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In this study, a diabetic kidney disease model was established by placing the test rats on a high-sugar/high-fat diet combined with streptozotocin induction. Histopathological examination (H&E, Masson, and PASM stain) showed pathological changes in the diabetic rat kidneys, in addition to fibrotic symptoms and collagen deposition. Immunohistochemistry and western blot analyses indicated that the diabetic condition significantly increased the expressions of fibrotic markers including collagen, α-SMA, and fibronectin. The levels of cholesterol, triglyceride, and low-density lipoprotein were also increased in diabetic kidney disease (DKD) rat blood, while the level of high-density lipoprotein was decreased. The results of Oil red O staining experiments indicated that the kidneys of diabetic rats exhibited appreciable fat deposition, with high contents of triglyceride and cholesterol. To inhibit fibrosis and reduce fat deposition, low molecular weight fucoidan (LMWF) may be used. Based on PCR and western blot analyses, LMWF can regulate the expression levels of important lipid metabolism regulators, thereby impeding the development of kidney fibrosis. Through the vitro model, it also be indicated that LMWF could inhibit fibrosis process through regulating lipid metabolism which induced by palmitic acid.

Genetic variants of FTO and MC4R have been linked with obesity and T2DM in populations of Europeans. In this study, we have investigated the association of FTO rs9939609 and MC4R rs17782313 with obesity and T2DM in the Chinese population and analyzed the relationship between rs9939609 and rs17782313. 2351 individuals were recruited. We tested the rs9939609 and rs17782313 by sequences retrieval method. Clinical and biochemical characteristics were measured. The rs9939609 per-A allele and rs17782313 per-C allele increases of OR for obesity was 1.42 (95% CI 1.39–3.74) and 1.39 (95% CI 1.21–3.53).The genotypic OR for obesity was 1.92 (95% CI 1.81–4.67) for AA genotype, 1.71 (95% CI 1.47–4.54) for AT genotype, 1.87 (95% CI 1.72–4.00) for CC genotype, and 1.44 (95% CI 1.20–3.18) for CT genotype. BMI of participants carrying neither FTO nor MC4R risk allele was 25.9 ± 4.9, one risk allele was 26.4 ± 5.1, two risk alleles was 28.1 ± 5.5, and there or four risk alleles was 33.2 ± 6.3. We found no association between FTO and MC4R and the Chinese population with T2DM (P > 0.05). Our data support that the rs9939609 and rs17782313 are strongly associated with obesity and BMI. Their combined effects were significant in Chinese population. No association between FTO and MC4R and Chinese population with T2DM was found.

Proliferation of human retinal endothelial cells (HRECs) is an important event in the development of diabetic retinopathy. Glucose fluctuations are strong predictor of diabetic vascular complications. In this study we have investigated the effect of intermittent high glucose on proliferation and expression of vascular endothelial growth factor (VEGF) in HRECs. The possible involvement of mitochondrial reactive oxygen species (ROS) was assessed. HRECs were incubated for 72 h in media containing different glucose concentrations: 5, 25, 5 mmol/l alternating with 25 mmol/l glucose, with or without Mn(III)tetrakis(4-benzoic acid) porphyrin chloride (MnTBAP) and thenoyltri-fluoroacetone (TTFA). The cell proliferation, VEGF expression, mitochondrial ROS, nitrotyrosine and 8-hydroxydeoxyguanosine (8-OHdG) were measured. In cultured HRECs, treatment with constant or intermittent high glucose significantly increased [(3)H]thymidine incorporation in a time-dependent manner. Treatment with constant high glucose for 48 h resulted in significant increases in [(3)H]thymidine incorporation, mRNA and protein levels of VEGF compared with HRECs treated with the normal glucose, which were markedly enhanced in cells exposed to intermittent high glucose. The levels of mitochondrial ROS, nitrotyrosine and 8-OhdG were significantly elevated under both intermittent and constant high glucose conditions, the effect being greater under intermittent high glucose. In addition, the antioxidants MnTBAP or TTFA can effectively prevent cell proliferation and overexpression of VEGF, as well as overproduction of mitochondrial ROS, nitrotyrosine and 8-OhdG in HRECs induced by constant or intermittent high glucose. Intermittent high glucose enhances cell proliferation and overexpression of VEGF through reactive oxygen species (ROS) overproduction at the mitochondrial transport chain level in HRECs, indicating that glycemic variability have important pathological effects on the development of diabetic retinopathy dependent of mitochondrial ROS.

