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Lin H, Geng S, Yang L, Yang L, Qi M, Dong B, Xu L, Wang Y, Lv W. The effect of metabolic factors on the association between hyperuricemia and chronic kidney disease: a retrospective cohort mediation analysis. Int Urol Nephrol 2024; 56:2351-2361. [PMID: 38381286 DOI: 10.1007/s11255-024-03958-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 01/09/2024] [Indexed: 02/22/2024]
Abstract
BACKGROUND Hyperuricemia, hyperglycemia, hypertension, hyperlipidemia, and hyperhomocysteinemia are all established risk factors for chronic kidney disease (CKD), and their interplay could exacerbate CKD progression. This study aims to evaluate the potential mediation effects of hyperglycemia, hypertension, hyperlipidemia, and hyperhomocysteinemia on the association between hyperuricemia (HUA) and chronic kidney disease (CKD). METHODS We collected electronic medical record data from 2055 participants who underwent physical examinations at the Affiliated Hospital of Qingdao University. The data were utilized to investigate the mediating effect of various factors including systolic blood pressure (SBP), diastolic blood pressure (DBP), homocysteine (HCY), triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), blood glucose (Glu), and hemoglobin A1c (HbA1c) on the relationship between HUA and CKD. RESULTS Upon adjusting for confounding variables, mediation analysis indicated that only HCY acted as a mediator in the HUA-CKD relationship (p value < 0.05), exhibiting a statistically significant mediation effect of 7.04%. However, after adjustment for multiple testing, none of these variables were statistically significant. CONCLUSIONS Considering the observed associations between hyperuricemia, hyperglycemia, hypertension, hyperlipidemia, and CKD, none of the factors of interest remained statistically significant after adjusting for multiple testing as potential mediators of hyperuricemia on CKD.
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Affiliation(s)
- Hua Lin
- Department of Endocrinology and Metabolism, The Affiliated Hospital of Qingdao University, Jiangsu Road No.16, Qingdao, 266003, Shandong, China
| | - Shuo Geng
- Department of Clinical Psychology, The Affiliated Hospital of Qingdao University, Qingdao, 266003, Shandong, China
| | - Libo Yang
- Department of Endocrinology and Metabolism, The Affiliated Taian City Central Hospital of Qingdao University, Longtan Road No.29, Taian, 271000, Shandong, China
| | - Lili Yang
- Outpatient Clinic of the Affiliated Hospital of Qingdao University, Jiangsu Road No.16, Qingdao, 266003, Shandong, China
| | - Mengmeng Qi
- Department of Endocrinology and Metabolism, The Affiliated Hospital of Qingdao University, Jiangsu Road No.16, Qingdao, 266003, Shandong, China
| | - Bingzi Dong
- Department of Endocrinology and Metabolism, The Affiliated Hospital of Qingdao University, Jiangsu Road No.16, Qingdao, 266003, Shandong, China
| | - Lili Xu
- Department of Endocrinology and Metabolism, The Affiliated Hospital of Qingdao University, Jiangsu Road No.16, Qingdao, 266003, Shandong, China
| | - Yangang Wang
- Department of Endocrinology and Metabolism, The Affiliated Hospital of Qingdao University, Jiangsu Road No.16, Qingdao, 266003, Shandong, China
| | - Wenshan Lv
- Department of Endocrinology and Metabolism, The Affiliated Hospital of Qingdao University, Jiangsu Road No.16, Qingdao, 266003, Shandong, China.
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Yakupova EI, Abramicheva PA, Bocharnikov AD, Andrianova NV, Plotnikov EY. Biomarkers of the End-Stage Renal Disease Progression: Beyond the GFR. BIOCHEMISTRY. BIOKHIMIIA 2023; 88:1622-1644. [PMID: 38105029 DOI: 10.1134/s0006297923100164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Revised: 07/20/2023] [Accepted: 08/20/2023] [Indexed: 12/19/2023]
Abstract
Chronic kidney disease can progress to the end-stage renal disease (ESRD) characterized by a high risk of morbidity and mortality. ESRD requires immediate therapy or even dialysis or kidney transplantation, therefore, its timely diagnostics is critical for many patients. ESRD is associated with pathological changes, such as inflammation, fibrosis, endocrine disorders, and epigenetic changes in various cells, which could serve as ESRD markers. The review summarizes information on conventional and new ESRD biomarkers that can be assessed in kidney tissue, blood, and urine. Some biomarkers are specific to a particular pathology, while others are more universal. Here, we suggest several universal inflammatory, fibrotic, hormonal, and epigenetic markers indicative of severe deterioration of renal function and ESRD progression for improvement of ESRD diagnostics.
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Affiliation(s)
- Elmira I Yakupova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia.
| | - Polina A Abramicheva
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
| | - Alexey D Bocharnikov
- International School of Medicine of the Future, Sechenov First Moscow State Medical University, Moscow, 119992, Russia
| | - Nadezda V Andrianova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
| | - Egor Y Plotnikov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia.
- Kulakov National Medical Research Center of Obstetrics, Gynecology, and Perinatology, Moscow, 117997, Russia
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Njeim R, Alkhansa S, Fornoni A. Unraveling the Crosstalk between Lipids and NADPH Oxidases in Diabetic Kidney Disease. Pharmaceutics 2023; 15:pharmaceutics15051360. [PMID: 37242602 DOI: 10.3390/pharmaceutics15051360] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 04/25/2023] [Accepted: 04/25/2023] [Indexed: 05/28/2023] Open
Abstract
Diabetic kidney disease (DKD) is a serious complication of diabetes mellitus and a leading cause of end-stage renal disease. Abnormal lipid metabolism and intrarenal accumulation of lipids have been shown to be strongly correlated with the development and progression of diabetic kidney disease (DKD). Cholesterol, phospholipids, triglycerides, fatty acids, and sphingolipids are among the lipids that are altered in DKD, and their renal accumulation has been linked to the pathogenesis of the disease. In addition, NADPH oxidase-induced production of reactive oxygen species (ROS) plays a critical role in the development of DKD. Several types of lipids have been found to be tightly linked to NADPH oxidase-induced ROS production. This review aims to explore the interplay between lipids and NADPH oxidases in order to provide new insights into the pathogenesis of DKD and identify more effective targeted therapies for the disease.
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Affiliation(s)
- Rachel Njeim
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL 33136, USA
- Peggy and Harold Katz Family Drug Discovery Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Sahar Alkhansa
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut 1107-2020, Lebanon
- AUB Diabetes, American University of Beirut, Beirut 1107-2020, Lebanon
| | - Alessia Fornoni
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL 33136, USA
- Peggy and Harold Katz Family Drug Discovery Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA
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Klemens CA, Dissanayake LV, Levchenko V, Zietara A, Palygin O, Staruschenko A. Modulation of blood pressure regulatory genes in the Agtrap-Plod1 locus associated with a deletion in Clcn6. Physiol Rep 2022; 10:e15417. [PMID: 35927940 PMCID: PMC9353118 DOI: 10.14814/phy2.15417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 07/15/2022] [Accepted: 07/18/2022] [Indexed: 06/15/2023] Open
Abstract
The AGTRAP-PLOD1 locus is a conserved gene cluster containing several blood pressure regulatory genes, including CLCN6, MTHFR, NPPA, and NPPB. Previous work revealed that knockout of Clcn6 on the Dahl Salt-Sensitive (SS) rat background (SS-Clcn6) resulted in lower diastolic blood pressure compared to SS-WT rats. Additionally, a recent study found sickle cell anemia patients with mutations in CLCN6 had improved survival and reduced stroke risk. We investigated whether loss of Clcn6 would delay the mortality of Dahl SS rats on an 8% NaCl (HS) diet. No significant difference in survival was found. The ability of Clcn6 to affect mRNA expression of nearby Mthfr, Nppa, and Nppb genes was also tested. On normal salt (0.4% NaCl, NS) diets, renal Mthfr mRNA and protein expression were significantly increased in the SS-Clcn6 rats. MTHFR reduces homocysteine to methionine, but no differences in circulating homocysteine levels were detected. Nppa mRNA levels in cardiac tissue from SS-Clcn6 rat in both normotensive and hypertensive conditions were significantly reduced compared to SS-WT. Nppb mRNA expression in SS-Clcn6 rats on a NS diet was also substantially decreased. Heightened Mthfr expression would be predicted to be protective; however, diminished Nppa and Nppb expression could be deleterious and by preventing or blunting vasodilation, natriuresis, and diuresis that ought to normally occur to offset blood pressure increases. The conserved nature of this genetic locus in humans and rats suggests more studies are warranted to understand how mutations in and around these genes may be influencing the expression of their neighbors.
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Affiliation(s)
- Christine A. Klemens
- Department of Molecular Pharmacology and PhysiologyUniversity of South FloridaTampaFloridaUSA
- Hypertension and Kidney Research CenterUniversity of South FloridaTampaFloridaUSA
| | - Lashodya V. Dissanayake
- Department of Molecular Pharmacology and PhysiologyUniversity of South FloridaTampaFloridaUSA
- Department of PhysiologyMedical College of WisconsinMilwaukeeWisconsinUSA
| | - Vladislav Levchenko
- Department of Molecular Pharmacology and PhysiologyUniversity of South FloridaTampaFloridaUSA
| | - Adrian Zietara
- Department of Molecular Pharmacology and PhysiologyUniversity of South FloridaTampaFloridaUSA
- Department of PhysiologyMedical College of WisconsinMilwaukeeWisconsinUSA
| | - Oleg Palygin
- Department of MedicineMedical University of South CarolinaCharlestonSouth CarolinaUSA
| | - Alexander Staruschenko
- Department of Molecular Pharmacology and PhysiologyUniversity of South FloridaTampaFloridaUSA
- Hypertension and Kidney Research CenterUniversity of South FloridaTampaFloridaUSA
- James A. Haley Veterans' HospitalTampaFloridaUSA
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Liu PT, Chen JD. Synergistic association of hyperuricemia and hyperhomocysteinemia with chronic kidney disease in middle-aged adults and the elderly population. Medicine (Baltimore) 2021; 100:e27202. [PMID: 34664851 PMCID: PMC8448071 DOI: 10.1097/md.0000000000027202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 08/26/2021] [Indexed: 01/08/2023] Open
Abstract
Chronic kidney disease (CKD) is a major global public health issue. Both hyperhomocysteinemia (HHcy) and hyperuricemia are independent risk factors for CKD. In this study, we evaluated the association of HHcy and hyperuricemia with CKD in the middle-aged and elderly populations in Taiwan.In this cross-sectional study, we collected the data of 5910 patients aged ≥50 years after their self-paid health examination at a single medical center. Homocysteine (Hcy) levels were divided into 4 quartiles (Q1, <8.2; Q2, 8.2-9.8; Q3, 9.9-11.7; and Q4, >11.7 μM/L). Renal function was determined using the Chronic Kidney Disease Epidemiology Collaboration equation. Patients were considered to have CKD if their estimated glomerular filtration rate was < 60 mL/min/1.73 m2.The prevalence of CKD significantly increased with the quartiles of uric acid (UA) and Hcy. In multiple logistic regression analysis, the odds ratios (ORs) of CKD increased with the quartiles of Hcy, independent of UA. There was 22.9 in Q4 in the normal serum UA group and 18.3 in the hyperuricemia group compared with Q1 of Hcy. Both hyperuricemia (OR 2.9) and Q4 of Hcy (OR 8.1) were significant independent risk factors for CKD. Furthermore, hyperuricemia and HHcy had significant synergistic association (synergy index, 1.7) with CKD.The ORs of CKD increased with the quartiles of Hcy, independent of hyperuricemia. Hyperuricemia and HHcy had synergistic association with CKD.
