Retinal microvascular changes in patients with pancreatitis and their clinical significance.

Acute pancreatitis, a common exocrine inflammatory disease affecting the pancreas, is characterized by intense abdominal pain and multiple organ dysfunction. However, the alterations in retinal blood vessels among individuals with acute pancreatitis remain poorly understood. This study employed optical coherence tomography angiography (OCTA) to examine the superficial and deep retinal blood vessels in patients with pancreatitis. Sixteen patients diagnosed with pancreatitis (32 eyes) and 16 healthy controls (32 eyes) were recruited from the First Affiliated Hospital of Nanchang University for participation in the study. Various ophthalmic parameters, such as visual acuity, intraocular pressure, and OCTA image for retina consisting of the superficial retinal layer (SRL) and the deep retinal layer (DRL), were recorded for each eye. The study observed the superficial and deep retinal microvascular ring (MIR), macrovascular ring (MAR), and total microvessels (TMI) were observed. Changes in retinal vascular density in the macula through annular partitioning (C1-C6), hemispheric quadrant partitioning (SR, SL, IL, and IR), and early diabetic retinopathy treatment studies (ETDRS) partitioning methods (R, S, L, and I). Correlation analysis was employed to investigate the relationship between retinal capillary density and clinical indicators. Our study revealed that in the superficial retinal layer, the vascular density of TMI, MIR, MAR, SR, IR, S, C2, C3 regions were significantly decreased in patients group compared with the normal group. For the deep retinal layer, the vascular density of MIR, SR, S, C1, C2 regions also reduced in patient group. The ROC analysis demonstrated that OCTA possesses significant diagnostic performance for pancreatitis. In conclusion, patients with pancreatitis may have retinal microvascular dysfunction, and OCTA can be a valuable tool for detecting alterations in ocular microcirculation in pancreatitis patients in clinical practice.

Retinal thickness and microvascular alterations observed by optical coherence tomography in antineutrophil cytoplasmic antibody-associated vasculitis: a cross-sectional study.

Background: As an autoimmune disease, antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) often affects multiple organs, including the ocular system. This study aims to investigate differences in retinal thickness (RT) and retinal superficial vascular density (SVD) between patients with AAV and healthy controls (HCs) using optical coherence tomography angiography (OCTA). Currently, these differences are not clear. Methods: A total of 16 AAV individuals (32 eyes) and 16 HCs (32 eyes) were recruited to this cross-sectional study conducted in the First Affiliated Hospital of Nanchang University from June 2023 to September 2023. The study protocol conformed with the tenets of the Declaration of Helsinki (as revised in 2013). Each image observed by OCTA was divided into 9 regions using the Early Treatment Diabetic Retinopathy Study (ETDRS) subzones as a guide. Results: In the full layer, the RT of AAV patients was found to be significantly reduced in the inner superior (IS, P<0.001), outer superior (OS, P=0.003), inner temporal (IT, P=0.003), and outer temporal (OT, P<0.001) regions; inner RT was significantly lower in the IS (P=0.006), OS (P<0.001), inner nasal (IN, P=0.005), outer nasal (ON, P<0.001), and center (C, P=0.01) regions than that in HCs. Outer RT of AAV patients showed a reduction in the IS (P<0.001), as well as IT (P=0.008), and OT (P<0.001) regions. No statistically significant differences were seen in the different subregions in other different layers (P>0.05). Only the inner inferior (II) and outer inferior (OI) regions of SVD in AAV patients did not differ significantly from controls. All other regions showed a reduction in SVD. The details are as follows: IS (P<0.001), OS (P<0.001), IT (P=0.005), OT (P<0.001), IN (P<0.001), ON (P<0.001), and C (P=0.003). According to receiver operating characteristic (ROC) curve analysis, the full IS region [area under the curve (AUC): 0.8892, 95% confidence interval (CI): 0.8041-0.9742, P<0.001] had the highest diagnostic value for AAV-induced reduction in RT. The IS (AUC: 0.9121, 95% CI: 0.8322-0.9920, P<0.001) region was also the most sensitive to changes in SVD of AAV individuals. In addition, we found that SVD in the IN region (r=-0.4224, 95% CI: -0.6779 to -0.0757, P=0.02) as well as mean visual acuity (r=-0.3922, 95% CI: -0.6579 to -0.0397, P=0.03) of AAV patients were negatively correlated with disease duration. However, we did not find an association between SVD and RT in this study. Conclusions: The findings from OCTA indicated a reduction in RT and SVD among patients with AAV. OCTA allows for the evaluation of AAV-related ocular lesions and holds promise for monitoring of disease progression through regular evaluations.

