Vitamin B12 levels and nerve conduction velocities in patients undergoing maintenance hemodialysis.

Serum vitamin B12 concentrations were measured in 60 patients undergoing repetitive hemodialysis and in undialyzed patients with chronic renal failure. Dialysis patients had significantly lower serum vitamin B12 levels than the nondialyzed group 321 +/- SEM 38 pg/ml versus 793 +/- 100), and 19 of 60 dialysis patients had vitamin B12 Concentrations less than 200 pg/ml. Folic acid concentration was 5 times greater in dialysis than in nondialysis patients, presumably because the latter received daily supplementation with folic acid. Serum vitamin B12 concentrations fell progressively during the patient's course of dialysis. Neither inadequate dietary intake nor vitamin B12 malabsorption accounted for the differences in the serum vitamin B12 concentrations seen in the two groups. Serum vitamin B12 levels and nerve conduction velocities in 51 dialyzed patients showed a significant correlation. Six dialyzed patients with low serum vitamin B12 levels and slow nerve conduction velocities showed improvement in nerve conduction (+ 14.6 +/- 3.3 m/sec) following the parenteral use of pharmacological doses of vitamin B12. The cause of the low serum vitamin B12 concentration is not clear, nevertheless, alterations in serum vitamin B12 seen in some dialysis patients may be a factor in the persistence of abnormal nerve conduction and may be reversed with large doses of parenteral vitamin B12.     

Erythrocyte ferritin levels in chronic renal failure patients.

The authors studied the level of erythrocyte ferritin and its importance as a marker of iron metabolism in renal anemia patients. METHODS: We studied 33 chronic renal failure patients--12 men and 21 women, aged 33-72 years. Hemoglobin levels, erythrocyte counts, hematocrit, mean corpuscular hemoglobin, serum creatinine, iron and ferritin in serum and erythrocytes were measured on a regular basis throughout the study period employing the monoclonal IRMA "Micromedic" kit. RESULTS: Serum iron levels were significantly lower in first degree chronic renal failure (CRF) patients (11.07 +/- 1.54 mmol/l) as compared with the controls (P < 0.01) whereas serum (91.10 +/- 4.00 ng/ml) and erythrocyte (0.83 +/- 0.08 ng/g Hb) ferritin levels were within normal limits. There was a moderately positive correlation (r = 0.37) between serum and erythrocyte ferritin levels. In second and third degree CRF patients the serum iron (7.82 +/- 0.72 mmol/l), serum ferritin (77.60 +/- 3.24 ng/ml) and erythrocyte (0.71 +/- 0.06 ng/g Hb) ferritin levels were significantly lower as compared with those of first degree CRF patients. In the hemodialysis patients erythrocyte ferritin levels showed a tendency towards increase as compared with those in second and third degree CRF patients (P < 0.05). There was a moderately negative correlation (r = -0.44) between serum iron and erythrocyte ferritin levels in this group of patients. CONCLUSIONS: 1. Erythrocyte ferritin levels can be useful in the complex diagnostic assessment of the anemic syndrome in CRF patients. 2. Erythrocyte ferritin is a reliable indicator of iron overload in hemodialysis patients. 3. Erythrocyte ferritin gives no advantage in the evaluation of iron metabolism of medically treated CRF patients.     

