Circulating homocysteine levels in patients with type 2 diabetes mellitus

Background and aimPrevious studies have shown conflicting results regarding circulating homocysteine levels in patients with type 2 diabetes.Methods and resultsThis observational study included 2121 patients with angiographically proven coronary artery disease (507 patients with type 2 diabetes and 1614 patients without diabetes). Circulating homocysteine levels, methylenetetrahydrofolate reductase (MTHFR) C677T gene polymorphism, renal function, presence of coronary artery disease (CAD) diagnosed by coronary angiography, and circulating folate and vitamin B₁₂ status were assessed. Plasma homocysteine levels [median (25th; 75th percentile)] were significantly higher in patients with diabetes than in those without [12.4 μmol/L (9.9 μmol/L; 15.9 μmol/L) versus 11.7 μmol/L (9.6 μmol/L; 14.5 μmol/L), P = 0.011]. Diabetes affected homocysteine levels only in patients with a glomerular filtration rate <90 mL/min [13.0 μmol/L (10.5 μmol/L; 16.7 μmol/L) in patients with diabetes versus 12.2 μmol/L (10.1 μmol/L; 15.2 μmol/L) in patients without diabetes, P = 0.006] but not in those with a glomerular filtration rate ≥90 mL/min [10.1 μmol/L (8.1 μmol/L; 12.4 μmol/L) versus 10.2 μmol/L (8.8 μmol/L; 12.3 μmol/L), P = 0.267]. Multivariable analysis did not show an independent association between diabetes and homocysteine level (P = 0.342).ConclusionCirculating homocysteine levels are increased in patients with type 2 diabetes compared with non-diabetic patients due to a more diabetes-associated adverse risk profile rather than to diabetes itself.     

2型糖尿病患者总同型半胱氨酸水平影响因素分析

目的:探讨2型糖尿病(DM)患者总同型半胱氨酸(tHcy)水平的影响因素.方法:随机选择308例患者,根据血糖分组:正常血糖组(Ⅰ组)109例,糖耐量减低组(Ⅱ组)75例,2型DM组(Ⅲ组)124例.所有患者均测量tHcy、身高、体重、腰围、血压、血脂、血糖、胰岛素及肌酐水平.结果:Ⅲ组和Ⅱ组的tHcy高于Ⅰ组,差异有统计学意义(P＜0.05).多元线性回归分析表明:tHcy与IR、肌酐呈正相关(β=0.158,P=0.022;β=0.163,P=0.029);男性tHcy水平高于女性(β=-0.164,P=0.03).结论:性别、肌酐水平、IR是同型半胱氨酸水平的影响因素.     

PINK1 and oxidative stress in lean and obese patients with type 2 diabetes mellitus

AimTo compare mRNA [messenger RNA] expression of PINK1 in whole blood and the levels of biomarkers of Oxidative Stress (mitochondrial DNA [mtDNA] content & Total Antioxidant status [TAS]) in newly diagnosed lean and obese patients with T2DM.MethodsNewly diagnosed patients of T2DM were enrolled in this study. The patients were divided into two groups of 30 patients each, lean (BMI < 18.5 kg/m²) and obese (BMI > 25 kg/m²). mRNA expression of PINK1 & mtDNA content was measured by real time PCR. Serum TAS was measured using a commercially available kit.ResultsThere was a 1.78-fold decrease in mRNA expression of PINK1 in obese group compared to the lean group. Mean mtDNA content was 300.82 ± 169.66 in the obese group and 332.78 ± 147.07 in the lean group (p = 0.06). Mean levels of TAS was 5.39 ± 2.28 μM Trolox Equivalents in the obese group and 3.85 ± 3.33 μM Trolox Equivalents in the lean group (p = 0.001).ConclusionThe T2DM patient with obesity had greater OS than the lean patients. Thus, there is a compensatory increase in antioxidants in obese patients with T2DM. Our findings also suggest that decreased levels of PINK1 in obese group are unable to protect the mitochondria against OS leading to decreased mtDNA content. Does it also result in beta cell dysfunction or contribute to insulin resistance in obese patients with T2DM needs to be explored.     

