Reactive Oxygen Metabolites: A Link between Oxidative Stress and Inflammation in Patients on Hemodialysis

Oxidative stress plays a significant role in the development of inflammation in patients undergoing hemodialysis (HD). This study intends to evaluate the relationship between C-reactive protein (CRP) and the newly established marker of lipid peroxidation, d-ROMs (reactive oxygen metabolites), in comparison with different indicators of oxidative stress. Plasma total antioxidant capacity (TAC), lipid peroxidation products malonaldehyde (MDA) and 4-hydroxyalkenals, as well as d-ROMs, were determined in 24 patients before HD and in 21 normal controls (NC). It was found that HD patients had higher levels of d-ROMs than NC (p = 0.033). A highly significant positive correlation was observed between logCRP and d-ROMs concentrations (p < 0.0001, r = 0.85) in patients, but not in NC. The concentrations of TAC and MDA were not associated with CRP in HD or in NC individuals. It is concluded that d-ROMs concentration is a potent marker of oxidative injury that is strongly indicative of the inflammatory status in HD patients.

Atherosclerotic risk factors and carotid stiffness in elderly asymptomatic HD patients

Several studies showed that carotid atherosclerosis and stiffness are independent prognostic factors of cardiovascular morbidity and mortality in the general population and in end-stage renal disease patients. However, the impact of established risk factors on carotid structural and elastic properties in non-diabetic elderly hemodialysis patients with negative history for cardiovascular disease has not been fully elucidated. In this paper, we investigated the effect of established and potential risk factors on carotid atherosclerosis and stiffness. Thirty stable, non-symptomatic, non-diabetic patients, aged 65-years and older (mean age 71.4+/-4.15, range 65-79) on hemodialysis for more than 6 months, were included. All patients underwent B-mode ultrasonography of common carotid artery estimating intima-media wall thickness and wall-to-lumen ratio bilaterally and checking for the presence of plaques. Carotid elasticity was evaluated by compliance, distensibility, and the incremental elastic modulus (Einc), whereas systemic arterial stiffening was evaluated by the augmentation index provided by tonometry of radial artery. Our results showed that presence of carotid plaques and wall thickening were frequent findings in this population (76% and 73.3%, respectively) and they were positively associated with fibrinogen (P<0.005), diastolic blood pressure (P<0.004), visceral obesity (P<0.001) and bio-intact PTH (i-PTH) (P=0.03). Overall, systemic and carotid stiffness were strongly correlated with hs-CRP (P=0.018), serum ferritin (P=0.02) with age (P=0.03), lipids (P=0.03) and i-PTH (P=0.05). In conclusion, our findings show that stiffening and atherosclerosis in non-symptomatic elderly HD patients are very common and they are related not only to hemodynamic changes (diastolic blood pressure), inflammation (hs-CRP, fibrinogen, ferritin) or metabolic dysfunction (increased i-PTH, abnormal lipid profile), but also to abnormal fat deposition (increased waist to hip ratio and waist circumference). Considering the high morbidity and mortality of elderly patients, close monitoring of these parameters could be useful to prevent cardiovascular events.

Effect of dialysis on plasma total antioxidant capacity and lipid peroxidation products in patients with end-stage renal failure

Dialysis is associated with an impairment of antioxidant defense and an overproduction of oxidative stress markers. This study focuses on the comparison of plasma total antioxidant capacity (TAC) and lipid peroxidation products in patients on hemodialysis (HD) before and after treatment and in peritoneal dialysis (PD) patients. Plasma TAC, malonaldehyde (MDA), and 4-hydroxyalkenal concentrations were measured in 31 HD patients, in 24 PD patients, and in 17 normal controls (NC). It was found that before HD, TAC and MDA levels were higher than those in the NC (p < 0.001). After HD, these levels decreased significantly but were higher than in NC and lower than in PD patients (p < 0.001). The levels of 4-hydroxyalkenals were elevated in patients as compared with NC, but did not differ between HD and PD patients. The MDA concentrations correlated positively with the TAC in the patients. It is concluded that the oxidative status of patients on HD is similar to that of patients on PD and that the susceptibility to oxidative stress is strongly related to the levels of MDA produced in plasma.

Ultrafiltration in the treatment of severe congestive heart failure

BACKGROUND

Fluid removal remains a fundamental goal in the treatment of congestive heart failure (CHF). Vacuum ultrafiltration, hemodialysis, or a combination of both was used in patients with severe CHF (NYHA class IV), severe edema, and insensitivity to pharmacological treatment with diuretics.

METHODS

The aim of the study was to remove the overload fluid in eighteen patients, 13 men and 5 women, aged 38 to 83, with a man age of 66 years with intractable congestive heart failure. All patients were hospitalized because of severe congestive heart failure and did not respond to treatment with intravenous administration of a high dose of diuretics and positive inotropic agents. They thus underwent vacuum ultrafiltration (1 to 27 sessions) while in 4 of them hemodialysis was also performed because of high serum creatinine levels (over 4 mg/dl). Subclavian catheters were used in all patients and arteriovenous fistula was later performed in 2, because of the need for long term treatment. The average fluid removed was 2 L per session and the total fluid removed ranged from 4 to 29 L.

RESULTS

Fourteen of the 18 patients (78%) showed significant improvement in their clinical status. Ten patients (56%) had a short term improvement but expired after 7 to 107 days of hospitalization. Four patients (22%) died after only one session of dialysis and 4 patients (22%) recovered after 8 to 23 dialysis sessions and were discharged from hospital.

CONCLUSION

The majority of patients with severe chronic CHF which is intractable to conventional therapy including intravenous diuretics and inotropes improve by the use of ultrafiltration. However, a limited proportion of them survive to be discharged from the hospital.

Association of serum nitric oxide levels with depressive symptoms: a study with end-stage renal failure patients

BACKGROUND

Nitric oxide (NO) is a soluble gas produced by the activity of an enzyme found in neurons. It has been implicated in a great number of normal physiological functions (such as noradrenaline and dopamine release, memory and learning, regulation of the cerebrovascular system, modulation of wakefulness, modulation of nociception, olfaction, food intake and drinking) as well as pathologies (Alzheimer's, Huntington's disease, cerebral ischemia, stroke). Two reports have addressed the involvement of NO in depression.

METHODS

The objective of the study was to examine the association between NO and specific depressive symptoms. For this purpose, in a sample of 28 end-stage renal failure patients (who have increased NO levels), we tested the hypothesis that the subgroup of patients with these specific depressive symptoms was differentiated from the patients without these symptoms with regard to serum levels of NO metabolites. The depressive symptoms were assessed using the Zung self-rating scale.

RESULTS

Our study revealed an association of NO with the following depressive symptoms: sexual dysfunction, weight loss, psychomotor retardation, indecisiveness and irritability.

CONCLUSION

The association between NO system and symptoms of depression does not necessarily imply a pathogenetic association between NO and depressive disorder. Further research is needed to verify these findings and study their possible pathogenetic implications.