Accumulation of vitamin E metabolites in the blood of renal failure patients

BACKGROUND & AIMS: Carboxyethyl-hydroxychromans (CEHC) are hydrosoluble vitamin E metabolites excreted through the renal filter. In this study we investigated the effect of the kidney damage on the blood levels of CEHC. METHODS: Plasma levels of alpha-CEHC, gamma-CEHC and their precursors (namely, alpha-tocopherol and gamma-tocopherol) were measured by HPLC with electrochemical detection in chronic (CRF) and end-stage renal failure patients on regular hemodialysis (HD) before and after dialysis. CRF patients (n = 26) were divided into three subgroups with different extent of kidney damage as measured by the intervals of creatinine clearance (CrCl, in ml/min): (a) 2-10, (b) 10-20, and (c) 20-45. HD patients (n = 8) did not show residual renal function. In all the subjects the intake of vitamin E (as alpha-tocopherol) was assessed using a food frequency questionnaire. In the HD group, the plasma concentrations of ascorbic and uric acid (AA and UA, respectively), total thiols, the total antioxidant status (TAS) and reactive carbonyls were also measured. RESULTS: The progressive deterioration of the kidney function in the different groups of patients produced an exponential increase of both alpha-CEHC and gamma-CEHC in plasma. Compared with healthy controls (alpha-CEHC = 20.1+/-13.4 and gamma-CEHC = 230.6+/-83.0 nmol/l) the levels of CEHC approximately doubled in patients with CrCl < or = 20ml/min (42.4+/-20.2 and 424.5.5+/-174.4; P <0.05 or higher in both) and reached a 3-fold maximum increase in HD patients (77.3+/-45.7 and 636.6+/-219.3). The hemodialysis provided a significant, but only a transient, correction of CEHC accumulation (44.8+/-23.5, 364.2+/-189.9). The HD patients showed lower intake and levels of vitamin E (alpha-tocopherol = 5.1+/-1.0 and gamma-tocopherol =0.32+/-0.11 micromol/mmol cholesterol; P <0.05) compared to healthy controls (5.8+/-0.8 and 0.43+/-0.14), but in the CRF patients tocopherol levels were normal or only slightly decreased even though approximately half of the subject had lowered vitamin E intake. When the entire patient population was considered, the blood concentrations of parental tocopherols and CEHC did not correlate. The HD patients before dialysis showed a marked decrease of TAS/UA, AA and thiols levels, while UA and free carbonyls significantly increased. After dialysis, the depletion of AA and thiols further worsened and also UA and TAS/UA decreased, but free carbonyls slightly increased. CONCLUSIONS: The results other than to confirm the key importance of the renal route for the excretion of CEHC, demonstrate that CEHC cannot be reliably used to investigate vitamin E biokinetics and transformation without a careful examination of the renal function. CEHC accumulation does not seem to influence the antioxidant status in the plasma of HD patients. Further studies are requested to establish whether such an increase in blood CEHC concentrations might be harmful or could contribute to the biological functions of the vitamin E in uremia and dialysis patients.     

辛伐他汀对维持性血液透析患者炎症因子的影响

[目的]探讨辛伐他汀对维持性血液透析患者炎症因子高敏C反应蛋白(hsCRP)、白介素-6(IL-6)、肿瘤坏死因子a(TNF-α)的影响。[方法]选择维持性血液透析的的慢性肾衰竭患者64例,随机分为辛伐他汀组和对照组,每组各32例。对照组予常规对症治疗,未服用辛伐他汀,观察组每晚口服辛伐他汀40mg,治疗连续24周。两组患者于治疗前,治疗后24周检测高敏C反应蛋白(hsCRP)、白介素-6(IL-6)、肿瘤坏死因子a(TNF-α)、甘油三酯(TG)、总胆固醇(TC)、高密度脂蛋白(HDL)、低密度脂蛋白(LDL)水平。[结果]治疗24周后,辛伐他汀组hsCRP、IL-6、TNF-α、TG、TC、LDL的水平均有所下降,HDL升高,与治疗前及对照组比较,差异有统计学意义(P﹤0.05)。[结论]辛伐他汀能显著改善慢性肾衰竭患者的脂质代谢和微炎症状态。     

Flaxseed oil supplementation decreases C-reactive protein levels in chronic hemodialysis patients