CRIP1 supports the growth and migration of AML-M5 subtype cells by activating Wnt/ß-catenin pathway.

Acute myeloid leukemia (AML) is a clinically and molecularly heterogeneous hematopoietic disorder. To effectively eradicate AML, it is urgent to develop new therapeutic approaches and identify novel molecular targets. In silico analysis indicated that the expression of cysteine-rich intestinal protein 1 (CRIP1) was significantly elevated in AML cells and correlated with worse overall survival of the AML patients. However, its specific roles in AML remain elusive. Here we demonstrated that CRIP1 acted as a key oncogene to support AML cell survival and migration. Using a loss-of-function analysis, we found that CRIP1 silencing in U937 and THP1 cells by lentivirus-mediated shRNAs resulted in a decrease in cell growth, migration and colony formation, and an increase in chemosensitivity to Ara-C. CRIP1 silencing induced cell apoptosis and G1/S transition arrest. Mechanically, CRIP1 silencing caused inactivation of Wnt/ß-catenin pathway through upregulating axin1 protein. The Wnt/ß-catenin agonist SKL2001 markedly rescued the cell growth and migration defect induced by CRIP1 silencing. Our findings reveals that CRIP1 may contribute to AML-M5 pathogenesis and represent a novel target for AML-M5 treatment.

Brown adipose tissue transplantation ameliorates diabetic nephropathy through the miR-30b pathway by targeting Runx1.

OBJECTIVE: Adipose tissue is a major source of circulating microRNAs (miRNAs) that can regulate target genes in distant organs. However, the role of brown adipose tissue (BAT) in diabetic kidney disease (DKD) is still unknown. We studied the original BAT miR-30b targeting two key fibrotic regulators, Runt-related transcription factor 1 (Runx1) and snail family zinc finger 1 (Snail1), to combat DKD. METHODS: First, we transplanted healthy BAT from normal mouse donors into diabetic mice (induced by a high-fat diet and streptozotocin injection). In vitro, we observed extracellular vesicles (EVs) secreted from brown adipocytes. AgomiR-30b was directly administered to the BAT of diabetic mice twice weekly for 4 consecutive weeks. Next, the role of Runx1 in DKD was determined by using siRUNX1 or pCMV-RUNX1 in HK-2 cells and in diabetic mice treated with AAV9-U6-shRunx1 or AAV9-EF1a-Runx1. RESULTS: BAT transplantation reactivated endogenous BAT activity in diabetic mice, increased circulating miR-30b levels and significantly ameliorated DKD. In TGFß1-treated HK-2 cells, miR-30b expression was significantly suppressed. miR-30b overexpression markedly decreased fibronectin and downregulated Runx1 and Snail1 expression, while silencing of miR-30b had the opposite effects. Next, Runx1 knockdown and overexpression mimicked the above phenotype of miR-30b mimics and inhibitors, respectively, both in vitro and in vivo. Moreover, Runx1 promoted TGFß1-induced fibrosis by upregulating the PI3K pathway. CONCLUSION: BAT-derived miRNAs might be a promising target for kidney protection in diabetes mellitus.

Role of PDK4 in insulin signaling pathway in periadrenal adipose tissue of pheochromocytoma patients.