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Affiliation(s)
- Peng-Tzu Liu
- Department of Family Medicine, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan
| | - Jong-Dar Chen
- Department of Family Medicine, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan
- School of Medicine, Fu Jen Catholic University, Taipei, Taiwan
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Bai W, Liu Q, Chang H, Liu Q, Gao C, Bai Y, Zhou H, Shi S. Metabolomics reveals the renoprotective effect of n-butanol extract and amygdalin extract from Amygdalus mongolica in rats with renal fibrosis. ARTIFICIAL CELLS NANOMEDICINE AND BIOTECHNOLOGY 2021; 49:556-564. [PMID: 34278886 DOI: 10.1080/21691401.2021.1952212] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Renal fibrosis (RF) is a pathological process of progression from chronic kidney disease to end-stage renal disease. Amygdalus mongolica is a traditional Chinese medicine, and our previous studies demonstrated that the n-butanol extract (BUT) and amygdalin extract (AMY) from its seeds can prevent RF. However, the underlying mechanism remains unclear. The present study investigated the exact mechanism of the protective effect of A. mongolica on RF. A renal fibrosis rat model was induced with unilateral ureteral obstruction. Biochemical indicators were measured and combined with histopathology of renal tissue to evaluate the anti-RF effects. A serum metabonomic method was used to clarify the changes in the metabolic profile. The tubulointerstitial damage and fibrosis were significantly improved and metabolic perturbations were restored after treatment with BUT and AMY. Thirty-eight metabolites associated with RF progression and related to the regulation of arginine and proline metabolism, nicotinate and nicotinamide metabolism, and histidine metabolism were identified. They were restored to levels similar to those in controls after treatment. Moreover, no significant differences in efficacy were observed between the BUT and AMY groups. This study reveals and compares the potential mechanisms of the renoprotective effects after treatment with BUT and AMY from a metabolomic perspective.
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Affiliation(s)
- Wanfu Bai
- Department of Pharmacy, Baotou Medical College, Baotou, China
| | - Qing Liu
- Department of Pharmacy, Baotou Medical College, Baotou, China
| | - Hong Chang
- Department of Pharmacy, Baotou Medical College, Baotou, China
| | - Quanli Liu
- Department of Pharmacy, Baotou Medical College, Baotou, China
| | - Chen Gao
- Department of Pharmacy, Baotou Medical College, Baotou, China
| | - Yingchun Bai
- Department of Pharmacy, Baotou Medical College, Baotou, China
| | - Hongbing Zhou
- Department of Pharmacy, Baotou Medical College, Baotou, China
| | - Songli Shi
- Department of Pharmacy, Baotou Medical College, Baotou, China
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Gao N, Zhang Y, Li L, Lei L, Cao P, Zhao X, Lin L, Xu R. Hyperhomocysteinemia-Induced Oxidative Stress Aggravates Renal Damage in Hypertensive Rats. Am J Hypertens 2020; 33:1127-1135. [PMID: 32484231 DOI: 10.1093/ajh/hpaa086] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 04/03/2020] [Accepted: 05/25/2020] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Hyperhomocysteinemia (HHcy) plays a synergistic role with hypertension in vascular injury; however, the relationship between HHcy and hypertension in renal injury remains unclear. Here, we sought to evaluate the relationship between HHcy and hypertension in the context of renal injury and to elucidate the mechanism of action underlying this relationship. METHODS Wistar Kyoto (WKY) rats and spontaneously hypertensive rats (SHR) were randomized into WKY, WKY + HHcy, SHR, and SHR + HHcy groups. Blood pressure, plasma homocysteine, serum malondialdehyde (MDA), serum superoxide dismutase (SOD), urinary albumin creatinine ratio (UACR), and glomerular filtration rate (GFR) were measured. Renal histopathology and expression levels of NOX2, NOX4, and nephrin in the kidneys were examined. RESULTS The WKY + HHcy and SHR groups exhibited lower serum SOD and GFR levels, relative to the WKY group, along with higher levels of both serum MDA and UACR. Higher mRNA and protein expression levels of NOX2 and NOX4, along with lower expression levels of nephrin, were observed in the kidneys of WKY + HHcy and SHR rats, relative to WKY controls, respectively. Similar effects were observed in the SHR + HHcy group, relative to the SHR group and WKY + HHcy group, respectively. Periodic acid-Schiff staining showed an increase in the glomerular extracellular matrix in the WKY + HHcy and SHR + HHcy groups compared with their respective controls. CONCLUSIONS HHcy appears to synergistically increase hypertensive renal damage by enhancing oxidative stress.
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Affiliation(s)
- Ning Gao
- Department of Cardiology, The First Affiliated Hospital of Shandong First Medical University, Jinan, Shandong, China
| | - Yuzhen Zhang
- Department of Neurosurgery, The First Affiliated Hospital of Shandong First Medical University, Jinan, Shandong, China
| | - Li Li
- Department of Clinical Nutrition, the People’s Hospital of Zhangqiu, Jinan, Shandong, China
| | - Lei Lei
- Department of Cardiology, The First Affiliated Hospital of Shandong First Medical University, Jinan, Shandong, China
| | - Ping Cao
- Department of Geriatric Medicine, Tai’an City Central Hospital, Tai’an, Shandong, China
| | - Xuan Zhao
- Department of Cardiovascular Medicine, People’s Hospital of Dongying, Dongying, Shandong, China
| | - Lin Lin
- Department of Cardiology, The First Affiliated Hospital of Shandong First Medical University, Jinan, Shandong, China
| | - Rui Xu
- Department of Cardiology, The First Affiliated Hospital of Shandong First Medical University, Jinan, Shandong, China
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Low doses of folic acid can reduce hyperhomocysteinemia-induced glomerular injury in spontaneously hypertensive rats. Hypertens Res 2020; 43:1182-1191. [DOI: 10.1038/s41440-020-0471-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 04/10/2020] [Accepted: 04/22/2020] [Indexed: 12/11/2022]
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Wan Z, Ren K, Wen W, Zhou D, Liu J, Fan Y, Wu Y, Mu J, Yuan Z, Gao F. Potassium supplementation ameliorates increased plasma homocysteine induced by salt loading in normotensive salt-sensitive subjects. Clin Exp Hypertens 2018; 39:769-773. [PMID: 28682116 DOI: 10.1080/10641963.2017.1334793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The mechanism by which high-salt and low-potassium diet contributes to hypertension remains poorly understood. Plasma homocysteine (Hcys) is recognized as a primary mediator of blood pressure (BP) response to some diets. Therefore, the present study tried to investigate whether plasma Hcys and BP could be regulated by salt loading in normotensive salt-sensitive (SS) persons, and further explored whether potassium supplementation could reverse the effect. We enrolled 47 normotensive subjects, aged 29-65 years. The protocol included 7 days on a low-salt diet (3g/day, NaCl), 7 days on a high-salt diet (18g/day), and then a high-salt diet with potassium supplementation (4.5g/day) for 7 days. After high-salt intake, BP was significantly increased and potassium supplementation lowered it in the SS group. Plasma Hcys were higher in SS subjects than in salt-resistant (SR) subjects after salt loading (34.4 ± 17.0 μmol/L versus 19.16 ± 6.4 μmol/L, P < 0.01). Plasma Hcys in SS subjects was increased on a high-salt diet than on a low-salt diet (34.4 ± 17.0 μmol/L versus 16.5 ± 8.3 μmol/L, P < 0.01), but plasma Hcys was ameliorated by potassium supplementation (34.4 ± 17.0 μmol/L versus 20.9 ± 10.4 μmol/L, P < 0.01). In SS subjects, the change of mean arterial blood pressure (MBP) correlated significantly and positively with the alteration of plasma Hcys during low-salt to high-salt intake and high-salt to high-salt with potassium supplementation (r = 0.75, P < 0.001; r = 0.74, P < 0.001, respectively). Our results indicate that Hcys may partly mediate the impact of high-salt intake and potassium supplementation on BP in SS subjects.
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Affiliation(s)
- Zhaofei Wan
- a Department of Cardiovascular Medicine , Affiliated Hospital of Yan'an University , Yan'an , Shaanxi , China.,b Department of Cardiovascular Medicine , First Affiliated Hospital of Medical College, Xi'an Jiaotong University , Xi'an , Shaanxi , China
| | - Keyu Ren
- b Department of Cardiovascular Medicine , First Affiliated Hospital of Medical College, Xi'an Jiaotong University , Xi'an , Shaanxi , China
| | - Wen Wen
- b Department of Cardiovascular Medicine , First Affiliated Hospital of Medical College, Xi'an Jiaotong University , Xi'an , Shaanxi , China
| | - Dong Zhou
- b Department of Cardiovascular Medicine , First Affiliated Hospital of Medical College, Xi'an Jiaotong University , Xi'an , Shaanxi , China
| | - Junhui Liu
- b Department of Cardiovascular Medicine , First Affiliated Hospital of Medical College, Xi'an Jiaotong University , Xi'an , Shaanxi , China
| | - Yan Fan
- b Department of Cardiovascular Medicine , First Affiliated Hospital of Medical College, Xi'an Jiaotong University , Xi'an , Shaanxi , China
| | - Yue Wu
- b Department of Cardiovascular Medicine , First Affiliated Hospital of Medical College, Xi'an Jiaotong University , Xi'an , Shaanxi , China
| | - Jianjun Mu
- b Department of Cardiovascular Medicine , First Affiliated Hospital of Medical College, Xi'an Jiaotong University , Xi'an , Shaanxi , China
| | - Zuyi Yuan
- b Department of Cardiovascular Medicine , First Affiliated Hospital of Medical College, Xi'an Jiaotong University , Xi'an , Shaanxi , China
| | - Feng Gao
- a Department of Cardiovascular Medicine , Affiliated Hospital of Yan'an University , Yan'an , Shaanxi , China
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Cigarette smoking reduced renal function deterioration in hypertensive patients may be mediated by elevated homocysteine. Oncotarget 2018; 7:86000-86010. [PMID: 27852066 PMCID: PMC5349892 DOI: 10.18632/oncotarget.13308] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2015] [Accepted: 11/02/2016] [Indexed: 11/25/2022] Open
Abstract
Elevated homocysteine (HCY) and smoking are both important risk factors for hypertensive patients. However, whether they have crossing effect on renal function deterioration of hypertensive patients and what is the underlying mechanism are unclear. In the present study, 3033 participants diagnosed as essential hypertension with estimated glomerular filtration rate (eGFR)> 30 ml/min/1.73 m2 from southern China were enrolled in this cross-sectional study. We collected the demographic and clinical data. In addition, the mediation effects were analyzed. The results showed that, comparing with non-smokers, smokers had significant higher levels of HCY (13.10 (11.20−16.87) vs. 11.00 (8.90−13.40) umol/L, P < 0.001) and lower eGFR (79.71 (66.83−91.05) vs. 82.89 (69.80−95.85) ml/min/1.73m2, P < 0.001). HCY levels and smoking were independently associated with decreased eGFR. Meanwhile, eGFR levels were significantly negatively correlated with HCY (P < 0.001), and this correlation might be stronger in current smokers. Current smoker consuming over 20 cigarettes per day would accelerate early renal function deterioration (OR = 1.859, P = 0.019). The mediation effects analysis further showed that the association between smoking and renal function deterioration was mediated by HCY. And elevated HCY was accounted for 56.94% of the estimated causal effect of smoking on renal function deterioration in hypertensive patients. Our findings indicated that cigarette smoking was associated with renal function deterioration in hypertensive patients, and the association between cigarette smoking and renal function deterioration was probably mediated by elevated HCY. Therefore, HCY-lowering therapy may be beneficial for renal function deterioration in hypertensive smoking patients.
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Fu S, Yao Y, Zhao Y, Luan F. Relationships of Hyperhomocysteinemia and Hyperuricemia With Metabolic Syndrome and Renal Function in Chinese Centenarians. Front Endocrinol (Lausanne) 2018; 9:502. [PMID: 30271378 PMCID: PMC6142902 DOI: 10.3389/fendo.2018.00502] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 08/09/2018] [Indexed: 11/30/2022] Open
Abstract
As the first time worldwide, this study aimed to investigate the relationships of hyperhomocysteinemia and hyperuricemia with metabolic syndrome (MetS) and renal function in Chinese centenarians. The China Hainan Centenarian Cohort Study was performed in 18 cities and counties of the Hainan Province. Home interview, physical examination, and blood analysis were performed on 808 centenarians following standard procedures. All centenarians had a median age of 102 (100-115) years. Prevalence of hyperhomocysteinemia and hyperuricemia was 91.6% (740 centenarians) and 28.5% (230 centenarians), respectively. The MetS was present in 117 centenarians (14.5%). In simple correlation analyses, hyperhomocysteinemia and hyperuricemia were significantly correlated with MetS and glomerular filtration rate (GFR) < 60 ml/min/1.73 m2 (P < 0.05 for all). Serum homocysteine levels were significantly correlated with GFR, waist circumference (WC), and triglyceride levels, while serum uric acid levels were significantly correlated with these variables plus high-density lipoprotein cholesterol (HDL-C) levels (P < 0.05 for all). In logistic regression analyses, hyperhomocysteinemia and hyperuricemia were significantly associated with MetS and GFR < 60 ml/min/1.73 m2 (P < 0.05 for all). In linear regression analyses, serum homocysteine levels were significantly associated with GFR, WC, and triglyceride, while serum uric acid levels were significantly associated with these variables plus HDL-C (P < 0.05 for all). Both hyperhomocysteinemia and hyperuricemia had important relationships with MetS and renal function in Chinese centenarians. Hyperuricemia and hyperhomocysteinemia that could help identify, while also affecting, the development of MetS and renal function may unfold complex relationships between MetS, renal function, and cardiovascular risk and provide effective prevention strategies for these conditions.
