Anemia as a risk factor for chronic kidney disease.

Chronic kidney disease (CKD) is an important and leading cause of end-stage renal disease (ESRD) and moreover, plays a role in the morbidity and mortality due to cardiovascular disease, infection, and cancer. Anemia develops during the early stages of CKD and is common in patients with ESRD. Anemia is an important cause of left ventricular hypertrophy and congestive heart failure. Correction of anemia by erthyropoiesis-stimulating agent (ESA) has been shown to improve survival in patients with congestive heart failure. Anemia is counted as one of the non-conventional risk factors associated with CKD. Hypoxia is one of the common mechanisms of CKD progression. Treatment by ESA is expected to improve quality of life, survival, and prevent the CKD progression. Several clinical studies have shown the beneficial effects of anemia correction on renal outcomes. However, recent prospective trials both in ESRD and in CKD stages 3 and 4 failed to confirm the beneficial effects of correcting anemia on survival. Similarly, treatment of other risk factors such as hyperlipidemia by statin showed no improvement in the survival of dialysis patients. Given the high prevalence of anemia in ESRD and untoward effects of anemia in CKD stages 3 and 4, appropriate and timely intervention on renal anemia using ESA is required for practicing nephrologists and others involved in the care of high-risk population. Lessons from the recent studies are to correct renal anemia (hemoglobin <10 g/dl not hemoglobin > or =13 g/dl). Early intervention for renal anemia is a part of the treatment option in the prevention clinic. In this study, clinical significance of anemia management in patients with CKD is discussed.

Successful management of critical limb ischemia with intravenous sodium thiosulfate in a chronic hemodialysis patient.

Vascular calcification is common among hemodialysis (HD) patients and contributes to the development of peripheral arterial disease. A 57-year-old Japanese man who had been on HD for 30 years was referred to us for severe pain with multiple ulcers on his toes and fingers. He was an ex-smoker and had no diabetes mellitus. On admission, he had ulcers on his big toes bilaterally and right 2nd - 4th fingers. Peripheral pulses were strong and his ankle-brachial pressure index was above 1.3. Laboratory data were as follows: calcium 9.9 mg/dl, albumin 3.3 g/dl, phosphate 3.0 mg/dl, Ca x P product 30, and parathyroid hormone 98 pg/ml. He had a parathyroidectomy in 1998 and 1999. X-rays of his hands and legs showed diffuse subcutaneous arteriolar calcification. Angiography revealed no local stenotic lesions. Despite intensive therapies including hyperbaric oxygen therapy, painful gangrene developed on his right big toe and the pain was so intense that he could not go to sleep in a supine position. We infused intravenous sodium thiosulfate (20 g) 3 times weekly, based on previous reports. Within 4 - 5 days, he experienced rapid and dramatic symptom relief. The score of the visual analogue pain scale improved from 10/10 - 2/10. The signs of ischemia, measured by transcutaneous partial oxygen pressure and thermography, improved significantly. During the infusion of sodium thiosulfate, the patient complained of nausea, vomiting and hyperosmia. These adverse symptoms were resolved after discontinuation of the infusion. Pain relief was sustained and he could walk after 2 weeks of infusion. Our case supports the use of sodium thiosulfate as a novel therapeutic choice for critical limb ischemia with severe vascular calcification in chronic HD patients.

Two unusual cases of Anderson-Fabry disease in a Japanese family.

A 16-year-old Japanese girl was admitted to our hospital on February 27, 2001, for acute renal failure. She had not shown proteinuria or hematuria in any school examination through 2000. The first renal biopsy specimen showed focal segmental glomerulosclerosis and tubulointerstitial change. Electron microscopy showed numerous myeloid bodies in the glomerular epithelium suggesting the diagnosis of Anderson-Fabry disease. After electron microscopy, we measured WBC alpha-galactosidase A, which was slightly decreased to 36.1 nmol/mg P/h (normal: 49.8 - 116.4). WBC alpha-galactosidase A levels for other family members were 74.3 for the mother, 4.8 for the father, 45.6 for the elder sister, and 16.3 for the younger sister. During the follow-up, she had two episodes of nephrotic syndrome, which responded well to steroid therapy. Both second and third renal biopsy showed numerous myeloid bodies by electron microscopy. A 52-year-old man, the father of the case one patient, was admitted for renal biopsy because of proteinuria and low levels of WBC alpha-galactosidase. Biopsy specimen showed typical changes under light microscopy and typical myeloid bodies by electron microscopy. Our cases underscore the importance of electron microscopy when examining the biopsy specimen and suggest that undiagnosed Anderson-Fabry disease may be present, in particular on chronic dialysis.

Involvement of cytochrome P450 metabolites in the vascular action of angiotensin II on the afferent arterioles.

