Variation of plantar pressure in Chinese diabetes mellitus

To investigate dynamic changes in plantar pressure in Chinese diabetes mellitus patients and to provide a basis for further preventing diabetic foot. This is a cross‐sectional investigation including 649 Chinese diabetes mellitus patients (diabetes group) and 808 “normal” Chinese persons (nondiabetes group) with normal blood glucose levels. All the subjects provided a complete medical history and underwent a physical examination and a 75‐g oral glucose tolerance test. All subjects walked barefoot with their usual gait, and their dynamic plantar forces were measured using the one‐step method with a plantar pressure measurement instrument; 5 measurements were performed for each foot. No significant differences were found in age, height, body weight, or body mass index between the two groups. The fasting blood glucose levels, plantar contact time, maximum force, pressure‐time integrals and force‐time integrals in the diabetes group were significantly higher than those in the nondiabetes group (p < 0.05). However, the maximum pressure was significantly higher in the nondiabetes group than in the diabetes group (p < 0.05). No difference was found in the contact areas between the two groups (p > 0.05). The maximum plantar force distributions were essentially the same, with the highest force found for the medial heel, followed by the medial forefoot and the first toe. The peak plantar pressure was located at the medial forefoot for the nondiabetes group and at the hallucis for the diabetes group. In the diabetes group, the momentum in each plantar region was higher than that in the nondiabetes group; this difference was especially apparent in the heel, the lateral forefoot and the hallucis. The dynamic plantar pressures in diabetic patients differ from those in nondiabetic people with increased maximum force and pressure, a different distribution pattern and significantly increased momentum, which may lead to the formation of foot ulcers.     

Thioredoxin-Interacting Protein Deficiency Protects against Diabetic Nephropathy

Expression of thioredoxin-interacting protein (TxNIP), an endogenous inhibitor of the thiol oxidoreductase thioredoxin, is augmented by high glucose (HG) and promotes oxidative stress. We previously reported that TxNIP-deficient mesangial cells showed protection from HG-induced reactive oxygen species, mitogen-activated protein kinase phosphorylation, and collagen expression. Here, we investigated the potential role of TxNIP in the pathogenesis of diabetic nephropathy (DN) in vivo. Wild-type (WT) control, TxNIP^−/−, and TxNIP^+/− mice were rendered equally diabetic with low-dose streptozotocin. In contrast to effects in WT mice, diabetes did not increase albuminuria, proteinuria, serum cystatin C, or serum creatinine levels in TxNIP^−/− mice. Whereas morphometric studies of kidneys revealed a thickened glomerular basement membrane and effaced podocytes in the diabetic WT mice, these changes were absent in the diabetic TxNIP^−/− mice. Immunohistochemical analysis revealed significant increases in the levels of glomerular TGF-β1, collagen IV, and fibrosis only in WT diabetic mice. Additionally, only WT diabetic mice showed significant increases in oxidative stress (nitrotyrosine, urinary 8-hydroxy-2-deoxy-guanosine) and inflammation (IL-1β mRNA, F4/80 immunohistochemistry). Expression levels of Nox4-encoded mRNA and protein increased only in the diabetic WT animals. A significant loss of podocytes, assessed by Wilms’ tumor 1 and nephrin staining and urinary nephrin concentration, was found in diabetic WT but not TxNIP^−/− mice. Furthermore, in cultured human podocytes exposed to HG, TxNIP knockdown with siRNA abolished the increased mitochondrial O₂⁻ generation and apoptosis. These data indicate that TxNIP has a critical role in the progression of DN and may be a promising therapeutic target.     

