Pathophysiological Roles of Peroxisome Proliferator Activated Receptor (PPAR) on Development and Progression of Chronic kidney diseases -Search for a New Therapeutic Target for Chronic Kidney Diseases-

(1)过氧化物酶体增殖物激活受体（PPAR）对肾小球细胞的致病作用：在培养的大鼠系膜细胞中，高环境葡萄糖（25mM），特别是随时间波动时，促进血管内皮生长因子（VEGF）的产生和DNA合成，而PPAR激动剂噻唑嗪二酮可抑制血管内皮生长因子（VEGF）的产生和DNA合成。在18例早期2型糖尿病肾病患者的肾脏标本中，原位杂交检测的肾小球VEGF信使RNA表达与血管极和系膜基质区新生血管^<1)>（肾小球硬化）^<6)>密切相关。我们报告了一例POEMS （crowo - fukase）综合征合并2型糖尿病，其与血浆VEGF水平升高有关，但未出现糖尿病肾病的迹象^<8)bb0。我们还测量了伴有正常、微量和大量蛋白尿的2型糖尿病患者的血浆VEGF浓度，结果显示DN的存在与循环血浆VEGF浓度升高无关(2)。这些结果表明，肾脏原位VEGF的过量产生可能在早期DN中发挥局部发病作用，其依赖于PPAR和PKC。(2)腺病毒载体基因转移体系的建立及其在肾脏疾病模型动物中的应用：我们建立了RT-real - time PCR（light-cycler）检测mRNA的体系，以及利用编码PPAR、、和PAF-AH cDNA的腺病毒载体（AdhPPAR、、和AdhPAF-AH）的基因转移体系，并证实在各种培养细胞体系中分别表达各自的mRNA和蛋白。首先，将adhpf - ah转染到肾硬化模型动物（SHC大鼠），通过PAF-AH在肝脏中的表达并通过HDL颗粒转移到肾脏，从而抑制肾硬化（12）。建立肾脏特异性的、有效的基因转移系统，将促进AdhPPAR和adhpf - ah在糖尿病肾病、IgA肾病等常见肾脏疾病的各种模型动物的基因治疗中应用。(3) PPAR及其相关因素在肾脏疾病动物模型中的致病作用：IgA肾病模型小鼠（HIGA小鼠）分别饲喂亚麻酸（a， 3系列多不饱和脂肪酸（PUFA））或亚油酸（a， 6系列PUFA），这两种物质也可能是PPAR的配体。与亚麻酸相比，饲用亚麻酸能抑制蛋白尿、肾功能障碍（血浆肌酐升高）和肾小球硬化改变^<13)，提示PPAR可能参与了IgA肾病的发病机制，是PPAR治疗IgA肾病的潜在靶点。前列腺素（pufa衍生的自身类）在肾脏中的生理作用通过受体敲除mce进行了测试，表明盐敏感性部分取决于前列腺素^<10)>，但缺血性急性肾功能衰竭^<3)>。此外，将1型血管紧张素II受体（AT1）的反义寡核苷酸直接微量稀释到单侧肾切除术、盐负荷大鼠的残肾中，可改善自发性高血压大鼠（SHR）的蛋白尿和病理组织学改变，而不改变血压^<11)>，支持血管紧张素II通过ATI受体信号在肾功能障碍进展中发挥重要作用的概念。(4)针对慢性肾脏疾病心血管事件的临床研究：我们登记了大约600名HD患者，并横断面检查了与心血管发病率相关的临床参数，结果表明，最强的事件预测因子是炎症（CRP），其次是糖尿病等，除了体重、血清白蛋白和体重外，使用ARB和/或ACE抑制剂代表良好的营养状态和血液透析（HD）的有效性（Kt/V），改善了生活预后^<5)>。摄入亚麻酸可改善对照人群的CRP，但在HD患者中没有改善（论文正在准备中），这部分解释了HD患者心血管事件导致的不良预后。少

(1)Pathogenetic actions of Peroxisome Proliferator Activated Receptor (PPAR) on glomerular cells: In rat mesangial cells in culture, high ambient glucose(25mM), especially when fluctuated time by time, promoted Vascular Endothelial Growth Factor(VEGF) production and DNA synthesis, which is inhibited by treatment of the cells with a thiazolizinedione, a PPAR, agonist. In the kidney specimens from 18 type 2 patients with early stage of diabetic nephropathy, glomerular VEGF messenger RNA expression determined by in situ hybridization is well correlated with neovasculization at the vascular pole and mesangial matrix area^<1)> (glomerular sclerosis) ^<6)>. We presented a case of POEMS (Crow-Fukase) syndrome with Type 2 diabetes, which was associated with elevated plasma VEGF level, but no sign of diabetic nephropathy^<8)>. We also measured plasma VEGF concentration in Type 2 diabetic patients with normo-, micro, and macro-albuminuria, the results of which showed that the presence of DN is n … More ot associated with an elevation of circulating plasma VEGF concentration2). These results suggest that overproduction of VEGF in situ in the kidney may play a local pathogenetic role in early-stage DN, which is dependent on PPAR,and PKC.