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Affiliation(s)
- Shihui Fu
- Department of Geriatric Cardiology, Chinese People's Liberation Army General Hospital, Beijing, China
- Department of Cardiology and Hainan Branch, Chinese People's Liberation Army General Hospital, Beijing, China
| | - Yao Yao
- Institute of Geriatrics, Chinese People's Liberation Army General Hospital, Beijing, China
- Beijing Key Laboratory of Geriatrics, Chinese People's Liberation Army General Hospital, Beijing, China
| | - Yali Zhao
- Central Laboratory, Hainan Branch of Chinese People's Liberation Army General Hospital, Sanya, China
- *Correspondence: Yali Zhao
| | - Fuxin Luan
- Central Laboratory, Hainan Branch of Chinese People's Liberation Army General Hospital, Sanya, China
- Fuxin Luan
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Kong X, Ma X, Zhang C, Su H, Xu D. Hyperhomocysteinemia increases the risk of chronic kidney disease in a Chinese middle-aged and elderly population-based cohort. Int Urol Nephrol 2016; 49:661-667. [PMID: 27822673 DOI: 10.1007/s11255-016-1452-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 10/28/2016] [Indexed: 11/26/2022]
Abstract
BACKGROUND Patients either with hyperhomocysteinemia or chronic kidney disease (CKD) have an increased risk of cardiovascular disease. Little is known regarding whether hyperhomocysteinemia can increase the risk of CKD in a Chinese middle-aged and elderly population. To help clarify this we conducted a prospective cohort study to measure the association of hyperhomocysteinemia with CKD. METHODS A total of 5917 adults aged 56.4 ± 9.6 years without CKD at baseline were enrolled. The highest homocysteine quartile (≥15 μmol/L) was defined as hyperhomocysteinemia. CKD was defined as decreased estimated glomerular filtration rate (eGFR < 60 mL/min/1.73 m2) or presence of proteinuria (urine protein ≥ 1+) assessed using a repeated dipstick method. RESULTS During 3 years of follow-up, 143 (2.4%) patients developed CKD, 85 (1.4%) patients with proteinuria and 59 (1.0%) patients with decreased eGFR. After adjusted for potential confounders, both homocysteine (per 1 μmol/L increase) and hyperhomocysteinemia were independently associated with increased risk of decreased eGFR [with a fully adjusted OR of 1.07 (95% CI 1.04-1.10) and 3.05 (95% CI 1.71-5.46)] and CKD [with a fully adjusted OR of 1.04 (95% CI 1.02-1.07) and 1.62 (95% CI 1.11-2.35)], respectively. By contrast, neither homocysteine (per 1 μmol/L increase) nor hyperhomocysteinemia were associated with proteinuria in the multivariable logistic regression analysis. CONCLUSIONS The study revealed that hyperhomocysteinemia increases the risk of decreased eGFR. This suggests that homocysteine could be considered as a useful molecular markers for delaying the development of CKD.
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Affiliation(s)
- Xianglei Kong
- Department of Nephrology, Qianfoshan Hospital, Shandong University, No. 16766, Jingshi Road, Jinan, 250014, People's Republic of China
| | - Xiaojing Ma
- Department of Health Examination Center, Qianfoshan Hospital, Shandong University, No. 16766, Jingshi Road, Jinan, 250014, People's Republic of China
| | - Chengyin Zhang
- Department of Nephrology, Yidu Central Hospital, Weifang Medical College, No. 4138, South Road of Linglong Mountain, Qingzhou, People's Republic of China
| | - Hong Su
- Department of Nephrology, Qianfoshan Hospital, Shandong University, No. 16766, Jingshi Road, Jinan, 250014, People's Republic of China
| | - Dongmei Xu
- Department of Nephrology, Qianfoshan Hospital, Shandong University, No. 16766, Jingshi Road, Jinan, 250014, People's Republic of China.
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Veeranki S, Gandhapudi SK, Tyagi SC. Interactions of hyperhomocysteinemia and T cell immunity in causation of hypertension. Can J Physiol Pharmacol 2016; 95:239-246. [PMID: 27398734 DOI: 10.1139/cjpp-2015-0568] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Although hyperhomocysteinemia (HHcy) is an independent risk factor for cardiovascular diseases (CVD), there is a debate on whether HHcy is a risk factor or just a biomarker. Interestingly, homocysteine lowering strategies in humans had very little effect on reducing the cardiovascular risk, as compared with animals; this may suggest heterogeneity in human population and epigenetic alterations. Moreover, there are only few studies that suggest the idea that HHcy contributes to CVD in the presence of other risk factors such as inflammation, a known risk factor for CVD. Elevated levels of homocysteine have been shown to contribute to inflammation. Here, we highlight possible relationships between homocysteine, T cell immunity, and hypertension, and summarize the evidence that suggested these factors act together in increasing the risk for CVD. In light of this new evidence, we further propose that there is a need for evaluation of the causes of HHcy, defective remethylation or defective transsulfuration, which may differentially modulate hypertension progression, not just the homocysteine levels.
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Affiliation(s)
- Sudhakar Veeranki
- Department of Physiology and Biophysics, Health Sciences Centre, A-1216, School of Medicine, University of Louisville, 500 South Pres Street, Louisville, KY, 40202, USA.,Department of Physiology and Biophysics, Health Sciences Centre, A-1216, School of Medicine, University of Louisville, 500 South Pres Street, Louisville, KY, 40202, USA
| | - Siva K Gandhapudi
- Department of Physiology and Biophysics, Health Sciences Centre, A-1216, School of Medicine, University of Louisville, 500 South Pres Street, Louisville, KY, 40202, USA.,Department of Physiology and Biophysics, Health Sciences Centre, A-1216, School of Medicine, University of Louisville, 500 South Pres Street, Louisville, KY, 40202, USA
| | - Suresh C Tyagi
- Department of Physiology and Biophysics, Health Sciences Centre, A-1216, School of Medicine, University of Louisville, 500 South Pres Street, Louisville, KY, 40202, USA.,Department of Physiology and Biophysics, Health Sciences Centre, A-1216, School of Medicine, University of Louisville, 500 South Pres Street, Louisville, KY, 40202, USA
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14
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Pushpakumar S, Kundu S, Narayanan N, Sen U. DNA hypermethylation in hyperhomocysteinemia contributes to abnormal extracellular matrix metabolism in the kidney. FASEB J 2015. [PMID: 26224753 DOI: 10.1096/fj.15-272443] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Hyperhomocysteinemia (HHcy) is prevalent in patients with chronic kidney disease (CKD) and end-stage renal disease (ESRD). Emerging studies suggest that epigenetic mechanisms contribute to the development and progression of fibrosis in CKD. HHcy and its intermediates are known to alter the DNA methylation pattern, which is a critical regulator of epigenetic information. In this study, we hypothesized that HHcy causes renovascular remodeling by DNA hypermethylation, leading to glomerulosclerosis. We also evaluated whether the DNA methylation inhibitor, 5-aza-2'-deoxycytidine (5-Aza) could modulate extracellular matrix (ECM) metabolism and reduce renovascular fibrosis. C57BL/6J (wild-type) and cystathionine-β-synthase (CBS(+/-)) mice, treated without or with 5-Aza (0.5 mg/kg body weight, i.p.), were used. CBS(+/-) mice showed high plasma Hcy levels, hypertension, and significant glomerular and arteriolar injury. 5-Aza treatment normalized blood pressure and reversed renal injury. CBS(+/-) mice showed global hypermethylation and up-regulation of DNA methyltransferase-1 and -3a. Methylation-specific PCR showed an imbalance between matrix metalloproteinase (MMP)-9 and tissue inhibitor of metalloproteinase (TIMP)-1 and -2 and also increased collagen and galectin-3 expression. 5-Aza reduced abnormal DNA methylation and restored the MMP-9/TIMP-1, -2 balance. In conclusion, our data suggest that during HHcy, abnormal DNA methylation and an imbalance between MMP-9 and TIMP-1 and -2 lead to ECM remodeling and renal fibrosis.
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Affiliation(s)
- Sathnur Pushpakumar
- Department of Physiology and Biophysics, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Sourav Kundu
- Department of Physiology and Biophysics, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Nithya Narayanan
- Department of Physiology and Biophysics, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Utpal Sen
- Department of Physiology and Biophysics, University of Louisville School of Medicine, Louisville, Kentucky, USA
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15
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Abais JM, Xia M, Li G, Chen Y, Conley SM, Gehr TWB, Boini KM, Li PL. Nod-like receptor protein 3 (NLRP3) inflammasome activation and podocyte injury via thioredoxin-interacting protein (TXNIP) during hyperhomocysteinemia. J Biol Chem 2014; 289:27159-27168. [PMID: 25138219 DOI: 10.1074/jbc.m114.567537] [Citation(s) in RCA: 106] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
NADPH oxidase-derived reactive oxygen species (ROS) have been reported to activate NLRP3 inflammasomes resulting in podocyte and glomerular injury during hyperhomocysteinemia (hHcys). However, the mechanism by which the inflammasome senses ROS is still unknown in podocytes upon hHcys stimulation. The current study explored whether thioredoxin-interacting protein (TXNIP), an endogenous inhibitor of the antioxidant thioredoxin and ROS sensor, mediates hHcys-induced NLRP3 inflammasome activation and consequent glomerular injury. In cultured podocytes, size exclusion chromatography and confocal microscopy showed that inhibition of TXNIP by siRNA or verapamil prevented Hcys-induced TXNIP protein recruitment to form NLRP3 inflammasomes and abolished Hcys-induced increases in caspase-1 activity and IL-1β production. TXNIP inhibition protected podocytes from injury as shown by normal expression levels of podocyte markers, podocin and desmin. In vivo, adult C57BL/6J male mice were fed a folate-free diet for 4 weeks to induce hHcys, and TXNIP was inhibited by verapamil (1 mg/ml in drinking water) or by local microbubble-ultrasound TXNIP shRNA transfection. Evidenced by immunofluorescence and co-immunoprecipitation studies, glomerular inflammasome formation and TXNIP binding to NLRP3 were markedly increased in mice with hHcys but not in TXNIP shRNA-transfected mice or those receiving verapamil. Furthermore, TXNIP inhibition significantly reduced caspase-1 activity and IL-1β production in glomeruli of mice with hHcys. Correspondingly, TXNIP shRNA transfection and verapamil attenuated hHcys-induced proteinuria, albuminuria, glomerular damage, and podocyte injury. In conclusion, our results demonstrate that TXNIP binding to NLRP3 is a key signaling mechanism necessary for hHcys-induced NLRP3 inflammasome formation and activation and subsequent glomerular injury.
