Terje Apeland

Antiepileptic drugs as independent predictors of plasma total homocysteine levels

Low folate levels have consistently been reported in patients with epilepsy on phenytoin (PHT), phenobarbital (PB) and primidone (PRD), while data on valproate (VPA) are conflicting. Furthermore, antiepileptic drugs (AEDs) may be associated with high levels of plasma total homocysteine (p-tHcy). Therefore, we have investigated the levels of p-tHcy, serum folate (S-FA) and erythrocyte folate (E-FA) in patients on PHT, PB and PRD (Group 1, n=21) and VPA (Group 2, n=24). Both groups had their own matched controls. Blood samples were drawn fasting and 6 h post methionine loading (6 h-PML). The Group 1 patients had fasting and 6 h-PML p-tHcy levels significantly higher than their controls (P=0.05 and <0.0001, respectively), and patients without dietary multivitamin supplementation (n=14), had lower fasting S-FA and E-FA levels than their controls (P=0.02 and 0.0003, respectively). The Group 2 patients had fasting and 6 h-PML levels of p-tHcy, S-FA and E-FA not different from their controls. In a multiple stepwise regression model comprising all subjects (n=90), the AEDs of Group 1 and the S-FA levels were independent predictors of p-tHcy levels. Thus, PHT, PB and PRD are associated with high p-tHcy and low folate levels, whereas VPA does not influence S-FA, E-FA and p-tHcy levels in adult patients.

The effect of B-vitamins on hyperhomocysteinemia in patients on antiepileptic drugs.

Patients on antiepileptic drugs (AEDs) may have elevated levels of plasma total homocysteine (p-tHcy). The aim of this study was to assess the effect of B-vitamin supplementation on the levels of p-tHcy and markers of endothelial activation and lipid peroxidation. A total of 33 adult patients on AEDs were identified with either fasting (Group 1, n=23) or post methionine load (PML) (Group 2, n=10) hyperhomocysteinemia. Subjects were supplemented with B-vitamins for 30 days: folic acid 0.4 mg, pyridoxine 120 mg and riboflavin 75 mg per day. After supplementation, serum folate and pyridoxal phosphate had increased, while fasting and PML p-tHcy had decreased (P<0.0001) by 36 and 26%, respectively. Prior to supplementation, the Group 1 patients had elevated levels of P-selectin and von Willebrand factor (vWF) (P=0.05 and 0.03, respectively). After supplementation, the levels of intercellular cell adhesion molecules had decreased (P=0.01) and E-selectin decreased nonsignificantly (P=0.07). However, the levels of vascular cell adhesion molecules had increased (P<0.0001), while lipid peroxidation were unchanged. In conclusion, the combined supplementation with folic acid, pyridoxine and riboflavin reduced fasting and PML hyperhomocysteinemia in patients on AEDs. Patients with fasting hyperhomocysteinemia had elevated levels of P-selectin and vWF, which may indicate an increased risk of cardiovascular disease. Furthermore, B-vitamin supplementation influenced endothelial activation, although the clinical implication is uncertain.

Fasting and Post-Methionine Loading Concentrations of Homocysteine, Vitamin B2, and Vitamin B6 in Patients on Antiepileptic Drugs