2型糖尿病患者血浆同型半胱氨酸水平与下肢动脉硬化的关系

目的 探讨血浆同型半胱氨酸（Hcy）水平与2型糖尿病（T2DM）患者下肢动脉硬化的关系,并分析影响2型糖尿病患者Hcy代谢的因素.方法 将118例2型糖尿病患者分为2组：无下肢动脉硬化并发症组（55例）和2型糖尿病合并下肢动脉硬化病变组（63例）;60例体检正常者作为正常对照组.采用酶联免疫吸附法（ELISA）测定血浆Hcy浓度,发光免疫法测定叶酸、VitB12浓度;自动生化分析仪测定空腹血糖（FBS）、总胆固醇（TC）、三酰甘油（TG）、低密度脂蛋白胆固醇（LDL-C）、高密度脂蛋白胆固醇（HDL-C）、糖化血红蛋白（HbA1c）.对各组不同指标的差异进行统计学分析.结果 2型糖尿病合并下肢动脉硬化组患者血浆Hcy浓度较2型糖尿病无下肢动脉硬化组和对照组高,差异有统计学意义（P＜0.05）,血浆Hcy水平与叶酸、VitB12水平呈负相关.结论 Hcy参与了2型糖尿病下肢动脉硬化病变的发病过程,Hcy水平与叶酸、VitB12水平有关.     

l-arginine infusion decreases plasma total homocysteine concentrations through increased nitric oxide production and decreased oxidative status in Type II diabetic patients

AIMS/HYPOTHESIS: Hyperhomocysteinaemia increases cardiovascular risk in Type II (non-insulin-dependent) diabetes mellitus by augmenting oxidative stress and reducing nitric oxide availability. In vitro, nitric oxide decreases homocysteine by its conversion to the vasodilative and antioxidant compound S-nitrosohomocysteine. We investigated whether or not changes in nitric oxide availability decrease homocysteine concentrations in vivo. METHODS: The study group consisted of 20 normotensive, normolipidaemic, non-atherosclerotic Type II diabetic patients in good metabolic control (16 men, 51.2+/-1.4 years) and 15 healthy subjects (12 men, 48.1+/-1.5 years). Circulating concentrations of homocysteine, nitrite+nitrate and sulphydryl groups, a marker of oxidative stress, were assessed at baseline and then 5', 10', 30' and 60' after the intravenous infusion of either L-arginine (3 g in 10 ml saline), the nitric oxide precursor, or vehicle according to a double-blind cross-over randomized protocol. RESULTS: At baseline diabetic patients showed lower plasma sulphydryl group concentrations (491.8+/-16.9 vs 551.3+/-21.0 micro mol/l, p<0.04) and nitrite+nitrate (21.4+/-0.8 vs 29.5+/-0.9 micro mol/l, p<0.0001) and higher total homocysteine concentrations (11.1+/-0.5 vs 8.3+/-0.6 micro mol/l, p<0.002) than the control subjects. After L-arginine infusion, blood pressure levels and total homocysteine concentrations ( p< or =0.05) decreased (peak at 5' and 30', respectively) whereas nitric oxide and sulphydryl group concentrations ( p< or =0.003) increased (peak at 10' and 30', respectively) in the patients and control subjects. CONCLUSION/INTERPRETATION: Acute L-arginine infusion in both Type II diabetic patients and healthy subjects decreases plasma total homocysteine concentrations, counteract oxidative stress and increases the availability of nitric oxide.     

Insulin decreases intracellular oxidative stress in patients with type 2 diabetes mellitus

Patients affected by diabetes mellitus have oxidative stress with an impaired glutathione (GSH) redox state. The objective of this study was to determine the influence of insulin on oxidative stress, defined as a reduced intracellular GSH/GSH disulfide (GSSG) ratio and lipid peroxidation by plasma thiobarbituric acid reactive substances (TBARSs) in patients with type 2 diabetes. Two experimental interventions were used: (1) measurement of GSH/GSSG ratio after insulin incubation in erythrocytes from 10 type 2 diabetic patients, and (2) measurement of intraerythrocytic GSH/GSSG ratio and plasma TBARS in 14 type 2 diabetic patients during an in vivo hyperinsulinemic condition obtained from a euglycemic hyperinsulinemic clamp study. We confirmed that our patients underwent oxidative stress as shown by the significant difference in intracellular GSH/GSSG ratio in diabetic patients as compared to controls (13.56+/-3.84 vs 27.89+/-8.37, P<.0001). We found a significant elevation in the GSH/GSSG ratio after 2 hours of incubation with insulin in erythrocytes from diabetic patients (11.56+/-1.98 to 15.61+/-2.62, P<.001). During the clamp studies, GSH/GSSG ratio had already increased after 60 minutes and even more after 120 minutes (baseline, 15.04+/-4.19; at 60 minutes, 19.74+/-6.33; at 120 minutes, 25.33+/-11.15; P<.0001). On the contrary, no significant changes were observed in plasma TBARS (3.59+/-0.77 to 3.56+/-0.83, NS). We conclude that insulin in patients with type 2 diabetes mellitus can reduce intracellular oxidative stress through increased GSH/GSSG ratio.     