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Affiliation(s)
- Justine M Abais
- Departments of Pharmacology and Toxicology and School of Medicine, Richmond, Virginia 23298.
| | - Min Xia
- Departments of Pharmacology and Toxicology and School of Medicine, Richmond, Virginia 23298
| | - Guangbi Li
- Departments of Pharmacology and Toxicology and School of Medicine, Richmond, Virginia 23298
| | - Yang Chen
- Departments of Pharmacology and Toxicology and School of Medicine, Richmond, Virginia 23298
| | - Sabena M Conley
- Departments of Pharmacology and Toxicology and School of Medicine, Richmond, Virginia 23298
| | - Todd W B Gehr
- Internal Medicine Virginia Commonwealth University, School of Medicine, Richmond, Virginia 23298
| | - Krishna M Boini
- Departments of Pharmacology and Toxicology and School of Medicine, Richmond, Virginia 23298
| | - Pin-Lan Li
- Departments of Pharmacology and Toxicology and School of Medicine, Richmond, Virginia 23298
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Anderson M, Roshanravan H, Khine J, Dryer SE. Angiotensin II activation of TRPC6 channels in rat podocytes requires generation of reactive oxygen species. J Cell Physiol 2014; 229:434-42. [PMID: 24037962 DOI: 10.1002/jcp.24461] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Accepted: 08/27/2013] [Indexed: 11/06/2022]
Abstract
Angiotensin II (AII) plays a major role in the progression of chronic kidney diseases. Podocytes are essential components of the ultrafiltration apparatus, and are targets for AII signaling. AII has been shown to increase generation of reactive oxygen species (ROS) in podocytes. Canonical transient receptor potential-6 (TRPC6) channels stimulate Ca(2+) influx in podocytes, and have been implicated in glomerular disease. We observed that AII increased cationic currents in rat podocytes in an isolated glomerulus preparation in which podocytes are still attached to the underlying capillary. This effect was completely blocked by SKF-96365, by micromolar La(3+) , and by siRNA knockdown of TRPC6, indicating that TRPC6 is the primary source of Ca(2+) influx mobilized by endogenously expressed angiotensin II receptors in these cells. These responses were also blocked by the AT1R antagonist losartan, the phospholipase C inhibitor D-609, and by inhibition of G protein signaling. The pan-protein kinase C inhibitor chelerythrine had no effect. Importantly, pretreating podocytes with the ROS quencher manganese (III) tetrakis (4-benzoic acid) porphyrin chloride (MnTBAP) eliminated AII activation of TRPC6. Significant reductions of AII effects on podocyte TRPC6 were also observed after pretreatment with NADPH oxidase inhibitors apocynin or diphenylene iodonium (DPI). These data suggest that ROS production permits activation of TRPC6 channels by G protein and PLC-dependent cascades initiated by AII acting on AT1Rs in podocytes. This pathway also provides a basis whereby two forms of cellular stress-oxidative stress and Ca(2+) overload-converge on common pathways relevant to disease.
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Affiliation(s)
- Marc Anderson
- Department of Biology and Biochemistry, University of Houston, Houston, Texas
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Kundal M, Saha A, Dubey NK, Kapoor K, Basak T, Bhardwaj G, Tanwar VS, Sengupta S, Batra V, Upadhayay AD, Bhatt A. Homocysteine metabolism in children with idiopathic nephrotic syndrome. Clin Transl Sci 2014; 7:132-6. [PMID: 24456587 DOI: 10.1111/cts.12145] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Homocysteine metabolism is altered in children with idiopathic nephrotic syndrome. Hyperhomocysteinemia is a risk factor of early atherosclerosis and glomerulosclerosis and may occur at time of first occurrence of idiopathic nephrotic syndrome. METHODS Thirty children with first episode of idiopathic nephrotic syndrome (FENS) aged 1-16 years along with 30 age- and sex-matched healthy controls were enrolled in this study. Homocysteine and cysteine were measured with HPLC; vitamin B12 and folic acid were measured with electro-chemilumiscence immunoassay. Primary outcome measure was plasma homocysteine level in children with FENS and in controls. Secondary outcome measures were (1) plasma and urine homocysteine and cysteine levels in children with FENS at 12 weeks and 1 year (remission) and (2) plasma and urine levels of vitamin B12 and folic acid in children with FENS, at 12 weeks and 1 year (remission). RESULTS Plasma homocysteine and cysteine levels were comparable to controls in children with FENS, at 12 weeks and 1-year remission. Plasma levels of vitamin B12 and folic acid were significantly decreased compared to controls in FENS due to increased urinary excretion, which normalize during remission at 12 weeks and 1 year. Urinary homocysteine and cysteine levels were significantly raised in FENS compared to controls and continued to be raised even at 12-week and 1-year remission. CONCLUSION Homocysteine metabolism is deranged in children with FENS. Renal effects of long-term raised urinary homocysteine levels need to be studied.
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Affiliation(s)
- Mohan Kundal
- Division of Pediatric Nephrology, Department of Pediatrics, Postgraduate Institute of Medical Education and Research associated Dr. Ram Manohar Lohia Hospital, New Delhi, India
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19
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DNA methylation status of the methylenetetrahydrofolate reductase gene promoter in peripheral blood of end-stage renal disease patients. Mol Biol Rep 2013; 41:683-8. [PMID: 24363223 DOI: 10.1007/s11033-013-2906-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2013] [Accepted: 12/12/2013] [Indexed: 12/20/2022]
Abstract
End-stage renal disease (ESRD) is one of the main causes of morbidity and mortality worldwide. DNA methylation is a major epigenetic modification of the genome that has the potential to silence gene expression. Methylenetetrahydrofolate reductase (MTHFR) gene inactivation was recognized as a predisposing factor of hyperhomocysteinemia in renal patients. The current study aimed to determine the methylation status within the MTHFR promoter region in DNA isolated from peripheral blood of ESRD patients and controls and the correlation of this methylation with the clinical and biochemical characteristics in ESRD patients. Ninety-six ESRD patients and 96 healthy ethnically, age and gender matched controls were included within the study. MTHFR promoter methylation was assessed using methylation specific polymerase chain reaction. The frequency of MTHFR methylation was significantly higher in ESRD patients than in controls (P = 0.003), additionally, MTHFR methylation was associated to a decrease in estimated glomerular filtration rate, serum high-density lipoprotein cholesterol level and an increase in both serum total cholesterol and low-density lipoprotein cholesterol levels. Data generated from this study suggest the possible involvement of MTHFR promoter methylation in the pathogenesis of ESRD and support a new dimension of MTHFR inactivation.
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Cao L, Lou X, Zou Z, Mou N, Wu W, Huang X, Tan H. Folic acid attenuates hyperhomocysteinemia-induced glomerular damage in rats. Microvasc Res 2013; 89:146-52. [DOI: 10.1016/j.mvr.2013.07.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 07/03/2013] [Accepted: 07/06/2013] [Indexed: 11/26/2022]
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Wang J, Ge J, Yang L, Zhang H, Li X, Xue D. Brain cell apoptosis and enhancement of nervous excitability in pregnant rats with high plasma levels of homocysteine. Neural Regen Res 2012; 7:2199-205. [PMID: 25538740 PMCID: PMC4268719 DOI: 10.3969/j.issn.1673-5374.2012.028.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2012] [Accepted: 08/20/2012] [Indexed: 11/20/2022] Open
Abstract
Hyperhomocysteinemia is an important risk factor for preeclampsia-eclampsia. This study established a pregnant rat model of hyperhomocysteinemia, in which blood plasma homocysteine concentrations were twice or three times greater than that of normal pregnant rats. TUNEL revealed an increase in the number of apoptotic cells in the frontal cortex of pregnant rats with hyperhomocysteinemia. In addition, immunohistochemical staining detected activated nuclear factor-κB-positve cells in the frontal cortex. Reverse transcription-PCR detected that mRNA expression of the anti-apoptotic gene bcl-2 diminished in the frontal cortex. In situ hybridization and western blotting revealed that N-methyl-D-aspartate receptor 1 mRNA and protein expression was upregulated in the frontal cortex and hippocampus. These results indicate that hyperhomocysteinemia can induce brain cell apoptosis, increase nerve excitability, and promote the occurrence of preeclampsia in pregnant rats.
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Affiliation(s)
- Jun Wang
- Department of Gynaecology and Obstetrics, General Hospital of Shenyang Military Region, Shenyang 110016, Liaoning Province, China
| | - Jing Ge
- Department of Gynaecology and Obstetrics, the 202 Hospital of Chinese PLA, Shenyang 110003, Liaoning Province, China
| | - Liu Yang
- Shenyang Women and Children Health Center, Shenyang 110014, Liaoning Province, China
| | - Haiyan Zhang
- Department of Gynaecology and Obstetrics, the 202 Hospital of Chinese PLA, Shenyang 110003, Liaoning Province, China
| | - Xuli Li
- Department of Gynaecology and Obstetrics, the 202 Hospital of Chinese PLA, Shenyang 110003, Liaoning Province, China
| | - Dan Xue
- Department of Gynaecology and Obstetrics, the 202 Hospital of Chinese PLA, Shenyang 110003, Liaoning Province, China
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Yi F, Jin S, Zhang F, Xia M, Bao JX, Hu J, Poklis JL, Li PL. Formation of lipid raft redox signalling platforms in glomerular endothelial cells: an early event of homocysteine-induced glomerular injury. J Cell Mol Med 2011; 13:3303-14. [PMID: 20196779 PMCID: PMC3752605 DOI: 10.1111/j.1582-4934.2009.00743.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
The present study tested the hypothesis that homocysteine (Hcys)-induced ceramide production stimulates lipid rafts (LRs) clustering on the membrane of glomerular endothelial cells (GECs) to form redox signalling platforms by aggregation and activation of NADPH oxidase subunits and thereby enhances superoxide (O2*-) production, leading to glomerular endothelial dysfunction and ultimate injury or sclerosis. Using confocal microscopy, we first demonstrated a co-localization of LR clusters with NADPH oxidase subunits, gp91(phox) and p47(phox) in the GECs membrane upon Hcys stimulation. Immunoblot analysis of floated detergent-resistant membrane fractions found that in LR fractions NADPH oxidase subunits gp91(phox) and p47(phox) are enriched and that the activity of this enzyme dramatically increased. We also examined the effect of elevated Hcys on the cell monolayer permeability in GECs. It was found that Hcys significantly increased GEC permeability, which was blocked by inhibition of LR redox signalling platform formation. Finally, we found that Hcys-induced enhancement of GEC permeability is associated with the regulation of microtubule stability through these LR-redox platforms. It is concluded that the early injurious effect of Hcys on the glomerular endothelium is associated with the formation of redox signalling platforms via LR clustering, which may lead to increases in glomerular permeability by disruption of microtubule network in GECs.
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Affiliation(s)
- Fan Yi
- Department of Pharmacology & Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, VA, USA
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Abstract
OBJECTIVE To assess the association of single-nucleotide polymorphisms (SNPs) in genes codifying for antioxidant enzymes to blood pressure (BP) values and risk of hypertension. METHODS Population-based study including 1388 participants (704 women) older than 18 years in which 300 were untreated hypertensive patients. In 335 untreated hypertensive patients referred to one hypertension clinic, the study was replicated. Thirty-five SNP throughout 13 genes were analyzed using SNPlex. In a subgroup of hypertensive patients, the amount of 8-oxo-deoxyguanosine and GPX activity levels was measured in mononuclear cells. RESULTS In the general population, genotypes with the G allele of the c.172G>A polymorphism in the SOD3 gene and those with the T allele of the c.-20C>T polymorphism in the CAT gene were associated with significant lower values of BP. Likewise, these genotypes were associated with less risk for hypertension after adjusting for confounder variables. Haplotypes in both genes increased the strength of associations. In the hypertensive patients, the same alleles of the two polymorphisms were associated with lower BP values too. In addition, two others, the CT-TT genotypes of the c.891C>T polymorphism in the GPX1 gene and the CT-CC genotypes of the c.-793T>C polymorphism of the TXN gene were also significantly associated to lower BP values. Furthermore, the CC genotype of the c.891C>T polymorphism in the GPX1 gene was associated with higher values of 8-oxo-dG and GPX activity levels as compared to those for the CT-TT genotype. CONCLUSIONS The results of the present study support the influence of antioxidant enzyme genes in BP values and hypertension risk.