Studies have shown that pheochromocytoma (PHEO) is associated with glucose intolerance and decreased insulin sensitivity. In adipocytes, pyruvate dehydrogenase kinase 4 (PDK4) is involved in glucose uptake. However, very little is known about the role of PDK4 in the insulin signaling pathway in the adipose tissue of PHEO patients. We analyzed the expression of adipokines, oxidative stress-related genes, PDK4, phosphorylated AMPK (pAMPK) and phosphorylated IRS1 (pIRS1) in the periadrenal adipose tissue (peri-A) of patients with PHEO and non-functioning adrenal adenoma (NFA). We also investigated the effects of epinephrine on PDK4, pAMPK and pIRS1 in human stromal vascular fraction (SVF) cells, mouse 3T3-L1 preadipocytes and brown preadipocytes. PHEO patients had higher mRNA levels of PGC1α, C/EBPα, C/EBPß, COXII and AP2 and lower mRNA levels of PPARγ in their peri-A than NFA patients. Decreased pAMPK and increased PDK4 and pIRS1 were observed in the peri-A of PHEO patients. PHEO patients also had significantly higher NOX4 protein expression and lower Nrf2 and HO-1 protein expression in their peri-A than NFA patients. In vitro, epinephrine treatment upregulated PDK4 expression, inhibited AMPK phosphorylation and enhanced IRS1 phosphorylation. The knockdown of PDK4 by siRNA upregulated pAMPK and downregulated pIRS1. In conclusion, PDK4 may play an essential role in hypercatecholamine-induced insulin resistance in the periadrenal adipose tissues of PHEO patients.

MiR-455 targeting SOCS3 improve liver lipid disorders in diabetic mice.

MiR-455 has been verified a key regulator of brown adipose tissue and adipose tissue-specific overexpression of miR-455 (ap2-miR-455) mice could combat high-fat-diet-induced obesity. This study is to verify overexpression of miR-455 could ameliorate the lipid accumulation and metabolism in the liver of db/db diabetic mice and explore the potential mechanisms. Diabetic mice (db/db) and control mice (db/m) were randomly divided into four groups. After overexpression of miR-455 in the liver of db/db mice, the triglycerides level in both serum and liver decreased, the lipid deposit in liver was improved, the expression of fatty acid synthase, stearoyl-CoA desaturase 1, sterol regulatory element binding protein 1c (SREBP-1c) and acetyl-CoA carboxylase (ACCα) was also significantly down-regulated. TargetScan indicated that suppressor of cytokine signalling 3 (SOCS3) is predicated to target miR-455 and the protein of SOCS3 in the liver of db/db mice after intervention was significantly decreased. The dual luciferase reporter assay showed that SOCS3 was target gene of miR-455. In vitro, in Palmitate (PA)-stimulated human normal liver (LO2) cells, transfected miR-455 mimic could significantly inhibit the expression of SOCS3, while transfected miR-455 inhibitor could up-regulate the expression of SOCS3. Transfecting LO2 cells with siRNA of SOCS3 could significantly down-regulate the protein expression of SREBP-1c and ACCα. Our study showed that overexpression of miR-455 in the liver could improve lipid metabolism in diabetic mice by down-regulating its target gene SOCS3.

Transplantation of brown adipose tissue up-regulates miR-99a to ameliorate liver metabolic disorders in diabetic mice by targeting NOX4.

Nonalcoholic fatty liver disease (NAFLD), main cause of liver damage, is inextricably linked to diabetes. However, there is no specific means to improve the pathology of fatty liver in diabetic patients. Brown adipose tissue (BAT) is an important endocrine organ that secretes adipokines and microRNAs (miRNAs) involved in systemic metabolic regulation. To investigate the effects of BAT transplantation on liver lipid metabolism in diabetic mice, we transplanted BAT from male donor mice into diabetic mice induced by streptozotocin (STZ) combined with high-fat diet (HFD). At 10 weeks after transplantation, BAT transplantation significantly decreased the blood glucose and lipid, downregulated FAS, CD36, Scd1, ACCα, NOX2, NOX4, TGF-ß1, FN and COL-1, up-regulated Nrf2, reversed the pathological changes of liver and increased the circulating miR-99a in diabetic mice. To verify whether circulating miR-99a improves oxidative stress by targeting inhibition of NOX4, we used 0.4mM palmitic acid (PA) to treat the LO2 cells. The expression of NOX4 protein was significantly decreased after transfection with miR-99a mimic, and increased after transfection with miR-99a inhibitor. Luciferase reporter assay confirmed that miR-99a could target NOX4 mRNA. These findings clarify the role of miR-99a and NOX4 in liver beneficial effect of BAT transplantation in diabetic mice.

Exendin-4 Improves Diabetic Kidney Disease in C57BL/6 Mice Independent of Brown Adipose Tissue Activation.

