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Li H, Liu C, Zhang J, Wang W, Cheng W, Yang R, Huang AM, Liang J, Guo J, Liu Z. The association of homocysteine level with the risk of diabetic nephropathy and diabetic retinopathy in NHANES. Acta Diabetol 2023; 60:907-916. [PMID: 36997800 DOI: 10.1007/s00592-023-02075-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 03/12/2023] [Indexed: 04/01/2023]
Abstract
AIMS To examine the association of homocysteine (Hcy) with diabetic nephropathy (DN) and diabetic retinopathy (DR) in a representative United States population. METHODS This was a cross-sectional study using data from participants in the National Health and Nutrition Examination Survey 2005-2006. Metrics including Hcy level, urinary albumin to creatinine ratio, estimated glomerular filtration rate, and retinopathy grading were collected. Multiple logistic regression models were employed to assess the association of Hcy with DN and DR. RESULTS 630 participants were included in this study. The Hcy level was significantly higher in those with DN and DR than those without DN and DR. Hcy was associated with an increased risk of DN (OR = 1.31, 95% CI 1.18-1.46; P < 0.001). In the fully adjusted model of DN (model II), compared to participants in quartiles 1 of Hcy, the adjusted ORs for participants in quartiles 2-4 were 1.49 (95% CI 0.52-4.26; P = 0.426), 3.81 (95% CI 1.35-10.73; P = 0.015), and 14.08 (95% CI 3.84-51.66; P = 0.001), respectively. Hcy was also associated with an increased risk of DR (OR = 2.260, 95% CI 1.212-4.216; P = 0.014), but this association was non-significant in the fully adjusted model of DR (model II). CONCLUSIONS In diabetic patients, Hcy was associated with increased risk of DN in a non-linear manner. In addition, Hcy was associated with the risk of DR, but the association was attenuated after adjusting for confounders. In the future, Hcy can potentially be used as an early screening indicator for diabetic microvascular complications.
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Affiliation(s)
- Huangdong Li
- Ophthalmic Center, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510260, Guangdong, China
| | - Chengyi Liu
- Ophthalmic Center, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510260, Guangdong, China
- Conghua Maternity and Children Health Care Center, Conghua District, Xincheng West Road 76, Guangzhou, 510900, China
| | - Jingyu Zhang
- Ophthalmic Center, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510260, Guangdong, China
| | - Wei Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510623, China
| | - Weijing Cheng
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510623, China
| | - Ruiming Yang
- Ophthalmic Center, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510260, Guangdong, China
| | - Amy Michelle Huang
- Department of Ophthalmology, University of Colorado, Aurora, CO, 80045, USA
| | - Jiamian Liang
- Ophthalmic Center, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510260, Guangdong, China
| | - Jian Guo
- Department of Ophthalmology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, 350004, China.
| | - Zhiping Liu
- Ophthalmic Center, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510260, Guangdong, China.
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2
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Lei X, Zeng G, Zhang Y, Li Q, Zhang J, Bai Z, Yang K. Association between homocysteine level and the risk of diabetic retinopathy: a systematic review and meta-analysis. Diabetol Metab Syndr 2018; 10:61. [PMID: 30083252 PMCID: PMC6071377 DOI: 10.1186/s13098-018-0362-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 07/30/2018] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Previous studies have demonstrated that elevated homocysteine (Hcy) level represents an independent risk factor for macrovascular disease. However, the relationship between hyperhomocysteinemia and the progression of diabetic retinopathy in patients remains controversial. Hence, the purpose of this systematic review and meta-analysis was to explore any potential association between Hcy and the risk of diabetic retinopathy. METHODS PubMed, Embase, and the Cochrane Library databases were searched to screen studies that fulfilled the inclusion criteria from date of database inception to November 2017. The summary odds ratio (OR) with 95% confidence intervals (CIs) was used to calculate the pooled effect estimate for the relationship between Hcy and diabetic retinopathy risk. Sensitivity, subgroup analyses, and publication bias were also assessed. RESULTS Eleven studies involving a total of 2184 diabetic patients were included in the meta-analysis. The summary OR suggested that increased Hcy level in diabetic patients was associated with an increased risk of diabetic retinopathy (OR 1.62; 95% CI 1.29-2.03; p < 0.001). Although significant heterogeneity was detected among the included studies, the findings of sensitivity analysis remained statistically significant. Subgroup analyses found a significant association between Hcy and diabetic retinopathy in most subsets, but no significant association was found if the sample size was < 100, participants had type 1 diabetes mellitus, and the study quality was low. CONCLUSIONS The findings of this study suggested that elevated Hcy level was associated with an increased risk of diabetic retinopathy, especially in type 2 diabetic patients. This finding may help diabetic patients to achieve effective management strategy to prevent the progression of diabetic retinopathy.