Plasma homocysteine, oxidative stress and endothelial function in patients with Type 1 diabetes mellitus and microalbuminuria.

AIMS: The purpose of this study was to examine the associations between endothelial function, plasma homocysteine and oxidative stress in patients with Type 1 diabetes mellitus (DM) and microalbuminuria compared with DM patients with normoalbuminuria and non-diabetic control subjects. We wished to test the hypothesis that increased cardiovascular risk in patients with Type 1 diabetes and microalbuminuria may be in part as a result of hyperhomocysteinaemia-mediated oxidative stress leading to impaired endothelial function. METHODS: We measured forearm blood flow, total plasma homocysteine, total antioxidant status (TAOS) and whole blood glutathione in 31 DM patients, 16 with microalbuminuria and 15 with normoalbuminuria, and 15 non-diabetic control subjects. RESULTS: Plasma homocysteine levels were significantly higher in the microalbuminuric diabetic patients compared with the normoalbuminuric patients and the control subjects. TAOS was significantly lower in the micoalbuminuric and normoalbuminuric diabetic patients compared with the control subjects, although TAOS levels were similar in both groups of diabetic patients. There was no difference in forearm blood flow between the groups and no association between measured endothelial function and antioxidant defence/oxidative stress and homocysteine in each group. There was no association between plasma total homocysteine and TAOS or whole blood glutathione within the groups. CONCLUSIONS: We have found mild hyperhomocysteinaemia in microalbuminuric DM patients compared with normoalbuminuric DM patients and non-diabetic subjects and some evidence for reduced antioxidant defence in DM patients. These findings add to our understanding of the increased risk of vascular disease in patients with Type 1 diabetes.     

肺结核并发糖尿病患者血浆氧化应激水平的检测结果分析

目的 分析肺结核并发糖尿病患者检测血浆氧化应激水平的情况。方法 收集2016年2月至2017年1月上海市公共卫生临床中心收治的45例肺结核患者(PTB 组)、28例肺结核并发2型糖尿病患者(PTB-DM2组),及24名健康对照志愿者(HC组)的肝素抗凝血浆,分别定量检测3组患者血浆总抗氧化能力(T-AOC)、过氧化氢酶(CAT)、血红素氧合酶-1(HO-1)、谷胱甘肽(GSH)、超氧化物歧化酶(SOD)及脂质损伤标志物丙二醛(MDA)的含量,以“中位数(四分位数)[M (P₂₅,P₇₅)]”表示。采用SPSS 23.0软件分析3组患者相关数据,GraphPad Prism 7.0软件作图,以P<0.05为差异有统计学意义。结果 HC组、PTB组、PTB-DM2组各生化指标T-AOC[4.65(4.16, 5.15)、2.70(3.50, 4.30)、 2.55 (2.03,3.48) U/ml]、CAT[54.20 (35.46,81.30)、23.49(9.49,44.72)、 5.66 (-14.00, 31.98) U/ml]、HO-1[16.12 (11.84,24.09)、11.44(7.95,15.53)、8.19 (7.53,11.58) ng/ml]、GSH[5.14(3.98,7.33)、4.69(3.02,6.47)、2.90 (1.90,6.14) μmol/ml]、SOD[14.31(10.63,17.33)、14.28(11.86,15.69)、13.78(12.26,18.00) U/ml]、MDA[ 3.60 (2.62,4.40)、5.11 (4.26,7.23)、12.77(9.47,14.89) nmol/ml] 比较差异均有统计学意义(χ ²=35.28,P<0.01;χ ²=28.94,P<0.01;χ ²=23.00,P<0.01;χ ²=9.24,P=0.010;χ ²=15.53,P<0.01;χ ²=59.46,P<0.01)。PTB组患者血浆的T-AOC、CAT、HO-1含量较HC组均明显下降,MDA水平较HC组明显升高,差异均有统计学意义(Z=-3.88,P<0.01; Z=-3.82,P<0.01;Z=-3.21,P=0.005;Z=-3.94,P=0.008)。PTB-DM2组患者的T-AOC、CAT、HO-1、GSH、SOD水平均较PTB组患者均明显下降,MDA水平较PTB组患者明显升高,差异均有统计学意义(Z=-3.08,P=0.047;Z=-2.44,P=0.046;Z=-2.27,P=0.023;Z=-2.45,P=0.096;Z=-3.50,P=0.002;Z=-6.01,P<0.01)。 结论 感染结核分枝杆菌后,PTB患者的抗氧化能力降低,且存在脂质氧化损伤;并发2型糖尿病可加重PTB患者的氧化应激状态,患者的抗氧化能力更低,脂质氧化损伤加剧。     