BACKGROUND: The role of exendin-4 in brown adipose tissue (BAT) activation was not very clear. This study is to verify the role of BAT involved in renal benefits of exendin-4 in diabetes mellitus (DM). METHODS: In vivo, C57BL/6 mice were randomly divided into nondiabetic (control) and diabetic groups (DM). The diabetic mice were randomized into a control group (DM-Con), BAT-excision group (DM+Exc), exendin-4-treated group (DM+E4), and BAT-excision plus exendin-4-treated group (DM+Exc+E4). The weight, blood glucose and lipids, 24 h urine albumin and 8-OH-dG, and renal fibrosis were analyzed. In vitro, we investigated the role of exendin-4 in the differentiation process of 3T3-L1 and brown preadipocytes and its effect on the rat mesangial cells induced by oleate. RESULTS: The expressions of UCP-1, PGC-1α, ATGL, and CD36 in BAT of DM mice were all downregulated, which could be upregulated by exendin-4 treatment with significant effects on ATGL and CD36. BAT-excision exacerbated high blood glucose (BG) with no significant effect on the serum lipid level. Exendin-4 significantly lowered the level of serum triglycerides (TG) and low-density lipoprotein- (LDL-) c, 24 h urine albumin, and 8-OH-dG; improved renal fibrosis and lipid accumulation; and activated renal AMP-activated protein kinase (AMPK) in diabetic mice regardless of BAT excision. In vitro, there was no significant effect of exendin-4 on brown or white adipogenesis. However, exendin-4 could improve lipid accumulation and myofibroblast-like phenotype transition of mesangial cells induced by oleate via activating the AMPK pathway. CONCLUSIONS: Exendin-4 could decrease the renal lipid deposit and improve diabetic nephropathy via activating the renal AMPK pathway independent of BAT activation.

Increased oxidative stress, inflammation and fibrosis in perirenal adipose tissue of patients with cortisol-producing adenoma.

Although much is known about that corticosteroids affect the functions of adipose tissues, little genetic information is available for perirenal adipose tissue (peri-N) from patients with cortisol-producing adenoma (CPA). We conducted microarray analysis of peri-N from patients with CPA by using an Affymetrix human U133 plus 2.0 array. We also analysed the inflammation, fibrosis and oxidative stress in vitro. Compared with normotension (NT) group, CPA group has significantly higher protein levels of TNFα, IL-6, fibronectin (FN) and collagen I (COLI). The protein level of NADPH oxidase 4 (Nox4) significantly increased, while nuclear factor erythroid 2-related factor 2 (Nrf2) and hemeoxygenase-1 (HO-1) levels were significantly reduced in the CPA group. Dexamethasone markedly induced fibrosis and adipogenesis-related gene expression in predifferentiated stromal vascular fraction (SVF) cells, 3T3-L1 preadipocytes and brown preadipocytes. Chronic exposure to endogenous glucocorticoids due to CPA increases peri-N oxidative stress, inflammation and fibrosis, which may contribute to the metabolic disturbances associated with hypercortisolism in these patients.

Genetic Analysis of SLC12A3 Gene in Chinese Patients with Gitelman Syndrome.

BACKGROUND The incidence of Gitelman syndrome (GS) has been increasing in our hospital. The aim of this study was to explore the diagnostic accuracy and features of SLC12A3 gene in Chinese patients with GS. MATERIAL AND METHODS We searched the literature about Chinese patients with GS in the PubMed database up to July 2018 and also included 8 GS Chinese patients from our hospital in our analysis that explored the features of SLC12A3 gene. We divided all the patients into 3 groups according to diagnostic consensus. Complete compliance was defined to mean containing 2 allelic mutations, partial compliance to mean one allelic mutation, and clinical compliance to mean no mutations. RESULTS Totally, 137 patients were enrolled in this study and 90 mutations were counted. Missense mutations accounted for over 72% in Chinese GS patients and the most common one was Thr60Met. According to the consensus, there were 102 patients (74.5%) in the complete compliance group, 31 patients (22.6%) in the partial compliance group, and only 4 patients (2.9%) in the clinical compliance group. CONCLUSIONS The SLC12A3 gene analysis in Chinese GS patients revealed that the most common mutation was Thr60Met, one of the missense mutations. Most of the patients were in the complete compliance group (i.e., 2 allelic mutations); the other cases might be explained by gene rearrangement.