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Affiliation(s)
- Xunwen Lei
- The First Clinical Medical College of Lanzhou University, Lanzhou, 730000 China
- Evidence-Based Medicine Center, School of Basic Medical Sciences of Lanzhou University, Lanzhou, 730000 China
- Key Laboratory of Evidence-Based Medicine and Knowledge Translation of Gansu Province, Lanzhou, 730000 China
| | - Guifeng Zeng
- Gansu Health Vocational College, Lanzhou, 730000 China
| | - Yuemei Zhang
- The First Clinical Medical College of Lanzhou University, Lanzhou, 730000 China
| | - Qiang Li
- The First Clinical Medical College of Lanzhou University, Lanzhou, 730000 China
| | - Jinzhi Zhang
- The First Clinical Medical College of Lanzhou University, Lanzhou, 730000 China
| | - Zhenggang Bai
- School of Public Affairs, Nanjing University of Science and Technology, Nanjing, 210094 China
| | - Kehu Yang
- Evidence-Based Medicine Center, School of Basic Medical Sciences of Lanzhou University, Lanzhou, 730000 China
- Key Laboratory of Evidence-Based Medicine and Knowledge Translation of Gansu Province, Lanzhou, 730000 China
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Wotherspoon F, Laight DW, Shaw KM, Cummings MH. Review: Homocysteine, endothelial dysfunction and oxidative stress in type 1 diabetes mellitus. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/14746514030030050401] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Type 1 diabetes is associated with an increased risk of cardiovascular disease, which cannot be fully explained by traditional risk factors. Elevated plasma homocysteine is an independent risk factor for macrovascular disease in the general population. This review examines the evidence for hyperhomocysteinaemia in patients with type 1 diabetes and describes the mechanisms that may lead to increased macrovascular susceptibility. While reports of plasma homocysteine levels in type 1 diabetes are inconsistent, increased plasma homocysteine levels have been found in subgroups of patients with microalbuminuria, nephropathy and macrovascular disease. Although a direct causal relationship between plasma homocysteine and atherosclerosis remains to be proven, potential mechanisms of vascular damage by homocysteine include endothelial dysfunction linked to increased oxidative stress. This could contribute to the association between hyperhomocysteinaemia and macrovascular disease in type 1 diabetes.
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Affiliation(s)
- Fiona Wotherspoon
- Academic Department of Diabetes and Endocrinology, Queen Alexandra Hospital, Southwick Park Road, Cosham, Portsmouth, PO6 3LY, UK,
| | - David W Laight
- School of Pharmacy and Biomedical Studies, University of Portsmouth, St. Michaels Building, White Swan Road, Portsmouth, PO1 2DT, UK
| | - Kenneth M Shaw
- Academic Department of Diabetes and Endocrinology, Queen Alexandra Hospital, Southwick Park Road, Cosham, Portsmouth, PO6 3LY, UK
| | - Michael H Cummings
- Academic Department of Diabetes and Endocrinology, Queen Alexandra Hospital, Southwick Park Road, Cosham, Portsmouth, PO6 3LY, UK
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4
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Xu C, Wu Y, Liu G, Liu X, Wang F, Yu J. Relationship between homocysteine level and diabetic retinopathy: a systematic review and meta-analysis. Diagn Pathol 2014; 9:167. [PMID: 25257241 PMCID: PMC4207897 DOI: 10.1186/s13000-014-0167-y] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Accepted: 08/16/2014] [Indexed: 02/06/2023] Open
Abstract
