The effect of vitamin K2 supplementation on vascular calcification in haemodialysis patients: a 1-year follow-up randomized trial.

PURPOSE: Vascular calcification (VC) is an independent risk factor for cardiovascular disease in hemodialysis patients while Matrix GLA protein (MGP) is one of the most potent inhibitors of VC and its activation is vitamin K dependent. The aim of this study is to investigate the role of oral vitamin K2 supplementation in the prevention of VC progression in haemodialysis patients. METHODS: We conducted a prospective randomized interventional study in patients on hemodialysis. Patients were randomly assigned to either receiving orally 200 µgr of vitamin K2 (vitamin K2/MK-7, Solgar) every day for 1 year or no treatment. Uncarboxylated MGP (uc-MGP) concentrations were quantified using ELISA at randomization, at 3 and at 12 months. Aortic calcification was evaluated using Agatston score after an abdominal computed tomography scan that was performed at the beginning and at 12 months of follow-up. RESULTS: There were 102 patients that were randomized. After 1 year of follow-up, 22 patients from the vitamin K2 group and 30 patients from the control group were included in the analysis. After 3 months of treatment, uc-MGP values remained unchanged in the vitK2 group but after 1 year were reduced by 47% (p = 0.005). Furthermore, uc-MGP at 1 year was increased by 12% in the control group. At 1 year, vitK2 group had significantly lower values of uc-MGP in comparison to controls (p = 0.03). Agatston score was increased significantly both in vitamin K2 and control group at 1 year with no difference between groups. CONCLUSIONS: Oral administration of vitamin K2 in patients on haemodialysis reduced serum uc-MGP levels but did not have an effect in the progression of aortic calcification.

Treatment of IgA nephropathy based on the severity of clinical and histological features.

Immunoglobulin A (IgA) nephropathy (IgAN) represents a common glomerular disease treated by various therapeutic regimens. We studied 50 IgAN patients to determine the effect of different regimens selected according to severity of the disease on the clinical outcome of patients over a follow-up period of five years. Patients with normal renal function and proteinuria <1 g/24-h received no treatment (Group A, n = 6). Thοse with normal renal function, proteinuria >1 g/24-h and mild to moderate histological lesions received angiotensin-converting enzyme inhibitors (ACEi) and corticosteroids (Group B, n = 23). Patients with baseline serum creatinine (Scr) <2.5 mg/dL, proteinuria >3.5 g/24-h and severe histological lesions received ACEi, corticosteroids and other immunosuppressive drugs (Group C, n = 18). Finally, patients with Scr >2.5 mg/dL, glomerulosclerosis and tubulointerstitial fibrosis received ACEi and fish oil (Group D, n = 3). Doubling of baseline Scr was observed in nine (18%) patients; two (8.7%) patients from Group B, five (27.7%) patients from Group C and two (66.7%) patients from Group D. Of the seven (14%) patients who reached end-stage renal disease, one (4.3%) patient was from Group B, four (21.0%) patients were from Group C and two (66.7%) patients were from Group D. Reduction of proteinuria was observed in all (100%) patients from Group B and in 15 (83.3%) patients from Group C. Adverse reactions occurred in three of 18 (16%) patients treated with immunosuppressive drugs. The choice of therapeutic regimen used in the treatment of patients with IgAN could be based on the severity of clinical and histological involvement in order to achieve the maximum effect with the least of adverse reactions.

Therapeutic approach of patients with IgA nephropathy.

Immunoglobulin A nephropathy (IgAN) is the most commonly encountered primary glomerulonephritis and it usually follows an indolent clinical course. However, hypertensive patients with proteinuria and renal insufficiency at presentation and patients with severe histological involvement are at high risk to develop end stage renal failure. There is no consensus for the treatment of patients with IgA nephropathy. In general, patients with normal renal function, mild proteinuria (3 g/24 h) and in progressive disease despite treatment with ACE inhibitors. Fish oil might be an alternative to corticosteroids in cases with renal insufficiency and chronic histological lesions. Combinations of corticosteroids and cytotoxic drugs are saved for patients with IgA nephropathy and a rapidly progressive course.