Preloading magnesium attenuates cisplatin-associated nephrotoxicity: pilot randomized controlled trial (PRAGMATIC study).

BACKGROUND: Cisplatin is one of the most potent chemotherapeutic drugs used in head and neck cancer treatment; however, nephrotoxicity is the major side-effect limiting usage. Magnesium supplementation has been reported to reduce risk in non-controlled studies. We investigated whether preloading with magnesium prevents nephrotoxicity with a low-dose weekly cisplatin regimen. METHODS: We carried out a prospective pilot, single-blinded, randomized controlled trial to compare cisplatin-associated acute kidney injury (cis-AKI) and acute kidney disease (cis-AKD) between two groups: intravenous 0.9% NaCl 500 ml + KCL 20 mEq over 4 h pre-cisplatin 40 mg/m2 weekly for 7-8 weeks (control group) compared with additional 16 mEq magnesium added to the saline infusion (Mg group) in 30 head and neck cancer patients. Cis-AKI was defined as an increased serum creatinine (SCr) ≥ 0.3 mg/dl within 7 days and cis-AKD is an increased SCr ≥ 0.3 mg/dl between last SCr and baseline pre-chemotherapy SCr. RESULTS: The overall cisplatin tumor response rate and survival were comparable between groups. The baseline characteristics were comparable between groups, although SCr was lower in the controls (0.70 ± 0.17 versus 0.87 ± 0.17 mg/dl, P = 0.01). The incidence of cis-AKI was similar (4.6% versus 1.3%); however, the incidence of cis-AKD was higher for the control group (46.7% versus 6.7%, hazard ratio = 0.082, 95% confidence interval 0.008-0.79, P = 0.03). The time to develop cis-AKD was significantly shorter in the control group (P = 0.007). CONCLUSIONS: The magnesium-preloading regimen was safe and significantly showed a decreased incidence of cis-AKD. The encouraging results of our pilot study need to be confirmed in a large-scale randomized controlled trial.

Early posttransplant nephrotic range proteinuria as a presenting feature of minimal change disease and acute T cell-mediated rejection.

Early-onset nephrotic range proteinuria is an extremely rare presentation of an acute rejection episode. Herein, we have reported a patient who developed nephrotic range proteinuria 7 days after receiving a renal allograft from his sister despite minor changes in serum creatinine levels. A kidney biopsy spcimen revealed a T cell-mediated acute rejection process concomitant with minimal change disease (MCD). Proteinuria and renal dysfunction improved dramatically in response to corticosteroids. The possibility of acute cellular rejection and coexisting MCD should be considered in patients with early posttransplantation nephrosis and normal serum creatinine levels. The coexistence of these entities provides support for the role of T cells in the pathogenesis of MCD.

Treatment of lupus nephritis and primary glomerulonephritis with enteric-coated mycophenolate sodium.

AIMS: Mycophenolate mofetil is an effective therapy for lupus nephritis (LN) and other glomerulonephritis (GN). However, gastrointestinal (GI) complications can limit its use. Enteric-coated mycophenolate sodium (EC-MPS) has been designed to reduce GI adverse events, but it has not been fully investigated in the treatment of GN. METHODS: Patients with LN and primary GN who had received EC-MPS were studied for effects on renal function. RESULTS: 30 subjects (17 LN, 13 primary GN) were studied. EC-MPS decreased proteinuria in both LN and GN. In LN, 16 patients had EC-MPS as induction therapy. Of these, 8 patients achieved complete remission (CR), 4 had partial remission (PR) and 1 improved renal function. In primary GN, CR was achieved in 4 out of 5 with minimal change disease, but only 1 did not relapse. PR was achieved in 1 of 4 patients with membranous glomerulopathy, 2 out of 2 patients with focal segmental glomerulosclerosis and 1 out of 2 patients with IgA nephropathy. Infections, anemia and alopecia were observed, but no patient had GI side effects. CONCLUSIONS: EC-MPS is effective in LN, but not as effective in primary GN. The risk of GI side effects appears to be low, but other side effects can still occur.

The metabolic syndrome and chronic kidney disease in a Southeast Asian cohort.

US adults with metabolic syndrome, as defined by National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) criteria, have been shown to be at increased risk of chronic kidney disease (CKD), but there is limited information in other populations. The relationship between metabolic syndrome and CKD (defined as estimated glomerular filtration rate <60 ml/min/1.73 m(2)) was examined in a Southeast Asian cohort. This relationship was examined when the subjects (n=3195) were initially recruited in a cross-sectional analysis. The risks of developing new CKD associated with metabolic syndrome were also examined prospectively in a subgroup (n=2067) without CKD at entry after 12 years follow-up. Metabolic syndrome was defined according to both NCEP ATP III and the new International Diabetes Federation (IDF) criteria. The prevalence of CKD was 1.6%, and the incidence of new CKD was 6.3%. Metabolic syndrome by NCEP ATP III definition was associated with the increased risk of CKD at baseline (adjusted odds ratio (OR) 2.48 and 95% confidence interval 1.33-4.62), and of developing new CKD at follow-up (adjusted OR 1.62 and 95% confidence interval 1.00-2.61). There was a significant graded relationship between the number of metabolic syndrome components present and risk of CKD. By contrast, metabolic syndrome by IDF definition was not associated with increased risk of CKD. These results suggest the relationship between CKD and metabolic syndrome in a Southeast Asian population is highly dependent on the criteria used to define metabolic syndrome.

