Proven strategies to reduce cardiovascular mortality in hemodialysis patients.

BACKGROUND: In hemodialysis patients, left ventricular hypertrophy (LVH) correlates with mortality. The reason for LVH in uremics is multifactorial. The primary objective of our study was to investigate the effects of a multi-interventional treatment strategy on LVH. METHODS: In 230 ambulatory patients, including patients with coronary artery disease, diabetes, diastolic and systolic dysfunction, we continued optimized cardiac therapy (beta-blockers, angiotensin-converting enzyme inhibitors and angiotensin receptor blockers) with full anemia correction by intravenous epoetin-beta. The dose of epoetin-beta for maintaining target hemoglobin (Hb) was 68 +/- 23 IU/kg/week. Serial echocardiograms were recorded every 3-6 months. The mean observation period was 4.8 +/- 1.2 years. RESULTS: Mean Hb at baseline was 11.2 +/- 2.0 versus 14.1 +/- 1.4 g/dl (p < 0.001) at study end. There was a significant reduction in left ventricular mass index (LVMI: 159 +/- 50.4 vs. 130.2 +/- 42.7 g/m(2); p < 0.001). In a subgroup of 2/3 of the patients, LVMI returned to normal (169 +/- 33 vs. 114 +/- 14 g/m2; p < 0.001). CONCLUSION: Baseline LVMI (p < 0.001), Hb increase (p < 0.03), and triple cardiac therapy (p < 0.03) were significant and independent prognostic factors for a reduction in LVMI. The annual cardiovascular mortality was 5%. Even anemia correction from 12 to 14 g/dl results in further (p < 0.001) regression of LVMI.

Oxidative stress in cardio renal anemia syndrome: correlations and therapeutic possibilities.

Cardiovascular injury has been shown to be the most critical factor affecting quality of life and mortality in patients suffering from chronic renal failure. Oxidative stress has been thought to be an important risk factor for cardiovascular disorders. As oxidative stress parameters with high cardiovascular risk factor 4-hydroxynonenal and other aldehydic lipid peroxidation products, F2-isoprostanes, homocysteine, and cholesterol oxidation products were measured in chronic renal failure patients. 4-Hydroxynonenal and some cholesterol oxidation products correlated well with the degree of renal anemia. F2-isoprostane levels were related to inflammation, whereas homocysteine was increased due to malnutrition. Further, cholesterol oxidation products correlated well with the consumption of lipophilic antioxidants such as alpha-tocopherol. There was an almost linear correlation between the left ventricular mass index and 4-hydroxynonenal. Both parameters furthermore showed an inverse relationship to hemoglobin concentration. The correction of renal anemia by means of erythropoietin therapy led to an efficient strengthening of the antioxidative defence system. The improvement of the antioxidative capacity is of complex nature comprising both enzymatic pathways and low molecular antioxidants. The correction of renal anemia with its well documented reduction of the cardiovascular risk can be regarded as an antioxidative therapy, demonstrating the clinical efficiency of antioxidative protection in patients with chronic renal failure.

Elevated serum concentration of cardiotoxic lipid peroxidation products in chronic renal failure in relation to severity of renal anemia.

Patients with end-stage renal disease undergoing hemodialysis (HD) are exposed to oxidative stress. Increased levels of malondialdehyde (MDA) and 4-hydroxylnonenal (HNE) were found in plasma of uremic patients indicating accelerated lipid peroxidation (LPO) as a consequence of multiple pathogenetic factors. The catabolism and action of those products was already intensively studied. As highly reactive metabolites they are able to bind to proteins, nucleic acids, and other molecules. Doing so, they exert molecular signal effects in cells and are able to exacerbate tissue and organ damage, e.g. cardiotoxic effects. Since renal anemia was shown to promote oxidative stress as well, the aim of our investigation was to examine its role in HD patients. Therefore, two groups of HD patients were investigated (group I Hb < 10 g/dl, group II Hb > 10 g/dl) and serum concentrations of MDA, HNE, and of protein carbonyls, a marker for protein oxidation, were determined. All HD patients had significantly higher levels of the LPO products MDA and HNE compared with controls. However, group I patients showed higher MDA and HNE concentrations compared to group II patients. The same result could be seen for protein carbonyls. During HD concentration of both LPO products decreased. However, this was not the case for protein carbonyls. These results lead to the conclusion that optimized correction of the renal anemia may result in a significant reduction of oxidative stress and therefore in the reduction of organ tissue damage. In this way correction of renal anemia will reduce the cardiovascular risk and comorbidity of HD patients improving their prognosis.