老年2型糖尿病患者中同型半胱氨酸与炎症相关细胞因子的检测

目的 探讨老年2型糖尿病（T2DM）大血管病变患者血清总同型半胱氨酸（they）水平与炎症相关细胞因子间的关系。方法135例老年T2DM患者分为2组：无大血管并发症组（71例）和T2DM合并大血管病变组（64例）;32例体检正常老人作为正常对照组（CTR）。酶联免疫吸附试验（enzyme linked immunosorbentassay,ELISA）法检测受试者血清中tHey、白细胞介素2（IL-2）、IL-4、IL-6、IL-8、IL—10、IL-18和γ-干扰素（INF-7）水平。对各指标的组间差异进行统计学分析。结果与正常对照组比较,T2DM患者血清tHey、IL-2、IL-6、IL-8、IL-18和INF-γ显著升高,IL—10显著降低（P〈0．05）;T2DM合并大血管病变组tHcy、IL-6、IL-8、IL-18和INF-γ显著高于无大血管病变组（P〈0．05）;IL-6、IL-8、IL-18与tHey呈正相关（r=0．33、0．49、0．27,P〈0．01、0．01、0．05）。结论老年糖尿病患者tHey、IL．2、IL-6、IL-8、IL—18、和INF-γ显著高于正常老年人;测定这些指标可能对T2DM患者的血管病变起辅助诊断作用。     

同型半胱氨酸对老年2型糖尿病患者大血管病变的影响

目的 探讨血清总同型半胱氨酸(tHcy)水平与2型糖尿病(T2DM)患者大血管病变间的关系,并分析影响T2DM患者tHcy代谢的因素. 方法 167例老年T2DM 患者分为2组:无大血管并发症组(75例)和T2DM合并大血管病变组(92例);42例正常体检老人作为正常对照组.酶联免疫吸附法测定血清tHcy浓度;自动生化分析仪测定空腹血糖(FBS)、尿素氮(BUN)、肌酐(CREA)、总胆固醇(TC)和三酰甘油(TG)、低密度脂蛋白胆固醇(LDL-C)、高密度脂蛋白胆固醇(HDL-C)、糖化血红蛋白(HbA1c);电化学发光仪测定血清胰岛素(INS).对各指标的组间差异进行统计学分析. 结果 tHcy在T2DM合并大血管病患者组血浆浓度较T2DM无大血管并发症组和对照组高,差异具有统计学意义(P＜ 0.05),血清Hcy水平仅与空腹INS水平呈正相关(r= 0.56,P＜0.01). 结论 tHcy参与了T2DM大血管病变的发病过程,tHcy水平可能与胰岛素抵抗有关.     

Associations of plasma homocysteine concentration in subjects with type 2 diabetes mellitus

We investigated the potential relationship between hyperhomocysteinemia and the presence of coronary heart disease (CHD) and chronic complications in a consecutive series of 358 (156 men) Kuwaiti type 2 diabetic subjects. The median (2.5^th, 97.5^th percentiles) fasting plasma concentration of total homocysteine (tHcy) in the patients was 10.2 (5.4, 19.1) μmol/l. Fasting tHcy concentration was significantly (p<0.001) higher among men [11.3 (7.1, 24.6) μmol/l] compared to women [8.8 (5.3, 16.3) μmol/l]. Of the 57 patients with a history of CHD and/or electrocardiographic (ECG) evidence of CHD, 9 (16%) had hyperhomocysteinemia (tHcy ≥15 μmol/l) compared to 8.3% (25 of 301) of patients without evidence of CHD. In univariate analysis, plasma tHcy concentration was significantly (p<0.01) higher in those diabetic subjects with history of CHD and/or abnormal ECG. Although hyperhomocysteinemia was more common in patients with microalbuminuria (15%) compared to patients with normoalbuminuria (12%), there was no significant association between hyperhomocysteinemia and the degree of albuminuria. After controlling for age and sex, multiple regression analyses showed significant associations of plasma tHcy concentration with glycated hemoglobin (p<0.05), plasma concentrations of creatinine (p<0.001) and apolipoprotein-B (p<0.05), but not with smoking, neuropathy or retinopathy. It seems that the association of hyperhomocysteinemia with diabetic microvascular complications is mediated by the confounding effect of other factors like age, sex and plasma creatinine concentration. In conclusion, we have found a univariate association between hyperhomocysteinemia and CHD but not with microalbuminuria, neuropathy and retinopathy. Although routine estimation of plasma homocysteine may be useful, the association with cardiovascular disease or microvascular complications in patients with type 2 DM deserves prospective studies. Received: March 2000 / Accepted in revised form: 4 June 2002 Correspondence to N.A. Abdella     