EGF Receptor Deletion in Podocytes Attenuates Diabetic Nephropathy

The generation of reactive oxygen species (ROS), particularly superoxide, by damaged or dysfunctional mitochondria has been postulated to be an initiating event in the development of diabetes complications. The glomerulus is a primary site of diabetic injury, and podocyte injury is a classic hallmark of diabetic glomerular lesions. In streptozotocin-induced type 1 diabetes, podocyte-specific EGF receptor (EGFR) knockout mice (EGFR^podKO) and their wild-type (WT) littermates had similar levels of hyperglycemia and polyuria, but EGFR^podKO mice had significantly less albuminuria and less podocyte loss compared with WT diabetic mice. Furthermore, EGFR^podKO diabetic mice had less TGF-β1 expression, Smad2/3 phosphorylation, and glomerular fibronectin deposition. Immunoblotting of isolated glomerular lysates revealed that the upregulation of cleaved caspase 3 and downregulation of Bcl2 in WT diabetic mice were attenuated in EGFR^podKO diabetic mice. Administration of the SOD mimetic mito-tempol or the NADPH oxidase inhibitor apocynin attenuated the upregulation of p-c-Src, p-EGFR, p-ERK1/2, p-Smad2/3, and TGF-β1 expression and prevented the alteration of cleaved caspase 3 and Bcl2 expression in glomeruli of WT diabetic mice. High-glucose treatment of cultured mouse podocytes induced similar alterations in the production of ROS; phosphorylation of c-Src, EGFR, and Smad2/3; and expression of TGF-β1, cleaved caspase 3, and Bcl2. These alterations were inhibited by treatment with mito-tempol or apocynin or by inhibiting EGFR expression or activity. Thus, results of our studies utilizing mice with podocyte-specific EGFR deletion demonstrate that EGFR activation has a major role in activating pathways that mediate podocyte injury and loss in diabetic nephropathy.     

Store–Operated Ca2+ Channels in Mesangial Cells Inhibit Matrix Protein Expression

Accumulation of extracellular matrix derived from glomerular mesangial cells is an early feature of diabetic nephropathy. Ca²⁺ signals mediated by store–operated Ca²⁺ channels regulate protein production in a variety of cell types. The aim of this study was to determine the effect of store–operated Ca²⁺ channels in mesangial cells on extracellular matrix protein expression. In cultured human mesangial cells, activation of store–operated Ca²⁺ channels by thapsigargin significantly decreased fibronectin protein expression and collagen IV mRNA expression in a dose-dependent manner. Conversely, inhibition of the channels by 2-aminoethyl diphenylborinate significantly increased the expression of fibronectin and collagen IV. Similarly, overexpression of stromal interacting molecule 1 reduced, but knockdown of calcium release–activated calcium channel protein 1 (Orai1) increased fibronectin protein expression. Furthermore, 2-aminoethyl diphenylborinate significantly augmented angiotensin II–induced fibronectin protein expression, whereas thapsigargin abrogated high glucose– and TGF-β1–stimulated matrix protein expression. In vivo knockdown of Orai1 in mesangial cells of mice using a targeted nanoparticle siRNA delivery system resulted in increased expression of glomerular fibronectin and collagen IV, and mice showed significant mesangial expansion compared with controls. Similarly, in vivo knockdown of stromal interacting molecule 1 in mesangial cells by recombinant adeno–associated virus–encoded shRNA markedly increased collagen IV protein expression in renal cortex and caused mesangial expansion in rats. These results suggest that store–operated Ca²⁺ channels in mesangial cells negatively regulate extracellular matrix protein expression in the kidney, which may serve as an endogenous renoprotective mechanism in diabetes.     

Disruption of Renal Tubular Mitochondrial Quality Control by Myo-Inositol Oxygenase in Diabetic Kidney Disease

Diabetic kidney disease (DKD) is associated with oxidative stress and mitochondrial injury. Myo-inositol oxygenase (MIOX), a tubular-specific enzyme, modulates redox imbalance and apoptosis in tubular cells in diabetes, but these mechanisms remain unclear. We investigated the role of MIOX in perturbation of mitochondrial quality control, including mitochondrial dynamics and autophagy/mitophagy, under high-glucose (HG) ambience or a diabetic state. HK-2 or LLC-PK1 cells subjected to HG exhibited an upregulation of MIOX accompanied by mitochondrial fragmentation and depolarization, inhibition of autophagy/mitophagy, and altered expression of mitochondrial dynamic and mitophagic proteins. Furthermore, dysfunctional mitochondria accumulated in the cytoplasm, which coincided with increased reactive oxygen species generation, Bax activation, cytochrome C release, and apoptosis. Overexpression of MIOX in LLC-PK1 cells enhanced the effects of HG, whereas MIOX siRNA or d-glucarate, an inhibitor of MIOX, partially reversed these perturbations. Moreover, decreasing the expression of MIOX under HG ambience increased PTEN-induced putative kinase 1 expression and the dependent mitofusin-2–Parkin interaction. In tubules of diabetic mice, increased MIOX expression and mitochondrial fragmentation and defective autophagy were observed. Dietary supplementation of d-glucarate in diabetic mice decreased MIOX expression, attenuated tubular damage, and improved renal functions. Notably, d-glucarate administration also partially attenuated mitochondrial fragmentation, oxidative stress, and apoptosis and restored autophagy/mitophagy in the tubular cells of these mice. These results suggest a novel mechanism linking MIOX to impaired mitochondrial quality control during tubular injury in the pathogenesis of DKD and suggest d-glucarate as a potential therapeutic agent for the amelioration of DKD.     

