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Endocrinology AND Hyperlipidemia [keywords]
- BMP7 activates brown adipose tissue and reduces diet-induced obesity only at subthermoneutrality. [Journal Article, Research Support, Non-U.S. Gov't]
- PLoS One 2013; 8(9):e74083.
Brown adipose tissue (BAT) dissipates energy stored in triglycerides as heat via the uncoupling protein UCP-1 and is a promising target to combat hyperlipidemia and obesity. BAT is densely innervated by the sympathetic nervous system, which increases BAT differentiation and activity upon cold exposure. Recently, Bone Morphogenetic Protein 7 (BMP7) was identified as an inducer of BAT differentiation. We aimed to elucidate the role of sympathetic activation in the effect of BMP7 on BAT by treating mice with BMP7 at varying ambient temperature, and assessed the therapeutic potential of BMP7 in combating obesity.High-fat diet fed lean C57Bl6/J mice were treated with BMP7 via subcutaneous osmotic minipumps for 4 weeks at 21 °C or 28 °C, the latter being a thermoneutral temperature in which sympathetic activation of BAT is largely diminished. At 21 °C, BMP7 increased BAT weight, increased the expression of Ucp1, Cd36 and hormone-sensitive lipase in BAT, and increased total energy expenditure. BMP7 treatment markedly increased food intake without affecting physical activity. Despite that, BMP7 diminished white adipose tissue (WAT) mass, accompanied by increased expression of genes related to intracellular lipolysis in WAT. All these effects were blunted at 28 °C. Additionally, BMP7 resulted in extensive 'browning' of WAT, as evidenced by increased expression of BAT markers and the appearance of whole clusters of brown adipocytes via immunohistochemistry, independent of environmental temperature. Treatment of diet-induced obese C57Bl6/J mice with BMP7 led to an improved metabolic phenotype, consisting of a decreased fat mass and liver lipids as well as attenuated dyslipidemia and hyperglycemia.Together, these data show that BMP7-mediated recruitment and activation of BAT only occurs at subthermoneutral temperature, and is thus likely dependent on sympathetic activation of BAT, and that BMP7 may be a promising tool to combat obesity and associated disorders.
- Gestational hyperlipidemia and acute pancreatitis with underlying partial lipoprotein lipase deficiency and apolipoprotein E3/E2 genotype. [Journal Article]
- Korean J Intern Med 2013 Sep; 28(5):609-13.
We report the case of a patient who experienced extreme recurrent gestational hyperlipidemia. She was diagnosed with partial lipoprotein lipase (LPL) deficiency but without an associated LPL gene mutation in the presence of the apolipoprotein E3/2 genotype. This is the first reported case of extreme gestational hyperlipidemia with a partial LPL deficiency in the absence of an LPL gene mutation and the apolipoprotein E 3/2 genotype. She was managed with strict dietary control and medicated with omega-3 acid ethyl esters. A patient with extreme hyperlipidemia that is limited to the gestational period should be considered partially LPL-deficient. Extreme instances of hyperlipidemia increase the risk of acute pancreatitis, and the effect of parturition on declining plasma lipid levels can be immediate and dramatic. Therefore, decisions regarding the timing and route of delivery with extreme gestational hyperlipidemia are critical and should be made carefully.
- Prevalence of and risk factors for primary aldosteronism among patients with resistant hypertension in China. [Journal Article, Research Support, Non-U.S. Gov't]
- J Hypertens 2013 Jul; 31(7):1465-71; discussion 1471-2.
