Aging and uremia: Is there cellular and molecular crossover?

Many observers have noted that the morphological changes that occur in chronic kidney disease(CKD) patients resemble those seen in the geriatric population, with strikingly similar morbidity and mortality profiles and rates of frailty in the two groups, and shared characteristics at a pathophysiological level especially in respect to the changes seen in their vascular andimmune systems. However, whilst much has been documented about the shared physical characteristics of aging and uremia, the molecular and cellular similarities between the two have received less attention. In order to bridge this perceived gap we have reviewed published research concerning the common molecular processes seen in aging subjects and CKD patients, with specific attention to altered proteostasis, mitochondrial dysfunction, post-translational protein modification, and senescence and telomere attrition. We have also sought to illustrate how the cell death and survival pathways apoptosis, necroptosis and autophagy are closely interrelated, and how an understanding of these overlapping pathways is helpful in order to appreciate the shared molecular basis behind the pathophysiology of aging and uremia. This analysis revealed many common molecular characteristics and showed similar patterns of cellular dysfunction. We conclude that the accelerated aging seen in patients with CKD is underpinned at the molecular level, and that a greater understanding of these molecular processes might eventually lead to new much needed therapeutic strategies of benefit to patients with renal disease.     

缬沙坦对自发性高血压大鼠脑超微结构和Klotho基因表达的影响

目的：探讨缬沙坦对自发性高血压模型鼠脑超微结构及其脑组织中Klotho基因和微炎症因子（ICAM-1和VCAM-1）表达的影响。方法：选取22周龄雄性自发性高血压模型鼠10只,随机分为高血压组与缬沙坦组（5只/组）,Wistar-kyoto大鼠（WKY）5只作为正常对照组。通过电镜观察各组大鼠脑的超微结构,RT-PCR、免疫组织化学技术和Western印迹检测Klotho基因和微炎症因子（ICAM-1和VCAM-1）的表达。结果：高血压组大鼠脑神经元细胞的超微结构主要表现为细胞固缩、染色质边集、典型凋亡小体形成,但经过缬沙坦干预后,其神经元损害有所减轻。RT-PCR结果显示缬沙坦干预能够上调Klotho mRNA表达水平、下调微炎症因子ICAM-1和VCAM-1 mRNA的表达;免疫组织化学技术和Western印迹检测证实缬沙坦干预能够增加Klotho蛋白、减少ICAM-1和VCAM-1蛋白的表达。结论：缬沙坦能够上调Klotho的表达,改善高血压脑超微结构的改变。     

高血压脑损害患者血清Klotho蛋白水平测定及相关危险因素分析

目的检测高血压脑损害患者血浆Klotho蛋白水平的变化,探讨高血压脑损害的发病机制及相关的危险因素。方法选取本科2007年9月至2008年3月留院观察的高血压、高血压合并脑损害患者及体检中心健康群共190例,分为高血压无脑损害组、高血压脑损害组与正常对照组。检测3组血清Klotho蛋白浓度与血清胆固醇、肌酐、血糖、血压水平,并针对以上因素及年龄和高血压病史等危险因素进行相关性分析。结果正常对照组血清Klotho蛋白浓度[(13.29±4.66)pg/ml]明显高于高血压无脑损害组[(8.66±3.08)pg/ml]与高血压脑损害组[(4.68±2.21)pg/ml](P<0.05),同时高血压无脑损害组明显高于高血压脑损害组(P<0.05)。血清Klotho蛋白浓度与高血压及高血压脑损害患者的胆固醇、肌酐、血糖、血压、年龄、性别以及高血压病史等均存在负相关(r值分别为-0.111、-0.225、-0.289、收缩压-0.428、舒张压-0.211、-0.404、-0.206、-0.516),胆固醇、肌酐、血糖、血压等越高、年龄越大以及高血压病史等越长,血清Klotho蛋白浓度越低。结论血清Klotho蛋白浓度...     