Homocysteine in chronic renal failure in relation to renal anemia and to oxidative stress parameters 4-hydroxynonenal and malondialdehyde.

Homocysteine serum levels were measured in patients with end-stage renal disease in relation to severity of renal anemia and oxidative stress parameters such as 4-hydroxynonenal (HNE) and malondialdehyde (MDA). The predialytic homocysteine serum levels of the patients are five times as high as in healthy controls. It was found that homocysteine does not correlate to hemoglobin concentration and to oxidative stress, but rather to parameters of nutrition status such as albumine concentration and protein catabolic rate. The homocysteine accumulation represents a cardiovascular risk factor which is statistically independent of oxidative stress, but dependent on nutrition or energy status in patients with chronic renal failure.

Renal anemia and its hemodynamic response--findings invasively determined over a period of 20 years.

Among the uremia-associated risk factor, which can be influenced today, anemia is considered most relevant because it induces functional and organic alterations of cardiac/circulatory function. Research concerning influence of the anemia on the pulmonary hemodynamic and cardiac output (CO) in pre-uremic patients are not available up to now. Cardiac and circulatory function of 52 patients were examined before initiation of dialysis therapy using a Swan-Ganz thermodilution catheter. After excluding patients with impaired cardiac pump function the results of 31 of the 52 patients could be analyzed. They were divided into two groups (Hb > resp. < 7.0 g/dl): in patients with severe anemia (Hb 5.7 +/- 0.6 g/dl; n = 7) cardiac index was higher (4.8 +/- 0.4 1/min/m2 < 0.01) compared with the other group (Hb 9.8 +/- 1.7 g/dl; n = 24; CI 3.9 +/- 1.1 1min/m2). The increase of cardiac index caused by anemia correlated with increased stroke volume and heart rate and lowered pulmonary and peripheral resistance. Patients with severe anemia showed a tendency to an impaired cardiac index below Hb < 5-6 g/dl. The hypercirculation did not cause an increase of the pulmonary arterial and pulmonary wedge pressure. Particularly in the case of already existing myocardial damage and coronary arteriosclerosis the presence of anemia and renal insufficiency leads to a highly increased morbidity and mortality. This "cardio-renal anemia-syndrom" is responsible for frequent refractory heart failure. Disturbances of cardiac/circulatory function are observed in pre-uremic patients three times more frequently than in patients after myocardial infarction. Early correction of anemia seems to reduce the risk of fatal cardial complications and to improve the quality of life and the prognosis of pre-uremic patients.

Regression of left ventricular hypertrophy in hemodialysis patients is possible.