Background The relationship between homocysteine (Hcy) and diabetic retinopathy (DR) remains unclear to date. Therefore, a systematic review and meta-analysis was performed on the relationship between Hcy level and DR. Methods Studies were identified by searching PubMed, Embase, and Web of Science databases until 5 May, 2014. Results A total of 31 studies involving 6,394 participants were included in the meta-analysis. After pooling the data from each included study, the blood Hcy concentration in the DR group was observed to be higher than that in the control group [WMD = 2.55; 95% confidence interval (CI), 1.70–3.40], and diabetes mellitus (DM) patients with hyperhomocysteinemia were at a risk for DR [odds ratio (OR) = 1.93; 95% CI, 1.46–2.53]. Considering the different DM types, hyperhomocysteinemia in T1DM (OR = 1.83, 95% CI, 1.28–2.62) was associated with DR rather than in T2DM (OR = 1.59, 95% CI, 0.72–3.51). Considerable statistical heterogeneity in the overall summary estimates was partly explained by the geographical differences. Conclusions Results from this current meta-analysis indicate that hyperhomocysteinemia is a risk factor for DR, especially proliferative DR. Differences between geographical regions were observed in the relationship between hyperhomocysteinemia with T1DM risk. Given the heterogeneous results, the relationship between high Hcy and DR needs further investigation. Virtual Slides The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_167
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5
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Bulum T, Blaslov K, Duvnjak L. Plasma Homocysteine is Associated with Retinopathy in Type 1 Diabetic Patients in the Absence of Nephropathy. Semin Ophthalmol 2014; 31:198-202. [PMID: 24785685 DOI: 10.3109/08820538.2014.912338] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
INTRODUCTION Previous cross-sectional studies suggested that plasma total homocysteine (tHcy) is associated with retinopathy in patients with type 1 diabetes (T1DM) only in cases of impaired renal function. The objective of this study was to examine whether there is an independent relationship between tHcy and retinopathy in normoalbuminuric T1DM patients with normal estimated glomerular filtration rate (eGFR). METHODS The study included 163 normoalbuminuric patients with T1DM and normal renal function (eGFR >60 ≤ 125 ml min(-1) 1.73 m(-2)). Urinary albumin excretion rate (UAE) was measured from at least two 24 h urine samples. Photodocumented retinopathy status was made according to the EURODIAB protocol. tHcy level was measured with the chemiluminescent immunoassay. RESULTS Retinopathy was present in 48% of normoalbuminuric patients. Patients with retinopathy were older (49 vs 42 years, p = 0.001), had higher systolic blood pressure (130 vs 120 mmHg, p = 0.001), triglycerides (0.89 vs 0.77 mmol/L, p = 0.01), tHcy (9.8 vs 9.1 µmol/L, p = 0.04), and lower eGFR (100 vs 106 ml min(-1) 1.73 m(-2), p = 0.03). In multivariate logistic regression analysis, after adjustment for variables that reached statistical significance in the univariate analysis, only tHcy was significantly associated with a risk of retinopathy in our subjects (p = 0.02), with odds ratios of 1.02 to 1.43. CONCLUSION These data suggest that tHcy is independently associated with retinopathy in normoalbuminuric T1DM with normal eGFR. The mechanisms relating tHcy and retinopathy in T1DM are not clear. Prospectives studies are needed to confirm whether higher tHcy in normoalbuminuric T1DM patients has predictive value for development of retinopathy.
