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Endocrinology AND Hyperlipidemia [keywords]
- Tissue-specific insulin signaling in the regulation of metabolism and aging. [Journal Article]
- IUBMB Life 2014 Jul; 66(7):485-95.
In mammals, insulin signaling regulates glucose homeostasis and plays an essential role in metabolism, organ growth, development, fertility, and lifespan. The defects in this signaling pathway contribute to various metabolic diseases such as type 2 diabetes, polycystic ovarian disease, hypertension, hyperlipidemia, and atherosclerosis. However, reducing the insulin signaling pathway has been found to increase longevity and delay the aging-associated diseases in various animals, ranging from nematodes to mice. These seemly paradoxical findings raise an interesting question as to how modulation of the insulin signaling pathway could be an effective approach to improve metabolism and aging. In this review, we summarize current understanding on tissue-specific functions of insulin signaling in the regulation of metabolism and lifespan. We also discuss the potential benefits and limitations in modulating tissue-specific insulin signaling pathway to improve metabolism and healthspan. © 2014 IUBMB Life, 66(7):485-495, 2014.
- Elevated GH/IGF-I promotes mammary tumors in high-fat, but not low-fat, fed mice. [JOURNAL ARTICLE]
- Carcinogenesis 2014 Aug 1.
GH and/or IGF-I are thought to promote breast cancer based on reports showing circulating IGF-I levels correlate, in epidemiological studies, with breast cancer risk. Also, mouse models with developmental GH/IGF-I deficiency/resistance are less susceptible to genetic- or chemical-induced mammary tumorigenesis. However, given the metabolic properties of GH, medical strategies have been considered to raise GH to improve body composition and metabolic function in elderly and obese patients. Since hyperlipidemia, inflammation, insulin resistance and obesity increase breast cancer risk, elevating GH may serve to exacerbate cancer progression. To better understand the role GH/IGF-I plays in tumor formation, this study used unique mouse models to determine if reducing GH/IGF-I in adults protects against DMBA-induced mammary tumor development, and if moderate elevations in endogenous GH/IGF-I alter DMBA-induced tumorigenesis in mice fed a standard-chow diet or in mice with altered metabolic function due to high-fat feeding. We observed that adult-onset isolated GH deficient (AOiGHD) mice, which also have reduced IGF-I levels, were less susceptible to DMBA-treatment. Specifically, fewer AOiGHD mice developed mammary tumors compared to GH-replete controls. In contrast, chow-fed mice with elevated endogenous GH/IGF-I (HiGH mice) were not more susceptible to DMBA-treatment. However, high-fat-fed, HiGH mice showed reduced tumor latency and increased tumor incidence compared to diet-matched controls. These results further support a role of GH/IGF-I in regulating mammary tumorigenesis but suggest the ultimate consequences of GH/IGF-I on breast tumor development are dependent on the diet and/or metabolic status.
- Glucagon-like peptide 1 receptor agonist is more efficacious than insulin glargine for poorly controlled type 2 diabetes: a systematic review and meta-analysis. [JOURNAL ARTICLE]
- J Diabetes 2014 Jul 21.
To compare the reported efficacy and safety of glucagon-like peptide-l receptor agonist (GLP-1RA) and insulin glargine (IGlar) for poorly controlled type 2 diabetes.Medline, EMBASE, Cochrane Library, and clinicaltrials.gov were carried out. References and cited papers of relevant articles were also checked.Seven trials met the inclusion criteria. GLP-1RA showed equivalent or superior efficacy to IGlar for reducing haemoglobin A1c (HbA1c) , with a greater proportion of patients achieving HbAlc<7%. GLP-1RA also favoured decreased body weight, total cholesterol (TC), low-density lipoprotein (LDL), and systolic blood pressure (SBP). Serious adverse events were uncommon and not significantly different. More patients taking GLP-1RA experienced gastrointestinal complications: nausea, diarrhoea, and vomiting. Severe hypoglycaemia events were rare, and minor hypoglycaemia was less common for GLP-1RA.GLP-1RA showed greater efficacy compared to IGlar for type 2 diabetes, and it may also prove beneficial for other diabetes-associated characteristics, including obesity, hypertension, and hyperlipidaemia.