Effects of dietary salt intake on plasma arginine.

Because L-arginine is degraded by hepatic arginase to ornithine and urea and is transported by the regulated 2A cationic amino acid y(+) transporter (CAT2A), hepatic transport may regulate plasma arginine concentration. Groups of rats (n = 6) were fed a diet of either low salt (LS) or high salt (HS) for 7 days to test the hypothesis that dietary salt intake regulates plasma arginine concentration and renal nitric oxide (NO) generation by measuring plasma arginine and ornithine concentrations, renal NO excretion, and expression of hepatic CAT2A, and arginase. LS rats had lower excretion of NO metabolites and cGMP, lower plasma arginine concentration (LS: 83 +/- 7 vs. HS: 165 +/- 10 micromol/l, P < 0.001), but higher plasma ornithine concentration (LS: 82 +/- 6 vs. HS: 66 +/- 4 micromol/l, P < 0.05) and urea excretion. However, neither the in vitro hepatic arginase activity nor the mRNA for hepatic arginase I was different between groups. In contrast, LS rats had twice the abundance of mRNA for hepatic CAT2A (LS: 3.4 +/- 0.4 vs. HS: 1.6 +/- 0.5, P < 0.05). The reduced plasma arginine concentration with increased plasma ornithine concentration and urea excretion during LS indicates increased arginine metabolism by arginase. This cannot be ascribed to changes in hepatic arginase expression but may be a consequence of increased hepatic arginine uptake via CAT2A.

Non-traditional cardiovascular disease risk factors in end-stage renal disease: oxidate stress and hyperhomocysteinemia.

Studies in experimental animals have shown that oxidative stress and hyperhomocyst(e)inemia culminate in abnormal vascular and endothelial regulation, functional nitric oxide deficiency, vascular hypertrophy, and atherosclerosis. Oxidative stress is accompanied by increased advanced glycation endproducts and oxidized low density lipoproteins. Studies of patients with end-stage renal disease provide extensive indirect, evidence of increased oxidative stress and more than ninety percent are hyperhomocyt(e)inemic. Presently, only uncontrolled or observational studies are available to assess the effects of anti-oxidant therapy for oxidative stress or folate therapy for hyperhomocyst(e)inemia in these patients. Promising developments include the reports of beneficial effects of a vitamin E coated dialyzer, and the reduction in homocyst(e)ine levels in patients with end-stage renal disease given an intravenous folate metabolite. However, there is presently no therapy available to reverse fully oxidative stress or hyperhomocyst(e)inemia. Therefore, the causative role of these nontraditional risk factors of cardiovascular disease remains untested.

Antioxidants for hypertension.

Increasing evidence implicates reactive oxygen species in the pathogenesis of hypertension and its cardiovascular complications. By altering the balance in the endothelium between vasoconstrictors such as thromboxane and isoprostanes and vasodilators such as nitric oxide, reactive oxygen species contribute to endothelium-dependent contractions and increased vascular resistance. Antioxidants can restore endothelial function and decrease blood pressure in several models of hypertension and in some, but not all, studies of humans with essential hypertension. The potential of antioxidant therapy for hypertension is considerable.

Malignant hypertension and hypertensive emergencies.

Hypertensive emergencies and urgencies are important causes of morbidity and mortality. Malignant hypertension is a hypertensive urgency characterized by grade III/IV retinopathy and widespread endothelial damage. Control of BP is essential in the treatment of these disorders. The effects of hypertension on target organ function need to be balanced against the risks of excessive BP lowering. In hypertensive emergencies, BP should be lowered within minutes with parenteral agents to prevent critical end-organ damage. In hypertensive urgencies, BP can be lowered more slowly over several hours, often with oral agents, to avoid a detrimental fall in BP. The absolute indications for treatment and the optimal therapy depend on the underlying condition.

Vasopressin V2-receptor antagonists: panaceas for hyponatremia?

The current treatment of hyponatremia is unsatisfactory and can be associated with significant morbidity. Vasopressin is inappropriately elevated in the majority of patients with hyponatremia and causes free water retention by stimulating V2-receptors in the collecting ducts. Recently, orally active, nonpeptide, selective vasopressin V2-receptor antagonists have been characterized and offer an exciting prospect for the treatment for hyponatremia. V2-receptor antagonists are effective aquaretic agents, that are capable of increasing free water clearance and plasma sodium and might be useful in the treatment of hyponatremia caused by syndrome of inappropriate secretion of antidiuretic hormone, heart failure, cirrhosis, and nephrotic syndrome. The rationale for their use and evidence from animal and human studies are discussed.