Circulating leptin and insulin in obese patients with and without type 2 diabetes mellitus: relation to ghrelin and oxidative stress

Aim

This case control study aimed to investigate relationship between appetite hormones (ghrelin and leptin) and body mass index (BMI), insulin and oxidative stress in simple obese and type 2 diabetes (T2DM) obese patients.

Methods

Thirty healthy controls; 30 simple obese and 30 T2DM obese patients were enrolled. Demographic and clinical data of all participants were reported. Serum levels of fasting blood glucose (FBG), postprandial blood glucose (PBG), lipid peroxide (LPO) and nitric oxide (NO) were measured by chemical methods while, insulin, leptin and ghrelin by ELISA kits.

Results

Serum levels of insulin, leptin, LPO were significantly higher while, ghrelin was significantly lower in simple obese and obese patients with diabetes versus controls. Insulin resistance was found in 76.67% simple obese and 93.33% obese patients with diabetes. Ghrelin showed a positive correlation with PBG in controls; but negative correlation with BMI in simple obese and with NO in obese patients with diabetes. Positive correlations were found between LPO and FBG, insulin, homeostasis model assessment of insulin resistance (HOMA-IR) and between leptin and FBG in obese patients with diabetes.

Conclusions

Our results suggested that hyperinsulinemia and hyperleptinemia may be most important mechanisms in decreasing ghrelin and inducing oxidative stress in simple obese and T2DM obese patients.     

2型糖尿病患者血浆总同型半胱氨酸水平与大血管病变的关系

目的　探讨 2型糖尿病患者 (T2 DM)血浆总同型半胱氨酸 (st Hcy)水平、影响因素及其与大血管病变的关系。　方法　对 1 91例 T2 DM患者及 2 3名正常对照人群采用高压液相层析方法测定 st Hcy、B型超声检查测定颈动脉内膜中层厚度 (IMT) ,并测定各临床、生化参数。　结果　 (1 )T2 DM患者组 st Hcy总体水平与正常对照组比较差异无显著意义 (P=0 .31 )。其中 st Hcy≥ 1 5 .1μm ol/L 组的年龄、高血压病程、血清肌酐、尿酸、尿白蛋白排泄率、IMT增厚发生率较 st Hcy<1 5 .1μm ol/L 组高 ,肾小球滤过率、糖化血红蛋白较 st Hcy<1 5 .1 μm ol/L 组低 (P<0 .0 0 1～ 0 .0 5 )。(2 ) IMT增厚组 st Hcy和高 st Hcy百分率较 IMT正常组和正常对照组明显增高 (P<0 .0 5～ 0 .0 0 1 )。多元逐步线性回归分析显示 ,st Hcy与 IMT增厚呈独立相关。 (OR=1 .36 5 ,P<0 .0 0 1 ,95 %可信区间 1 .1 39～1 .6 37)。　结论　 T2 DM患者 st Hcy受病程不同阶段的多种因素影响。st Hcy增高是大血管病变的独立危险因素     

Circulating leptin and insulin in obese patients with and without type 2 diabetes mellitus: Relation to ghrelin and oxidative stress

AimThis case control study aimed to investigate relationship between appetite hormones (ghrelin and leptin) and body mass index (BMI), insulin and oxidative stress in simple obese and type 2 diabetes (T2DM) obese patients.MethodsThirty healthy controls; 30 simple obese and 30 T2DM obese patients were enrolled. Demographic and clinical data of all participants were reported. Serum levels of fasting blood glucose (FBG), postprandial blood glucose (PBG), lipid peroxide (LPO) and nitric oxide (NO) were measured by chemical methods while, insulin, leptin and ghrelin by ELISA kits.ResultsSerum levels of insulin, leptin, LPO were significantly higher while, ghrelin was significantly lower in simple obese and obese patients with diabetes versus controls. Insulin resistance was found in 76.67% simple obese and 93.33% obese patients with diabetes. Ghrelin showed a positive correlation with PBG in controls; but negative correlation with BMI in simple obese and with NO in obese patients with diabetes. Positive correlations were found between LPO and FBG, insulin, homeostasis model assessment of insulin resistance (HOMA-IR) and between leptin and FBG in obese patients with diabetes.ConclusionsOur results suggested that hyperinsulinemia and hyperleptinemia may be most important mechanisms in decreasing ghrelin and inducing oxidative stress in simple obese and T2DM obese patients.     