- Ovarian leydig cell hyperplasia: an unusual case of virilization in a postmenopausal woman. [Journal Article]
- Case Rep Endocrinol 2014.:762745.
Objective.To report an unusual case of ovarian Leydig cell hyperplasia resulting in virilization in a postmenopausal woman. Methods. Patient's medical history and pertinent literature were reviewed.
Results.A 64-year-old woman presented with virilization with worsening hirsutism, deepening of her voice, male musculature, and male pattern alopecia. Her pertinent past medical history included type 1 diabetes, hyperlipidemia, and hypertension. Her pertinent past surgical history included hysterectomy due to fibroids. On further work-up, her serum total testosterone was 506 ng/dL (nl range: 2-45) and free testosterone was 40 pg/mL (nl range: 0.1-6.4). After ruling out adrenal causes, the patient underwent an empiric bilateral oophorectomy that showed Leydig cell hyperplasia on pathology. Six weeks postoperatively, serum testosterone was undetectable with significant clinical improvement.
Conclusion.Postmenopausal hyperandrogenism can be the result of numerous etiologies ranging from normal physiologic changes to ovarian or rarely adrenal tumors. Our patient was found to have Leydig cell hyperplasia of her ovaries, a rarely reported cause of virilization.
- Erectile dysfunction and risk of end stage renal disease requiring dialysis: a nationwide population-based study. [Journal Article]
- PLoS One 2014; 9(7):e102055.
Previous studies have suggested that erectile dysfunction (ED) is an independent risk factor for macrovascular disease. Very few studies have evaluated the relationship between ED and risk of end stage renal disease (ESRD) requiring dialysis.A random sample of 1,000,000 individuals from Taiwan's National Health Insurance database was collected. We selected the control group by matching the subjects and controls by age, diabetes, hypertension, coronary heart disease, hyperlipidemia, area of residence, monthly income and index date. We identified 3985 patients with newly-diagnosed ED between 2000 and 2008 and compared them with a matched cohort of 23910 patients without ED. All patients were tracked from the index date to identify which patients subsequently developed a need for dialysis.The incidence rates of dialysis in the ED cohort and comparison groups were 10.85 and 9.06 per 10000 person-years, respectively. Stratified by age, the incidence rate ratio for dialysis was greater in ED patients aged <50 years (3.16, 95% CI: 1.62-6.19, p = 0.0008) but not in aged 50-64 (0.94, 95% CI: 0.52-1.69, p = 0.8397) and those aged ≧ 65 (0.69, 95% CI: 0.32-1.52, p = 0.3594). After adjustment for patient characteristics and medial comorbidities, the adjusted HR for dialysis remained greater in ED patients aged <50 years (adjusted HR: 2.08, 95% CI: 1.05-4.11, p<0.05). The log-rank test revealed that ED patients <50-years-old had significantly higher cumulative incidence rates of dialysis than those without (p = 0.0004).Patients with ED, especially younger patients, are at an increased risk for ESRD requiring dialysis later in life.
- Protection against high-fat diet-induced obesity in Helz2-deficient male mice due to enhanced expression of hepatic leptin receptor. [Journal Article, Research Support, Non-U.S. Gov't]
- Endocrinology 2014 Sep; 155(9):3459-72.