Objective Hyperglycemia induces vascular smooth muscle cells (VSMCs) proliferation and may thus contribute to the formation of atherosclerotic lesions. Glucose fluctuations are strong predictor of diabetic vascular complications. We investigate the effects of exposure to constant and intermittent high glucose concentrations on the proliferation and matrix metalloproteinase (MMP)-2 activity of rat aortic VSMCs in culture, as well as the expression of osteopontin (OPN). Methods Rat aortic VSMCs were grown to confluence and then exposed to 5 mmol/L glucose, 25 mmol/L glucose, or 5 mmol/L alternating with 25 mmol/L glucose in the absence or presence of neutralizing antibodies to OPN, β3 integrin receptor and β5 integrin receptor. The cell proliferation, MMP-2 activity and the expression of OPN were assessed. Results In cultured VSMCs, treatment with constant or intermittent high glucose significantly increased [3H]thymidine incorporation in a time-dependent manner. A modest increase was observed at 12 h, and further deteriorated afterwards, and reached the maximum expression at 48 h. However, [3H]thymidine incorporation was more pronounced in intermittent high glucose than in constant high glucose. Treatment with constant high glucose for 48 h significantly increase cell number, MMP-2 activation, OPN protein and mRNA expression compared with VSMCs treated with the cells normal glucose, and these effects were further enhanced when VSMCs were treated with intermittent high glucose. In addition, neutralizing antibodies to either OPN or its receptor β3 integrin but not neutralizing antibodies to β5 integrin significantly suppressed increase in [3H]thymidine incorporation and MMP-2 activity induced by constant or intermittent high glucose. Conclusions In cultured VSMCs, constant high glucose concentrations enhanced MMP-2 activity, cell proliferation and OPN expression. These effects are enhanced following intermittent exposure to high glucose, indicating that short lived excursions in glycaemic control have important pathological effects on the development of diabetic atherosclerosis, which is mediated by the stimulation of OPN expression and synthesis.

Elevated circulating concentrations of interleukin-18 (IL-18), monocyte chemoattractant protein-1 (MCP-1), and plasminogen activator inhibitor-1 (PAI-1) and decrease of adiponectin are associated with obesity-related diseases. The mechanism that mediates the aberrant production of the adipokines remains poorly understood. The aim of this study was to investigate the effect of intermittent high glucose on the expression of IL-18, MCP-1, and PAI-1 and adiponectin in 3T3-L1 adipocytes. 3T3-L1 adipocytes were incubated for 24 h in media containing different glucose concentrations: 5 mmol/l, 20 mmol/l and a daily alternating 5 or 20 mmol/l glucose, with or without the addition of 1.0 mmol/l N-acetylcysteine (NAC). The expression and secretion of IL-18, MCP-1, PAI-1, and adiponectin were determined by real-time RT-PCR and ELISA, respectively. The production of reactive oxygen species (ROS) and 8-hydroxydeoxyguanosine (8-OHdG) were measured. Stable high glucose significantly increased expression and secretion of IL-18, MCP-1, and PAI-1, and reduced adiponectin expression and secretion compared to normal glucose conditions. These effects were significantly greater under intermittent high glucose conditions compared to stable high glucose. The level of ROS and 8-OHdG were significantly elevated under both intermittent and stable high glucose conditions, the effect being greater under intermittent high glucose. The intermittent glucose was more effective in triggering the generation of ROS than stable high glucose. The adding of the NAC, a specific pharmacological inhibitor of ROS, normalized the expression of these adipokines and the levels of ROS and 8-OHdG under both stable and intermittent glucose conditions. Intermittent high glucose induces a greater aberrant production of key adipokines than stable high glucose, and this effect seems to be related to over-production of ROS.

Summary Aim In this study we investigated the association of FTO rs9939609 and MC4R. rs17782313 with elevated blood pressure in the Chinese Han population, and analysed the relationship between the rs9939609 and rs17782313 variants. Methods We tested the rs9939609 and rs17782313 variants with the sequence-retrieval method. Results The increase in odds ratios of the A allele of rs9939609 and the C allele of rs17782313 for nocturnal blood pressure were 1.37 and 1.69. The nocturnal blood pressure of participants simultaneously carrying the A and C alleles was significantly higher than the blood pressure of those carrying neither FTO nor MC4R risk alleles (p < 0.05), and that of the controls carrying only the A or C alleles (p < 0.05). No association between the FTO or MC4R genes with daytime hypertension was found in this Chinese population (p > 0.05). Conclusion Our data suggest that the rs9939609 and rs17782313 variants may be significantly associated with nocturnal but not daytime blood pressure levels and their combined effects were significant in this Chinese Han population.