Malnutrition and chronic inflammation in dialysis patients negatively impact their survival prognosis, and nutrients, such as omega-3 oils, are postulated to reduce proinflammatory response. In this randomized, double-blind, multicenter, placebo-controlled trial, we investigated the effects of flaxseed oil (FO) on the inflammatory state of patients with chronic renal failure undergoing renal replacement therapy with hemodialysis (HD). We hypothesized that FO supplementation lowers C-reactive protein (CRP) levels. One hundred sixty patients with chronic renal failure who received HD therapy of 3 dialysis units over a 3-month period in South Brazil were included. The patients received blind doses of FO (1 g twice a day) and placebo (mineral oil, 1 g twice a day) for a period of 120 days. Inflammation was observed in 89 patients (61%) at the beginning of the study. There was a correlation between CRP and the body mass index (R_s = 0.22; P = .022) and high-density lipoprotein cholesterol (R_s = −0.23; P = .032), and the CRP levels decreased significantly over time in the group that received FO compared with the control group (P < .001). During the study period, 33.3% of the FO group changed from an inflamed to a not-inflamed category, whereas only 16.9% changed in the mineral oil group (P = .04). We conclude that the administration of FO decreases the CRP levels and that inflammation in HD patients appears to be correlated to their body mass index and reduced high-density lipoprotein cholesterol levels. Studies with a larger number of patients and over a longer duration are necessary to corroborate these findings.     

Dynamic follow-up of the intact parathormone levels in hemodialysis patients treated with Rocaltrol and calcium.

The object of the present study was to follow prospectively the serum levels of intact parathormone (PTH) of hemodialysis patients and the subsequent changes following the oral administration of 1.25(OH)D3 and calcium. METHODS: We studied 30 chronic renal failure hemodialysis patients--16 men and 14 women, aged 20-70 years. Twenty-one of them were on hemodialysis with duration of up to 5 years (Group 1) and nine--up to 10 years (Group 2). All patients received oral supplementation therapy with 1.0 elemental calcium and Rocaltrol (Roche) 0.25 microgram/day. We measured the serum calcium, ionized calcium, serum phosphorus, alkaline phosphatase and the intact serum PTH levels in intervals of 12 months. RESULTS: Patients with duration of dialysis of up to 5 years had a significantly lower baseline PTH level of 392.5 +/- 94.7 pg/ml versus 896.4 +/- 160.7 pg/ml for those from the second group (P < 0.01). The intact PTH levels showed a tendency towards decrease--at the end of the study they were as follows: 372.02 +/- 76.9 for group 1 versus a significant increase for those from group 2--serum PTH levels of 1793.65 +/- 290.3 (P < 0.02). The differences in alkaline phosphatase and serum phosphorus levels at the end of the study period failed to reach statistical significance. Serum calcium levels were increased in both groups following the initiation of treatment but the difference was statistically significant only for group 2. A significant positive correlation was observed between the duration of hemodialysis treatment and the intact serum PTH levels. CONCLUSIONS: 1. Long-term low-dose conventional calcitriol therapy in combination with calcium supplementation could slow the progression of secondary hyperparathyroidism in some hemodialysis patients. 2. Low-dose therapy with active vitamin D-metabolites is effective only in hemodialysis patients with baseline serum PTH levels below 500 pg/ml and without pronounced hyperphosphatemia.     

The influence of vitamin E on rheological parameters in high altitude mountaineers

Vitamin E is a fat-soluble antioxidant which plays an important role in maintaining cells in a reduced state. Oxidation reactions can lead to damage of both endothelial cells and circulating blood cells and may thus influence the rheological conditions. A group of 13 mountaineers was selected as a model for persons at increased risk of oxidative stress. 6 subjects received 200 mg vitamin E twice daily for 4 weeks, and 7 subjects received placebo. Erythrocyte filterability, blood viscosity, changes in the blood picture, and three blood coagulation factors (antithrombin III, protein C, and fibrin monomers) were investigated. The baseline values (t1) were determined at 1.500 m, and after supplementation the investigations were repeated twice at 4.300 m (t2 und t3). There was a marked rise in the hematocrit in both groups during the ascent which was due to an increase not only of the erythrocytes but also of the leucocytes. This change was more pronounced in the control group. The erythrocyte filterability was unaltered in the vitamin E group in comparison with baseline but was significantly impaired in the control group. The changes in these two parameters-hematocrit and filterability--resulted in a significant higher blood viscosity. Furthermore in the control group, but not in the vitamin E group, a significant fall in the protein C activity was observed. The cause may be an additional release from degenerated leucocytes of various proteases which degrade protein C. A further possible cause is a derangement of metabolic reactions in the vascular endothelium. All these possible causes could be counteracted by the higher antioxidative potential of the verum group.(ABSTRACT TRUNCATED AT 250 WORDS)     