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Hwang SY, Siow YL, Au-Yeung KKW, House J, O K. Folic acid supplementation inhibits NADPH oxidase-mediated superoxide anion production in the kidney. Am J Physiol Renal Physiol 2010; 300:F189-98. [PMID: 20980407 DOI: 10.1152/ajprenal.00272.2010] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Hyperhomocysteinemia, a condition of elevated blood homocysteine (Hcy) levels, is a metabolic disease. It is a common clinical finding in patients with chronic kidney diseases and occurs almost uniformly in patients with end-stage renal disease. Hyperhomocysteinemia is also a risk factor for cardiovascular disease. Our recent studies indicate that hyperhomocysteinemia can lead to renal injury by inducing oxidative stress. Oxidative stress is one of the important mechanisms contributing to Hcy-induced tissue injury. Folic acid supplementation is regarded as a promising approach for prevention and treatment of cardiovascular disease associated with hyperhomocysteinemia due to its Hcy-lowering effect. However, its effect on the kidney is not clear. The aim of this study was to examine the effect of folic acid supplementation on Hcy-induced superoxide anion production via nicotinamide adenine dinucleotide phosphate (NADPH) oxidase in the kidney during hyperhomocysteinemia. Hyperhomocysteinemia was induced in male Sprague-Dawley rats fed a high-methionine diet for 12 wk with or without folic acid supplementation. A group of rats fed a regular diet was used as control. There was a significant increase in levels of superoxide anions and lipid peroxides in kidneys isolated from hyperhomocysteinemic rats. Activation of NADPH oxidase was responsible for hyperhomocysteinemia-induced oxidative stress in the kidney. Folic acid supplementation effectively antagonized hyperhomocysteinemia-induced oxidative stress via its Hcy-lowering and Hcy-independent effect. In vitro study also showed that 5-methyltetrahydrofolate, an active form of folate, effectively reduced Hcy-induced superoxide anion production via NADPH oxidase. Xanthine oxidase activity was increased and superoxide dismutase (SOD) activity was decreased in the kidney of hyperhomocysteinemic rats, which might also contribute to an elevation of superoxide anion level in the kidney. Folic acid supplementation attenuated xanthine oxidase activity and restored SOD activity in the kidney of hyperhomocysteinemic rats. These results suggest that folic acid supplementation may offer renal protective effect against oxidative stress.
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Affiliation(s)
- Sun-Young Hwang
- Department of Animal Science, University of Manitoba, and Integrative Biology Laboratory, St. Boniface Hospital Research Centre, 351 Tache Ave., Winnipeg, Manitoba, Canada R2H 2A6
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A 31 year old woman with essential hypertension grade III and branch retinal vein occlusion with homozygous C677T MTHFR hyperhomocysteinemia and high Lp(a) levels. Int J Cardiol 2010; 143:e42-4. [DOI: 10.1016/j.ijcard.2008.12.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2008] [Accepted: 12/04/2008] [Indexed: 11/18/2022]
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Sen U, Munjal C, Qipshidze N, Abe O, Gargoum R, Tyagi SC. Hydrogen sulfide regulates homocysteine-mediated glomerulosclerosis. Am J Nephrol 2010; 31:442-55. [PMID: 20395677 DOI: 10.1159/000296717] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2010] [Accepted: 03/08/2010] [Indexed: 12/19/2022]
Abstract
BACKGROUND/AIMS In this study we tested the hypothesis that H(2)S regulates collagen deposition, matrix metalloproteinases (MMP) and inflammatory molecules during hyperhomocysteinemia (HHcy) resulting in attenuation of glomerulosclerosis and improved renal function. MATERIALS AND METHODS A genetic model of HHcy, cystathionine beta-synthase heterozygous (CBS+/-) and wild-type (WT) 2-kidney (2K) mice were used in this study and supplemented with or without NaHS (30 micromol/l, H(2)S donor) in drinking water for 8 weeks. To expedite the renal damage associated with HHcy, uninephrectomized (1K) mice of similar groups were also used. RESULTS Results demonstrated that NAD(P)H oxidase (p47(phox)subunit) and blood pressure were upregulated in WT 1K, CBS+/- 2K and CBS+/- 1K mice with downregulation of H(2)S production and reduced glomerular filtration rate. These changes were normalized with H(2)S supplementation. Both pro- and active MMP-2 and -9 and collagen protein expressions and glomerular depositions were also upregulated in WT 1K, CBS+/- 2K and CBS+/- 1K mice. Increased expressions of inflammatory molecules, intercellular cell adhesion molecule-1 and vascular cell adhesion molecule-1, as well as increased macrophage infiltration, were detected in WT 1K, CBS+/- 2K and CBS+/- 1K mice. These changes were ameliorated with H(2)S supplementation. CONCLUSION Together, these results suggest that increased oxidative stress and decreased H(2)S in HHcy causes matrix remodeling and inflammation resulting in glomerulosclerosis and reduced renal function.
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Affiliation(s)
- Utpal Sen
- Department of Physiology and Biophysics, University of Louisville School of Medicine, Louisville, KY 40202, USA. u0sen001 @ louisville.edu
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Chandler DL, Llinas MT, Reckelhoff JF, LaMarca B, Speed J, Granger JP. Effects of hyperhomocysteinemia on arterial pressure and nitric oxide production in pregnant rats. Am J Hypertens 2009; 22:1115-9. [PMID: 19629051 DOI: 10.1038/ajh.2009.130] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND An elevated plasma level of homocysteine (hyperhomocysteinemia) is thought to be an important risk factor for a variety of cardiovascular diseases including preeclampsia. Although clinical studies have reported a two- to threefold elevation in plasma levels of homocysteine in women who developed preeclampsia, the importance of hyperhomocysteinemia in causing endothelial dysfunction and increases in arterial pressure during pregnancy is unknown. METHODS Therefore, the purpose of this study was to determine the effects of a two- to threefold elevation in plasma homocysteine levels on arterial pressure, chronic pressure-natriuresis relationship, and endothelial factors during pregnancy in the rat. Homocysteine treatment for 4 weeks increased plasma homocysteine levels in pregnant rats from 7.1 +/- 1.9 to 16.7 +/- 2.3 micromol/l. RESULTS Homocysteine treatment decreased urinary nitrate/nitrite levels from 53 +/- 7 vs. 39 +/- 5 (micromol/24 h/kg body weight) in pregnant rats whereas having no effect on urinary excretion of endothelin. Homocysteine treatment had no effect on mean arterial pressure (MAP) in pregnant rats (104 +/- 2 vs. 107 +/- 3 mm Hg) nor on the chronic pressure-natriuresis relationship. CONCLUSIONS These results suggest that although hyperhomocysteinemia decreases nitric oxide (NO) production in pregnant rats, hyperhomocysteinemia does not affect MAP, the chronic pressure-natriuresis relationship, or urinary excretion of endothelin in pregnant rats. Moreover, the reported two- to threefold elevation in plasma level of homocysteine in women with preeclampsia is unlikely to contribute to the hypertension of preeclampsia.
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Sen U, Basu P, Abe OA, Givvimani S, Tyagi N, Metreveli N, Shah KS, Passmore JC, Tyagi SC. Hydrogen sulfide ameliorates hyperhomocysteinemia-associated chronic renal failure. Am J Physiol Renal Physiol 2009; 297:F410-9. [PMID: 19474193 DOI: 10.1152/ajprenal.00145.2009] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Elevated level of homocysteine (Hcy), known as hyperhomocysteinemia (HHcy), is associated with end-stage renal diseases. Hcy metabolizes in the body to produce hydrogen sulfide (H(2)S), and studies have demonstrated a protective role of H(2)S in end-stage organ failure. However, the role of H(2)S in HHcy-associated renal diseases is unclear. The present study was aimed to determine the role of H(2)S in HHcy-associated renal damage. Cystathionine-beta-synthase heterozygous (CBS+/-) and wild-type (WT, C57BL/6J) mice with two kidney (2-K) were used in this study and supplemented with or without NaHS (30 micromol/l, H(2)S donor) in the drinking water. To expedite the HHcy-associated glomerular damage, uninephrectomized (1-K) CBS(+/-) and 1-K WT mice were also used with or without NaHS supplementation. Plasma Hcy levels were elevated in CBS(+/-) 2-K and 1-K and WT 1-K mice along with increased proteinuria, whereas, plasma levels of H(2)S were attenuated in these groups compared with WT 2-K mice. Interestingly, H(2)S supplementation increased plasma H(2)S level and normalized the urinary protein secretion in the similar groups of animals as above. Increased activity of matrix metalloproteinase (MMP)-2 and -9 and apoptotic cells were observed in the renal cortical tissues of CBS(+/-) 2-K and 1-K and WT 1-K mice; however, H(2)S prevented apoptotic cell death and normalized increased MMP activities. Increased expression of desmin and downregulation of nephrin in the cortical tissue of CBS(+/-) 2-K and 1-K and WT 1-K mice were ameliorated with H(2)S supplementation. Additionally, in the kidney tissues of CBS(+/-) 2-K and 1-K and WT 1-K mice, increased superoxide (O(2)(*-)) production and reduced glutathione (GSH)-to-oxidized glutathione (GSSG) ratio were normalized with exogenous H(2)S supplementation. These results demonstrate that HHcy-associated renal damage is related to decreased endogenous H(2)S generation in the body. Additionally, here we demonstrate with evidence that H(2)S supplementation prevents HHcy-associated renal damage, in part, through its antioxidant properties.
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Affiliation(s)
- Utpal Sen
- Dept. of Physiology & Biophysics, Univ. of Louisville School of Medicine, 500 S. Preston St., Louisville, KY 40202, USA.
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Homocysteine enhances cell proliferation in hepatic myofibroblastic stellate cells. J Mol Med (Berl) 2008; 87:75-84. [PMID: 18825355 DOI: 10.1007/s00109-008-0407-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2008] [Revised: 09/08/2008] [Accepted: 09/12/2008] [Indexed: 10/21/2022]
Abstract
Homocysteine is an intermediate in sulfur amino acid metabolism, which takes place mainly in the liver. Recent studies have shown that hyperhomocysteinemia in patients and murine models develop hepatic fibrosis. To define mechanisms underlying homocysteine-induced hepatic fibrosis, the effect of homocysteine on hepatic stellate cell (HSC) proliferation was examined. In the present study, homocysteine promoted proliferation in myofibroblastic HSCs. Homocysteine elicited a transient formation of reactive oxygen species (ROS). The initial ROS activated extracellular signal-regulated kinase and p38 mitogen-activated protein kinase, which were involved in the activation of NAD(P)H oxidases and the generation of more ROS. The activation of NAD(P)H oxidases resulted from upregulation of the expression of p22(phox) and the phosphorylation of p47(phox). The ROS derived from NAD(P)H oxidases activated the PI3K/Akt pathway, thus promoting cellular proliferation in HSCs. These findings provide a mechanistic explanation for the development and progression of hepatic fibrosis in hyperhomocysteinemia.
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Cheung GTY, Siow YL, O K. Homocysteine stimulates monocyte chemoattractant protein-1 expression in mesangial cells via NF-kappaB activation. Can J Physiol Pharmacol 2008; 86:88-96. [PMID: 18418435 DOI: 10.1139/y08-002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Hyperhomocysteinemia is regarded as an independent risk factor for cardiovascular disorders. Although renal dysfunction or failure is one of the important factors causing hyperhomocysteinemia, the role of homocysteine (Hcy) in the development of glomerulosclerosis is largely unknown. One of the key events in the pathogenesis of glomerulosclerosis is the infiltration of circulating monocytes into affected glomeruli. The objective of the present study was to investigate the effect of Hcy on the expression of monocyte chemoattractant protein-1 (MCP-1) in kidney mesangial cells and the mechanisms involved. Levels of MCP-1 and mRNA were significantly elevated in Hcy-treated rat mesangial cells. This increase was associated with activation of NF-kappaB as a result of increased phosphorylation of the inhibitor protein IkappaBalpha. Monocyte chemotactic activity in these cells was also enhanced. In addition, there was a significant elevation of superoxide anion produced by Hcy-treated cells, which preceded the increased phosphorylation of IkappaBalpha. Addition of superoxide dismutase or NF-kappaB inhibitors to the culture medium abolished Hcy-induced NF-kappaB activation and MCP-1 expression. Taken together, these results indicate that Hcy induced MCP-1 expression in mesangial cells. Such a process was mediated by oxidative stress and NF-kappaB activation. This may further aggravate renal function in patients with hyperhomocysteinemia.