Regression of left ventricular hypertrophy in hemodialysis patients is possible. Left ventricular hypertrophy represents the major risk factor for cardiac morbidity and mortality. Therefore, their regression is mandatory. Since the causes of uremia-associated left ventricular hypertrophy are multifactorial, various therapeutic options can be considered: optimal control of arterial hypertension and volume status, optimal correction of metabolic acidosis, best possible correction of hypoalbuminemia and severe secondary hyperparathyroidism, modern pharmacotherapeutic strategy for the treatment of heart failure (use of angiotensin-converting enzyme inhibitors in combination with angiotensin II receptor blockers and beta-blockers) and total correction of renal anemia. Following the proposed therapeutic strategies we could, by using echocardiography, distinguish in 100 hemodialysis patients the following 3 groups (on the average after 1.5 years): 36 patients with initially normal left ventricular mass index (LVMI (g/m2), F < 110; M < 130) maintained normal (group 1); in 31 patients with moderately increased LVMI full regression resulted (group 2); 33 patients with severely increased LVMI (group 3) had to be further divided into 2 sub-groups: 22 patients with significant improvement of LVMI, 11 patients with no, regression. For the first time we were able to show that it is possible to maintain initially normal LVMI during long-term treatment and to achieve complete regression and significant improvement of LVMI in our patients. However, since LVMI requires a long time to develop, a similarly long time must be estimated for its regression. However, 11 patients remained therapeutically resistant. In this group, severe heart diseases were often combined and highly prevalent, including ischemic heart and valve diseases and end-stage dilatative cardiomyopathy. These patients had to be transferred to cardiac surgery. Anemia is considered to be one of the most important factors for the development of left ventricular hypertrophy. Therefore, total correction of renal anemia has to be strongly recommended in addition to other measures of our therapeutic strategy to maintain full or significant regression of left ventricular hypertrophy.

Oxidation parameters in complete correction of renal anemia.

UNLABELLED: Chronic hemodialysis (HD) patients are more exposed to oxidative stress, with its adverse impact on many cell functions and not least on patient survival. There is evidence that partial correction of renal anemia by erythropoietin (rhEPO) therapy reduces oxidative stress. The aim of this study was to clarify whether complete correction of renal anemia with rhEPO reduces free radical generation in HD patients and increases antioxidant supply. The following parameters: malondialdehyde (MDA), reduced glutathione (GSH) and glutathione disulfide (GSSG) were investigated in patients with a hematocrit (Hct) normalized on rhEPO therapy (Hct > or = 0.4), and compared with those in anemic patients (Hct 0.3 - 0.39 and Hct < 0.3). The groups were similar in age, sex or body weight. Patients with normal Hct were significantly longer in the chronic HD program (74.0 +/- 70.3 vs. 23.0 +/- 30.9 and 30.6 +/- 34.8 months; p < 0.05) and received significantly lower doses of iron (35.7 +/- 19.5 vs. 55.4 +/- 26.0 and 80.0 +/- 47.1 mg/week; p < 0.05) and rhEPO (68.9 +/- 63.6 vs. 106.5 +/- 63.9 and 152.8 +/- 86.0 IU/kg/week; p < 0.05). MDA levels were significantly lower in the group with normal Hct than in the comparison groups (1.54 +/- 0.27 vs. 1.98 +/- 0.52 and 2.23 +/- 0.93 micromol/l; p < 0.01), but did not differ significantly between the anemic groups. GSH and GSSG concentrations corrected for erythrocyte levels showed no significant differences, but whole-blood levels in patients with Hct > or = 0.4 and 0.3 - 0.39 were significantly higher than in patients with Hct < 0.3 (GSH: 0.97 +/- 0.42 vs. 1.03 +/- 0.38 and 0.62 +/- 0.34 micromol/ml; GSSG: 14.57 +/- 6.06 vs 13.07 +/- 5.18 and 7.28 +/- 3.64 micromol/l; p < 0.05). CONCLUSION: After correction of renal anemia, MDA levels are significantly lower - reflecting decreased free radical generation - than in anemic HD patients. Whole-blood antioxidant capacity is significantly increased. Overall, rhEPO therapy has clearly positive effects on free radical metabolism.

Does treatment of renal anemia with recombinant erythropoietin influence oxidative stress in hemodialysis patients?