Klotho在急性缺血再灌注性肾损伤中的变化及其与凋亡的关系

目的 观察Klotho蛋白在缺血再灌注急性肾损伤中的表达变化,探讨其在肾小管上皮细胞凋亡中的作用。方法 10只BALB/c小鼠随机分为肾脏缺血再灌注组（I/R组, n=5）和假手术组（Sham组, n=5）,采用双侧肾蒂夹闭术建立肾缺血再灌注模型,于造模后24 h留取小鼠的血清及肾组织。应用酶法分别测定血清尿素氮和肌酐,ELISA法检测血清Klotho蛋白水平,TUNEL染色法检测肾脏细胞凋亡水平,Real-Time PCR及Western blotting技术分别检测肾组织Klotho、Bax、Bcl-2和Caspase-3的基因及蛋白表达,应用Pearson直线相关法分析急性肾损伤时小鼠全身及局部的Klotho水平和肾脏凋亡的关系。结果 与Sham组相比,I/R组小鼠术后24 h肾小管上皮细胞明显变性、坏死,肾脏凋亡细胞明显增加,肾组织cleaved Caspase-3蛋白水平、Bax/Bcl-2 mRNA及蛋白表达比值均显著升高。I/R组小鼠血清Klotho蛋白水平较Sham组小鼠显著降低[（669.89±136.51） pg/mL vs. （2 107.92±549.22） pg/mL,P〈0.01],肾组织Klotho mRNA及蛋白表达分别较Sham组下调约9/10 （P〈0.001）及1/5 （P〈0.05）。相关性分析显示肾组织bax/bcl-2 mRNA比值与血清Klotho蛋白及肾组织klotho mRNA均呈显著负相关（r=-0.833,P〈0.01;r=-0.916,P〈0.001）,肾组织Bax/Bcl-2蛋白比值和肾组织Klotho蛋白也呈显著负相关（r=-0.637,P〈0.05）。结论 缺血再灌注急性肾损伤后小鼠全身及肾组织局部Klotho表达均显著下调,Klotho水平的下降可能与凋亡诱导的肾损害密切相关。     

草酸钙肾结石大鼠模型肾组织中Klotho的表达及其意义

目的:初步探究Klotho在草酸钙肾结石大鼠模型肾组织中的表达及其意义.方法:将30只6～8周龄雄性SD大鼠随机分为结石组和对照组,每组15只,结石组采用乙二醇和氯化铵诱导法构建草酸钙肾结石模型.28 d造模完成后采集大鼠24 h尿液、血清标本,比较两组血肌酐(Cr)、尿素氮(BUN)、血Ca2+、24 h尿Ca2+及草酸(Ox)指标;采集肾组织标本,HE染色比较各组肾脏病理改变及草酸钙结晶的沉积情况,荧光定量PCR、Western印迹及免疫组织化学染色检测两组肾组织中Klotho mRNA及蛋白表达,并对肾脏氧化应激相关指标总抗氧化能力(total antioxidant capacity,T-AOC)、丙二醛(malondialdehyde,MDA)、过氧化氢酶(catalase,CAT)进行测定.结果:结石组在光学显微镜观察下可见草酸钙结石晶体沉积并有伴肾小管病理性改变,血清Cr,BUN,24 h尿Ca2+及Ox较对照组升高,差异有统计学意义(P＜0.01),血Ca2+差异无统计学意义(P＞0.05);结石组Klotho mRNA及蛋白表达较对照组下降,差异有统计学意义(P＜0.01);肾脏氧化应激相关指标中,结石组T-AOC,CAT较对照组降低,MDA较对照组升高,差异均有统计学意义(P＜0.01).结论:草酸钙肾结石的形成与Klotho表达异常及氧化应激反应有关;Klotho可能通过调控Ca2+代谢和氧化应激反应参与草酸钙肾结石的发病过程.     

可溶性Klotho蛋白抑制THP-1源性泡沫细胞形成

目的:探讨可溶性Klotho(KL)蛋白对THP-1源性泡沫细胞形成的影响。方法:THP-1单核细胞与160 nmol/L佛波酯孵育48 h后,诱导分化为THP-1源性巨噬细胞,给予THP-1源性巨噬细胞不同浓度(25、50、100和200μg/L)的可溶性KL蛋白预处理后,再由氧化型低密度脂蛋白(ox-LDL)诱导其转变为泡沫细胞。油红O染色观察细胞内脂滴形成情况,通过液体闪烁计数法测定THP-1源性泡沫细胞内胆固醇流出情况,酶荧光法检测细胞内游离胆固醇及胆固醇酯的含量,并分别用Western blot法及RT-qPCR法检测酰基辅酶A:胆固醇酰基转移酶1(ACAT1)和ATP结合盒转运体A1(ABCA1)的蛋白及mRNA表达。结果:可溶性KL蛋白能增加THP-1源性巨噬细胞内胆固醇流出,抑制THP-1源性泡沫细胞形成,且可溶性KL蛋白呈一定浓度依赖性地抑制ox-LDL诱导的泡沫细胞形成过程中ACAT1表达的上调和ABCA1表达的下调(P<0.05)。结论:可溶性KL蛋白能够抑制THP-1源性泡沫细胞形成,其机制可能与靶向调控细胞内ACAT1和ABCA1的表达有关。     