女性肥胖和2型糖尿病患者高葡萄糖钳夹过程中胰岛素原的分泌和释放

目的 探讨女性肥胖和2型糖尿病患者在持续高糖情况下胰岛素原分泌和释放的变化.方法 12例肥胖、7例2型糖尿病和9例正常对照组,行150分钟高葡萄糖钳夹试验,用酶联免疫法测定各时点胰岛素原.结果 肥胖组和2型糖尿病组空腹胰岛素原(PI)水平高于对照组.2型糖尿病组在10～150分钟期间胰岛素原/胰岛素比值高于肥胖组和对照组.Spearman相关分析显示,PI与胰岛素原分泌第一时相(FPPR)(r=0.464,P=0.026)和内脏脂肪(VA)(r=0.447,P=0.033)呈正相关;与葡萄糖代谢清除率(GDR)(r=-0.533,P=0.009)呈负相关.结论 胰岛素原分泌与胰岛素抵抗密切相关.持续高糖情况下肥胖患者由于胰岛素抵抗代偿性高分泌胰岛素原,2型糖尿病患者存在胰岛功能损害,胰岛素原分泌降低,而且胰岛素原转换胰岛素过程中存在缺陷.     

AOPP and its relations with selected markers of oxidative/antioxidative system in type 2 diabetes mellitus

BACKGROUND: The aim of this study was to evaluate the selected components of the oxidative/antioxidative system in T2DM; estimation of relationships between them; search for the more expressive one and examine their alterations in angiopathy and obesity. METHODS: In 94 diabetic patients and 36 healthy people, plasma levels of TRAP, as a marker of antioxidative defence, as well as concentrations of CO, SH, and NH(2) groups and AOPP, as markers of oxidative protein damage (OPD) were determined. RESULTS: Patients had significantly lower levels of TRAP and SH groups, as well as higher NH(2), CO and AOPP in comparison to control. Significant correlation was observed between TRAP and SH groups and AOPP as well as between AOPP and SH and CO groups. Concentration of AOPP was significantly higher in the macroangiopathy and obese subgroups. CONCLUSIONS: Our results support the idea that diabetes mellitus is a complex metabolic disorder with oxidant/antioxidant defence disturbances. Among the studied parameters AOPP showed the most expressive raise in plasma of diabetic patients and significant differences between their subgroups with vascular complications and overweight. We can conclude that AOPP seems to be considered as a useful marker to estimate the degree of OPD in diabetic patients.     

Decreased nitric oxide end-products and its relationship with high density lipoprotein and oxidative stress in people with type 2 diabetes without complications

Lipid peroxides are thought to be formed by free radicals and may play an important role in the development of atheromatous vascular diseases. The relationship between serum lipids, lipoproteins, lipid peroxides [thiobarbituric acid reactive substances (TBARS)] and erythrocyte antioxidant enzymes [catalase (CAT), glutathione peroxidase (GPx) and superoxide dismutase (SOD)] was investigated in non-insulin-dependent diabetic patients with and without coronary heart disease (CHD), and a comparison was made for all the above parameters with non-diabetic patients with CHD. Lipid peroxide concentrations were significantly increased in both groups of diabetic patients and also in non-diabetic patients with CHD, compared to those in control subjects. Diabetic patients with CHD had higher levels of TBARS compared to those diabetics without CHD. Hyperlipidaemia and abnormal lipoprotein levels were observed in all three groups of patients. Increased total cholesterol and LDL-cholesterol were observed in diabetics with CHD compared to those without CHD. Among the erythrocyte antioxidant enzymes, CAT activity was increased, GPx activity was decreased and no change was observed in SOD activity in both groups of diabetic patients and non-diabetic patients with CHD compared to those in controls. A clear correlation was observed between the CAT activity and lipid peroxide concentrations in all the diabetic patients. These observations suggest that there are similar abnormalities in lipid metabolism and erythrocyte antioxidant enzymes in diabetic patients and non-diabetic patients with CHD.