Neuroprotective mechanism of Kai Xin San: upregulation of hippocampal insulin-degrading enzyme protein expression and acceleration of amyloid-beta degradation

Kai Xin San is a Chinese herbal formula composed of Radix Ginseng, Poria, Radix Polygalae and Acorus Tatarinowii Rhizome. It has been used in China for many years for treating amnesia. Kai Xin San ameliorates amyloid-β （Aβ） induced cognitive dysfunction and is neuroprotective in vivo, but its precise mechanism remains unclear. Expression of insulin-degrading enzyme （IDE）, which degrades Aβ, is strongly correlated with cognitive function. Here, we injected rats with exogenous Aβ42 （200 μM, 5 μL） into the hippocampus and subsequently administered Kai Xin San （0.54 or 1.08 g/kg/d） intragastrically for 21 consecutive days. Hematoxylin eosin and Nissl staining revealed that Kai Xin San protected neurons against Aβ-induced damage. Furthermore, enzyme linked immunosorbent assay, western blot and polymerase chain reaction results showed that Kai Xin San decreased Aβ42 protein levels and increased expression of IDE protein, but not mRNA, in the hippocampus. Our findings reveal that Kai Xin San facilitates hippocampal Aβ degradation and increases IDE expression, which leads, at least in part, to the alleviation of hippocampal neuron injury in rats.

Maternal Lead Exposure Induces Down-regulation of Hippocampal Insulin-degrading Enzyme and Nerve Growth Factor Expression in Mouse Pups

Lead exposure is a known potential risk factor for neurodegenerative diseases such as Alzheimer’s disease （AD）. Exposure to lead during the critical phase of brain development has been linked with mental retardation and hypophrenia in later life.

Early renal injury indicators can help evaluate renal injury in patients with chronic hepatitis B with long-term nucleos(t)ide therapy

BACKGROUND Patients with chronic hepatitis B(CHB)with long-term nucleos(t)ide therapy may experience renal insufficiency.Traditional renal function indicators,such as urine protein,serum urea nitrogen(BUN),and serum creatinine,are normal when early mild lesions occur.Therefore,more sensitive renal function indicators are needed.AIM To investigate the significance of early renal injury indicators in evaluating renal injury in patients with CHB with long-term nucleos(t)ide therapy.METHODS We collected the clinical data of 69 outpatients with CHB at Peking University First Hospital from March 2018 to January 2020 who had been treated with longterm nucleos(t)ide therapy and analyzed the results of early renal injury indicators.Continuous normal distribution data were analyzed by the t-test to determine the difference between two groups.Continuous non-normally distributed data were analyzed by the Mann-Whitney U-test between two groups.The Kruskal-Wallis H test was used to determine the differences among multiple groups.Enumeration data were analyzed by the chi-square test.The related factors of early renal injury indicators were analyzed by logistic regression analysis.RESULTS The average treatment duration with nucleos(t)ide analogs of the 69 patients with CHB was 99.7±28.7 mo.The cases of patients with elevated BUN and hypophosphatemia were 6(8.7%)and 13(18.8%),respectively;31(44.9%)patients had abnormal early renal injury indicators,including 9 patients with abnormal urine microalbumin,7 patients with abnormal urine immunoglobulin,6 patients with abnormal urine transferrin,and 19 patients with abnormalα1 microglobulin.There were no significant differences in the mean values of age,sex,BUN,estimated glomerular filtration rate(eGFR),serum uric acid,serum calcium,or serum phosphorus between the two groups of patients with and without early renal injury indicators.However,the mean levels of serum creatinine and urine creatinine,N-acetyl-β-D-glucosidase enzyme,α1 microglobulin,and urine immunoglobulin in the former group of patients were significantly higher than those in the latter group of patients(P<0.05).The incidence of early renal injury in patients with eGFR≥90,60-89,and 30-59 mL/(min·1.73 m2)was 36.4%(8/22),47.6%(20/42),and 60%(3/5),respectively.Logistic regression analysis results showed that gamma-glutamyl transpeptidase[odds ratio(OR)=1.05(1.008-1.093),P=0.020],direct bilirubin[OR=1.548(1.111-2.159),P=0.010],serum creatinine[OR=1.079(1.022-1.139),P=0.006],and age[OR=0.981(0.942-1.022),P=0.357]were independent predictors of early renal injury.CONCLUSION Patients with CHB treated with long-term nucleos(t)ide analog therapy had a high probability of early renal injury,and early renal injury indicators were highly sensitive and could be used to monitor early renal impairment.