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Affiliation(s)
- Tomislav Bulum
- a Vuk Vrhovac Clinic for Diabetes, Endocrinology and Metabolic Diseases, University Hospital Merkur, University of Zagreb , Zagreb , Croatia
| | - Kristina Blaslov
- a Vuk Vrhovac Clinic for Diabetes, Endocrinology and Metabolic Diseases, University Hospital Merkur, University of Zagreb , Zagreb , Croatia
| | - Lea Duvnjak
- a Vuk Vrhovac Clinic for Diabetes, Endocrinology and Metabolic Diseases, University Hospital Merkur, University of Zagreb , Zagreb , Croatia
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6
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Clinical risk factors and association of hyperhomocysteinemia with diabetic retinopathy in Iranian type 2 diabetes patients. Diabetes & Metabolic Syndrome: Clinical Research & Reviews 2008. [DOI: 10.1016/j.dsx.2008.05.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Abstract
OBJECTIVE Homocysteine is an emerging risk factor for cardiovascular and nondiabetic ocular vaso-occlusive diseases. However, studies of the relationship between homocysteine and diabetic retinopathy have reported inconsistent results. The purpose of this study was to evaluate the relationship between plasma total homocysteine concentration and diabetic retinopathy. RESEARCH DESIGN AND METHODS We assessed the homocysteine-retinopathy relationship in 168 men and women with type 2 diabetes in a community-based, cross-sectional study. We photodocumented diabetic retinopathy status and measured plasma total homocysteine concentration using a commercial fluorescence polarization immunoassay enzymatic kit. Data for selected clinical/demographic variables and established risk factors for diabetic retinopathy were obtained from fasting blood samples and an interviewer-assisted lifestyle questionnaire. RESULTS A higher mean plasma total homocysteine concentration was observed in diabetic individuals with retinopathy than in those without retinopathy (11.5 mumol/l [95% CI 10.4-12.5] vs. 9.6 mumol/l [9.1-10.2], P = 0.001). Furthermore, the relationship between homocysteine and diabetic retinopathy was not explained by renal dysfunction and was independent of the other major risk factors for diabetic retinopathy (duration of diabetes, A1C, and systolic blood pressure) and determinants of higher homocysteine concentrations (age, sex, and red cell folate) (odds ratio 1.20 [95% CI 1.023-1.41], P = 0.024). CONCLUSIONS Plasma total homocysteine concentration may be a useful biomarker and/or a novel risk factor for increased risk of diabetic retinopathy in people with type 2 diabetes.
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Affiliation(s)
- Laima Brazionis
- Department of Medicine, University of Melbourne, St. Vincent's Hospital, P.O. Box 2900, Fitzroy, Victoria 3065, Australia.
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8
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Soedamah-Muthu SS, Chaturvedi N, Teerlink T, Idzior-Walus B, Fuller JH, Stehouwer CDA. Plasma homocysteine and microvascular and macrovascular complications in type 1 diabetes: a cross-sectional nested case-control study. J Intern Med 2005; 258:450-9. [PMID: 16238681 DOI: 10.1111/j.1365-2796.2005.01560.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
OBJECTIVES To examine the independent relationship between plasma total homocysteine (tHcy) and microvascular and macrovascular complications. DESIGN We performed a cross-sectional nested case-control study from the EURODIAB Prospective Complications Study. SETTING A hospital-based multicentre study at 24 centres in 13 European countries. SUBJECTS A total of 533 type 1 diabetic patients, diagnosed at <36 years of age. Cases (n=359) were defined as those with one or more complications of diabetes and control subjects (n=174) were all those with no evidence of any complication. Main outcome measures. Retinopathy, albumin excretion rate (AER), glomerular filtration rate (GFR) estimated by Cockcroft-Gault formula, hypertension and cardiovascular disease (CVD) were assessed. RESULTS In unadjusted models, tHcy (per 5 micromol L(-1)) was significantly associated with nonproliferative retinopathy (OR=1.45, 95% CI: 1.10-1.91), proliferative retinopathy (OR=1.74, 95% CI: 1.34-2.27), macroalbuminuria (OR=1.90, 95% CI: 1.49-2.42), hypertension (OR=2.23, 95% CI: 1.69-2.93) and CVD (OR=1.59, 95% CI: 1.18-2.14). In multivariate models, tHcy was significantly related to macroalbuminuria (OR=1.66, 95% CI: 1.24-2.24) and hypertension (OR=1.57, 95% CI: 1.19-2.07), independent of age, sex, diabetes duration, GFR, microvascular and macrovascular complications and cardiovascular risk factors. There was a significant relationship between tHcy and decreased GFR, independent of established risk factors. The relationship between tHcy and retinopathy was not independent of albuminuria or GFR. The initial positive relationship with CVD was explained by cardiovascular risk factors. CONCLUSION In this large study of European type 1 diabetic subjects, increased concentrations of tHcy were independently related to macroalbuminuria, renal function and hypertension, which suggests that tHcy might play an important role in the pathogenesis of vascular complications in type 1 diabetes.
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Affiliation(s)
- S S Soedamah-Muthu
- Department of Epidemiology and Public-Health, Royal Free and University College London Medical School, London, UK.