Recent studies have demonstrated that cytochrome P450-dependent metabolites of arachidonic acid (CYP450-AA) play important roles in the control of renal vascular resistance (RVR). In the present study, we examined the possible involvement of CYP450-AA in the vasoconstrictor action of angiotensin II (Ang II) on the afferent arterioles (Af-Arts), a vascular segment crucial to the control of RVR. Rabbit Af-Arts were microperfused at 60 mmHg in vitro, and the vasoconstrictor action of Ang II (10(-11)-10(-8) M, added to both the bath and lumen) was examined with or without blocking the activity of CYP450 epoxygenase or hydroxylase. Ang II decreased the luminal diameter of Af-Arts in a dose-dependent manner (34+/-2% of control diameter at 10(-8) M, n=9, p<0.0001). Pretreatment with miconazole, an inhibitor of CYP450 epoxygenase, at 10(-6) M decreased the basal diameter by 14+/-1% (n=6, p<0.01) and augmented the vasoconstrictor action of Ang II (7+/-3% of control diameter at 10(-8) M, p<0.001 vs. without miconazole). This augmentation was abolished by blocking the Ang II type 2 (AT2) receptor with PD 123319 at 10(-7) M. In contrast, pretreatment with 17-octadecynoic acid (17-ODYA, 10(-6) M), which inhibits both epoxygenase and hydroxylase activity, had no effect on the basal diameter but attenuated the vasoconstrictor action of Ang 11(46+/-2% of control diameter at 10(-8) M, p<0.01 vs. without 17-ODYA). Our results demonstrate that in the Af-Art, endogenous CYP450-AA are involved not only in the control of basal tone but also in the action of Ang II. Further, it appears that the CYP450 epoxygenase pathway attenuates Ang II action via AT2 receptors.

[A female case of Fournier's gangrene in a patient with lupus nephritis].

Infection is one of the common causes of death in patients with systemic lupus erythematosus (SLE). It is associated with the use of immunosuppressive agents, renal failure, and increased disease activity. Fournier's gangrene is a necrotizing fasciitis occurring in the genital region. It is rare, but can be crucial if surgical drainage is delayed. We report a female case of Fournier's gangrene occurring in a patient with lupus nephritis and chronic renal failure. The patient was a 21-year-old female with chronic renal failure due to lupus nephritis. She had suffered from watery diarrhea one month before admission. It improved after increasing the dose of prednisolone, but, she was complicated with Bartholin abscess. The vaginal pain rapidly spread to the left lower quadrant abdomen despite treatment with oral cephalosporin. Focal incision was performed and black fluid emerged with a foul smell. Pelvic computed tomography (CT) revealed many bubbles in that region. She was found to have septic shock on transfer to our hospital. Thereafter, emergency debridement was performed, followed by antibiotic therapy and hyperbaric oxygen therapy. Organisms were found to be 5 anerobes, such as Bacteroides species, and 3 aerobics, such as Morganella morganii. Fournier's gangrene was improved via these treatments, but she needed maintenance hemodialysis. Fournier's gangrene complication should be considered in SLE with urogenital infection.

Endogenous nitric oxide and epoxyeicosatrienoic acids modulate angiotensin II-induced constriction in the rabbit afferent arteriole.

Nitric oxide (NO) and epoxyeicosatrienoic acids (EETs), cytochrome P450 epoxygenase metabolites of arachidonic acid, are released by the vascular endothelium and play important roles in the control of glomerular haemodynamics. We examined whether endogenous NO or EETs modulate angiotensin II- (AngII) induced constriction in isolated microperfused afferent arteriole (Af-Art) of the rabbit kidney. When Af-Arts were treated with NG-nitro-L-arginine methyl ester (L-NAME, an inhibitor of NO synthese; 10-4 mol L-1) or miconazole (an inhibitor of P450 epoxygenase; 10-6 mol L-1), basal diameter was decreased by 34.5 +/- 2.2 and 13.9 +/- 3.2%, respectively. AngII added to both the bath and lumen decreased the diameter of Af-Arts in a dose-dependent manner. Pretreatment with either L-NAME or miconazole also augmented the constrictor response to AngII. AngII at 10-8 mol L-1 decreased the diameter to 39.2 +/- 1.4, 32.9 +/- 3.6, and 12.7 +/- 4.6%, in control, L-NAME-, and miconazole-treated group, respectively. In order to study whether the AngII type2 (AT2) receptor modulates AngII action via NO or EETs, we repeated the experiments in the presence of PD123319 (an AT2 receptor antagonist; 10-7 mol L-1). In the presence of PD123319, L-NAME still augmented the constrictor response to AngII, however, miconazole had no effect. In the presence of PD123319, AngII at 10-8 mol L-1 decreased the diameter to 25.0 +/- 4.6, 9.4 +/- 4.0, and 26.0 +/- 3.3%, in control, L-NAME-, and miconazole-treated group, respectively. These results suggest that (1) tonic release of NO and EETs attenuates the vasoconstrictor response to AngII in Af-Arts and (2) AT2 receptor seems to be coupled to EETs rather than the NO pathway.