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Affiliation(s)
- Giselle T Y Cheung
- Department of Animal Science, University of Manitoba, Integrative Biology Laboratory, St. Boniface Hospital Research Centre, Winnipeg, MB R2H2A6, Canada
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Pin-Lan L, Fan Y, Ningjun L. Hyperhomocysteinemia: association with renal transsulfuration and redox signaling in rats. Clin Chem Lab Med 2008; 45:1688-93. [PMID: 18067450 DOI: 10.1515/cclm.2007.344] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Despite substantial evidence indicating the association of hyperhomocysteinemia (hHcys) and end-stage renal disease (ESRD), the pathogenic role of increased plasma homocysteine (Hcys) levels in the progression of ESRD remains unclear. This review will briefly summarize recent findings regarding the role of hHcys in the development of glomerulosclerosis, the association of hHcys with reduced renal transsulfuration and Hcys-induced changes of redox signaling in the development of glomerulosclerosis in rat kidneys. Based on these results, it is concluded that hHcys is implicated in glomerular sclerosis in hypertension, elevated plasma Hcys in Dahl salt-sensitive (SS) hypertensive rats is due to downregulation of cystathionine beta-synthase (CBS) expression and consequent abnormality of transsulfuration in the kidney compared with normotensive rats. Hcys-induced superoxide (O(2)(*-)) production by activation of NADPH oxidase as a triggering mechanism contributes to the effects of Hcys on the homeostasis of extracellular matrix and consequent sclerosis in the glomeruli, and NADPH oxidase activation by Hcys is associated with enhanced Rac GTPase activity.
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Affiliation(s)
- Li Pin-Lan
- Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA 23298, USA.
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Hwang SY, Woo CWH, Au-Yeung KKW, Siow YL, Zhu TY, O K. Homocysteine stimulates monocyte chemoattractant protein-1 expression in the kidney via nuclear factor-κB activation. Am J Physiol Renal Physiol 2008; 294:F236-44. [DOI: 10.1152/ajprenal.00331.2007] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Hyperhomocysteinemia, or an elevation of blood homocysteine (Hcy) levels, is associated with cardiovascular disorders. Although kidney dysfunction is an important risk factor causing hyperhomocysteinemia, the direct effect of Hcy on the kidney is not well documented. There is a positive association between an elevation of blood Hcy levels and the development of chronic kidney disease. Inflammatory response such as increased chemokine expression has been implicated as one of the mechanisms for renal disease. Monocyte chemoattractant protein-1 (MCP-1) is a potent chemokine that is involved in the inflammatory response in renal disease. Nuclear factor-κB (NF-κB) plays an important role in upregulation of MCP-1 expression. We investigated the effect of hyperhomocysteinemia on MCP-1 expression and the molecular mechanism underling such an effect in rat kidneys as well as in proximal tubular cells. Hyperhomocysteinemia was induced in rats fed a high-methionine diet for 12 wk. The MCP-1 mRNA expression and MCP-1 protein levels were significantly increased in kidneys isolated from hyperhomocysteinemic rats. The NF-κB activity was significantly increased in the same kidneys. Pretreatment of hyperhomocysteinemic rats with a NF-κB inhibitor abolished hyperhomocysteinemia-induced MCP-1 expression in the kidney. To confirm the causative role of NF-κB activation in MCP-1 expression, human kidney proximal tubular cells were transfected with decoy NF-κB oligodeoxynucleotide to inhibit NF-κB activation. Such a treatment prevented Hcy-induced MCP-1 mRNA expression in tubular cells. Our results suggest that hyperhomocysteinemia stimulates MCP-1 expression in the kidney via NF-κB activation. Such an inflammatory response may contribute to renal injury associated with hyperhomocysteinemia.
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Kassab S, Garadah T, Abu-Hijleh M, Golbahar J, Senok S, Wazir J, Gumaa K. The angiotensin type 1 receptor antagonist valsartan attenuates pathological ventricular hypertrophy induced by hyperhomocysteinemia in rats. J Renin Angiotensin Aldosterone Syst 2007; 7:206-11. [PMID: 17318789 DOI: 10.3317/jraas.2006.039] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
INTRODUCTION Clinical and experimental studies have reported the role of homocysteine in ventricular hypertrophy. Activation of the renin-angiotensin system mediated by angiotensin II type 1 (AT1) receptor has also been suggested to contribute to the pathogenesis of ventricular hypertrophy. There are also reports suggesting the affect of angiotensin II (Ang II) on cardiac hypertrophy is mediated by hyperhomocysteinemia. However, there is limited information on the mechanisms of the possible relationship between homocysteine and Ang II in ventricular hypertrophy. In this study we tested the hypothesis that hyperhomocysteinemia induced ventricular hypertrophy and remodelling may be mediated through activation of Ang II AT1-receptors in rats. METHODS This study was conducted on control non-treated rats (n=13), methionine-treated rats (1.5 mg/kg/day, n=18) and methionine plus oral AT1 antagonist (valsartan, 30 mg/kg/day, n=13) treated rats for 56 days. Systolic blood pressure (SBP) was determined in rats at baseline, 28 and 56 days. Echocardiography was also performed in all rats after eight weeks, and blood samples were obtained for determination of plasma tHcy. Rats were then sacrificed for histopathological and biochemical assessment of cardiac structure. RESULTS The SBP in the methionine-treated rats was significantly higher compared with controls and significantly lower compared with the methionine-valsartan group at 28 and 56 days (p<0.001). In addition, left ventricular wall thickness (LVWT) in the methionine-valsartan group (4.36+0.11 mm) was significantly lower compared with the methionine group (5.0+0.23 mm, p=0.03). Furthermore, cardiac collagen to total protein ratio was significantly lower in the methionine-valsartan group (2.19+0.11%) compared with the methionine group (2.64+0.08%, p=0.026). Fractional shortening (FS) was not significantly different between groups. CONCLUSION Results from this study suggest that hyperhomocysteinemia-induced hypertension and ventricular hypertrophy in rats are mediated, at least partly; by Ang II activation of AT1-receptors.
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Affiliation(s)
- Salah Kassab
- Department of Physiology, College of Medicine and Medical Sciences, Arabian Gulf University, Manama, Kingdom of Bahrain.
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Yi F, dos Santos EA, Xia M, Chen QZ, Li PL, Li N. Podocyte injury and glomerulosclerosis in hyperhomocysteinemic rats. Am J Nephrol 2007; 27:262-8. [PMID: 17396029 DOI: 10.1159/000101471] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2007] [Accepted: 03/02/2007] [Indexed: 11/19/2022]
Abstract
BACKGROUND/AIMS We previously reported that increase in plasma homocysteine (Hcys) levels by a 6-week methionine treatment produced remarkable glomerular injury. However, the mechanism by which hyperhomocysteinemia (hHcys) produces glomerular injury remains unknown. The present study was to observe when glomerular injury happens during hHcys and to explore the possible role of podocyte injury in the progression of glomerulosclerosis associated with hHcys. METHODS Uninephrectomized Sprague-Dawley rats treated with methionine were used to examine the time course of glomerular injury induced by hHcys. RESULTS Creatinine clearance was not different until rats were treated with methionine for 6 weeks, although plasma Hcys levels significantly increased at the 1st week of methionine treatment. However, urinary albumin excretion increased at the 2nd week of methionine treatment. Morphological examinations showed that mesangial expansion occurred at the 2nd week and podocyte effacement was also observed as processed glomerular damage during hHcys. Immunofluorescence analyses demonstrated that podocin and nephrin expressions were reduced, while alpha-actinin-4 increased during hHcys. CONCLUSIONS Increased plasma Hcys level is an important pathogenic factor resulting in glomerular injury even in the very early time of hHcys. These pathogenic effects of Hcys are associated with podocyte injury and changed expression and distribution of podocyte-associated proteins.
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Affiliation(s)
- Fan Yi
- Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA 23298, USA
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Díez N, Pérez R, Hurtado V, Santidrián S. Hyperhomocysteinaemia induced by dietary folate restriction causes kidney oxidative stress in rats. Br J Nutr 2007; 94:204-10. [PMID: 16115354 DOI: 10.1079/bjn20051468] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Diet is the most common cause of mild hyperhomocysteinaemia (HHcy), which occurs in approximately 5–7 % of the general population. Since HHcy causes endothelial damage by oxidative stress in different organs, the present study was designed to examine whether HHcy might be involved in renal oxidative stress. Twenty-five male Wistar rats were randomly divided into two groups: one (n13) was fedad libituma folate-free diet (FF) and the other (n12) was fed the same diet supplemented with folic acid (control, CO). After 8 weeks the animals were killed and kidneys removed. Malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities were measured in plasma and kidney homogenates. Renal tissue sections were analysed by indirect immunostaining with the primary antibody against oxidatively modified LDL receptor (LOX-1). A marked HHcy was confirmed in the FF group. As compared with CO animals, MDA levels in plasma and kidney homogenate were significantly higher in FF rats (P<0·05). Similarly, renal GPx and SOD activities were significantly higher in the FF group (P<0·001). No differences were found in LOX-1 immunohistochemical expression, which in the two groups was displayed in tubular cells. The present study provides evidence that HHcy does produce renal oxidative stress mediated by lipid peroxidation, and that the increased kidney MDA displayed by FF animals may enhance kidney antioxidant activity and thereby attenuate both kidney damage and expression of LOX-1.
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Affiliation(s)
- Nieves Díez
- Department of Human Physiology, School of Medicine, University of Navarra, 31080 Pamplona, Spain
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Perez FP, Ilie JI, Zhou X, Feinstein D, Jurivich DA. Pathomolecular effects of homocysteine on the aging process: A new theory of aging. Med Hypotheses 2007; 69:149-60. [PMID: 17208383 DOI: 10.1016/j.mehy.2006.10.056] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2006] [Accepted: 10/23/2006] [Indexed: 10/23/2022]
Abstract
Homocysteine has been associated with the most common age-related diseases but never associated with the acceleration of the aging process. This theoretical paper will try to demonstrate the pro-aging effects of homocysteine at the molecular, cellular, and organ level. High homocysteine levels in homocystinuria are associated with premature disease of the cardiovascular, skeletal, neurological, and other systems. These observations are similar to those noted in the aging process and should be considered as a progeroid syndrome. There is enough scientific evidence to support that homocysteine accelerates the aging process at the cellular and at the organism level. Most importantly, decreasing homocysteine levels by dietary or pharmacological interventions could prolong maximum life span in humans and/or delay the onset of the most common age-related diseases.
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Affiliation(s)
- Felipe P Perez
- Geriatric Medicine Section, Department of Medicine, University of Illinois, College of Medicine, M/C 717, 840 South Wood Street, Chicago, IL 60612, USA.
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Shastry S, Ingram AJ, Scholey JW, James LR. Homocysteine induces mesangial cell apoptosis via activation of p38-mitogen-activated protein kinase. Kidney Int 2006; 71:304-11. [PMID: 17149372 DOI: 10.1038/sj.ki.5002031] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Hyperhomocysteinemia is prevalent among patients with chronic kidney disease (CKD) and has been linked to progressive kidney and vascular diseases. Increased glomerular mesangial cell (MC) turnover, including proliferation and apoptosis, is a hallmark of CKD. Activation of p38-mitogen-activated protein kinase (p38-MAPK) has been linked to apoptosis in many cell lines. Accordingly, we studied the effect of homocysteine (Hcy) on MC p38-MAPK signalling and apoptosis. Hcy (50 microM/24 h) increased MC apoptosis as determined by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate (dUTP) nick end labelling (TUNEL) and single-stranded DNA (ssDNA) analysis. In addition to increases in pro-caspase-3 protein and caspase-3 activity, cells exposed to Hcy manifested enhanced reactive oxygen species content. Hcy increased p38-MAPK activity (fivefold), with maximal effect at 50 microM and 20 min; p38-MAPK activation was attenuated by N-acetylcysteine (Nac) and catalase (Cat), further indicating that the effect was via oxidative stress. Confocal microscopy revealed activation and nuclear translocation of p38-MAPK that was attenuated by Cat. In addition, Hcy-induced apoptosis as determined by TUNEL and ssDNA assay was abrogated by Nac, Cat, and SB203580 (p38-MAPK inhibitor). We conclude that in MC, Hcy (i) activates p38-MAPK and increases p38MAPK nuclear translocation via an oxidative stress dependent mechanism and (ii) induces DNA damage and apoptosis that is dependent on oxidative stress and p38-MAPK activation.