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9
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Yücel I, Yücel G, Müftüoglu F. Plasma homocysteine levels in noninsulin-dependent diabetes mellitus with retinopathy and neovascular glaucoma. Int Ophthalmol 2005; 25:201-5. [PMID: 16200446 DOI: 10.1007/s10792-004-6740-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2003] [Accepted: 11/11/2004] [Indexed: 12/27/2022]
Abstract
AIM This study was designed to evaluate plasma homocysteine levels in noninsulin-dependent diabetes mellitus patients (NIDDM) with preproliferative retinopathy and neovascular glaucoma. The experimental goal was to determine the relationship between plasma homocysteine content and the development of microvascular lesions. METHODS Plasma homocysteine levels were assessed in three experimental groups consisting of healthy controls (n = 30), NIDDM patients with preproliferative retinopathy (n = 20) and NIDDM patients with neovascular glaucoma (n = 20). Homocysteine levels were determined via a fluorescence polarization immunoassay method by an Abbot IMX instrument. RESULTS Plasma homocysteine levels in NIDDM patients with preproliferative retinopathy and neovascular glaucoma (n = 40) were found to be significantly higher than those of controls (n = 30) (p < 0.01). When statistical analysis was performed separately among the three experimental groups, no significant difference in plasma homocysteine levels were found in patients with preproliferative retinopathy compared to controls. However, homocysteine levels in patients with neovascular glaucoma were found to be significantly higher than the control group (p < 0.001). No significant difference in plasma homocysteine levels could be detected between patients with preproliferative retinopathy and neovascular glaucoma. CONCLUSIONS Hyperhomocysteinemia is a risk factor for the development of microvascular lesions in patients with NIDDM but cannot be used as a marker to assess the progression of lesions observed in neovascular glaucoma.
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Affiliation(s)
- Iclal Yücel
- Department of Ophthalmology, School of Medicine, Akdeniz University, Turkey.
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10
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Elias AN, Eng S. Homocysteine concentrations in patients with diabetes mellitus--relationship to microvascular and macrovascular disease. Diabetes Obes Metab 2005; 7:117-21. [PMID: 15715884 DOI: 10.1111/j.1463-1326.2004.00376.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Alan N Elias
- Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, University of California, Irvine Medical Center, Orange, CA 92868, USA.
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Meloni GF, Tonolo GC, Zuppi C, Zappacosta B, Musumeci S. Hyper-homocysteinemia is Not a Main Feature of Juvenile Uncomplicated Type 1 Diabetes. J Atheroscler Thromb 2005; 12:14-9. [PMID: 15725691 DOI: 10.5551/jat.12.14] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Total plasma homocysteine (tHcy) was measured by high pressure liquid chromatography (HPLC) method in 28 patients (12 females and 16 males) at the onset of type 1 diabetes mellitus (T1DM), 4 females during diabetes ketoacidosis (DKA) and 154 (68 females and 86 males) during follow-up. Serum folate, pyridoxal 5' phosphate (PLP) and Vitamin B12 (Vit B12) were also measured. Plasma tHcy levels were not found significantly different in T1DM patients known to have diabetes (males 9.2 +/- 7.7 and females 7.0 +/- 2.8 micromol/l) and in those who were newly diagnosed (males 9.7 +/- 4.8 and females 7.16 +/- 2.8 micromol/l) than in healthy controls (males 8.7 +/- 3.5 and females 7.8 +/- 2.55 micromol/l). Only a significant difference for sex was observed in known diabetes (p = 0.0281). Serum folate, PLP and Vit B12 were normal (12.6 +/- 3.6 ng/ml, 20.11 +/- 0.8 ng/ml and 416.7 +/- 41.9 pg/ml) in all T1DM patients. Age significantly correlated with plasma tHcy. Only in 4 patients, studied during DKA, plasma tHcy was significantly lower (2.76 +/- 1.33 micromol/l, p < 0.001) than the healthy controls.
