pituitary deficiencies (APD) but no CDI and healthy controls (HC) of similar age and body mass index, would have lower plasma OT levels, associated with increased psychopathology. DESIGN: Cross-sectional. SETTING: Clinical research center. PARTICIPANTS: Sixty-two men (20 CDI, 20 APD, 22 HC), age 18 to 60 years. INTERVENTIONS: Frequent sampling of blood every 5 minutes for OT over 1 hour and validated questionnaires to assess psychopathology. MAIN OUTCOMES: Pooled plasma OT levels; depressive, anxiety, and alexithymia symptoms; and quality of life. RESULTS: The mean 1-hour pool of fasting OT levels was lower in CDI compared with APD and HC (P = 0.02 and P = 0.009, respectively), with no differences between APD and HC (P = 0.78). Symptoms of depression, anxiety, and alexithymia were more pronounced in CDI than in HC (P = 0.001, P = 0.004, and P = 0.02, respectively). Although CDI and APD reported worse physical health compared with HC (P = 0.001 and P = 0.005) with no differences between APD and CDI, only CDI reported worse mental health compared with HC (P = 0.009). CONCLUSIONS: We have demonstrated low plasma OT levels and increased psychopathology in hypopituitary men with CDI, suggestive of a possible OT-deficient state. Larger studies of both sexes are required to confirm these findings and clinically characterize hypopituitary patients with OT deficiency.

Functional potentiation of leptin-signal transducer and activator of transcription 3 signaling by the androgen receptor.

Hypogonadism is associated with increased fat mass and dysregulation of metabolic homeostasis in men. Our previous study revealed that androgen receptor (AR)-null male mice (ARL-/Y) develop late-onset obesity and are leptin-resistant. The present study evaluated how hypothalamic AR contributes to central leptin-signal transducer and activator of transcription 3 (STAT3) signaling. We evaluated leptin action in wild-type and ARL-/Y mice, the anatomic co-relationship between AR and leptin signaling in the hypothalamus, and the effects of AR on leptin-mediated STAT3 transactivation and nuclear translocation. AR deletion in male mice results in a weaker leptin-induced suppression of food intake and body weight drop even before the onset of overt obesity. In wild-type male but not female mice, AR was highly expressed in various hypothalamic nuclei that also expressed the long-form leptin receptor (OBRB) and co-resided with OBRB directly in the arcuate neurons. In vitro, AR significantly enhanced STAT3-mediated transcription of leptin target genes including POMC and SOCS3. This effect relied on the AR N-terminal activation function-1 (AF-1) domain and was specific to AR in that none of the other sex steroid hormone receptors tested showed similar effects. AR enhanced the low concentrations of leptin-induced STAT3 nuclear translocation in vitro, and ARL-/Y mice receiving leptin had impaired STAT3 nuclear localization in the arcuate neurons. These findings indicate that AR in the hypothalamus functions as a regulator of central leptin-OBRB-STAT3 signaling and has a physiological role in energy homeostasis and metabolic regulation in male mice.

Androgens and metabolic syndrome: lessons from androgen receptor knock out (ARKO) mice.

Testosterone (T) is an important factor for determining body composition in males. Abdominal obesity is inversely correlated with serum T levels in men, leading to greater mortality. Pathologically hypogonadal men also have a significantly higher fat mass, which is reversed by T administration. However, the mechanism for such anti-obesity effect of androgen has not been well clarified. Androgen receptor (AR) null male mice revealed late-onset obesity. Male ARKO mice were euphagic compared to the wild-type male controls, but also less dynamic and less oxygen consuming. Transcript profiling indicated that male ARKO mice had lower transcripts for the thermogenetic uncoupling protein 1 (UCP1). We also found enhanced secretion of adiponectin, which is insulin-sensitizing, from adipose tissue in comparison to wild type, which might partly explain why the overall insulin sensitivity of male ARKO mice remained almost intact despite their apparent obesity. In addition, decreased lipolysis rather than increased lipid synthesis was observed, which might also account for the increased adiposity in male ARKO mice. The results revealed that AR plays important roles in male metabolism by affecting the energy balance, and is negative to both adiposity and insulin sensitivity.