肾衰宁联合血液透析治疗慢性肾衰竭效果分析

目的对慢性肾衰竭患者实施肾衰宁联合血液透析治疗,观察治疗效果。方法选择本院2020年3月-2020年6月期间收治的60例肾衰竭患者,根据治疗性质随机分组,两组患者均采取血液透析治疗,其中30例单纯维持血液透析(对照组),30例采取血液透析+肾衰宁胶囊(研究组)。对比两组治疗效果。结果研究组血生化指标改善效果较对照组显著;研究组在联合治疗下有效率高于对照组;研究组并发症概率为(6.7%),低于对照组(26.7%)。结论对慢性肾衰竭患者实施肾衰宁联合血液透析治疗能够有效改善患者的血生化指标,同时能够提高治疗效果。     

Effect of L-methionine supplementation on plasma homocysteine and other free amino acids: a placebo-controlled double-blind cross-over study

OBJECTIVE: The essential amino acid L-methionine is a potential compound in the prophylaxis of recurrent or relapsing urinary tract infection due to acidification of urine. As an intermediate of L-methionine metabolism, homocysteine is formed. The objective was to study the metabolism of L-methionine and homocysteine, and to assess whether there are differences between patients with chronic urinary tract infection and healthy control subjects. DESIGN: A randomized placebo-controlled double-blind intervention study with cross-over design. SETTING: Department of Nutritional Physiology, Institute of Nutrition in cooperation with the Department of Internal Medicine III, Friedrich Schiller University of Jena, Germany. SUBJECTS: Eight female patients with chronic urinary tract infection and 12 healthy women (controls). INTERVENTIONS: After a methionine-loading test, the volunteers received 500 mg L-methionine or a placebo three times daily for 4 weeks.Main outcome measures:Serum and urinary concentrations of methionine, homocysteine, cystathionine, cystine, serine, glycine and serum concentrations of vitamin B12, B6 and the state of folate. RESULTS: Homocysteine plasma concentrations increased from 9.4+/-2.7 micromol/l (patients) and 8.9+/-1.8 micromol/l (controls) in the placebo period to 11.2+/-4.1 micromol/l (P=0.031) and 11.0+/-2.3 micromol/l (P=0.000), respectively, during L-methionine supplementation. There were significant increases in serum methionine (53.6+/-22.0 micromol/l; P=0.003; n=20) and cystathionine (0.62+/-0.30 micromol/l; P=0.000; n=20) concentrations compared with the placebo period (33.0+/-12.0 and 0.30+/-0.10 micromol/l; n=20). Simultaneously, renal excretion of methionine and homocysteine was significantly higher during L-methionine intake. CONCLUSIONS: Despite an adequate vitamin status, the supplementation of 1500 mg of L-methionine daily significantly increases homocysteine plasma concentrations by an average of 2.0 micromol/l in patients and in control subjects. An optimal vitamin supplementation, especially with folate, might prevent such an increase.     