Correlation of IDE gene rs11187007 locus polymorphism with insulin resistance and systemic inflammatory response in patients with GDM

Objective:To study the correlation of insulin-degrading enzyme (IDE) gene rs11187007 locus polymorphism with insulin resistance and systemic inflammatory response in patients with gestational diabetes mellitus (GDM).Methods: The pregnant women diagnosed with GDM in our hospital between March 2015 and January 2018 were selected as the GDM group, and healthy pregnant women who had prenatal examination and gave birth during the same period were selected as the control group. Peripheral blood was collected to measure the genotype of IDE gene rs11187007 locus as well as the contents of cytokines IL-6, IL-10, TNF-α, Chemerin and Omentin-1, and placenta was collected to measure the expression levels of IRS-1, IRS-2, GLUT3 and GLUT4.Results: The constituent ratio of IDE gene rs11187007 locus AA genotype, IL-10 and Omentin-1 contents in peripheral blood as well as IRS-1, IRS-2, GLUT3 and GLUT4 mRNA expression levels in placenta of GDM group were all lower than those of control group whereas the constituent ratio of IDE gene rs11187007 locus AG genotype and GG genotype as well as IL-6, TNF-α and Chemerin contents in peripheral blood were higher than those of control group;IRS-1, IRS-2, GLUT3 and GLUT4 mRNA expression levels in the GDM placenta with AG genotype and GG genotype as well as IL-10 and Omentin-1 contents in the peripheral blood were lower than those in the GDM placenta with AA genotype whereas IL-6, TNF-α and Chemerin contents in the peripheral blood were higher than those in the GDM placenta with AA genotype.Conclusion: The mutation from IDE gene rs11187007 allele A to G in GDM patients can aggravate the insulin resistance and systemic inflammatory response.

黑逍遥散对AD模型小鼠海马区Aβ_(1-42),GSK-3β,NEP,IDE表达的影响

目的:研究黑逍遥散对阿尔茨海默症(Alzheimer disease,AD)小鼠海马区β淀粉样多肽1-42(β-amyloid 1-42peptide,Aβ1-42),糖原合成酶激酶-3(glycogen synthase kinase-3β,GSK-3β),脑啡肽酶(neprilysin,NEP),胰岛素抵抗酶(insulindegrading enzyme,IDE)表达的影响。方法:42只APP/PSI双转基因小鼠称体质量后,按随机原则分为4组,分别为模型组,阳性药组(盐酸多奈哌齐,3. 25 mg·kg-1),黑逍遥散高、低剂量组(6,3 g·kg-1)。10只同月龄、同种系的野生型C57BL/6J小鼠为正常组。连续灌胃12周后,Morris水迷宫予以行为学检测,苏木素-伊红(HE)染色观察海马神经元的形态改变,采用免疫组化技术分别检测小鼠海马区Aβ1-42,GSK-3β,NEP,IDE蛋白的表达。结果:治疗3个月后,与正常组比较,AD模型组小鼠,逃避潜伏期均延长,跨原平台次数减少(P <0. 01),小鼠海马区Aβ1-42,GSK-3β蛋白阳性表达显著增强,NEP与IDE蛋白阳性表达显著减弱(P <0. 01),HE染色显示AD模型小鼠海马神经细胞损伤严重;与模型组比较,用药各组小鼠的逃避潜伏期均显著缩短、跨原平台次数均显著增加(P <0. 05,P <0. 01),小鼠海马区Aβ1-42,GSK-3β蛋白阳性表达显著减弱,NEP与IDE蛋白阳性表达显著增强(P <0. 05,P <0. 01),HE染色显示各治疗组小鼠海马神经细胞损伤减轻。结论:黑逍遥散能够显著改善AD小鼠的学习记忆能力,可能与调节Aβ在海马区的异常沉积和降解作用等方面来减轻AD小鼠认知能力损伤有关。

Advances in the pathogenesis of Alzheimer’s disease:a re-evaluation of amyloid cascade hypothesis

Alzheimer’s disease(AD)is a common neurodegenerative disease characterized clinically by progressive deterioration of memory,and pathologically by histopathological changes including extracellular deposits of amyloid-beta(A-beta)peptides forming senile plaques(SP)and the intracellular neurofibrillary tangles(NFT)of hyperphosphorylated tau in the brain.This review focused on the new developments of amyloid cascade hypothesis with details on the production,metabolism and clearance of A-beta,and the key roles of some important A-beta-related genes in the pathological processes of AD.The most recent research advances in genetics,neuropathology and pathogenesis of the disease were also discussed.