Patients with chronic renal failure (CRF) undergoing hemodialysis (HD) are exposed to constant oxidative stress, as shown by elevated malondialdehyde (MDA) plasma concentrations in HD patients. The aim of our study was to investigate the role of renal anemia in oxidative stress. To this end, MDA and 4-hydroxynonenal (HNE) were measured in three groups of patients. Group I comprised 8 patients with hemoglobin (Hb) < 10 g/dl (mean Hb 8.1 +/- 1.3 g/dl) and group II 8 patients with Hb > 10 g/dl (mean Hb 12.4 +/- 1.9 g/dl). None of these 16 patients had been previously treated with recombinant erythropoietin (rhEPO). Group III comprised 27 patients with mean Hb 10.5 +/- 1.6 g/dl after long-term treatment with rhEPO. The plasma concentrations of both MDA and HNE in all 43 HD patients were significantly higher (p < 0.0001) than in 20 healthy controls (MDA 2.85 +/- 0.25 vs 0.37 +/- 0.03 microM, HNE 0.32 +/- 0.03 versus 0.10 +/- 0.01 microM). Comparison between the three groups showed that the HD patients with Hb < 10 g/dl had significantly higher plasma concentrations of lipid peroxidation products (MDA 3.81 +/- 0.86 microM, HNE 0.45 +/- 0.07 microM) than either HD patients with Hb > 10 g/dl (MDA 2.77 +/- 0.58 microM, HNE 0.25 +/- 0.05 microM) or HD patients treated with rhEPO (MDA 2.50 +/- 0.12 microM, HNE 0.29 micro 0.03 microM). An inverse correlation was also demonstrated between plasma HNE and Hb (r= 0.62, p < 0.0001). It follows that a substantial part of the oxidative stress is due to renal anemia. Treatment with rhEPO can therefore effectively reduce oxidative stress in HD patients.

Long-term effects of rhEPO therapy on erythrocyte rheology in dialysis patients with different target hematocrits.

UNLABELLED: Successful treatment of renal anemia with recombinant erythropoietin (rhEPO) raises the question of whether the renal anemia symptom complex requires complete correction. Current arguments against increasing hemoglobin (Hb) levels above 10-11 g/dl are impaired hemodynamics, increased risk of vascular access occlusion, unmanageable hypertension and dialysis complications. The aim of the study was to determine whether sustained Hb normalization using long-term rhEPO causes hemorheological changes with a potentially negative hemodynamic impact. The study was conducted in 42 rhEPO-treated dialysis patients with stable Hb > 11.0 g/dl for at least 20 weeks. The mean Hb of the total study group was 12.8 1.1 g/dl. To study the effect of Hb as a risk indicator in greater detail, the patients were divided into two groups, with hematocrits above and below 0.40. Hemorheology (erythrocyte deformability and aggregation, plasma viscosity) showed no significant changes, including vs a healthy control group. Throughout the period of increased rhEPO administration, no increase was observed in the incidence of hypertension or vascular thrombosis. CONCLUSION: the marked additional quality-of-life benefit achieved by complete correction of renal anemia harbors no substantial increase in treatment risk.

Complete correction of renal anemia by recombinant human erythropoietin.

The target-hematocrit (Hct) for the correction of renal anemia by recombinant human erythropoeitin (rhEPO) therapy is discussed controversially. A normalization of the Hct that could lead to a further improvement of the patients status, is often rejected, because of possible side effects as a result of an increase in blood viscosity. Hemodialysis (HD) induces an acute hemoconcentration due to ultrafiltration that might influence these risk factors negatively and therefore conflict with the normalization of Hct. The aim of this study was to investigate the changes in rheological and biochemical parameters in chronic HD patients with a normal initial Hct before hemodialysis. Results in 39 patients are given as mean +/- SD before/after HD: Hct 0.42 +/- 0.05/0.45 +/- 0.05 (p < 0.001), hemoglobin (g/dI) 13.3 +/- 1.0/14.4 +/- 1.3 (p < 0.001), MCV (fl) 99.3 +/- 5.7/99.1 +/- 5.5, MCHC (mM/l) 19.9 +/- 0.6/20.1 +/- 0.6 (p < 0.01), red blood cell (RBC) elongation (%) 60.97 +/- 3.67/60.99 +/- 3.73, RBC aggregation index AI0 0.52 +/- 0.12/0.50 +/- 0.12, AI4 0.52 +/- 0.14/0.51 +/- 0.12, plasma viscosity 1.74 +/- 0.14/1.92 +/- 0.20 (p < 0.001), whole blood viscosity (WBV), etaabs.100(mPas) 5.91 +/- 0.78/6.80 +/- 1.2 (p < 0.001), etaabs.0.01(mPas) 75.81 +/- 35.48/167.656 +/- 98.686 (p < 0.05), ultrafiltration (FM) 2.1 +/- 1.1. The biochemical parameters protein, albumin, IgG, IgA, IgM, cholesterol, transferrin and fibrinogen are significantly increased after HD. The hemoconcentration during HD is associated with a significant increase in WBV, mainly associated with the increase in Hct (r = 0.83), but not exceeding the normal range compared to healthy controls. The increase in plasma viscosity is correlated mainly with an increase in protein (r = 0.80), albumin (r = 0.74), and fibrinogen (r = 0.54). No significant changes in RBC aggregation and deformability were observed during the HD session. In conclusion, from the rheological point of view it is unlikely that the normalization of the Hct will contribute to an increased risk in access thrombosis or thromboembolic events in HD patients.