Defective photoproduction of cholecalciferol in normal and uremic humans

The initial step in cholecalciferol (vitamin D3) metabolism is the photo-conversion of 7-dehydrocholesterol to previtamin D3. This reaction occurs in the epidermis and requires ultraviolet light. We measured the circulating concentration of vitamin D (ergocalciferol and cholecalciferol), 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D in 14 normal white, 9 normal black subjects, and in 9 white and 17 black hemodialysis patients. The mean plasma vitamin D in normal white subjects was greater than in normal black subjects, 4.01 +/- 1.02 ng/ml versus 0.96 +/- 0.30 ng/ml, respectively (P less than 0.05). Plasma 25-hydroxyvitamin D in normal blacks was also less than in normal whites, 17.7 +/- 1.5 ng/ml versus 31.3 +/- 3.0 ng/ml, respectively (P less than 0.01). In uremic white subjects, plasma vitamin D, 6.7 +/- 2.6 ng/ml, was similar to normal white subjects. However, vitamin D was not detectable in 12 of 17 uremic black subjects and was depressed in the remainder of the group. Following exposure to a single minimal erythema dose of ultraviolet-B irradiation, the maximal increase in plasma vitamin D was depressed in white dialysis patients as compared to healthy white subjects, 6.3 +/- 1.9 ng/ml versus 21.3 +/- 2.8 ng/ml, respectively (P less than 0.02). 7-Dehydrocholesterol content was similar in epidermis from site-matched skin of fresh cadavers and white hemodialysis patients, 131 +/- 23 ng/mg versus 124 +/- 14 ng/mg skin, respectively. It is concluded that chronic hemodialysis patients exhibit defective photoproduction of cholecalciferol, despite normal epidermal content of substrate, 7-dehydrocholesterol.     

Modification of postoperative nitrogen balance with preoperative anabolic steroid

Thirty six patients undergoing abdominal operations were randomly allocated to receive an anabolic steroid, stanozolol (50 mg) or placebo 24 h before surgery. Patients were fasted during the first four postoperative days. During this period the mean daily nitrogen balance was significantly less negative in the stanozolol group (-8.0+/-3.0 gN/day) than in the control group (-10.9+/-4.1 gN/day), although improvement in nitrogen balance was greater in male than in female patients. Muscle catabolism as measured by 3-methylhistidine excretion was similar in both treatment groups. Significant fluid retention occurred in the stanozolol treated group and was more marked in female patients. Improved nitrogen balance in the absence of a measurable change in muscle catabolism suggests that this anabolic steroid acts by improving protein synthesis in the early period after surgery.     

Effects of long-term supplementation with moderate pharmacologic doses of vitamin E are saturable and reversible in patients with type 1 diabetes

BACKGROUND: Vitamin E supplementation has been proposed as adjunctive therapy to counteract the increased LDL oxidation in diabetes and thus prevent or delay cardiovascular complications. OBJECTIVE: The objective of this study was to investigate the effect of a moderate pharmacologic dose of vitamin E for 相似文献   

Comparative effects of dietary supplementation with red grape juice and vitamin E on production of superoxide by circulating neutrophil NADPH oxidase in hemodialysis patients

BACKGROUND: Atherosclerotic cardiovascular disease is the most common cause of death among hemodialysis patients; it has been attributed to increased oxidative stress, dyslipidemia, malnutrition, and chronic inflammation. Activation of neutrophils is a well-recognized feature in dialysis patients, and superoxide-anion production by neutrophil NADPH oxidase may contribute significantly to oxidative stress. OBJECTIVE: The aim of the study was to compare the effects of dietary supplementation with concentrated red grape juice (RGJ), a source of polyphenols, and vitamin E on neutrophil NADPH oxidase activity and other cardiovascular risk factors in hemodialysis patients. DESIGN: Thirty-two patients undergoing hemodialysis were recruited and randomly assigned to groups to receive dietary supplementation with RGJ, vitamin E, or both or a control condition without supplementation or placebo. Blood was obtained at baseline and on days 7 and 14 of treatment. RESULTS: RGJ consumption but not vitamin E consumption reduced plasma concentrations of total cholesterol and apolipoprotein B and increased those of HDL cholesterol. Both RGJ and vitamin E reduced plasma concentrations of oxidized LDL and ex vivo neutrophil NADPH oxidase activity. These effects were intensified when the supplements were used in combination; in that case, reductions in the inflammatory biomarkers intercellular adhesion molecule 1 and monocyte chemoattractant protein 1 also were observed. CONCLUSIONS: Regular ingestion of concentrated RGJ by hemodialysis patients reduces neutrophil NADPH-oxidase activity and plasma concentrations of oxidized LDL and inflammatory biomarkers to a greater extent than does that of vitamin E. This effect of RGJ consumption may favor a reduction in cardiovascular risk.     