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Affiliation(s)
- Gian Franco Meloni
- Department of Pharmacology, Ginecology and Obstetrics, Pediatrics, University of Sassari, Sassari, Italy
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12
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Saeed BO, Nixon SJ, White AJ, Summerfield GP, Skillen AW, Weaver JU. Fasting homocysteine levels in adults with type 1 diabetes and retinopathy. Clin Chim Acta 2004; 341:27-32. [PMID: 14967155 DOI: 10.1016/j.cccn.2003.10.034] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2003] [Accepted: 10/16/2003] [Indexed: 12/01/2022]
Abstract
BACKGROUND AND METHODS Whether hyperhomocysteinemia is associated with diabetic retinopathy is still being debated. We measured homocysteine and thrombomodulin, a marker of endothelial cell damage, in patients with type 1 diabetes mellitus and retinopathy (n=25) and in a well-matched group of diabetic patients without retinopathy (n=23). All patients had normal serum creatinine and no macroalbuminuria. RESULTS Fasting homocysteine levels were higher in the group with retinopathy than in the group without retinopathy (8.75+/-1.9 vs. 7.69+/-1.6 micromol/l, P<0.05). Microalbuminuria was more prevalent in the group with diabetic retinopathy and it correlated with homocysteine levels in this group (p<0.05). Microalbuminuria was the most powerful independent determinant of homocysteine levels in multiple regression analysis in the group with retinopathy (p<0.01). Thrombomodulin levels were not different in the two groups (36.6+/-9.7 vs. 34.9+/-11.1, p>0.1) and there was no correlation between homocysteine and thrombomodulin levels in either group. CONCLUSIONS The slight rise in homocysteine levels in patients with diabetic retinopathy was possibly caused by the early nephropathy as indicted by microalbuminuria. This small rise in homocysteine levels was not associated with endothelial dysfunction, as measured by serum thrombomodulin levels.
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Affiliation(s)
- Bakri O Saeed
- Department of Clinical Biochemistry, Queen Elizabeth Hospital, Gateshead, UK.
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13
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Roybal CN, Yang S, Sun CW, Hurtado D, Vander Jagt DL, Townes TM, Abcouwer SF. Homocysteine increases the expression of vascular endothelial growth factor by a mechanism involving endoplasmic reticulum stress and transcription factor ATF4. J Biol Chem 2004; 279:14844-52. [PMID: 14747470 DOI: 10.1074/jbc.m312948200] [Citation(s) in RCA: 163] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Vascular endothelial growth factor (VEGF) plays a key role in the development and progression of diabetic retinopathy. We previously demonstrated that amino acid deprivation and other inducers of endoplasmic reticulum-stress (ER stress) up-regulate the expression of VEGF in the retinal-pigmented epithelial cell line ARPE-19. Because homocysteine causes ER stress, we hypothesized that VEGF expression is increased by ambient homocysteine. dl-Homocysteine-induced VEGF expression was investigated in confluent ARPE-19 cultures. Northern analysis showed that homocysteine increased steady state VEGF mRNA levels 4.4-fold. Other thiol-containing compounds, including l-homocysteine thiolactone and DTT, induced VEGF expression 7.9- and 8.8-fold. Transcriptional run-on assays and mRNA decay studies demonstrated that the increase in VEGF mRNA levels was caused by increased transcription rather than mRNA stabilization. VEGF mRNA induction paralleled that of the ER-stress gene GRP78. Homocysteine treatment caused transient phosphorylation of eIF2alpha and an increase in ATF4 protein level. Overexpression of a dominant-negative ATF4 abolished the VEGF response to homocysteine treatment and to amino acid deprivation. VEGF mRNA expression by ATF4-/- MEF did not respond to homocysteine treatment and the response was restored with expression of wild-type ATF4. These studies indicate that expression of the pro-angiogenic factor VEGF is increased by homocysteine and other thiol-containing reductive compounds via ATF4-dependent activation of VEGF transcription.