Patients on antiepileptic drugs (AEDs) frequently have low serum folate and high plasma total homocysteine (tHcy) (1)(2)(3)(4). This metabolic disturbance has been implicated in an increased rate of cardiovascular disease, fetal malformations, dementia, and neuropsychiatric symptoms among patients on AEDs (5)(6)(7). Homocysteine metabolism is dependent on four B vitamins as cofactors: The methylation of homocysteine to methionine requires folate and vitamin B12, and the irreversible transsulfuration to cysteine requires vitamin B6 (8). The recycling of folate cofactors is dependent on vitamin B6 and B2, and vitamin B2 is necessary for activating vitamin B6 to pyridoxal 5′-phosphate (PLP) (9). Vitamin B2 and B6 status thus may have an impact on tHcy concentrations in patients taking AEDs, but few studies have reported on this matter (3)(4)(10)(11). The methionine loading test detects individuals with impaired homocysteine metabolism not detected by fasting Hcy concentrations alone and is often considered primarily a test of the transsulfuration pathway (1)(8)(12). We therefore determined the fasting and 6 h post-methionine loading (postload) plasma concentrations of thiols and B vitamins in patients taking AEDs. We recruited 101 patients with symptomatic, cryptogenic, or primary generalized epilepsy from our outpatient clinic. None of them had epilepsy secondary to ischemic stroke or other conditions considered to be associated with high tHcy, and none were on prescribed vitamin supplements. We recruited 101 controls among blood donors and hospital employees. All participants gave written informed consent before entering the study, and The Regional Ethics Committee (University of Bergen, Norway) approved the study. The number of male patients and controls was identical (n = 53), as was the mean (SD) age [37.9 (15.0) and 37.3 …

Rituximab therapy in early recurrent focal segmental sclerosis after renal transplantation

Kidney transplants may be lost due to recurrence of the primary disease. In glomerulonephritis, all kinds taken together, 3% of the patients lose their grafts due to recurrence [1]. If, however, a first kidney graft has been lost from recurrence, the rate of failure caused by recurrence in subsequent grafts is ∼48% [1]. Focal segmental glomerulosclerosis (FSGS) in a young patient is associated with the highest rate of recurrence in kidney grafts, i.e. 20–40% of first time kidney recipients [1–3]. With recurrence of childhood FSGS, the 2-year graft survival is poor—∼35% [1]. A circulating factor, which may increase the glomerular permeability to albumin, has been found in some patients with FSGS. Therefore, several trials with plasmapheresis or protein A immunoabsorption have been conducted in patients with recurrent FSGS, but the response appears to be variable and unpredictable [2,3]. Rituximab was first given to a few patients with post-transplant lymphoproliferative disorder and early recurrent FSGS. The lymphoproliferative disorders dissolved, and as a side effect, proteinuria improved [4,5]. Subsequently, rituximab therapy has been reported in several kidney transplants with early recurrent FSGS, but has achieved variable results (Table 1) [6–13]. It is difficult to organize randomized trials in this small patient group. Therefore, we report a case of sustained remission after rituximab in a young patient with resistant early remission of FSGS in his second kidney graft.

Drug-induced pertubation of the aminothiol redox-status in patients with epilepsy : Improvement by B-vitamins

OBJECTIVES Patients with epilepsy have excess morbidity and mortality due to ischemic cardiovascular disease. Many of these patients have elevated concentrations of plasma total homocysteine (Hcy), which is an acknowledged risk factor for cardiovascular disease, venous thromboembolic disease, foetal malformations and dementia. Hyperhomocysteinemia may have negative effects through mechanisms involving oxidative damage. In the present study, we have investigated the aminothiol redox-status in patients on antiepileptic drugs. Thereafter, in a subset of patients with elevated total Hcy, we evaluated the effect of B-vitamin therapy. METHODS In the first part of the study, 101 patients on antiepileptic drugs were compared with 101 matched healthy controls. The redox-species of Hcy, cysteine and cysteinylglycine, the major aminothiols in plasma, were analyzed by high-performance liquid chromatography (HPLC). Hyperhomocysteinemia was defined as fasting total Hcy above 12 micromol/L and/or post-methionine load concentrations above 38 micromol/L. In the second part of the study, 33 patients identified with hyperhomocysteinemia were supplemented with three B-vitamins for 30 days; folic acid (B9), pyridoxine (B6) and riboflavin (B2). RESULTS All redox-species of Hcy were significantly elevated in the patients, except the fasting concentrations of reduced Hcy (p=0.09). The reduced/total ratio of cysteine in fasting plasma was lower in the patients than in the controls: 5.20% vs. 6.19%, respectively (p=0.006). After 30 days of B-vitamin supplementation, the plasma concentrations of reduced, oxidized and protein-bound Hcy species were significantly lowered by 17%, 22% and 28%, respectively. The reduced/total ratio of cysteine rose from 4.9% to 7.9% (p=0.007). CONCLUSIONS Patients on antiepileptic drugs have abnormal aminothiol redox-status associated with hyperhomocysteinemia. This is similar to findings in patients with cardiovascular disease. B-vitamin supplementation partially corrects the abnormal aminothiol redox-status. Possibly, B-vitamin supplementation may be useful in drug-induced hyperhomocysteinemia.