It is estimated that there are more than 16 million adults with drug-resistant hypertension in China. Nevertheless, the prevalence of and risk factors for primary aldosteronism, a highly curable condition among adults with drug-resistant hypertension, has not been fully investigated.Between January 2010 and October 2011, a multicenter epidemiologic study was conducted among 1656 patients with resistant hypertension in 11 provinces of China. Serum aldosterone and plasma renin activity were measured in every participant and aldosterone-to-renin ratio (ARR) was calculated. Patients with ARR more than 20 underwent an intravenous (i.v.) sodium infusion test, and diagnosis of primary aldosteronism was established by the presence of unsuppressed postinfusion aldosterone (>8 ng/dl). Patients with biochemically proved primary aldosteronism then underwent adrenal computed tomography (CT) scanning and adrenal vein sampling (AVS) for subtype classification.Among the 1656 patients, 494 (29.8%) had ARR greater than 20 and underwent i.v. sodium infusion. Of these 494, 118 were diagnosed as primary aldosteronism, yielding a prevalence of 7.1% (95% confidential interval 5.9-8.3%). Seventy of the 118 patients were categorized into unilateral (39) and bilateral (31) by AVS. Generalized additive regression analysis revealed that among all the factors investigated (age of hypertension onset, BMI, family history of hypertension, cigarette smoking, alcohol consumption, diabetes, serum potassium, hyperlipidemia, and creatinine), only age of hypertension onset and serum potassium were independently associated with the presence of primary aldosteronism.The prevalence of primary aldosteronism among Chinese patients with resistant hypertension is relatively lower than that reported previously for other ethnic populations. The screening for primary aldosteronism should be focused on those with early onset hypertension and/or hypokalemia.
- Carotid intima media thickness in type 2 diabetes mellitus with ischemic stroke. [Journal Article]
- Indian J Endocrinol Metab 2013 Jul; 17(4):716-22.
Diabetes mellitus is associated with high cardiovascular risk. Carotid intima media thickness (CIMT) is used commonly as a noninvasive test for the assessment of degree of atherosclerosis. The objective of this study was to find out the cut-off point for CIMT for ischemic stroke in patients with type 2 diabetes mellitus (T2DM) and to correlate CIMT with various parameters like smoking, hypertension, lipid profile and duration of T2DM.A total of 80 subjects in the age group of 30-75 years (M:F = 57:23) were selected and divided into three groups, i.e. diabetes with ischemic stroke, diabetes and healthy subjects. All the participants were subjected to B-mode ultrasonography of both common carotid arteries to determine CIMT, along with history taking, physical examination and routine laboratory investigations including included fasting and 2-hour postprandial blood sugar, blood urea, serum creatinine, lipid profile, glycated hemoglobin, and microalbuminuria.Patients with T2DM with or without ischemic stroke were found to have significantly higher prevalence of increased CIMT and a value greater than 0.8 mm was found to be associated with the occurrence of stroke. The mean carotid IMT of the group as a whole was 0.840 ± 0.2 mm. The mean carotid IMT was not significantly different between T2DM patients with or without ischemic stroke (1.06 ± 0.2 vs. 0.97 ± 0.26 mm, P = 0.08). However, the mean CIMT was significantly higher in diabetic subjects compared to healthy subjects (1.01 ± 0.28 mm vs. 0.73 ± 0.08, P = 0.006). Other parameters like higher age, smoking, hypertension, hyperlipidemia, low HDL cholesterol, the glycemic parameters and the duration of diabetes were independently and significantly related to CIMT.A high CIMT is a surrogate and reliable marker of higher risk of ischemic stroke amongst type 2 diabetic patients. Our study demonstrates the utility of carotid IMT as a simple non-invasive screening test for the assessment of atherosclerosis risk/prognosis in type 2 diabetics.
- The Anabolic Effect of Teriparatide is Undermined by Low Levels of High-Density Lipoprotein Cholesterol. [JOURNAL ARTICLE]
- Calcif Tissue Int 2013 Aug 2.