[Effect of glucagon-like peptide 1 receptor agonists on body fat redistribution and muscle mass in overweight and obese type 2 diabetic patients].

OBJECTIVE: To investigate the effect of glucagon-like peptide 1 receptor agonists (GLP-1RAs) on body fat redistribution and muscle mass in overweight/obese patients with type 2 diabetes (T2DM). METHODS: We retrospectively analyzed the data of 76 patients with body mass indexes (BMI)≥24 kg/m2, who had an established diagnosis of T2DM in our department between December, 2014 and September, 2015. We divided these patients according to their BMI in overweight group (BMI of 24-27.9 kg/m2, n=14), obese group (BMI of 28-31.9 kg/m2, n=35) and severely obese group (BMI≥32 kg/m2, n=27). All the patients received treatment with GLP-1RAs (Exenatide or Liraglutide) for 3.0 to 29.0 weeks (mean 8.9 weeks), and their blood glucose, HbA1c and serum lipids were analyzed. For each patient, the fat and muscle masses were analyzed using a human body composition analyzer (JAWON-IOI353, Korea) before and after GLP-1RAs treatment. RESULTS: Treatment with GLP-1RAs significantly decreased BMI and visceral adiposity index (VAI) in all the patients in the 3 groups (P < 0.05). The treatment significantly decreased the body weight in the overweight group and obese group by 2.70 kg (0.60-4.95 kg) and 2.65 kg (1.45-6.40 kg), respectively (P < 0.05), and significantly decreased the waist-to-hip ratio (WHR) in the overweight group (P < 0.05). The obese and severely obese patients showed significantly decreased percentage body fat (including both subcutaneous and visceral fat) and increased muscle mass after the treatment (P < 0.05). Compared with those in the overweight group, the percentage body fat and VAI were significantly decreased in the obese group after the treatment (P < 0.05), and the percentage of subcutaneous fat reduced and the muscle ratio increased more obviously in the obese and severely obese patients (P < 0.05). CONCLUSIONS: GLP-1RAs treatment can significantly lower BMI and improve body fat distribution in obese patients with T2DM, especially in patients with a greater BMI.

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.

Verapamil Attenuated Prediabetic Neuropathy in High-Fat Diet-Fed Mice through Inhibiting TXNIP-Mediated Apoptosis and Inflammation.

Diabetic neuropathy (DN) is a common and severe complication of diabetes mellitus. There is still a lack of an effective treatment to DN because of its complex pathogenesis. Thioredoxin-interacting protein (TXNIP), an endogenous inhibitor of thioredoxin, has been shown to be associated with diabetic retinopathy and nephropathy. Herein, we aim to investigate the role of TXNIP in prediabetic neuropathy and therapeutic potential of verapamil which has been shown to inhibit TXNIP expression. The effects of mediating TXNIP on prediabetic neuropathy and its exact mechanism were performed using high-fat diet- (HFD-) induced diabetic mice and palmitate-treated neurons. Our results showed that TXNIP upregulation is associated with prediabetic neuropathy in HFD-fed mice. TXNIP knockdown improved DN in HFD-induced prediabetic mice. Mechanistically, increased TXNIP in dorsal root ganglion is transferred into the cytoplasm and shuttled to the mitochondria. In cytoplasm, TXNIP binding to TRX1 results in the increased oxidative stress and inflammation. In mitochondria, TXNIP binding to TRX2 induced mitochondria dysfunction and apoptosis. TXNIP isolated from TRX2 then shuttles to the cytoplasm and binds to NLRP3, resulting in further increased TXNIP-NLRP3 complex, which induced the release of IL-1ß and the development of inflammation. Thus, apoptosis and inflammation of dorsal root ganglion neuron eventually cause neural dysfunction. In addition, we also showed that verapamil, a known inhibitor of calcium channels, improved prediabetic neuropathy in the HFD-fed mice by inhibiting the upregulation of TXNIP. Our finding suggests that TXNIP might be a potential target for the treatment of neuropathy in prediabetic patients with dyslipidemia.

Bitter melon (Momordica charantia) attenuates atherosclerosis in apo-E knock-out mice possibly through reducing triglyceride and anti-inflammation.