(2)Establishment of gene transfer system using adenovirus vector and application for model animals with renal diseases : We established a system of mRNA measurement by RT-real time PCR(light-cycler) and that of gene transfer system using adeno-virus vector encoding PPAR,, and PAF-AH cDNA (AdhPPAR,,nd AdhPAF-AH) which are confirmed to express respective mRNA and protein in various culture cell systems.First, AdhPAF-AH was trasfected to a nephrosclerosis model animal (SHC rat), which resultantly inhibited nephrosclerosis through PAF-AH expression in the liver and transferred to the kidney on HDL particles12). Estabulishment of kidney specific, effective gene transfer system would promote application of AdhPPAR,、,nd AdhPAF-AH for gene therapy of various model animals for common renal disease such as diabetic nephropathy or IgA nephropathy.(3)Pathogenetic roles of PPAR and its related factors for the pathophysiology in animal models with renal diseases: IgA nephropathy model mice (HIGA mouse) were feeded with,inolenic acid (an, 3 series poly-unsaturated fatty acid (PUFA))-or linolic acid (, 6 series PUFA) which are also possible ligands for PPAR. Feeding with,inolenic acid compared to that with linolic acid inhibited proteinuria, renal dysfunction(increase in plasma creatinine) and glomerular sclerotic change^<13)>, suggesting a potential involvement in pathogenesis and a potential therapeutic target of PPAR for IgA nephropathy. The physiological roles of prostanoids (PUFA-derived autacoid) in the kidney are tested using their receptor knoch-out mce, suggesting that salt-sensitivity is partly dependent upon prostanoids^<10)>, but ischemic acute renal failure^<3)>. In additon, direct micro-dilution into the remnant kidney in unilateral nephrectomizen, salt-loaded rats of an anti-sense oligonucleotide to type 1 angiotensin II receptor(AT1) amelionate proteinuria and patho-histological changes without changing blood pressure in spontaneous hypertensive rats (SHR) ^<11)>, supporting the concept that angiotensin II locally produced plays a significant roles in progression of renal dysfunction via ATI receptor signals.(4)Clinical studies targeted for cardio-vascular events in chronic kidney diseases : We registered about 600 HD patients and cross-sectionally examined the clinical parameters responsible for incidence of cardiovascular, which showed that the strongest predictor for events is inflammation (CRP) followed by diabetes and so forth and that use of ARB and/or ACE inhibitors inaddition of BW, serum albumin and body weight representative for good nutritional state and effectiveness of hemodialysis (HD) (Kt/V) improved life prognosis^<5)>. Intake of, inolenic acid improved CRP in the control population, but not in the HD patients (manuscript in preparation), explaining partly poor prognosis due to cardiovascular events of HD patients. Less