Amino acid and alpha-keto acid metabolism depends on oxygen availability in chronic hemodialysis patients.

Amino acid and alpha-keto acid metabolism depends on oxygen availability in chronic hemodialysis patients. Malnutrition in hemodialysis (HD) patients with renal anemia is reflected in an abnormal plasma amino acid profile. We wished to determine the extent to which malnutrition can be improved by correcting anemia with recombinant human erythropoietin (rhEPO) and supplemental iron. As specific parameters we measured and compared the plasma concentrations of the branched-chain amino acids valine, leucine and isoleucine and their transamination products - major participants in proteolysis and protein biosynthesis - using HPLC with fluorescence detection in 45 severely anemic HD patients (group A: Hb 7.2 +/- 0.8 g/dl), 34 patients with partially corrected anemia (group B: Hb 10.3 +/- 0.6 g/dl) and 35 HD patients with totally corrected anemia (group C: Hb 13.5 +/- 0.7 g/dl). Sixty healthy subjects (group N: Hb 14.2 +/- 1.1 g/dl) served as controls. Correlating with the degree of correction (A/B/C/N), a significant shift to anabolic metabolism was observed in the plasma levels of valine: 130/146/155/205 micromol/l; leucine: 73/71/80/110 micromol/l and alpha-ketoisocaproate (KIC): 11.4/11.8/15.1/ 30.4 micromol/l. It is concluded that energy metabolism becomes increasingly anabolic as hemoglobin levels are normalized.

How can hemodialysis-associated hypotension and dialysis-induced symptoms be explained and controlled--particularly in diabetic and arteriosclerotic patients?

Patients with diabetes and/or severe arteriosclerosis are often unable to tolerate volume removal during hemodialysis (HD) and develop hemodialysis-induced symptoms. These problems can be omitted by well-balanced correction of the acid/base status. We compared 20 high-risk patients which were either treated with standard HD (dialysate bicarbonate 33 mmol/l, treatment A) or treated with standard HD and additional administration of NaHCO3 (120-160 ml 8.4% NaHCO3 solution over the venous line during HD) to correct the metabolic acidosis to upper normal values (treatment B). The following parameters were compared: 1. Acid/base status; 2. EEG monitoring and clinical observation of dialysis-induced symptoms; 3. Invasive monitoring of circulation by Swan-Ganz thermodilution; 4. Ventilation, oxygen consumption and lactate production. Optimal correction of acid/base values resulted in symptom-free hemodialysis sessions with stable PaCO2 in the normal range, cardiovascular stability assessed by invasive monitoring, normal ventilation and higher oxygen consumption and decreased lactate production. Optimal correction of acid/base balance further led to the absence of EEG alterations and of dialysis-induced symptoms during treatment B as compared to treatment A. The baroreceptor response in these patients is usually disturbed due to sclerosis of the pressosensible vessels, especially the aortic arch and the pulmonary arteries impairing a compensatory increase of heart rate upon volume removal. However, chemoreceptors are able to increase sympathetic tone with preservation of blood pressure in this situation. In addition a decrease of PaO2 during volume removal can only be answered by an early increase of ventilation response due to stimulation of chemoreceptors provided that PaCO2 is maintained normal. Furthermore, normal cerebral blood flow also depends on a normal PaCO2. Based on these pathophysiological mechanisms the therapeutic strategy of additional bicarbonate administration to correct the acid/base status guarantees a stable normal PaCO2 and facilitates a symptom-free HD in high-risk patients.