BACKGROUND: Bitter melon (BM, Momordica charantia) has been accepted as an effective complementary treatment of metabolic disorders such as diabetes, hypertension, dyslipidemia and etc. However it is unclear whether BM can prevent the progression of atherosclerosis. To confirm the effects of BM on atherosclerosis and explore its underlying mechanisms, we design this study. METHODS: Twenty four male apolipoprotein E knock-out (ApoE-/-) mice aged 8 weeks were randomly divided into control group fed with high fat diet (HFD) only and BM group fed with HFD mixed with 1.2%w/w BM. After 16 weeks, body weight, food intake, blood glucose, serum lipids were measured and the atherosclerotic plaque area and its histological composition were analyzed. The expression of vascular cell adhesive molecules and inflammatory cytokines in the aortas were determined using quantitative polymerase chain reaction. RESULTS: Body weight gain and serum triglycerides (TG) significantly decreased in BM group. BM reduced not only the atherosclerotic plaque area and the contents of collagen fibers in atherosclerotic plaques but also the serum soluble vascular cell adhesion molecule (VCAM)-1 and P-selectin levels, as well as the expressions of monocyte chemoattractant protein (MCP)-1 and interleukin (IL)-6 in aortas. CONCLUSION: Our study indicates that dietary BM can attenuate the development of atherosclerosis in ApoeE-/- mice possibly through reducing triglyceride and anti-inflammation mechanism.

Metformin Improves Epithelial-to-Mesenchymal Transition Induced by TGF-ß1 in Renal Tubular Epithelial NRK-52E Cells via Inhibiting Egr-1.

The early growth response- (Egr-) 1 has been found to play a key role in organ fibrosis. Metformin has been shown to be effective in attenuating renal tubular epithelial-to-mesenchymal transition (EMT), which is involved in renal fibrosis. However, it is unknown whether metformin improves EMT via inhibiting Egr-1. In this study, rat renal tubular epithelial (NRK-52 E) cells, treated by transforming growth factor- (TGF-) ß1 of 10 ng/ml with or without metformin of 1 mmol/l, were transfected by siEgr-1 or M61-Egr-1 plasmids to knock down or overexpress Egr-1, respectively. The gene and protein expressions of E-cadherin, α-SMA, fibronectin (FN), and Egr-1 were determined by real-time quantitative PCR and Western blotting, respectively. We observed that TGF-ß1 significantly reduced E-cadherin expression and upregulated the expressions of FN, α-SMA, and Egr-1, which can be reversed by metformin. M61-Egr-1 transfection could exacerbate EMT, which can be reversed by metformin. Taken together, our data show that Egr-1 plays an important role in TGF-ß1-induced EMT of renal tubular epithelial cells and metformin improves EMT while inhibiting Egr-1, which provides a potential novel target to combat renal fibrosis.

The dipeptidyl peptidase-4 inhibitor sitagliptin protects against dyslipidemia-related kidney injury in Apolipoprotein E knockout mice.

The goal of this study was to investigate the possible protective effects of sitagliptin against dyslipidemia-related kidney injury in apolipoprotein E knockout (apoE-/-) mice. Eight-week-old male apoE-/- mice were randomized to receive either a high fat diet (HFD, apoE-/- group) or HFD mixed with sitagliptin (sita + apoE-/- group) for 16 weeks. A control group of age- and gender-matched C57BL/6J mice were fed a HFD. The apoE-/- group exhibited increases in body weight and serum lipid levels in addition to high-density lipoprotein, and increases in 24-h urinary 8-hydroxy-2-deoxyguanosine and albuminuria excretion. Decreased insulin sensitivity was also observed in the apoE-/- group. These mice additionally contained enlargements of the glomerular mesangial matrix area, lipid deposition area, and renal interstitium collagen area. The apoE-/- group also demonstrated down-regulation of phosphorylated AMP-activated protein kinase (AMPK), increases in renal mRNA expression of transforming growth factor-beta 1 (TGF-ß1) and fibronectin (FN), and increased protein expression of Akt, TGF-ß1, FN and p38/ERK mitogen-activated protein kinase (MAPK). Sitagliptin treatment successfully ameliorated all the deleterious effects of dyslipidemia tested. To our knowledge, this is the first time that sitagliptin has been shown to reverse the renal dysfunction and structural damage induced by dyslipidemia in apoE-/- mice. Our results suggest that the renoprotective mechanism of sitagliptin may be due to a reduction in Akt levels, a restoration of AMPK activity, and inhibition of TGF-ß1, FN, and p38/ERK MAPK signaling pathways.

