Renoprotective effects of brown adipose tissue activation in diabetic mice.

BACKGROUND: Brown adipose tissue (BAT) has been regarded as a potential target organ to combat obesity and related metabolic disorders. However, the effect of BAT activation on the development of diabetic kidney disease (DKD) remains unclear. METHODS: Diabetic mice were induced by streptozotocin (STZ) combined with a high-fat diet. To activate BAT, mice were administered 1 mg/kg per day, i.p., CL316,243, a ß3 -adrenergic receptor agonist, for 4 weeks. Blood glucose, serum lipids, adipokines, 24-hour urinary albumin, 8-hydroxydeoxyguanosine (8-OHdG), and circulating microRNA (miRNA) levels were analyzed, in addition to renal pathology. Histological changes (fibrosis, inflammation) were evaluated in the kidneys, as was the expression of oxidative stress-related genes. Renal signaling pathways (fibroblast growth factor [Fgf]21/ß-klotho/FGF receptor 1c and AMP-activated protein kinase[AMPK]/sirtuin 1 [Sirt1]/peroxisome proliferator-activated receptor-γ coactivator-1α [Pgc1α]) were also evaluated. RESULTS: Compared with untreated STZ-diabetic mice, CL316,243 treatment reduced blood glucose, albeit not significantly (20.58 ± 3.55 vs 23.60 ± 3.90 mM), and significantly decreased triglycerides and low-density lipoprotein cholesterol and increased high-density lipoprotein cholesterol. Simultaneously, BAT activation significantly decreased 24-hour urinary albumin (34.21 ± 6.28 vs 70.46 ± 15.81 µg/24 h; P < 0.05) and 8-OHdG, improved renal fibrosis, inflammation, and oxidative stress, and ameliorated renal morphological abnormalities. In addition to enhancing BAT activity, CL316,243 significantly increased serum adiponectin concentrations and renal Fgf21 sensitivity, and reactivated the renal AMPK/Sirt1/Pgc1α signaling pathway. Furthermore, CL316,243 treatment increased levels of some circulating miRNAs and downregulated expression of their target genes in the kidney. CONCLUSIONS: Activating BAT could improve kidney injury in diabetic mice via metabolic improvements and renal AMPK activation by beneficial adipokines and miRNAs.

[Exendin-4 alleviates diabetic cardiomyopathy in mice by regulating Sirt1/PGC1α].

OBJECTIVE: To investigate the protective effect of exendin-4 against diabetic cardiomyopathy in mice and explore the underlying mechanism. METHODS: C57BL/6J mice were randomly divided into normal control group with normal diet and diabetic group with high-fat diet for 4 weeks before streptozotocin injection. The successfully established diabetic mouse models were divided into diabetic group with exendin-4 treatment and diabetic control group for daily treatment with intraperitoneal injection of 1 nmol/kg exendin-4 and saline of equivalent volume for 8 weeks, respectively. The physiological parameters such as blood glucose and body weight were recorded. RT-PCR was used to examine the transcription levels of genes related with myocardial hypertrophy and fibrosis and the genes related with mitochondrial functions including PGC1α, NRF and CytoC. The expressions of oxidative stress markers and Sirt1/PGC1 proteins were measured using Western blotting. and HE staining was used to observe the myocardial structural changes in the mice. RESULTS: Compared with the normal control mice, the mice in diabetic control group showed significantly increased blood glucose and blood lipid levels (P<0.001), which were obviously improved by Exendin-4 treatment. The expressions of ANP, BNP, TGFß1, CytoC1 and NOX1 were significantly increased (P<0.05) while Sirt1, PGC1α, NRF and SOD1 expression were markedly decreased in the myocardial tissue of the diabetic mice (P<0.05). Exendin-4 treatment resulted in obviously reduced expressions of ANP, BNP, TGFß1, CytoC1 and NOX1 (P<0.05) and increased expressions of Sirt1, PGC1α, NRF and SOD1 (P<0.05) in the diabetic mice. CONCLUSIONS: Exendin-4 protects against myocardial injury in diabetic mice by improving mitochondrial function and inhibiting oxidative stress through the Sirt1/PGC1α signaling pathway.