Long-term outcomes after cyclosporine or mycophenolate withdrawal in kidney transplantation – results from an aborted trial

Long‐term triple immunosuppressive therapy with cyclosporine (CsA), mycophenolate mofetil (MMF) and prednisolone may be excessively powerful for many transplant recipients. We compared withdrawal of either MMF or CsA in stable kidney transplants on triple immunosuppression. The study was a prospective, randomized, controlled 12‐months trial in stable kidney transplants. The patients who withdrew CsA were given MMF 2 g/d, and CsA troughs were between 75 and 125 ng/mL in MMF withdrawal. Planned inclusion was 298 patients. The study was prematurely aborted after inclusion of 39 patients. Acute rejection rates were 6/20 (30%) in the MMF group compared with 0/19 (0%) in the CsA group (p = 0.02). Time to acute rejections was 4.0–28.7 months after withdrawal. Trough concentrations of mycophenolic acid (MPA) and CsA showed therapeutic levels. The subjects have been observed for eight yr, and of the 28 patients remaining on randomized therapy, the MMF patients preserved graft function better than CsA patients. Death‐censored graft survival was 75% and 95% (p = 0.18) and patient survival was 70% and 68% (p = 0.99) in the MMF and CsA groups, respectively, at the end of long‐term follow‐up. CsA withdrawal was associated with a high rate of acute rejections. Initially, the treatment of acute rejections was successful. However, five of six lost their grafts in the long term.

Serum Folate Is Significantly Correlated with Plasma Cysteine Concentrations in Healthy Industry Workers

Background: A low concentration of serum folate is associated with an increased risk of cardiovascular disease. Extracellular cysteine is involved in aging, cancer and cardiovascular disease. The relationship between serum folate and plasma cysteine is poorly understood. Therefore, we investigated this relationship in industry workers, whose health has economic implications. Methods: The concentration of serum folate was determined by the Access ImmunoAssay System Sanofi Pasteur. Plasma cysteine and homocysteine were measured by an ion-pair HPLC method. The concentrations of serum triglycerides were determined by an enzymatic colorimetric method. Results: We detected a positive correlation between the concentration of serum folate and plasma cysteine, whereas the concentration of serum folate was negatively correlated with plasma homocysteine and serum triglycerides. In a multiple regression analysis with adjustment for age, BMI and smoking, serum folate as the dependent variable exhibited a strong relationship with plasma cysteine, and a negative relationship with plasma homocysteine and serum triglycerides. Conclusion: We observed significant correlations between serum folate, plasma cysteine and serum triglyceride concentrations in industry workers, implying that folate may modulate key aspects of the body’s cysteine and lipid metabolism.

The aminothiol redox status in haemodialysis patients does not improve with folate therapy.

Background. Patients on haemodialysis suffer from high cardiovascular morbidity and mortality, and oxidative stress may play a role in the pathophysiology of cardiovascular disease in these patients. Hyperhomocysteinemia is common in dialysis patients and may have pro‐oxidant effects. Moreover, the redox status of the major plasma aminothiols (homocysteine [Hcy], cysteine and cysteinylglycine) may be regarded as a biomarker of oxidative stress. In the present study, we investigated the aminothiol redox status during a period of homocysteine‐lowering therapy with folinic acid. Material and methods. In the first part of the study, 32 stable patients receiving maintenance haemodialysis were compared with 32 reference subjects. In the second part, the patients were given folinic acid intravenously for 3 months. Results. Before intervention with folinic acid, the patients had elevated concentrations of all redox species of Hcy. The aminothiol redox ratios were low. Folinic acid therapy lowered the concentrations of all Hcy redox species; however, the redox ratios did not improve. Conclusions. The low aminothiol redox ratios indicate the presence of oxidative stress in haemodialysis patients. Therapy with folinic acid lowered total Hcy concentrations, but did not improve the redox status. Thus, hyperhomocysteinemia appears to be of little importance in regard to the total level of oxidative stress in uraemia.