Intermittent parathyroid hormone (PTH) administration has a potent ability to increase bone mass, regardless of underlying conditions or species. A recent study using LDLR (-/-) mice showed that the anabolic effect of PTH was blunted by hyperlipidemia, whereas PTH anabolism was rescued by enhancement of high-density lipoprotein cholesterol (HDL-C) function. We conducted a retrospective longitudinal study to determine whether lipid profiles also affect the anabolic effect of intermittent PTH treatment in humans. Fifty-two patients (8 males and 44 females, ages 38-85 years) with severe osteoporosis who had been treated with teriparatide (TPTD, recombinant human PTH(1-34) for 12 months were studied at Severance Hospital, Yonsei University. C-telopeptide (CTX) and osteocalcin (OCN) were measured at 0, 3, and 12 months; and total cholesterol, triglycerides, and HDL-C were measured at baseline. Bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry at 0 and 12 months. Lumbar spine BMD increased significantly after 12 months of treatment with TPTD (10.0 ± 9.3 %, p < 0.001). Initial 3-month changes in CTX and OCN levels revealed positive correlations with the increase in lumbar BMD (r = 0.546, p = 0.001 and r = 0.500, p = 0.006, respectively). Moreover, percentage change in lumbar BMD at 12 months showed a negative correlation with baseline total cholesterol (r = -0.438, p = 0.009) and a positive correlation with HDL-C (r = 0.498, p = 0.016). A smaller 3-month increase in OCN and a lower HDL-C level at baseline were associated with a smaller lumbar BMD increase after TPTD treatment, even after adjustment for age, sex, and other confounding factors (β = 0.462, p = 0.031 for ΔOCN and β = 0.670, p = 0.004 for HDL-C). Plasma levels of lipids, especially HDL-C, seem to be associated with the extent of osteoanabolic effects of TPTD in humans.
- The upstream enhancer elements of the G6PC promoter are critical for optimal G6PC expression in murine glycogen storage disease type Ia. [Journal Article, Research Support, N.I.H., Intramural, Research Support, Non-U.S. Gov't]
- Mol Genet Metab 2013 Nov; 110(3):275-80.
Glycogen storage disease type-Ia (GSD-Ia) patients deficient in glucose-6-phosphatase-α (G6Pase-α or G6PC) manifest impaired glucose homeostasis characterized by fasting hypoglycemia, growth retardation, hepatomegaly, nephromegaly, hyperlipidemia, hyperuricemia, and lactic acidemia. Two efficacious recombinant adeno-associated virus pseudotype 2/8 (rAAV8) vectors expressing human G6Pase-α have been independently developed. One is a single-stranded vector containing a 2864-bp of the G6PC promoter/enhancer (rAAV8-GPE) and the other is a double-stranded vector containing a shorter 382-bp minimal G6PC promoter/enhancer (rAAV8-miGPE). To identify the best construct, a direct comparison of the rAAV8-GPE and the rAAV8-miGPE vectors was initiated to determine the best vector to take forward into clinical trials. We show that the rAAV8-GPE vector directed significantly higher levels of hepatic G6Pase-α expression, achieved greater reduction in hepatic glycogen accumulation, and led to a better toleration of fasting in GSD-Ia mice than the rAAV8-miGPE vector. Our results indicated that additional control elements in the rAAV8-GPE vector outweigh the gains from the double-stranded rAAV8-miGPE transduction efficiency, and that the rAAV8-GPE vector is the current choice for clinical translation in human GSD-Ia.
- Influence of growth hormone on circulating fibroblast growth factor 21 levels in humans. [Journal Article, Multicenter Study, Research Support, Non-U.S. Gov't]
- J Intern Med 2013 Sep; 274(3):227-32.
Findings from animal studies indicate that growth hormone (GH) may stimulate the production of the putative metabolic regulator fibroblast growth factor 21 (FGF21). We investigated whether circulating FGF21 levels are altered in patients with GH deficiency and characterized how levels of this growth factor are influenced by acute and long-term administration of GH, and the potential relationship between FGF21 and nonesterified fatty acids (NEFAs).GH-deficient patients (n = 9) were studied prior to and during 1 year of replacement with GH. Healthy subjects (n = 8) received an intravenous bolus of GH with or without concomitant oral glucose. Healthy subjects and patients with heterozygous familial hypercholesterolaemia (n = 23) were monitored following increasing doses of GH for 3 weeks. The main outcome measures were serum FGF21 and NEFA levels. Studies were performed at two academic centres.GH-deficient patients had FGF21 levels within the normal range, and GH replacement did not influence circulating FGF21 or NEFA concentrations. Acute GH administration to healthy control subjects did not change FGF21 levels, whereas an oral glucose load increased serum FGF21 by 25% and reduced NEFA levels by 48%. Similar effects were seen on administration of glucose together with GH. However, FGF21 levels increased dose dependently up to 3.7-fold in control subjects treated with GH for 3 weeks; simultaneously NEFA levels were increased by 47%.GH is not critical for the maintenance of basal serum FGF21 levels in humans, but circulating FGF21 levels increase following administration of GH to healthy individuals. There is no correlation between plasma NEFA and circulating FGF21 levels.