Cardiac mortality prevention in uremic patients. Therapeutic strategies with particular attention to complete correction of renal anemia.

BACKGROUND: Left ventricular hypertrophy represents the major risk factor for cardiac mortality and morbidity, with cardiac mortality being the most important determinant for survival in dialysis patients. The prevalence of left ventricular hypertrophy is already high at initiation of dialysis and increases with time. Anemia is considered as the most important factor for the development of left ventricular hypertrophy. Others already demonstrated that with partial correction of renal anemia by erythropoietin a partial regression of the left ventricular mass can be achieved. PATIENTS AND METHODS: We investigated the effect of complete correction of renal anemia to normal hemoglobin values of 14 g/dl (Hct 42%) on left ventricular hypertrophy by echocardiography. Eight Patients entered the study 4-8 weeks after initiation of chronic hemodialysis with a mean hemoglobin of 9.5 +/- 1.3 g/dl). RESULTS: Left ventricular mass index (LVMI) decreased from 155 +/- 45 g/m2 to 123 +/- 18g/m2 (p < 0.05) within the observation period of 12 +/- 5 months. The results showed, that either normal left ventricular dimensions could be preserved or, if left ventricular hypertrophy was already present, complete regression was possible. CONCLUSION: Therefore, we propose that complete correction of renal anemia should be introduced into the therapy of dialysis patients along with strict adherence to established measures for the control of left ventricular hypertrophy: control of fluid overload and arterial hypertension and the use of ACE-inhibitors and betablockers. In addition, optimal correction of metabolic acidosis, control of the calcium-phosphate product and hyperparathyreoidism must be attempted. Thus, it should be possible to reverse left ventricular hypertrophy and its deleterious consequences in the dialysis population in order to improve survival and quality of life.

Long-term results of total parathyroidectomy without autotransplantation in patients with and without renal failure.

The optimal surgical procedure for severe renal secondary hyperparathyroidism (sHPT) is still a point of controversy. Total parathyroidectomy (PTX) without auto-transplantation was abandoned for fear of an adynamic bone condition; however, in the case of autotransplantation recurrent sHPT is frequent and promotes atherosclerosis. We studied 11 hemodialysis patients (age 59+/-12 years) on dialysis for 18 (12-30) years in whom total PTX was performed due to severe sHPT (group I; intact PTH: 1,240+/-230 pg/ml), and 5 patients (age 55+/-10 years) without renal insufficiency who inadvertently received total PTX during thyroid surgery (group II). After total PTX (group I, 26+/-18 [9-59] months; group II, 252+/-188 [22 480] months) both groups showed no measurable intact PTH levels. Calcium homeostasis was maintained by oral substitution with calcium (group I, calcium dialysate of 2.0 mmol/l), vitamin D and calcitriol (serum parameters in groups I and II: calcium 2.4 and 2.2 mmol/l; phosphate 1.8 and 1.1 mmol/l; 25(OH)-vitamin D(3) 21 and 34 ng/ml; 1,25(OH)(2)-vitamin D(3) 32 and 41 pg/ml, respectively). In group I, after total PTX there was a rapid and sustained improvement in bone pain with markedly enhanced physical activity and endurance. High turnover osteopathy markedly improved as indicated by declining levels of native osteocalcin (90+/-17 vs. 26+/-18 ng/ml), bone alkaline phosphatase (74+/-12 vs. 12+/-6 ng/ml), and carboxyterminal cross-linked telopeptide of type-I collagen (65+/-16 vs. 40+/-21 ng/ml) but increasing levels of carboxyterminal propeptide of type-I procollagen (120+/-36 vs. 148+/-41 ng/ml). Recalcification of bone was excellent as demonstrated by X-ray and confirmed by bone histology. Itching extravascular calcific deposits and calcifications of blood vessel and cardiac valves immediately stopped after total PTX. Moreover, 6 sHPT patients suffered from severe atherosclerotic lesions such as thoracic aortic aneurysm (n = 3) or abdominal aortic aneurysm (n = 3) which showed size progression before but not after total PTX when annually controlled by ultrasonography. In group II, even long after total PTX, there was no clinical, radiological, histological or biochemical evidence for low turnover osteopathy. In conclusion, our data indicate that substitution with vitamin D(3) metabolites and calcium can prevent deleterious bone effects of hypoparathyroidism in hemodialysis patients and in patients with normal kidney function and may compensate for the missing PTH action. Over this, a better survival rate is expected as a consequence of the beneficial effect of total PTX on the progression of atherosclerotic lesions. We suggest reconsideration of total PTX without autotransplantation in dialysis patients with severe sHPT who are not eligible for renal transplantation.