The DPP-4 inhibitor sitagliptin attenuates the progress of atherosclerosis in apolipoprotein-E-knockout mice via AMPK- and MAPK-dependent mechanisms.

BACKGROUND: The dipeptidyl peptidase-4 inhibitor sitagliptin, a new anti-diabetic medicine, is effective in treating type 2 diabetes mellitus by increasing the activation and duration of action of glucagon-like peptide-1. Since atherosclerosis is the main pathological feature of diabetic cardiovascular complications, it is important to investigate the anti-atherosclerotic effect of sitagliptin and explore the relevant mechanisms. METHODS: Male apolipoprotein-E-knockout mice were randomly divided into two groups and fed either high-fat diet (HFD) or HFD plus sitagliptin at a concentration of 0.3% for 16 weeks. Body weight, food intake, blood glucose, serum lipids and adhesion molecules were measured. The atherosclerotic plaque area and its histological composition were analyzed using Sudan staining and immunohistochemistry. The expression of inflammatory cytokines (monocyte chemoattractant protein (MCP)-1 and interleukin (IL)-6) and the activation of AMP-activated protein kinase (AMPK) and mitogen-activated protein kinase (MAPK) in the aortas were determined using quantitative polymerase chain reaction and western blot, respectively. RESULTS: Mice treated with sitagliptin developed fewer atherosclerotic plaques than the control group (7.64 ± 1.98% vs 12.91 ± 1.15%, p < 0.001), particularly in the aortic arch and abdominal aorta, where plaques were decreased 1.92- and 2.74-fold, respectively (p < 0.05 and p < 0.01). Sitagliptin significantly reduced the content of collagen fiber in plaques 1.2-fold (p < 0.05). Moreover, sitagliptin significantly reduced the expression of monocyte chemoattractant protein-1 and interleukin-6 in the aorta (p < 0.01 and p < 0.05), as well as the serum levels of soluble vascular cell adhesion molecule-1 and P-selectin (both p < 0.05). In addition, Sitagliptin induced phosphorylation of AMPK and Akt (p < 0.05 and p < 0.01), while suppressed phosphorylation of p38 and extracellular signal-regulated kinase (Erk) 1/2 (p < 0.05 and p < 0.01) in aortas. CONCLUSIONS: Our present study indicates that sitagliptin can reduce the area of the atherosclerotic lesion, possibly by regulating the AMPK and MAPK pathways and then reducing leukocyte -endothelial cell interaction and inflammation reactions. These actions are independent of weight loss and glucose-reducing effects.

Exendin-4 alleviates high glucose-induced rat mesangial cell dysfunction through the AMPK pathway.

BACKGROUND/AIMS: Glucagon-like peptide-1 (GLP-1), which counteracts insulin resistance in humans with type 2 diabetes, has been shown to ameliorate diabetic nephropathy in experimental models. However, the mechanisms through which GLP-1 modulates renal function remained illdefined. The present study investigated the putative mechanisms underlying effects of exendin-4, a GLP-1 analog, on mesangial cell proliferation and fibronectin. METHODS: Rat mesangial cells (MCs) were treated with exendin-4 under high glucose conditions. AMP-activated protein kinase (AMPK) inhibitors (compound C) and agonists (AICAR) were used to analyze the role of this kinase. Cell proliferation was measured using a MTT assay. Fibronectin expression and AMPK-signaling pathway activity were assessed using ELISA and Western blotting, respectively. The production of matrix metalloproteinase (MMP)-2 and tissue inhibitors of metalloproteinases (TIMP)-2 was evaluated using quantitative real-time RT-PCR. RESULTS: Exendin-4 inhibited cell proliferation and fibronectin secretion in high glucose-induced MCs. It also caused phosphorylation of AMPK and subsequently increased the ratio of MMP-2 to TIMP-2, which resulted in the degradation of fibronectin. Exendin-4 reversed extracellular signal-regulated kinase (ERK) phosphorylation and enhanced expression of mammalian target of rapamycin (mTOR) in MCs. Moreover, the activation of the AMPK pathway by exendin-4 was induced by AICAR, which was inhibited by compound C. CONCLUSION: Exendin-4 exerts an inhibitory effect on cell proliferation and fibronectin secretion in rat MCs, partly through AMPK activation. These results may explain some of the beneficial effects of exendin-4 on the kidney.