- Role of dyslipidemia in patients with chronic kidney disease. [Journal Article, Review]
- Postgrad Med 2013 Jul; 125(4):28-37.
- Increased thyroid cancer risk in acromegaly. [JOURNAL ARTICLE]
- Pituitary 2013 Jul 9.
Acromegaly increases cancer risk. We aimed to determine the prevalence and the predictors of tumors in acromegalic patients treated at our department. We retrospectively evaluated 160 acromegalic patients [79 female (mean age 52.0 ± 10.4 years) and 81 male (mean age 49.1 ± 12.4 years)] between 1990 and 2012, with a mean follow up period of 7.1 ± 5.7 years. The patients were screened with colonoscopy, mammography, thyroid and prostate ultrasonography. Malignancy was found in 34 (21.3 %) patients. No significant difference was observed in the distribution of malignancy among sexes (20.3 % in F vs. 22.2 % in M). Thyroid cancer was the most frequent (n = 17, 10.6 %) followed by the breast cancer (n = 4, 2.5 %) and colorectal cancer (n = 3, 1.8 %). Renal cell cancer in two patients, bladder cancer in two patients, periampullary tumor, rectal carcinoid tumor, malignant melanoma, prostate cancer, lung cancer, parotid mucoepidermoid carcinoma and malignant mesenchymal tumor in brain in one patient were detected. One patient had both thyroid and renal cell cancer. Age of patients at diagnosis of acromegaly was significantly higher in patients with cancer (45.8 ± 9.9 vs. 40.9 ± 11.3 years, p < 0.05). No significant difference was found in duration of the disease, initial GH levels and IGF-1 % upper limit of normal values, the prevalence of diabetes, hypertension, coronary heart disease, hyperlipidemia and treatment modalities between the patients with/without cancer. In logistic regression analysis, older age at diagnosis was associated with malignancy risk. The risk of cancer in acromegaly especially the thyroid cancer risk seems to be more increased than known in the literature. Therefore, acromegaly patients should be screened routinely for cancer, especially for thyroid cancer due to it being up to four times higher prevalence than breast and colorectal cancer.
- Fibroblast growth factor 21 improves insulin resistance and ameliorates renal injury in db/db mice. [Journal Article, Research Support, Non-U.S. Gov't]
- Endocrinology 2013 Sep; 154(9):3366-76.
Despite the emerging importance of fibroblast growth factor 21 (FGF21) as a metabolic hormone regulating energy balance, its direct effects on renal function remain unexplored. FGF21 was injected ip daily for 12 weeks into db/db mice. Compared with control vehicle injection, FGF21 treatment significantly improved lipid profiles and insulin resistance and resulted in significantly higher serum adiponectin levels. In contrast, serum insulin and 8-isoprostane levels were significantly decreased. Interestingly, FGF21 and its receptor components in the kidneys were found to be significantly up-regulated in db/db mice, which suggests an FGF21-resistant state. FGF21 treatment significantly down-regulated FGF21 receptor components and activated ERK phosphorylation. FGF21 administration also markedly decreased urinary albumin excretion and mesangial expansion and suppressed profibrotic molecule synthesis. Furthermore, FGF21 improved renal lipid metabolism and oxidative stress injury. In cultured renal cells, FGF21 was mainly expressed in mesangial cells, and knockdown of FGF21 expression by stealth small interfering RNA further aggravated high-glucose-induced profibrotic cytokine synthesis in mesangial cells. Our results suggest that FGF21 improves insulin resistance and protects against renal injury through both improvement of systemic metabolic alterations and antifibrotic effects in type 2 diabetic nephropathy. Targeting FGF21 could therefore provide a potential candidate approach for a therapeutic strategy in type 2 diabetic nephropathy.