Does long-term treatment of renal anaemia with recombinant erythropoietin influence oxidative stress in haemodialysed patients?

BACKGROUND: Patients with end-stage renal failure undergoing haemodialysis (HD) are exposed to oxidative stress. Increased levels of malondialdehyde (MDA) were demonstrated in plasma of uraemic patients, indicating accelerated lipid peroxidation (LPO) as a consequence of multiple pathogenetic factors. The aim of our investigation was to examine the role of renal anaemia in oxidative stress in HD patients. METHODS: MDA and 4-hydroxynonenal (HNE) were measured in three groups of patients undergoing HD: group I comprised eight patients with a blood haemoglobin (Hb) < 10 g/dl (mean Hb = 8.1+/-1.3 g/dl), and group II were eight patients with a Hb > 10 g/dl (mean Hb=12.4+/-1.9g/dl); none of these 16 patients had been treated with human recombinant erythropoietin (rHuEpo). Group III comprised 27 patients with a mean Hb of 10.5+/-1.6 g/dl after long-term rHuEpo treatment. RESULTS: Mean plasma concentrations of both MDA and HNE were significantly higher (P<0.0001) in all 43 HD patients than in 20 healthy controls (MDA 2.85+/-0.25 vs 0.37+/-0.03 microM, HNE 0.32+/-0.03 vs 0.10+/-0.01 microM). Comparing the three groups, it was shown that HD patients with a Hb <10 g/dl had significantly higher plasma levels of LPO products (MDA 3.81+/-0.86 microM, HNE 0.45+/-0.07 microM) than HD patients with a Hb >10g/dl (MDA 2.77+/-0.58 UM, HNE 0.25+/-0.05 microM), and than HD patients treated with rHuEpo (MDA 2.50+/-0.12 microM, HNE 0.29+/-0.03 microM). Furthermore, an inverse correlation between plasma concentration of LPO products and haemoglobin levels was seen (r=0.62, P<0.0001). CONCLUSION: Radical generation in HD patients might be caused in part by renal anemia itself. Treatment with rHuEpo may decrease radical generation effectively in HD patients due to the increase in the number of red blood cells and blood haemoglobin concentration.

Emerging viral pathogens in long-term expatriates (I): Hepatitis E virus.