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MESH Headings
- Activating Transcription Factor 4
- Blotting, Northern
- Blotting, Western
- CCAAT-Enhancer-Binding Proteins/metabolism
- Carrier Proteins/metabolism
- Cell Line
- Cell Nucleus/metabolism
- DNA, Complementary/metabolism
- Dactinomycin/pharmacology
- Dose-Response Relationship, Drug
- Endoplasmic Reticulum/metabolism
- Endoplasmic Reticulum Chaperone BiP
- Enzyme-Linked Immunosorbent Assay
- Epithelial Cells/cytology
- Genes, Dominant
- Heat-Shock Proteins
- Homocysteine/chemistry
- Homocysteine/physiology
- Humans
- Molecular Chaperones
- Mutation
- Neovascularization, Pathologic
- Nucleic Acid Synthesis Inhibitors/pharmacology
- Phosphorylation
- Promoter Regions, Genetic
- Protein Binding
- RNA, Messenger/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Stress, Physiological
- Time Factors
- Transcription Factor CHOP
- Transcription Factors/metabolism
- Transcription, Genetic
- Up-Regulation
- Vascular Endothelial Growth Factor A/biosynthesis
- Vascular Endothelial Growth Factor A/metabolism
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Affiliation(s)
- C Nathaniel Roybal
- Department of Biochemistry and Molecular Biology, University of New Mexico School of Medicine, Albuquerque, New Mexico 87131-0001, USA
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14
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Becker A, Smulders YM, van Guldener C, Stehouwer CDA. Epidemiology of Homocysteine as a Risk Factor in Diabetes. Metab Syndr Relat Disord 2003; 1:105-20. [DOI: 10.1089/154041903322294434] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- A. Becker
- Institute for Research in Extramural Medicine, VU University Medical Center,Amsterdam, The Netherlands
| | - Y. M. Smulders
- Department of Internal Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - C. van Guldener
- Department of Internal Medicine, and Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands
| | - C. D. A. Stehouwer
- Department of Internal Medicine, and Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands
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Moore P, El-sherbeny A, Roon P, Schoenlein PV, Ganapathy V, Smith SB. Apoptotic cell death in the mouse retinal ganglion cell layer is induced in vivo by the excitatory amino acid homocysteine. Exp Eye Res 2001; 73:45-57. [PMID: 11428862 DOI: 10.1006/exer.2001.1009] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Homocysteine, an excitatory amino acid and a homolog of cysteine, induces neuronal cell death in brain via stimulation of N-methyl-D-aspartate (NMDA) receptors. It also selectively activates NMDA receptors of retinal ganglion cells, but it is not known if high levels of homocysteine are toxic to these cells. The purpose of this study was to determine whether increased levels of homocysteine caused death of neurons in the ganglion cell layer; if so whether this death occurred via an apoptotic mechanism and to determine the consequences of simultaneous elevation of homocysteine and glutamate, a known retinal excitotoxin, on the viability of neurons of the ganglion cell layer. C57BL/6 mice were injected intravitreally with either homocysteine or glutamate/homocysteine combined (final concentrations: 25, 75, and 200 microM); injection of glutamate (25 and 200 microM) served as a positive control. Eyes were harvested and cryosections prepared 5-6 days post-injection. Systematic morphometric analysis of retinas of mice injected with homocysteine indicated that the total number of cells in the ganglion cell layer decreased by about 23% following exposure to 200 microM homocysteine. To determine whether the neurons of the ganglion cell layer were dying by apoptosis, the TUNEL method was used and was confirmed by immunohistochemical studies of caspase-3, known to be expressed at high levels during retinal ganglion cell apoptosis. Microscopic analysis revealed significantly more TUNEL-positive cells in the ganglion cell layer in homocysteine-injected eyes than in contralateral PBS-injected eyes. Retinas injected with 75 and 200 microM homocysteine displayed significantly more TUNEL-positive neurons in the ganglion cell layer (2 and 2.9, respectively) than PBS-injected retinas (0.25). In eyes injected simultaneously with homocysteine/glutamate, the number of apoptotic cells in the ganglion cell layer almost doubled that for homocysteine or glutamate injections alone. Immunohistochemical analysis of activated caspase-3 revealed numerous positively labelled neurons in the ganglion cell layer in homocysteine and homocysteine/glutamate-injected eyes, but not in PBS-injected eyes. Quantification of this data revealed a significantly greater number of caspase-3-positive neurons in the ganglion cell layer of retinas injected with 75 and 200 microM homocysteine (2.9 and 4.4, respectively) than for PBS-injected retinas (0.5). This confirms that death of neurons in the ganglion cell layer is occurring by apoptosis. The present study provides the first evidence that homocysteine is toxic to neurons of the ganglion cell layer. In addition, it provides evidence that these retinal neurons are dying by apoptosis and it demonstrates for the first time that excitotoxic damage to neurons of the ganglion cell layer is potentiated by simultaneous elevation of homocysteine and glutamate. These findings are relevant to retinal ganglion cell death characteristic of diabetic retinopathy, which is thought to be mediated by overstimulation of the NMDA receptor.
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Affiliation(s)
- P Moore
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta, GA 30912-2000, U.S.A
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