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Affiliation(s)
- S Shastry
- Department of Medicine, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75287, USA
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Yi F, Zhang AY, Li N, Muh RW, Fillet M, Renert AF, Li PL. Inhibition of ceramide-redox signaling pathway blocks glomerular injury in hyperhomocysteinemic rats. Kidney Int 2006; 70:88-96. [PMID: 16688115 DOI: 10.1038/sj.ki.5001517] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Ceramide-activated NAD(P)H oxidase has been reported to participate in homocysteine (Hcys)-induced abnormal metabolism of the extracellular matrix (ECM) in rat glomerular mesangial cells. However, it remains unknown whether this ceramide-redox signaling pathway contributes to glomerular injury induced by hyperhomocysteinemia (hHcys) in vivo. The present study was designed to address this question, defining the role of ceramide and activated NAD(P)H oxidase in the development of hHcys-induced glomerular injury. Uninephrectomized Sprague-Dawley rats were fed a folate-free diet for 8 weeks to produce hHcys and the de novo ceramide synthesis inhibitor myriocin or the NAD(P)H oxidase inhibitor apocynin was administrated. Rats with folate-free diet significantly increased plasma Hcys levels, renal ceramide levels, and NAD(P)H oxidase activity accompanied by marked glomerular injury. Treatment of rats with myriocin significantly reduced ceramide levels and improved glomerular injury, as shown by decreased urinary albumin excretion and reduced glomerular damage index. ECM components changed towards to normal levels with decreased tissue inhibitor of metalloproteinase-1 and increased matrix metalloproteinase-1 activity. NAD(P)H oxidase activity and Rac GTPase activity were reduced by 69 and 66%, respectively. In rats treated with apocynin, similar beneficial effects in protecting glomeruli from hHcys-induced injury were observed. These results support the view that de novo ceramide production is involved in Hcys-induced NAD(P)H oxidase activity in the kidney of hHcys rats and indicate the important role of ceramide-mediated redox signaling in hHcys-induced glomerular injury in rats.
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Affiliation(s)
- F Yi
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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Kassab SE, Abu-Hijleh MF, Al-Shaikh HB, Nagalla DS. Hyperhomocysteinemia in pregnant rats: effects on arterial pressure, kidneys and fetal growth. Eur J Obstet Gynecol Reprod Biol 2005; 122:177-81. [PMID: 16051422 DOI: 10.1016/j.ejogrb.2005.02.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2004] [Revised: 09/07/2004] [Accepted: 02/18/2005] [Indexed: 10/25/2022]
Abstract
OBJECTIVE This study aimed to test the hypothesis that hyperhomocysteinemia plays a role in the development of pathological changes similar to human preeclampsia in pregnant rats. STUDY DESIGN Arterial pressure and 24-h urinary excretion of proteins and electrolytes were measured during pre-pregnancy, pregnancy and postpartum periods in control (n = 12) and methionine-treated (2.0 g/kg/day, n = 11) Sprague-Dawley rats. Rats were then sacrificed at the end of this protocol and renal histological examination was performed. In another protocol, control (n = 6) and methionine-treated (n = 6) rats were anaesthetized at day 20 of gestation and pregnancy outcome was assessed. Hemodynamic and renal excretory differences between groups were analyzed using ANOVA and differences in renal histology and gestation outcome using t-test. RESULTS Serum homocysteine in the methionine group (24.0+/-2.0 micromol/L) was significantly higher compared with controls (8.5+/-0.5 micromol/L). Systolic pressure, urinary protein excretion and renal histological changes were not significantly different between the two groups. However, fetal weights were significantly smaller and percent of dead fetuses were 15% higher in methionine-treated compared with control rats. CONCLUSION Hyperhomocysteinemia is unlikely to cause maternal hypertension, proteinuria or renal damage in pregnant rats. However, hyperhomocysteinemia may restrict fetal growth and increase fetal mortality.
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Affiliation(s)
- Salah E Kassab
- Department of Physiology, College of Medicine and Medical Sciences, Arabian Gulf University, P.O. Box 22979, Manama, Bahrain.
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Abstract
Homocysteine is a thiol-containing amino acid that has gained notoriety because its elevation in the plasma is correlated with complex and multifactorial diseases, including cardiovascular diseases, neurodegenerative diseases, and neural tube defects. Homocysteine is redox-active, and its toxic effects have been frequently attributed to direct or indirect perturbation of redox homeostasis. Although the literature on the pathophysiology of elevated homocysteine is rather extensive, a very wide range of concentrations of this amino acid has been used in these studies ranging from normal to pathophysiological to unphysiological. It is clear that homocysteine induces varied responses that are specific to cell type and that cells, depending on their origin, display a wide range of sensitivity to homocysteine. In this review, we focus on the redox signaling pathways that have been connected to homocysteine in vascular (endothelial and smooth muscle) cells and in neuronal cells. We also discuss redox regulation of the key enzymes involved in homocysteine clearance: methionine synthase, betaine-homocysteine methyltranferase, and cystathionine beta-synthase.
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Affiliation(s)
- Cheng-Gang Zou
- Biochemistry Department, University of Nebraska, Lincoln, NE 68588, USA
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Ossani GP, Fischer PA, Caram SG, Dominguez GN, Monserrat AJ, Masnatta LD. Mild hyperhomocysteinemia promotes renal hemodynamic dysfunction without histopathologic changes in adult rats. Kidney Int 2005; 66:1866-72. [PMID: 15496157 DOI: 10.1111/j.1523-1755.2004.00960.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Hyperhomocysteinemia is able to promote glomerular damage and generate tubulointerstitial lesions. These findings were reported in rats with unilateral nephrectomy or in weanling rats with normal function, two experimental models that are exposed to other concomitant vascular risk factors. The aim of this work is to study whether mild hyperhomocisteinemia per se can induce renal histopathologic changes in adults rats with normal renal function at either 10 or 44 weeks of hyperhomocysteinemia. METHODS Two months old male Wistar rats (N= 52) were randomly allocated to either a normal control (N= 26) or hyperhomocysteinemic (N= 26) group. Control and hyperhomocysteinemic groups had free access to either tap water or homocysteine thiolactone 50 mg/kg/day, during 10 or 44 weeks. Plasma homocysteine levels were determined by a high-performance liquid chromatography (HPLC) method. Glomerular filtration rate (GFR) and renal plasma flow (RPF) were calculated from inulin and sodium para-aminohippurate (PAH) clearance determinations. Structural renal changes were investigated in kidneys fixed by perfusion. Histopathologic and morphometric analysis were carried out by standard methods. RESULTS Plasma total homocysteine levels were 53% (10 weeks) and 56% (44 weeks) higher in hyperhomocysteinemic group compared to the control group. GFR and RPF were significantly lower in hyperhomocysteinemic than in control group. The histopathologic and morphometric studies did not show any differences between the control and hyperhomocysteinemic rats at 10 or 44 weeks. CONCLUSION The present results show that mild hyperhomocysteinemia is able to induce renal functional and biochemical alterations in male adult rats that are not associated with renal histopathologic changes.
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Affiliation(s)
- Georgina P Ossani
- Patología Experimental, Departamento de Patología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina.
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Herrmann W, Schorr H, Obeid R, Makowski J, Fowler B, Kuhlmann MK. Disturbed homocysteine and methionine cycle intermediates S-adenosylhomocysteine and S-adenosylmethionine are related to degree of renal insufficiency in type 2 diabetes. Clin Chem 2005; 51:891-7. [PMID: 15774574 DOI: 10.1373/clinchem.2004.044453] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
BACKGROUND Diabetic nephropathy is a common complication in patients with type 2 diabetes that may increase atherothrombotic risk. Hyperhomocysteinemia (HHcy) further increases the risk in those patients. We studied concentrations of total homocysteine (tHcy) and its related metabolites S-adenosylmethionine (AdoMet) and S-adenosylhomocysteine (AdoHcy) in relation to B-vitamin status and renal function in patients with type 2 diabetes who developed diabetic nephropathy. METHODS The study included 93 patients with renal failure and type 2 diabetes. Chronic kidney disease was classified into four subgroups according to the National Kidney Foundation based on glomerular filtration rate plus pathologic abnormalities or markers of kidney damage. RESULTS Serum or plasma concentrations of the metabolites increased significantly with worsening of renal function, whereas serum concentrations of the B vitamins (folate, vitamins B12 and B6) did not differ appreciably between the groups. Moreover, plasma concentrations of AdoHcy and AdoMet were markedly increased in patients with kidney failure compared with those in stage 2 (median AdoHcy, 112.7 vs 10.5 nmol/L; median AdoMet, 162.0 vs 80.0 nmol/L). The AdoMet/AdoHcy ratio was more than 80% lower in patients with renal failure compared with stage 2. Vitamin B12 was a significant determinant of concentrations of AdoMet, tHcy, methylmalonic acid (MMA), and cystathionine. CONCLUSIONS Increased plasma concentrations of tHcy and methionine cycle intermediates (AdoMet, AdoHcy) are related to disturbed renal function in patients with type 2 diabetes. Vitamin B12 and/or folate are significant predictors of tHcy, cystathionine, MMA, and AdoMet. The effect of therapeutic doses of the B vitamins on AdoMet, AdoHcy, and their ratio should be tested in renal patients.
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Affiliation(s)
- Wolfgang Herrmann
- Department of Clinical Chemistry, Central Laboratory, Saarland University Hospital, Homburg, Germany.
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Bar-Or D, Curtis CG, Sullivan A, Rael LT, Thomas GW, Craun M, Bar-Or R, Maclean KN, Kraus JP. Plasma albumin cysteinylation is regulated by cystathionine beta-synthase. Biochem Biophys Res Commun 2005; 325:1449-53. [PMID: 15555590 DOI: 10.1016/j.bbrc.2004.10.191] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2004] [Indexed: 11/24/2022]
Abstract
High homocysteine (Hcy) levels are a well-known independent risk factor for endothelial damage in atherosclerosis. We examined whether a rat intestinal model of ischemia-reperfusion was associated with high Hcy and with the modification of plasma albumin into cysteinylated species (CysAlb). The three treatment groups were as follows: midline abdominal incision (group A, n=10), followed by ligation of the superior mesenteric artery for a period of 2h (group B, n=3), and followed by reperfusion for 1h (group C, n=10). Hcy levels were 2.5-fold higher in group C than group A (p<0.05). 100% and 73.44+/-0.04% of Alb were modified into Cys species in groups C and B, respectively, compared to 51.2% in group A. A cystathionine beta-synthase (CBS) deficient mouse model, known to have high plasma Hcy levels, was also used to determine the extent of CysAlb. Hcy levels, %CysAlb, and %HcyAlb were 180.1+/-45.7 microM, 0%, and 23.4+/-4.4% in CBS deficient mice, while in control mice, those values were 5.7+/-1.8 microM, 24.2+/-4.1%, and 0%, respectively (p<0.05). High CysAlb and Hcy levels were observed in a rat model of bowel ischemia/reperfusion while high HcyAlb and Hcy levels with no CysAlb were observed in the CBS deficient mice. CysAlb may serve as a biomarker for the severity of gut ischemia, and high Hcy may explain endothelial damage associated with this model. Additionally, active CBS is essential for the formation of CysAlb.
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Affiliation(s)
- David Bar-Or
- Trauma Research Department, Swedish Medical Center, Englewood, CO, USA.