[Clinical analysis of 939 patients with adrenal lesions detected by abdominal computed tomography].

OBJECTIVE: To investigate the prevalence, etiology and clinical characteristics of adrenal lesions detected by abdominal computed tomography (CT). METHODS: This retrospective study was conducted in patients with adrenal lesions detected by abdominal CT examinations in Nanfang Hospital between July, 2014 and June, 2015. The clinical data of the patients were collected for analysis of the demographics, comorbidities, imaging characteristics, biochemical profiles, clinical diagnosis and intervention. RESULTS: A total of 939 patients with adrenal lesions were identified from 19 004 patients undergoing abdominal CT scan over the defined period. The mean age of the patients was 53.2 years and 560 of the patients were male. Among the total cases with adrenal lesions, the percentages of cases with adrenal masses tended to increase progressively with age. Endocrine studies were done in 270 of the total patients, which identified non-functioning masses in 38.9%, primary aldosteronism in 16.3%, Cushing's syndrome in 4.1%, subclinical Cushing's syndrome in 7.0%, and pheochromocytomas in 7.0% of the cases. Adrenal incidentalomas was detected in 191 patients, with a detection rate of 1.0% among the overall patients undergoing abdominal CT scans. Imaging study detected adenomas (70.3%), cortical carcinomas (2.4%), and metastases (0.5%). Of 191 patients with adrenal incidentalomas, only 76 (39.8%) underwent endocrine evaluation, including 34 with nonfunctioning adrenal masses, 17 with pheochromocytoma, 7 with primary aldosteronism, and 5 with subclinical Cushing's syndrome. CONCLUSION: s The overall detection rates of adrenal lesions and adrenal incidentalomas by abdominal CT were 4.9% and 1.0%, respectively, in our cohort of patients undergoing the examination over the defined period. Although most of the lesions were benign and nonfunctioning, malignant and functional lesions were also detected. As many as 60% of the patients with adrenal incidentalomas did not have hormonal testing. Clinicians need to have greater awareness of adrenal incidentalomas and standard protocol for its management should be established.

[Expressions of inflammatory and fibrogenic factors in perinephric and subcutaneous adipose tissues of patients with adrenocorticotropic hormone-independent Cushing's syndrome].

OBJECTIVE: To investigate the expressions of inflammation- and fibrosis-related genes in perinephric and subcutaneous adipose tissues in patients with adrenocorticotropic hormone (ACTH)-independent Cushing's syndrome. METHODS: The perinephric and subcutaneous adipose tissues adipose tissues were obtained from 8 patients with ACTH-independent Cushing's syndrome undergoing laparoscopic retroperitoneal adrenalectomy. Real-time PCR was used to detect the mRNA expression levels of interleukin 6 (IL-6), tumor necrosis factor-α (TNF-α), matrix metallopeptidase 2 (MMP-2), TIMP metallopeptidase inhibitor 1 (TIMP-1), early growth response 1 (EGR1), CCAAT/enhancer binding protein ß(CEBPß), uncoupling protein 1(UCP-1), PPARγ coactivator 1 alpha (PGC1α) and cell death-inducing DFFA-like effector a (CIDEA). RESULTS: The mRNA level of CIDEA was significantly higher in the perinephric adipose tissue (peri-N) than in the subcutaneous adipose tissue (subQ) (P<0.05). The expressions of CEBPß, UCP-1, and PGC1α mRNA in the peri-N were similar with those in the subQ. The expressions of IL-6, TIMP1 and EGR1 mRNA in the subQ were significantly higher than those in the peri-N (P<0.05). No significant difference in TNF-α and MMP-2 mRNA levels was found between peri-N and subQ. CONCLUSION: The expression levels of the inflammation- and fibrosis-related genes are higher in the subQ than in the peri-N of patients with ACTH-independent Cushing's syndrome, suggesting that chronic exposure to endogenous hypercortisolism may cause adipose tissue dysfunction.