Carnitine treatment improved quality-of-life measure in a sample of Midwestern hemodialysis patients

BACKGROUND: Previously, we demonstrated that selected groups of hemodialysis patients might be more likely to have abnormalities of carnitine metabolism. The purpose of the present study was to examine the effects of carnitine therapy in these selected groups of hemodialysis patients on quality-of-life measures and erythropoietin dose. METHODS: This was a double-blind, randomized, controlled trial, in which 50 hemodialysis patients were treated with either 2 g i.v. carnitine or placebo. The treatment period was for 24 weeks. RESULTS: Thirty-four patients (15 in the treatment group) completed the study. The mean age was 69 +/- 15 years, 35% were women, and 44% had diabetes. Mean initial plasma total, free, short-chain acyl and long-chain acyl carnitine concentrations (micromol/L; mean +/- SEM) were 35.9 +/- 1.8, 18.2 +/- 1.1, 11.6 +/- 0.6, and 6.0 +/- 0.3, whereas the plasma acyl-to-free-carnitine ratio was 1.02 +/- 0.05. With respect to the Medical Outcomes Short Form-36 (SF-36), improvements from baseline were noted in the treatment group (n = 13) for role-physical (33.9 +/- 1.9 to 43.2 +/- 3.0, p < .05) and the SF-36 physical component summary score (36.1 +/- 2.7 to 39.7 +/- 2.3, p = .09) relative to changes in the control group (n = 14). The erythropoietin dose over the 24-week period was reduced from baseline in the treatment group relative to the placebo group (-1.62 +/- 0.91 vs 1.33 +/- 0.79 units erythropoietin/dry weight/hemoglobin concentration, respectively, p < .05). CONCLUSIONS: After 24 weeks of i.v. carnitine therapy, SF-36 scores were improved and erythropoietin doses were reduced in hemodialysis patients, relative to the control group.     

Chronic green tea extract supplementation reduces hemodialysis-enhanced production of hydrogen peroxide and hypochlorous acid, atherosclerotic factors, and proinflammatory cytokines

BACKGROUND: Oxidative stress increases in patients with end-stage renal disease and exaggerates the related comorbidities. OBJECTIVE: The aim of the study was to evaluate the effects of supplementation with decaffeinated green tea extract (catechins) on hemodialysis-induced reactive oxygen species, atherosclerotic disease risk factors, and proinflammatory cytokines. DESIGN: We enrolled 6 healthy subjects and 54 hemodialysis patients for the study. First, the pharmacokinetics of one oral dose of catechins was compared between healthy subjects (n = 6) and hemodialysis patients (n = 10). Second, in the 10 hemodialysis patients, we compared the antioxidant effects of 3 different doses (0, 455, and 910 mg) of oral catechins with that of oral vitamin C (500 mg) during a hemodialysis session. Third, the other 44 hemodialysis patients participated in a 7-mo interventional study, in which 30 patients received placebo throughout and 14 patients received catechins (455 mg/d) from the third to the fifth month. RESULTS: After one oral dose, the hemodialysis patients (n = 10) had later peaks and slower decay of plasma catechins than did the healthy subjects. In the 10 hemodialysis patients, catechin supplementation reduced hemodialysis-enhanced plasma hypochlorous acid activity more effectively than did placebo or vitamin C. Between treatments with 455 or 910 mg catechins, no significant difference was found in the reduction of plasma hypochlorous acid activity. Catechins also significantly reduced proinflammatory cytokine expression enhanced by hemodialysis. In the 7-mo interventional study, the 14 patients who received daily supplementation of catechins for 3 mo had less predialysis plasma hydrogen peroxide activity, lower hypochlorous acid activity, and lower phosphatidylcholine hydroperoxide, C-reactive protein, and proinflammatory cytokine concentrations than did the 30 hemodialysis patients who received placebo. CONCLUSION: Catechins reduce hemodialysis-induced production of hydrogen peroxide and hypochlorous acid, atherosclerotic disease risk factors, and proinflammation.     