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Neves MF, Endemann D, Amiri F, Virdis A, Pu Q, Rozen R, Schiffrin EL. Small artery mechanics in hyperhomocysteinemic mice: effects of angiotensin II. J Hypertens 2004; 22:959-66. [PMID: 15097236 DOI: 10.1097/00004872-200405000-00018] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Elevated plasma homocysteine has been associated with cardiovascular disease, although a causal relationship is unclear. The purpose of this study was to evaluate whether mild hyperhomocysteinemia (H-Hcy) may increase vascular stiffness of small arteries. METHODS Wild-type (+/+) and heterozygous (+/-) methylenetetrahydrofolate reductase (Mthfr) knockout mice, a new model of mild H-Hcy, were treated with vehicle or angiotensin (Ang) II infusion (400 ng/kg per min s.c.). Second-order mesenteric arteries were studied on pressurized myograph. They were exposed to intraluminal pressures ranging from 3 to 140 mmHg. Media thickness and lumen diameter were measured at each pressure level to determine wall mechanical properties. Collagen type I/III and elastin deposition in the vascular wall were evaluated by confocal immunofluorescence microscopy. RESULTS Media-to-lumen ratio was similar in Mthfr and Mthfr mice, and significantly increased by Ang II. The stress-strain relationship was shifted to the left in small mesenteric arteries from Mthfr compared to Mthfr mice, indicating that mild H-Hcy is associated with stiffer vessels. Ang II treatment in Mthfr mice enhanced the leftward shift in the stress-strain relationship and significantly increased the elastic modulus, suggesting the presence of stiffer wall components in small arteries in these animals. Increased collagen type I/III accumulation and decreased elastin content in the media of mesenteric arteries was noted in Mthfr compared to Mthfr mice. Ang II infusion augmented vascular collagen deposition in both groups, more substantially in Mthfr mice. CONCLUSIONS Mild hyperhomocysteinemia is associated with stiffer small arteries with increased collagen deposition in the media. These changes are accentuated by Ang II-induced blood pressure elevation.
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Affiliation(s)
- Mario F Neves
- Canadian Institutes of Health Research, Multidisciplinary Research Group on Hypertension, Clinical Research Institute of Montreal, University of Montreal, 110 Pine Avenue West, Montreal, Quebec, Canada H2W 1R7
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Zhang F, Siow YL, O K. Hyperhomocysteinemia activates NF-kappaB and inducible nitric oxide synthase in the kidney. Kidney Int 2004; 65:1327-38. [PMID: 15086472 DOI: 10.1111/j.1523-1755.2004.00510.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Hyperhomocysteinemia is an independent risk factor for cardiovascular disorders. Injury of multiple organs, including the kidney, was observed in hyperhomocysteinemic individuals. Activation of a transcription factor, namely, nuclear factor kappa B (NF-kappaB), plays an important role in inflammatory response and can exacerbate organ injury. The objective of the present study was to investigate the effect of hyperhomocysteinemia on renal NF-kappaB activation and the consequence of such activation. METHODS Hyperhomocysteinemia was induced in Sprague-Dawley rats after 4 weeks of a high-methionine diet. Activation of NF-kappaB was determined by electrophoretic mobility shift assay. Role of inhibitor protein IkappaBalpha was examined by Western immunoblotting analysis. RESULTS There was a significant increase in the level of phosphorylated IkappaBalpha protein in kidneys of hyperhomocysteinemic rats. This resulted in a decrease in the IkappaBalpha protein level leading to NF-kappaB activation. As a consequence, the expression of inducible nitric oxide synthase (iNOS) mRNA and protein was significantly elevated in kidneys of hyperhomocysteinemic rats. Increased nitric oxide production (150% of the control) resulted in peroxynitrite formation in these kidneys. Pretreatment of rats with a NF-kappaB inhibitor not only abolished NF-kappaB activation, but also reversed hyperhomocysteinemia-induced iNOS expression in the kidney. CONCLUSION Hyperhomocysteinemia alone can activate NF-kappaB and hence induce iNOS-mediated nitric oxide production in the kidney leading to increased peroxynitrite formation. This may represent one of the mechanisms for renal dysfunction in hyperhomocysteinemia.
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Affiliation(s)
- Fan Zhang
- Department of Pharmacology, Faculty of Medicine, University of Hong Kong, Hong Kong, China
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Ingram AJ, Krepinsky JC, James L, Austin RC, Tang D, Salapatek AM, Thai K, Scholey JW. Activation of mesangial cell MAPK in responseto homocysteine. Kidney Int 2004; 66:733-45. [PMID: 15253728 DOI: 10.1111/j.1523-1755.2004.00795.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
BACKGROUND Alteration in mesangial cell function is central to the progression of glomerular disease in numerous models of chronic renal failure (CRF). Animal models of chronic glomerular disease are characterized by mesangial cell proliferation and elaboration of extracellular matrix protein (ECM), resulting in glomerulosclerosis. Elevated plasma levels of homocysteine (Hcy) are seen in both animal models and humans with CRF, and have been proposed to contribute to the high prevalence of vascular disease in this group. Some of the pathogenetic effects of Hcy are thought to be mediated via the induction of endoplasmic reticulum stress. Thus, Hcy effects on mesangial cells could contribute to the progression of CRF. Previous work has shown Hcy- mediated induction of Erk mitogen-activated protein kinase (MAPK) in vascular smooth muscle cells (VSMCs). Erk induces increases in activator protein-1 (AP-1) transcription factor activity which may augment mesangial cell proliferation and ECM protein production. Consequently, we studied the effect of Hcy on mesangial cell Erk signaling. METHODS Mesangial cells were exposed to Hcy after 24 hours of serum starvation and Erk activity assessed. Nuclear translocation of phospho-Erk was visualized by confocal microscopy. AP-1 nuclear protein binding was measured in response to Hcy by mobility shift assay. Hcy-induced mesangial cell calcium flux was measured in Fura-2 loaded cells. Mesangial cell DNA synthesis in response to Hcy was assessed by [3H]-thymidine incorporation and proliferation by Western blotting for proliferating cell nuclear antigen (PCNA). Expression of endoplasmic reticulum stress response genes were determined by Northern and Western analysis. RESULTS Hcy led to an increase in Erk activity that was maximal at 50 micromol/L and 20 minutes of treatment. Subsequent experiments used this concentration and time point. Erk activity in response to Hcy was insensitive to n-acetylcysteine and catalase, indicating oxidative stress did not play a role. However, Hcy50 micromol/L induced a brief increase in intracellular mesangial cell calcium within 5 minutes, and the calcium ionophores A23187 and ionomycin increased Erk activity while chelation of intracellular calcium with BAPTA-AM abrogated the Erk response to Hcy. Confocal microscopy of activated Erk nuclear translocation mirrored these results as did mesangial cell nuclear protein binding to AP-1 consensus sequences. Hcy- induced increases in thymidine incorporation and PCNA expression at 24 hours were Erk dependent. The expression of endoplasmic reticulum stress response genes was significantly elevated by Hcy in an Erk-dependent manner. CONCLUSION Hcy increases Erk activity in mesangial cells via a calcium-dependent mechanism, resulting in increased AP-1 nuclear protein binding, cell DNA synthesis and proliferation and induction of endoplasmic reticulum stress. These observations suggest potential mechanisms by which Hcy may contribute to progressive glomerular injury.
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Rodrigo R, Passalacqua W, Araya J, Orellana M, Rivera G. Homocysteine and essential hypertension. J Clin Pharmacol 2004; 43:1299-306. [PMID: 14615465 DOI: 10.1177/0091270003258190] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The authors examine the available clinical and experimental data supporting the view that homocysteine, an alternative risk factor of cardiovascular disease, may play a role in the pathogenesis of essential hypertension. The mechanism of this disease has not been elucidated, but it may be related to impairment of vascular endothelial and smooth muscle cell function. Therefore, the occurrence of endothelial dysfunction could contribute to alterations of the endothelium-dependent vasomotor regulation. Elevated homocysteinemia diminishes the vasodilation by nitric oxide, increases oxidative stress, stimulates the proliferation of vascular smooth muscle cells, and alters the elastic properties of the vascular wall. Thus, homocysteine contributes to elevate the blood pressure. Also it is known that elevated plasma levels of homocysteine could lead to oxidant injury to the endothelium. The correction of elevated homocysteinemia by administration of vitamins B12 and B6 plus folic acid, could be a useful adjuvant therapy of hypertension. However, further controlled randomized trials are necessary to establish the efficacy and tolerability of these potentially therapeutic agents.
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Affiliation(s)
- Ramón Rodrigo
- Instituto de Ciencias Biomédicas, Programa de Farmacología Molecular y Clínica, Facultad de Medicina, Universidad de Chile, Santiago, Chile
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Rodrigo R, Passalacqua W, Araya J, Orellana M, Rivera G. Implications of oxidative stress and homocysteine in the pathophysiology of essential hypertension. J Cardiovasc Pharmacol 2004; 42:453-61. [PMID: 14508229 DOI: 10.1097/00005344-200310000-00001] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The present review examines the clinical and experimental data to support the view that homocysteine and oxidative stress, two alternative risk factors of vascular disease, may play a role in the pathogenesis of primary or essential hypertension. Although the precise mechanism of this disease has not been elucidated, it may be related to impairment of vascular endothelial and smooth muscle cell function. Thus, the occurrence of endothelial dysfunction could contribute to alterations of the endothelium-dependent vasomotor regulation. Hyperhomocysteinemia limits the bioavailability of nitric oxide, increases oxidative stress, stimulates the proliferation of vascular smooth muscle cells, and alters the elastic properties of the vascular wall. The link between oxidative stress and hyperhomocysteinemia is also biologically plausible, because homocysteine promotes oxidant injury to the endothelium. Cumulated evidence suggests that the diminution of oxidative stress with antioxidants or the correction of hyperhomocysteinemia with vitamins-B plus folic acid, could be useful as an adjuvant therapy for essential hypertension. Further studies involving long-term trials could help to assess the tolerability and efficacy of the use of these therapeutic agents.
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Affiliation(s)
- Ramón Rodrigo
- Instituto de Ciencias Biomédicas, Programa de Farmacología Molecular y Clínica, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
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Tylicki L, Rutkowski B, Hörl WH. Multifactorial determination of hypertensive nephroangiosclerosis. Kidney Blood Press Res 2003; 25:341-53. [PMID: 12590197 DOI: 10.1159/000068698] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Essential hypertension causes renal injury. Hypertensive nephroangiosclerosis (HN) or hypertensive nephropathy are terms most commonly used to describe this renal pathology. Although specific histological lesions occurring in affected kidneys are well known, pathogenesis of hypertension-related renal scarring is not completely understood. Evidence exists to support the theory that other factors such as aging, black race or smoking, beside blood pressure, contribute to the development and progression of HN. Metabolic disturbances, cocaine and nonsteroidal anti-inflammatory drug abuse, ochratoxin A exposure, dietary salt intake, heavy metal toxicity, hantavirus infection and perinatal programming are also considered risk factors. Renal susceptibility genes may determine whether hypertension-induced progressive renal damage occurs and how severe it is. Determination of all risk factors may identify patients at high risk of renal failure and help tailor an appropriate management. In the present paper, the knowledge available on this clinically important objective is discussed.
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Affiliation(s)
- Leszek Tylicki
- Department of Internal Medicine, Nephrology and Transplantology, Medical University, Gdansk, Poland
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Hörl WH. [Atherosclerosis and uremia: signifance of non-traditional risk factors]. Wien Klin Wochenschr 2003; 115:220-34. [PMID: 12778774 DOI: 10.1007/bf03040320] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Arteriosclerosis, atherosclerosis and vascular calcification are causally related to the high morbidity and mortality of patients with chronic renal failure. Oxidative stress and carbonyl stress of uremia, dialysis procedure and/or intravenous iron therapy result in AGE (advanced glycation end-product), ALE (advanced lipoxidation end-product) and AOPP (advanced oxidation protein product) formation, favouring together with elevated CRP (C-reactive protein) levels the development of cardiovascular and cerebrovascular complications. Enhanced plasma levels of homocysteine and ADMA (asymmetric dimethylarginine) contribute to this process. In addition, in chronic renal insufficiency hyperphosphatemia and an enhanced calcium x phosphorus ion product are associated with the morbidity and mortality of the patients, particularly in the presence of fetuin deficiency. Phosphorus, AGEs and AOPPs, beside other factors, catalyze the conversion of vascular smooth muscle cells to osteoblast--like cells (particularly in the presence of monocytes/macrophages), resulting in bone matrix protein formation. Other risk factors, such as age, male sex, smoking, hypertension, diabetes, chronic inflammation, insulin resistance or dyslipidemia (enhanced non-HDL-cholesterol) also contribute to the atherosclerotic risk profile of the patient with chronic renal insufficiency. While there is growing understanding of the mechanisms involved in arteriosclerosis, atherosclerosis and vascular calcification in uremia, we are still missing effective therapeutic maneuvers for reduction of excess mortality in uremic patients.
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Affiliation(s)
- Walter H Hörl
- Klinische Abteilung für Nephrologie und Dialyse, Medizinische Universitätsklinik III, Wien, Osterreich.
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