肾素原受体在糖尿病视网膜病变中的作用及其机制研究

目的：观察糖尿病视网膜病变发生过程中肾素原受体（PRR）及血管紧张素Ⅱ受体2（AT2R）的表达水平及视网膜神经细胞凋亡情况,阐明 PRR 与糖尿病视网膜神经细胞凋亡的关系。方法建立链尿佐菌素诱导的糖尿病 SD 大鼠模型,建模成功后分别在4周、8周和12周用免疫组化法检测 CD14及8-羟脱氧鸟苷分子的表达,检测糖尿病及对照组视网膜 AT2R、PRR mRNA 的表达及细胞外信号调节激酶（ERK1/2）、磷酸化 ERK1/2（p-ERK1/2）蛋白的表达。结果各病程 SD 大鼠视网膜 AT2R 和 PRR 的 mRNA 表达水平较对照组明显升高（P <0.05）,随病程的延长表达量随之增多。病程越长糖尿病组大鼠视网膜组织凋亡细胞数量越多,各阶段病程 CD14染色未见明显新生血管。通过相关性分析显示,PRR 和 AT2R 表达水平与神经节细胞凋亡相关。各病程大鼠视网膜 ERK1/2、p-ERK1/2蛋白的表达量显著高于对照组。结论糖尿病视网膜病变中 PRR 和 AT2R 的表达与大鼠糖尿病视网膜病变的神经节细胞凋亡相关,可能通过增加 ERK 的磷酸化水平发挥功能作用。     

白芍总苷对糖尿病大鼠肾组织Txnip、Trx与ASK1表达的调节作用

目的：了解白芍总苷( TGP)对糖尿病大鼠肾组织硫氧还蛋白相互作用蛋白( Txnip)、硫氧还蛋白( Trx)与凋亡信号激酶1(ASK1)表达的影响,探讨TGP对糖尿病肾组织Trx系统调节作用。方法将链脲佐菌素( STZ)诱导的糖尿病大鼠随机分为模型组、TGP [50、100、200 mg/(kg·d)]给药组,另取正常大鼠为对照组,8周后测定大鼠尿白蛋白排泄率( UAER)。应用免疫组化、Western blot法及实时定量PCR法检测大鼠肾组织Txnip、Trx与ASK1表达。结果实验8周后TGP[50、100、200 mg/(kg·d)]给药组及对照组大鼠UAER水平均低于模型组(P<0．01);免疫组化和(或)West-ern blot法显示TGP [50、100、200 mg/(kg·d)]给药组及对照组大鼠肾组织Txnip、ASK1表达低于模型组( P<0．05,P<0．01),而Trx高于模型组(P<0．05,P<0．01);实时定量PCR显示TGP [50、100、200 mg/(kg·d)]给药组及对照组Txnip mRNA低于模型组(P<0．01,P<0．05),Trx mRNA高于模型组(P<0．01,P<0．05)。结论糖尿病肾病大鼠肾组织存在Trx系统异常,TGP对糖尿病大鼠肾组织保护作用可能与抑制Txnip表达、提高Trx表达有关。     