Expression and localization of fibroblast growth factor (FGF)23 and Klotho in the spleen: its physiological and functional implications

The FGF23–Klotho signaling axis is known to exert anti-aging effects via calcium–phosphorus metabolism. In mice deficient in FGF23–Klotho signaling, however, the number of splenocytes is reduced. FGF23 is expressed in both bone and spleen, with regulation of its production differing in these organs. As FGF23–Klotho signaling may play an immunological role in the spleen, splenocytes in male C57BL/6J mice were assayed for expression of Klotho or FGF23 by flow cytometry and immunohistochemistry. Cells that expressed Klotho included CD45R/B220⁺ CD21/CD35⁺ CD1d⁺ CD43^? marginal zone B cells. These cells also expressed FGF receptor 1, indicating that Klotho-positive B cells could respond to FGF23. Plasmacytoid dendritic cells (pDCs) with CD11c⁺ CD45R/B220⁺ CD11b^? CD8α^? were found to produce FGF23. Klotho-positive cells and FGF23-producing cells were present in close proximity to each other, suggesting that FGF23 produced by pDCs may act within a limited area. These findings indicate that FGF23–Klotho signaling could play a biological or immunological role in the spleen.     

Klotho upregulation contributes to the neuroprotection of ligustilide in an Alzheimer's disease mouse model

Klotho, an aging-suppressor gene, encodes a protein that potentially acts as a neuroprotective factor by modulating insulin-like growth factor 1 signaling and oxidative stress. In the present study, we investigated the potential role of Klotho in the therapeutic effect of ligustilide against Alzheimer’s disease (AD)-like neuropathologies and memory impairment in aged senescence-accelerated mouse prone-8 (SAMP8) mice. Ligustilide treatment (10 and 40 mg/kg for 8 weeks, intragastrically) in 10-month-old SAMP8 mice reduced memory deficits, amyloid-β_1–42 accumulation, tau phosphorylation, and neuron loss, increased mitochondrial manganese-superoxide dismutase and catalase expression and activity, and decreased malondialdehyde, protein carbonyl, and 8-hydroxydesoxyguanosine levels in the brain. Ligustilide upregulated Klotho expression in the cerebral choroid plexus and serum, decreased Akt and Forkhead box class O1 phosphorylation. Moreover, ligustilide inhibited the insulin-like growth factor 1 pathway and induced Forkhead box class O1 activation in 293T cells along with Klotho upregulation. An inverse correlation was found between Klotho expression and the AD phenotype, suggesting that Klotho might be a novel therapeutic target for age-related AD, and Klotho upregulation might contribute to the neuroprotective effect of ligustilide against AD.     

Fibroblast growth factor 23 and 25(OH)D levels are related to abdominal obesity and cardiovascular risk in patients with polycystic ovarian syndrome

Abstract

Fibroblast growth factor 23 (FGF23) and Klotho are extensively studied in relation to bone metabolism and progression of chronic kidney disease. There is very limited information about their role in polycystic ovarian syndrome (PCOS). The aim of the present study was to investigate some bone markers in women with PCOS in relation to obesity and cardiovascular risk. In the study were included 80 patients, divided into three age-matched groups –Non-obese PCOS (n?=?40); Obese PCOS (n?=?20) and Obese control group (n?=?20). Bone marker levels were measured by an enzyme-linked immunosorbent assay. Obese PCOS patients had higher levels of FGF23 and sRANKL, lower levels of 25(OH)D and higher prevalence of vitamin D deficiency compared to non-obese subjects. Patients with abdominal obesity (waist circumference >80?cm) independently of PCOS status had significantly higher levels of FGF23 (112.5?±?86.5 vs. 73.4?±?37.9?pg/ml; p?=?.023) and lower of 25(OH)D (35.8?±?21.4 vs 47.8?±?26.5?nmol/l; p?=?.034). Patients with PCOS at risk of cardiovascular diseases according to AE-PCOS consensus also had increased levels of FGF23 (111.6?±?84.5 vs. 66.5?±?35.1?pg/ml; p?=?.031) and decreased levels of 25(OH)D (31.9?±?16.8 vs. 47.1 vs 28.4?nmol/l; p?=?.017) compared to those not at risk. There was no correlation between bone markers and blood glucose levels, insulin resistance or hormonal levels.