Hepatitis E virus (HEV) is one of the so-called 'emerging' viral pathogens, whose role is increasingly being recognized. To estimate the risk of HEV infection during long-term stays in HEV-endemic countries, 500 serum samples obtained from development aid workers and their family members who had spent on average 9 years in HEV-endemic regions were tested for antibodies against HEV by ELISA and Immunoblot. We found seroprevalence rates of 5-6% with no significant differences related to gender or area of upbringing (raised in an HEV-endemic vs. nonendemic region). Seroprevalence rates did not increase with increasing number of stays or number of expatriate years. None of 77 children and adolescents tested was positive for anti-HEV. The Indian subcontinent showed the highest seropositive rate with 10%. In subjects returning from West and Central Africa, East Africa, South-east Asia and Latin America seroprevalence rates were around 7%. We found a comparatively low seroprevalence rate of 2.1% for the Arab countries and the Middle East. Our results show that there definitely is a risk for long-term expatriates to acquire HEV infection; however, in most of our cases infection seems to have been non- or oligo-symptomatic.

Envelope sequence variability and serologic characterization of HIV type 1 group O isolates from equatorial guinea.

Four sera from Equatorial Guinea (EG) suspected to contain antibody against HIV-1 group O-related viruses were identified on the basis of unusual and differential serologic reactivity in selected commercial assays and Western blot. Degenerate primers, designed from HIV-1 group O published sequences, were used to PCR amplify envelope (env) gene sequences from the suspect EG sera. A complete envelope gene sequence from each serum was determined from the overlapping env gene fragments. Analysis (PHYLIP package of programs) of Env amino acid sequences (translated from nucleotide sequences) indicated that the amino acid sequences obtained from EG sera clustered more closely with HIV Env sequences of group O compared to group M. The amino acid sequences at the octameric tip of the V3 loop were either RIGPLAWY (one isolate), RIGPMAWY (two isolates), or GLGPLAVY (one isolate). The V3 tip tetrameric sequence GPLA is represented only once in the 1995 HIV (Los Alamos) database, but was present in two of our group O-related EG samples. The gp41 immunodominant regions (IDR) protein sequences were identical for sequences from three of the sera, RLLALETLIQNQQLLNLWGCKGR(K)L(I)VCYTSVK(T)W, whereas sequence from the fourth serum contained three changes as noted in parentheses. IDR sequences derived from EG sera were unique compared to those reported for other HIV-1 group O isolate ANT70, VAU, or MVP5180. Antibody in each EG serum directed against the IDR could be detected using synthetic peptides comprising sequences from the ANT70 or MVP5180 IDRs, but were most reactive against the sequences derived from the samples themselves. Little or no serologic reactivity was detected when EG sera were reacted against peptides comprising the IDR of HIV-1 group M (subtype B consensus) or HIV-2 (consensus).

PIP: The genetic variation and epidemiology of HIV-1 group O isolates are of considerable importance to the design of HIV-1 diagnostic and screening assays, especially since current serologic and genetic methods to detect HIV-1 have been developed mainly on the basis of sequences from isolates belonging to HIV-1 group M. The HIV envelope protein, especially the gp41 immunodominant region, plays a major antigenic role in the detection of HIV infection and for discriminating HIV-1 from HIV-2 antibody. This paper reports upon genetic variation and the serologic characterization of env sequences from 4 people living in Equatorial Guinea (EG) who were infected with HIV-1 group O. Selected commercial assays and Western blot were first used to identify the sera, then degenerate primers, designed from HIV-1 group O published sequences, were used to PCR amplify envelope (env) gene sequences. A complete envelope gene sequence from each serum was determined from the overlapping env gene fragments. The env amino acid sequence analysis found the EG sera sequences to be clustered more closely with the HIV env sequences of group O rather than to group M. The amino acid sequences at the octameric tip of the V3 loop were either RIGPLAWY, RIGPMAWY, or GLGPLAVY. Although the V3 tip tetrameric sequence GPLA is represented only once in the 1995 HIV database, it was present in 2 of the group O-related EG samples. The gp41 immunodominant regions (IDR) protein sequences were identical for sequences from 3 of the sera. IDR sequences derived from the EG sera were unique compared to those reported for other HIV-1 group O isolates ANT70, VAU, or MVP5180. Other findings are discussed in detail.