Estimating HbA1c from timed Self-Monitored Blood Glucose values.

AIMS: To analyze mathematical relationships between timed Self-Monitored Blood Glucose (SMBG) and HbA1c, and to identify the SMBG values that correlate most strongly with HbA1c. METHODS: We utilized the average premeal (Pre) and 90-min postmeal (Post) SMBG results from 547 A1c-Derived Average Glucose (ADAG) study participants (285 type 1, 178 type 2 and 84 non-diabetic) to analyze the mathematical relationships with HbA1c levels. Specific times of daily SMBG that best correlate with HbA1c were identified. RESULTS: Linear regression analyses showed the following correlations for Pre and Post, Pre only and Post only, respectively: HbA1c = 2.488 + 0.018 × Premg/dl + 0.012 × Postmg/dl, R2 = 0.741, P < 0.0001; HbA1c = 2.887 + 0.029 × Premg/dl, R2 = 0.695, P < 0.0001; and HbA1c = 2.815 + 0.025 × Postmg/dl, R2 = 0.657, P < 0.0001. Among patients with type 2 diabetes mellitus (DM), of the 6 individual timepoints, pre-dinner SMBG had the strongest correlation with HbA1c (R2 = 0.577). This was followed by pre-breakfast (R2 = 0.562). Examining combinations of timepoints revealed that pre-breakfast + pre-dinner (R2 = 0.666) performed similarly to the full 6-timepoints (pre-meals + post-meals, R2 = 0.712). CONCLUSIONS: We have established mathematical relationships between HbA1c and timed SMBG values and identified pre-dinner and pre-breakfast as the two SMBG timepoints that best correlate with HbA1c in patients with type 2 DM.

Atrazine-induced aromatase expression is SF-1 dependent: implications for endocrine disruption in wildlife and reproductive cancers in humans.

BACKGROUND: Atrazine is a potent endocrine disruptor that increases aromatase expression in some human cancer cell lines. The mechanism involves the inhibition of phosphodiesterase and subsequent elevation of cAMP. METHODS: We compared steroidogenic factor 1 (SF-1) expression in atrazine responsive and non-responsive cell lines and transfected SF-1 into nonresponsive cell lines to assess SF-1's role in atrazine-induced aromatase. We used a luciferase reporter driven by the SF-1-dependent aromatase promoter (ArPII) to examine activation of this promoter by atrazine and the related simazine. We mutated the SF-1 binding site to confirm the role of SF-1. We also examined effects of 55 other chemicals. Finally, we examined the ability of atrazine and simazine to bind to SF-1 and enhance SF-1 binding to ArPII. RESULTS: Atrazine-responsive adrenal carcinoma cells (H295R) expressed 54 times more SF-1 than nonresponsive ovarian granulosa KGN cells. Exogenous SF-1 conveyed atrazine-responsiveness to otherwise nonresponsive KGN and NIH/3T3 cells. Atrazine induced binding of SF-1 to chromatin and mutation of the SF-1 binding site in ArPII eliminated SF-1 binding and atrazine-responsiveness in H295R cells. Out of 55 chemicals examined, only atrazine, simazine, and benzopyrene induced luciferase via ArPII. Atrazine bound directly to SF-1, showing that atrazine is a ligand for this "orphan" receptor. CONCLUSION: The current findings are consistent with atrazine's endocrine-disrupting effects in fish, amphibians, and reptiles; the induction of mammary and prostate cancer in laboratory rodents; and correlations between atrazine and similar reproductive cancers in humans. This study highlights the importance of atrazine as a risk factor in endocrine disruption in wildlife and reproductive cancers in laboratory rodents and humans.