The impact of vitamins and/or mineral supplementation on blood pressure in type 2 diabetes

OBJECTIVE: The present study designed to assess the effect of Mg+Zn, vitamin C+E, and combination of these micronutrients on blood pressure in type 2 diabetic patients. MATERIALS AND METHODS: In a randomized, double-blind, placebo controlled clinical trial, 69 type 2 diabetic patients were randomly divided into four groups, each group receiving one of the following daily supplement for three months; group M: 200 mg Mg and 30 mg Zn (n = 16), group V: 200 mg vitamin C and 150 mg vitamin E (n = 18), group MV: minerals plus vitamins (n = 17), group P: placebo (n = 18). Blood pressure was measured at the beginning and at the end of the trial. Treatment effects were analyzed by general linear modeling. RESULTS: Results indicate that after three months of supplementation levels of systolic, diastolic and mean blood pressure decreased significantly in the MV group by 8 mmHg (122 +/- 16 vs. 130 +/- 19 mmHg), 6 mmHg (77 +/- 9 vs. 83 +/- 11 mmHg), and 7 mmHg (92 +/- 9 vs. 99 +/- 13 mmHg), respectively (p < 0.05). Also combination of vitamin and mineral supplementation had significantly effects in increasing serum potassium (p < 0.05) and in decreasing serum malondialdehyde (p < 0.05). There was no significant change in the levels of these parameters in the other three groups. CONCLUSION: The results of the present study indicated that in type 2 diabetic patients a combination of vitamins and minerals, rather than vitamin C and E or Mg and Zn, might decrease blood pressure.     

Pilot study on the effect of parenteral vitamin E on ischemia and reperfusion induced liver injury: a double blind, randomized, placebo-controlled trial

BACKGROUND AND AIMS: Liver surgery usually involves ischemia and reperfusion (I/R) which results in oxidative stress and cell damage. The administration of antioxidants should diminish or prevent this damage. The purpose of this study was to investigate the effect of the antioxidant vitamin E on I/R injury. METHODS: We carried out a placebo-controlled double-blind study on 68 patients undergoing elective, tumor-related, partial liver resection. 47 patients were qualified for the per protocol population based evaluation. The patients were randomly assigned to two groups. The day before surgery one group received three infusions containing vitamin E (600 IU=540 mg vitamin E emulsion). The other group received three infusions of placebo. RESULTS: Length of stay in the intensive care unit (ICU) was significantly shorter in the verum group than in the placebo group (P<0.05). There were signs of improvement for AUC AST (P<0.05), ALT and GLDH in the verum group after surgery. Serum vitamin E concentration increased after administration of vitamin E infusion and declined in both treatment groups after surgery (P<0.01). In the verum group vitamin E deficiency was prevented while vitamin E concentration remained low in the placebo group (P<0.01). CONCLUSIONS: The findings from this study indicate that preoperative administration of vitamin E is safe and that this treatment may have beneficial effects by reducing the impact of I/R injury in liver surgery.     

Frequency of hyperhomocysteinemia in hemodialysis patients with folic acid supplementation