[Secondary organic tracers in summer PM2.5 aerosols from Baima Spring Scenic Area, Yaan, Sichuan Province].

Integrated PM2.5 aerosol samples were collected at Baima Spring Scenic Area, a forest site of Yaan, Sichuan Province, during the summer of 2010. Organic speciation including isoprene oxidation products (2-methyltetrols, C5-alkene trols, 2-methylyceric acid), alpha-/beta-pinene oxidation products (norpinic acid, 3-hydroxyglutaric acid, 3-methy-1,2,3-butanetricarboxylic acid), and small molecular carboxylic acid (malic acid, 2-hydroxyglutaric acid) were analyzed. The generation mechanisms of SOA as well as their influencing factors were particularly discussed. Results show that average concentrations of 2-methyltetrols, C5-alkene triols, 2-methyglyceric acid, norpinic acid, 3-hydroxyglutaric acid and 3-methy-1,2,3-butanetricarboxylic acid are 63.3, 45.0, 4.4, 4.1, 5.0, 5.3 ng x m(-3) respectively, of 24-hour lapse samples. SOA compounds are consistent with higher concentrations in the day than during the night only except for norpinic acid. Relatively high level of biogenic SOA at the study area is concerned with many environmental factors, i. e. local abundant vegetations, warm and humid climate, sunken valley topography, the atmospheric pollution state, etc.

[Regulation of hepatic lipid metabolism by adiponectin via IRS-2 phosphorylation in OLETF rats].

OBJECTIVE: To explore the effect and mechanism of adiponectin on hepatic lipid metabolism in Otsuka Long Evans Tokushima fatty (OLETF) rats. METHODS: Twenty male OLETF rats and 10 male Long-Evans Tokushima (LETO) rats were sacrificed at 8, 32 or 40-week old to examine the fasting blood glucose, plasma insulin, adiponectin and blood lipid profile. The levels of triglyceride, cholesterol, adiponectin, phosphotyrosine of IRS-2, acetyl-coenzyme A carboxylase and sterol regulatory element-binding protein 1 (SREBP-1) mRNA in liver tissue were determined by chemical enzymatic assay, enzyme-linked immunosorbent assay (ELISA) or Western blot. RESULTS: Higher insulin level, lower insulin sensitivity index and deteriorated lipid metabolism was observed in OLETF rats since 32-week age. ACC (acetyl coenzyme A carboxylase) and SREBP-1 mRNA expression, lowered plasma adiponectin (OLETF vs LETO: 8 weeks age, 2.38 ± 0.23 vs 3.1 ± 0.17, P < 0.05; 32 weeks age, 1.51 ± 0.05 vs 2.84 ± 0.34, P < 0.01; 40 weeks age, 1.24 ± 0.04 vs 2.64 ± 0.49 ng/ml, P < 0.01) and liver tissue (8, 32 or 40 weeks age, 2.24 ± 0.18 vs 2.68 ± 0.13, 2.04 ± 0.19 vs 2.51 ± 0.14, 1.76 ± 0.12 vs 2.47 ± 0.21 µg/g respectively, P < 0.05) as well as elevated triglyceride (TG) (40 weeks age, TG 1.88 ± 0.11 vs 0.51 ± 0.07 mmol/L, P < 0.01) and cholesterol (40 weeks age, total cholesterol 0.94 ± 0.17 vs 0.69 ± 0.14 mmol/L, P < 0.01) and lowered IRS-1 (insulin receptor substrate 1) tyrosine phosphorylation in liver tissue in OLETF rats were observed. The hepatic adiponectin was positively correlated with the level of py-IRS2 and inversely with those of hepatic ACC, SREBP-1 mRNA, triglyceride and cholesterol (r = -0.431, -0.396, -0.353, -0.349, P < 0.05). CONCLUSION: Adiponectin may affect the signaling pathway of hepatic insulin via tyrosine phosphorylation of IRS-2. It is involved in the regulation of hepatic lipid metabolism.