Obesity arises from impaired energy balance, which is centrally coordinated by leptin through activation of the long form of leptin receptor (Leprb). Obesity causes central leptin resistance. However, whether enhanced peripheral leptin sensitivity could overcome central leptin resistance remains obscure. A peripheral metabolic organ targeted by leptin is the liver, with low Leprb expression. We here show that mice fed a high-fat diet (HFD) and obese patients with hepatosteatosis exhibit increased expression of hepatic helicase with zinc finger 2, a transcriptional coactivator (Helz2), which functions as a transcriptional coregulator of several nuclear receptors, including peroxisome proliferator-activated receptor γ in vitro. To explore the physiological importance of Helz2, we generated Helz2-deficient mice and analyzed their metabolic phenotypes. Helz2-deficient mice showing hyperleptinemia associated with central leptin resistance were protected against HFD-induced obesity and had significantly up-regulated hepatic Leprb expression. Helz2 deficiency and adenovirus-mediated liver-specific exogenous Leprb overexpression in wild-type mice significantly stimulated hepatic AMP-activated protein kinase on HFD, whereas Helz2-deficient db/db mice lacking functional Leprb did not. Fatty acid-β oxidation was increased in Helz2-deficeint hepatocytes, and Helz2-deficient mice revealed increased oxygen consumption and decreased respiratory quotient in calorimetry analyses. The enhanced hepatic AMP-activated protein kinase energy-sensing pathway in Helz2-deficient mice ameliorated hyperlipidemia, hepatosteatosis, and insulin resistance by reducing lipogenic gene expression and stimulating lipid-burning gene expression in the liver. These findings together demonstrate that Helz2 deficiency ameliorates HFD-induced metabolic abnormalities by stimulating endogenous hepatic Leprb expression, despite central leptin resistance. Hepatic HELZ2 might be a novel target molecule for the treatment of obesity with hepatosteatosis.
- Clinical association of circulating VEGF-B levels with hyperlipidemia and target organ damage in type 2 diabetic patients. [Journal Article]
- Int J Immunopathol Pharmacol 2014 Jul-Sep; 28(2):225-36.
Vascular endothelial growth factor-B (VEGF-B is an important member of the VEGF protein family. Recent animal studies indicated that VEGF-B signaling had determinant roles in insulin resistance, lipid distribution and metabolism in type 2 diabetes. The clinical significance of VEGF-B in type 2 diabetes is still not clear. This study aimed to correlate VEGF-B levels with biochemistry characteristics and target organ damage in type 2 diabetic patients. Serum VEGF-B levels were measured using ELISA. A crosssectional control study, which included 180 type 2 diabetic patients and 62 healthy subjects, was carried out. Diabetic patients who were undergoing insulin therapy were not included. This results showed that serum VEGF-B levels did not differ between the type 2 diabetic patients and the healthy controls (169.2∓118.8 vs 163.5∓115.2 pg/mL; P=0.734). VEGF-B levels in type 2 diabetic patients were significantly associated with the levels of c-peptide, total cholesterol and triglyceride. T-test analysis showed that the associations of serum VEGF-B levels with insulin resistance, pancreatic reserve, HDL and LDL were not significant. Regression analysis showed that VEGF-B levels were significantly correlated with diabetic retinopathy and nephropathy. No significant association between VEGF-B and macro-vasculopathy was found. In conclusion, our study findings suggested that VEGF-B levels did not differ between the type 2 diabetic patients and the normal controls. High VEGF-B levels might correlate with the presence of hyperlipidemia and target organ damage in type 2 diabetic patients.
- New drug therapies for the treatment of overweight and obese patients. [Journal Article]
- Am Health Drug Benefits 2013 Sep; 6(7):423-30.
Obesity is a serious and costly disease that is growing in epidemic proportions. Obesity-related hospitalizations have nearly tripled from 1996 to 2009. If the current trend in the growth of obesity continues, the total healthcare costs attributable to obesity could reach $861 billion to $957 billion by 2030. The American Medical Association has officially recognized obesity as a disease. Obesity is a public health crisis affecting approximately more than 33% of Americans and costing the healthcare system more than $190 billion annually.To review the 2 new drugs that were recently approved by the US Food and Drug Administration (FDA) for the treatment of obesity, lorcaserin HCl (Belviq) and phentermine/topiramate (Qsymia) and their potential impact on the treatment of obese patients.Lifestyle modification is the first and mainstay treatment for obesity. Antiobesity drugs are indicated as adjuncts to a healthy, low-fat, low-calorie diet and an exercise plan. Currently, 4 drugs are approved by the FDA for the treatment of obesity, 2 of which were approved after June 2012. These 2 drugs, Belviq and Qsymia, have added new tools for the treatment of obesity. In addition to reducing body mass index, these drugs have been shown to reduce hemoglobin A1c levels in patients with diabetes and blood pressure levels in patients with hypertension, as well as to decrease lipid levels in patients with hyperlipidemia. This article reviews the drugs' mechanisms of action, evaluates landmark clinical studies leading to the FDA approval of the 2 drugs, their common side effects, and the benefits these new drugs can provide toward the management of the obesity epidemic that are different from other medications currently available.The weight loss seen in patients who are using the 2 new medications has been shown to further improve other cardiometabolic health parameters, including blood pressure, blood glucose levels, and serum lipid levels. Based on clinical trials evidence, it is likely that many obese patients could benefit from these therapies, if used appropriately.