Kidney donors and kidney transplants have abnormal aminothiol redox status, and are at increased risk of oxidative stress and reduced redox buffer capacity.

OBJECTIVE Living kidney donors have been part of a successful kidney transplant programme in Norway for almost 50 years. Glomerular filtration rates (GFRs) have tended to remain stable at about 70% of pre-donation levels. Plasma total homocysteine (Hcy) has an inverse relationship to kidney function, and previous reports indicate elevated levels of Hcy in kidney donors. We wanted to examine the most important plasma aminothiols in kidney donors, i.e. Hcy, cysteine (Cys) and cysteinylglycine (CG) with their redox species. The aminothiol redox-system appears to be an integral part of the extracellular antioxidant defence system in the body. DESIGN AND METHODS Plasma concentrations of total Hcy were obtained in 82 previous kidney donors, 82 healthy controls and 26 kidney transplants with stable and good kidney function. In a subset of 30 kidney donors, 30 matched controls and 12 kidney transplants plasma samples were analysed for Hcy, Cys, CG and their redox species. There were no differences between groups for B-vitamin status. RESULTS Kidney donors and kidney transplants had elevated plasma concentrations of total Hcy, Cys and CG. The plasma levels of reduced Hcy species were high - with a high reduced/oxidized ratio. The plasma levels of reduced Cys species were low - with a low reduced/oxidized ratio. CONCLUSIONS Previous kidney donors have abnormal plasma aminothiol redox status. The present findings indicate that donors may have increased risk of oxidative stress with low redox buffer capacity and disturbed cellular redox-dependent signalling pathways. Similar observations were made in the kidney transplants.

Systemic redox biomarkers and their relationship to prognostic risk markers in autosomal dominant polycystic kidney disease and IgA nephropathy

BACKGROUND Oxidative stress is evident from an early stage in chronic kidney disease (CKD). Therefore, we investigated redox biomarkers in polycystic kidney disease (ADPKD) and IgA nephropathy (IGAN). METHODS This is a case-control study with three groups: ADPKD (n = 54), IGAN (n = 58) and healthy controls (n = 86). The major plasma aminothiols with their redox species were examined: homocysteine (Hcy), cysteinglycine (CG), cysteine (Cys) and glutathione (GSH). The redox ratio was the ratio of reduced free and oxidized aminothiols in plasma. We investigated malonedialdehyde (MDA) and advanced oxidation protein products (AOPP), and ten single nucleotide polymorphisms of antioxidant enzymes. RESULTS Patients had elevated oxidized free Hcy and Cys with associated low redox ratios - most pronounced in IGAN. Patients with IGAN had elevated AOPP and possibly MDA. Oxidized free Hcy and Cys with redox ratios were correlated to AOPP, MDA and proteinuria. Furthermore, there was an independent relationship to parathyroid hormone (PTH). IGAN had an elevated frequency of Val16Ala SNP rs4880, which influence the function of mitochondrial superoxide dismutase 2 (p = 0.03). CONCLUSIONS Patients with ADPKD and IGAN have evidence of oxidative stress from stage 1 to 4 - most pronounced in IGAN. In patients, aminothiol redox biomarkers were correlated to AOPP, proteinuria and PTH, which are known prognostic markers in CKD. It may be possible that oxidative stress influences PTH dysregulation in CKD. The association between IGAN and the redox related variant allele rs4880(C) might indicate a new susceptibility locus for IGAN, but this needs verification.