BACKGROUND: It is known that hyperhomocystinemia is an independent risk factor for development of atherosclerosis. In end stage renal disease the frequency of hyperhomocystinemia is much greater than in normal populations. AIM: In this study homocystein (Hcy), folic acid and vitamin B12 concentrations were determined in 125 chronic renal failure patients being on folic acid supplementation (3 mg/day). In 107 patients the frequency of C667T polymorphism of methylene tetrahyrofolate reductase (MTHFR) was also determined. The relationships between these parameters were also studied. RESULTS: It was found that in these patients who are under continuous folic acid supplementation the mean level of homocysteine was 16.8 +/- 7.2 mumol/L, a value considerably lower than the homocysteine concentration reported for non-supplemented patients. The elevation of homocysteine concentrations was independent of gender, time spent in renal replacement therapy, and the type of renal replacement therapy (hemodialysis: 17.6 +/- 12.6; hemodiafiltration: 16.6 +/- 12.9 mumol/L). Data showed an inverse relation between plasma homocysteine concentrations and the concentrations of folic acid and vitamin B12. Moderately severe hyperhomocystinemia (Hcy > 20 mumol/L) was found in about 30% of patients. In those the frequency of patients for homozygous T677 allele of MTHFR was about 25-30%. However, in all ESRD patients the frequency of the homozygotes was the same then in the normal population. Homocysteine plasma levels correlated with MTHFR polymorphism: in the wild type group Hcy was 14 +/- 7 mumol/L, in the heterozygous group was 17.2 +/- 6.2 mumol/L, and in the homozygous group was 21 +/- 19 mumol/L. CONCLUSIONS: Long-term folic acid supplementation decreased the homocysteine level in end stage renal disease patients. However, in folic acid resistant group, who were in 30% homozygotes for C667T of MTHFR (suggesting that homocysteine-methionine remethylation cycle is disturbed), instead of the administration of folic acid, methylene tetrahydrofolate supplementation might be considered.     

Energy metabolism in acute and chronic renal failure

Energy metabolism was measured by indirect calorimetry in 86 patients with various forms of renal failure and in 24 control subjects. In patients with acute renal failure with sepsis, oxygen consumption, carbon dioxide production, and resting energy expenditure were increased (P less than 0.05). In other groups with renal failure (acute renal failure without sepsis, chronic renal failure with conservative treatment or hemodialysis, and severe untreated azotemia) these indices were not different from those of control subjects. Urea nitrogen appearance was decreased in patients with chronic renal failure undergoing conservative treatment, in those with severe untreated azotemia, and in hemodialysis patients (P less than 0.05). We conclude that renal failure has no influence on energy expenditure as long as septicemia is absent. Reduced urea nitrogen appearance rates in chronic renal failure are due to a reduced energy and protein intake. Wasting is a consequence of decreased food intake but not of hypermetabolism in chronic renal failure.     

Effect of modest vitamin E supplementation on blood glycated hemoglobin and triglyceride levels and red cell indices in type I diabetic patients.

The glycation of proteins and elevated triglyceride (TG) levels are two of the major risk factors in the development of complications of diabetes. Previous studies have found some beneficial effects of supplementation of pharmacological doses (900-2000 IU/day) of vitamin E in Type II diabetic patients. This study examined whether supplementation with a modest dose of vitamin E (100 IU/day) had any effect on blood glucose, glycated hemoglobin (GHb), TG or red cell counts in Type I diabetic patients.

35 diabetic patients were supplemented with either DL-alpha-tocopherol (vitamin E) capsules (orally, 100 IU/day) or a placebo for 3 months in a double-blind clinical trial. Fasting blood was collected from each diabetic patient before and after vitamin E or placebo supplementation. Data were analyzed using paired “t” tests and the Wilcoxon Signed Rank Test.

Levels of GHb (mean +/? SEM) were 11.5 +/? 0.4 and 12.8 +/? 0.9% (p < 0.05); glucose, 8.8 +/? 1.2 and 11.6 +/? 1.3 mM; and TG, 2.2 +/? 0.2 and 2.9 +/? 0.3 mM (p < 0.03) after vitamin E supplementation versus before supplementation. There were no differences in these parameters after supplementation with the placebo. There was no effect on blood RBC, hematocrit, and hemoglobin levels after supplementation of vitamin E or the placebo. There were no differences in ages and duration of diabetes between placebo and vitamin E-supplemented groups.

This study suggests that modest vitamin E supplementation (100 IU/day) can significantly lower blood GHb and TG levels and does not have any effect on red cell indices in Type I diabetic patients.