Arginine decreases Cryptosporidium parvum infection in undernourished suckling mice involving nitric oxide synthase and arginase.

OBJECTIVE: This study investigated the role of L-arginine supplementation to undernourished and Cryptosporidium parvum-infected suckling mice. METHODS: The following regimens were initiated on the fourth day of life and injected subcutaneously daily. The C. parvum-infected controls received L-arginine (200 mmol/L) or phosphate buffered saline. The L-arginine-treated mice were grouped to receive NG-nitro-arginine methyl ester (L-NAME) (20 mmol/L) or phosphate buffered saline. The infected mice received orally 10(6) excysted C. parvum oocysts on day 6 and were euthanized on day 14 at the infection peak. RESULTS: L-arginine improved weight gain compared with the untreated infected controls. L-NAME profoundly impaired body weight gain compared with all other groups. Cryptosporidiosis was associated with ileal crypt hyperplasia, villus blunting, and inflammation. L-arginine improved mucosal histology after the infection. L-NAME abrogated these arginine-induced improvements. The infected control mice showed an intense arginase expression, which was even greater with L-NAME. L-arginine decreased the parasite burden, an effect that was reversed by L-NAME. Cryptosporidium parvum infection increased urine NO(3)(-)/NO(2)(-) concentrations compared with the uninfected controls, which was increased by L-arginine supplementation, an effect that was also reversed by L-NAME. CONCLUSION: These findings show a protective role of L-arginine during C. parvum infection in undernourished mice, with involvement of arginase I and nitric oxide synthase enzymatic actions.

Acute kidney injury due to rhabdomyolysis-associated gangrenous myositis.

Rhabdomyolysis is associated with infectious diseases in approximately 5% of cases and acute kidney injury occurs in 33-50% of cases. Gangrenous myositis is a deep seated infection of the subcutaneous and muscular tissues. We report the case of an 18 year-old man who was admitted to the emergency room with leg pain, fever, nausea, vomiting and oliguria. Physical examination showed moderate dehydration, peripheral cyanosis and skin necrosis with severe myalgia and no subcutaneous gas. Laboratory findings at admission were: serum urea 111 mg/dL, creatinine 1.3 mg/dL, potassium 6.3 mEq/L, creatine kinase (CK) 112,452 IU/L, aspartate amino transaminase (AST) 1116 IU/L, alanine amino transaminase (ALT) 1841 IU/L, pH 7.31, bicarbonate (HCO3) 11 mEq/L and lactate 4.3 mmol/L. Emergency hemodyalisis was started, and antibiotics were given due to high suspicion for bacterial infection. The patient developed respiratory insufficiency and septic shock needing mechanical ventilation and vasoactive drugs. He presented spontaneous gangrenous myositis in both legs and in his left arm. After 26 sessions of hemodialysis, partial recovery of renal function was observed. He was discharged from the ICU after 38 days, still with leg pain. Acute kidney injury due to rhabdomyolysis should be considered as a possible complication of gangrenous myositis.