Hypoadiponectinemia and hyperresistinemia may be important in mediating signals from adipocytes to insulin-sensitive tissue and vasculature. However, the mechanism that mediates the aberrant production of adipokines remains poorly understood. In this study, we have investigated the effect of intermittent high glucose on the expression of adiponectin and resistin, and the production of 8-hydroxydeoxyguanosine (8-OHdG) and nitrotyrosine in the adipocytes, either in the presence or in the absence of Mn(III) tetrakis(4-benzoic acid) porphyrin chloride (MnTBAP) or thenoyltrifluoroacetone (TTFA). 3T3-L1 adipocytes were incubated for 72 h in media containing different glucose concentrations: 5 mmol/l, 20 mmol/l, 5 mmol/l alternating with 20 mmol/l glucose, with or without MnTBAP and TTFA. We measured the expression of resistin and adiponectin. The production of nitrotyrosine and 8-OHdG as oxidative stress parameter was measured. Both constant and intermittent high glucose significantly suppressed the expression and secretion of adiponectin, and increased expression and secretion of resistin in mature adipocytes compared to normal glucose conditions. However, these effects were significantly greater under intermittent high glucose conditions compared to constant high glucose. The levels of nitrotyrosine and 8-OHdG were significantly elevated under both intermittent and constant high glucose conditions, the effect being greater under intermittent high glucose. In addition, the antioxidants MnTBAP or TTFA reversed the aberrant production of adiponectin and resistin, as well as overproduction of nitrotyrosine and 8-OHdG in adipocytes induced by constant or intermittent high glucose. Intermittent high glucose exacerbates the aberrant production of adiponectin and resistin through reactive oxygen species overproduction at the mitochondrial transport chain level in adipocytes, indicating that glycemic variability has important pathological effects on the secretion of adipokines.

Glucose fluctuations are strong predictor of diabetic vascular complications. We explored the effects of constant and intermittent high glucose on the proliferation and collagen synthesis of cultured rat mesangial cells. Furthermore, the possible involvement of osteopontin (OPN) was assessed. In rat mesangial cells cultured in 5, 25, or 5 mmol/L alternating with 25 mmol/L glucose in the absence or presence of neutralizing antibodies to OPN, beta3 integrin receptor and beta5 integrin receptor, the cell proliferation, collagen synthesis, and the expression of OPN and type IV collagen were assessed. In cultured mesangial cells, treatment with constant or intermittent high glucose significantly increased [(3)H]thymidine incorporation in a time-dependent manner. A modest increase was observed at 12 h, and further deteriorated afterwards, and reached the maximum incorporation at 48 h. Treatment with constant high glucose for 48 h resulted in significant increases in [(3)H]thymidine incorporation, cell number, [(3)H]proline incorporation, mRNA, and protein levels of type IV collagen and OPN compared with mesangial cells treated with the normal glucose, which were markedly enhanced in cells exposed to intermittent high glucose medium. In addition, neutralizing antibodies to either OPN or its receptor beta3 integrin but not neutralizing antibodies to beta5 integrin can effectively prevented proliferation and collagen synthesis of mesangial cells induced by constant or intermittent high glucose. Intermittent high glucose exacerbates mesangial cells growth and collagen synthesis by upregulation of OPN expression, indicating that glycemic variability have important pathological effects on the development of diabetic nephropathy, which is mediated by the stimulation of OPN expression and synthesis.

Purpose: Various genetic variants of the fat mass and obesity associated gene (FTO) have been linked to obesity in populations of Europeans. Low-grade inflammation is a key feature of obesity, characterized by elevated plasma levels of C-reactive protein (CRP). In the present study, we have investigated whether the FTO-risk variant is associated with obesity and CRP in the Chinese population. Methods: 1799 individuals aged 50-70 years (896 men and 903 women), including both obese (560 cases) and control individuals, (1200 cases) were recruited. The FTO rs9939609 polymorphism was tested using sequences retrieval. Waist circumference, body fat, hs-CRP, blood total cholesterol, triglycerides and LDL-C were also measured. Results: The FTO rs9939609 polymorphism per-A allele was associated with an increased odds ratio for obesity of 1.42 (95%CI 1.23-1.64). The genotypic odds ratio for obesity was 1.92 (95%CI 1.43-2.57) for the AA genotype, 1.71 (95%CI 1.35-2.16) for the AT genotype. The association between FTO rs9939609 polymorphism and CRP levels was r=0.78. Conclusion: Our data support the hypothesis that FTO rs9939609 polymorphism is strongly associated with obesity and CRP levels in the Chinese population as reported in the European population.