青蒿琥酯对高糖诱导的肾小管上皮细胞TLR4、NF-κB表达及合成的影响

目的：探讨青蒿琥酯( Art)对高糖诱导下的大鼠肾小管上皮细胞(NRK-52E)Toll样受体4(TLR4)、核转录因子-κB( NF-κB)表达及合成的影响。方法体外培养NRK-52E细胞,分为6组：正常对照组、高糖组、Art小剂量组、Art中剂量组、Art高剂量组、依那普利组。培养48 h后收集各组细胞,采用逆转录-聚合酶链反应( RT-PCR)法检测细胞TLR4、NF-κB mRNA 含量;采用 Western blot 法检测细胞TLR4、NF-κB蛋白表达水平。结果①与正常对照组比较,高糖组细胞TLR4、NF-κB mRNA和蛋白表达水平明显升高( P <0．05);②与高糖组比较, Art 小、中、高剂量组细胞TLR4、NF-κB mRNA和蛋白表达水平明显降低,且呈剂量依赖性(P<0．05);③与依那普利组比较,Art小、中、高剂量组细胞TLR4水平表达均升高,且Art高剂量组与依那普利组差异无统计学意义。与依那普利组比较,Art小、中剂量组细胞NF-κB水平表达升高,Art高剂量组细胞NF-κB水平表达降低,且Art中、高剂量组与依那普利组差异无统计学意义。结论 Art可呈剂量依赖性地抑制高糖环境下NRK-52E细胞TLR4、NF-κB的高表达及合成。     

芪藿复方合剂联合西药治疗糖尿病肾病Ⅲ期临床研究

目的观察芪藿复方合剂治疗脾肾气虚型早期糖尿病肾病(diabetic nephropathy,DN)Ⅲ期的临床疗效。方法将60例脾肾气虚型DNⅢ期患者随机分为治疗组和对照组,每组30例。对照组给予降血糖、降血压等对症处理,治疗组加用芪藿复方合剂治疗,疗程3个月。观察两组治疗前后24h尿微量蛋白(urinary microalbumin,UmAlb)、24h尿微量蛋白排泄率(urinary albumin excretion rate,UAER)、血清肌酐(serum creatinine,SCr)、血尿素氮(blood urine nitrogen,BUN)、空腹血糖(fasting blood glucose,FBG)、总胆固醇(total cholesterol,TC)、三酰甘油(triglycerides,TG)、C反应蛋白(C-reactive protein,CRP)及中医证候积分的变化。结果治疗组临床疗效显著优于对照组(P<0.05),治疗组总有效率显著高于对照组(83.3%vs 60.0%,P<0.05);治疗组在降低中医证候积分、FBG、TC、TG、CRP、SCr、24hUmAlb和24h UAER方面显著优于对照组。结论芪藿复方合剂对DN有一定的干预作用,可延缓DN的发展。     

芪归糖痛宁颗粒调节炎性因子预防糖尿病周围神经病变的机制研究

目的 通过观察芪归糖痛宁颗粒预防性给药对相关炎性因子的影响,探究其改善糖尿病周围神经病变(diabetic peripheral neuropathy,DPN)的机制。方法 将120只SD大鼠分为正常组,模型组,芪归糖痛宁颗粒高、中、低剂量组和甲钴胺组,采用链脲佐菌素腹腔注射联合高脂饲料喂养法复制糖尿病大鼠模型,预防性给予相应药物8周,以运动神经传导速度（motor nerve conduction velocity,MNCV）和摆尾温度阈值评价DPN的改善情况,采用酶联免疫吸附法测定大鼠血清基质金属蛋白酶-1 (matrix metalloproteinase 1,MMP-1)、肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)、白细胞介素-1（interleukin 1,IL-1）、单核细胞趋化蛋白-1（monocyte chemotactic protein 1,MCP-1)含量。结果 与正常组比较,模型组大鼠摆尾温度阈值显著升高（P<0.05）,MNCV显著下降（P<0.05）,血清MMP-1、TNF-α、IL-1和MCP-1均显著升高（P<0.05）。芪归糖痛宁颗粒对DPN大鼠的MNCV、摆尾温度阈值及血清MMP-1、TNF-α、IL-1和MCP-1的效应具有明显的剂量依赖性（P<0.05）,不同剂量对不同指标的效应呈现不同的量效关系;不同剂量芪归糖痛宁颗粒与甲钴胺对DPN大鼠的MNCV、摆尾温度阈值及血清MMP-1、TNF-α和IL-1的效应相比较,差异均具有统计学意义（P<0.05）。结论 芪归糖痛宁颗粒能预防DPN,其机制与调控复杂的炎性因子网络有关,其效应具有明显的剂量依赖性。