- Prevalence of metabolic syndrome in the family members of women with polycystic ovary syndrome from North India. [Journal Article]
- Indian J Endocrinol Metab 2014 May; 18(3):364-9.
Polycystic ovary syndrome (PCOS) is the most complex and common endocrine disorder of women in reproductive years. In addition to irregular menstrual cycles, chronic anovulation and hyperandrogenism, it has many metabolic manifestations such as obesity, hyperlipidemia, hyperinsulinemia, insulin resistance, dysglycemia, increased risk of cardiovascular disease or possibly endometrial cancer. Familial clustering of PCOS in consistence with the genetic susceptibility has been described.The present study assessed the clinical, biochemical and hormonal parameters including prevalence of metabolic syndrome by two different criteria in the first- degree relatives of patients with PCOS.The average age of 37 index patients was 23 ± 3.6 years, with the mean age of menarche as 13.3 ± 1.2 years. The mean age and age of menarche in mothers (n = 22) was 48.8 ± 5.1 and 13 ± 1.3 years, respectively, whereas as it was 23.5 ± 4.7 and 13.3 ± 1.2 years in sisters (n = 22), respectively. Metabolic syndrome (MS) defined by International Diabetes Federation (IDF) criteria was present in 10 index patients, 1 brother, 4 sisters, 17 mothers and 15 fathers while as by Adult Treatment Panel III (ATP III) it was in 8 index patients, 5 sisters, 16 mothers and 11 fathers.The presence of MS or related metabolic derangements is high in the family members of women with PCOS.
- Effect of Atorvastatin on Pancreatic Beta-Cell Function and Insulin Resistance in Type 2 Diabetes Mellitus Patients: A Randomized Pilot Study. [JOURNAL ARTICLE]
- Can J Diabetes 2014 Jun 3.
Statins are commonly used for the management of dyslipidemia in type 2 diabetes mellitus patients. We hypothesized that atorvastatin could modulate the beta-cell function by altering the levels of proapoptotic and antiapoptotic lipoproteins and could also have an effect on insulin resistance. The aim of the present pilot study was to assess the effect of atorvastatin 10 mg on pancreatic beta-cell function and insulin resistance in patients with hyperlipidemia and type 2 diabetes by using the homeostasis model assessment-2 (HOMA2) index.Fifty-one type 2 diabetes patients receiving oral antidiabetes drugs, not taking statins, with baseline low-density lipoprotein cholesterol between 2.6 mmol/L and 4.1 mmol/L were included. Forty-three patients (21 in placebo group and 22 in atorvastatin group) completed the study and were taken up for final analysis. Fasting blood samples were obtained at baseline and at 12 weeks to determine levels of blood glucose, lipid profile, insulin, C-peptide and glycosylated hemoglobin (A1C).Atorvastatin nonsignificantly increased fasting serum insulin (+14.29%, p=0.18), accompanied by marginal nonsignificant increases in fasting plasma glucose and A1C. There was a decrease in HOMA2 percent beta-cell function (-2.9%, p=0.72) and increase in HOMA2 insulin resistance (+14%, p=0.16) in the atorvastatin group as compared with baseline, but the difference was not statistically significant.Atorvastatin in the dose used failed to produce significant change in pancreatic beta-cell function and insulin resistance in type 2 diabetes patients as assessed by the HOMA2 index. The possible explanations include absence of lipotoxicity at prevailing levels of dyslipidemia at baseline or inadequacy of statin dose used in the study. (Clinical Trials Registry-India: CTRI/2008/091/000099).