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SHORT-TERM EFFECT OF DIETARY PHOSPHORUS RESTRICTION AND LANTHANUM CARBONATE ON FGF23 IN CHRONIC KIDNEY DISEASE PATIENTS Tamara Isakova,1 O Gutiérrez,2 K Smith,1 M Epstein,1 N Patel,2 H Jüppner and M Wolf.2 Massachusetts General Hospital, Boston, MA,1

and University of Miami Miller School of Medicine, Miami, FL, USA.2

Dietary phosphorus stimulates FGF23 secretion, but the effects of dietary phosphorus restriction and/or phosphorus binders on FGF23 levels in pre-dialysis CKD have not been studied in detail. We investigated the hypothesis that dietary phosphorus restriction alone or in combination with lanthanum carbonate would lead to decreased FGF23 levels in normophosphatemic stage 3-4 CKD patients. Sixteen subjects (mean eGFR 40 ± 12 ml/min/m2) were randomly assigned to 1 of 4 groups (N=4 per group) for 2 weeks: 1) 800 mg of daily dietary phosphorus and lanthanum carbonate 1000 mg three times a day; 2) 1500 mg of daily dietary phosphorus and lanthanum carbonate 1000 mg three times a day; 3) 800 mg of daily dietary phosphorus and placebo; or 4) 1500 mg of daily dietary phosphorus and placebo. Dietary phosphorus restriction was accomplished with the use of tightly controlled diets prepared by a metabolic kitchen. Serial measurements of 24-hr urine phosphate, serum phosphate, calcium and cFGF23 were used in the repeated-measures analyses. The post-intervention response in 24-hr urine phosphate and cFGF23 was significantly different between group 4 and groups 1-3 (p<0.05 for both). The 24-hr urine phosphate decreased significantly in all groups, except for group 4. The greatest lowering in 24-hr urine phosphate was detected in group 1 (from 659 ± 270 mg/day at baseline to 214 ± 163 mg/day at day 3, p <0.0001). While there was no significant change in serum phosphate or calcium in any group, cFGF23 levels rose early and significantly in group 4 (from 121.8 ± 60 RU/ml at baseline to 178.5 ± 61.7 RU/ml at day 3, p=0.02). Despite a significant drop in 24-hr urine phosphate, there was no change in cFGF23 levels in groups 1-3. Dietary phosphorus restriction alone or in combination with lanthanum carbonate effectively lowers 24-hour urine phosphate without accompanying changes in serum phosphate or calcium. Reductions in FGF23 levels may require interventions with longer duration.

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MONOCLONAL GAMMOPATHY OF UNCERTAIN SIGNIFICANCE (MGUS) AND FOCAL SEGMENTAL GLOMERULOSCLEROSIS (FSGS)-A CASE REPORT Nishank Jain, Mary Rose Tantoco, Beje Thomas, Jeffrey Laut, University of Connecticut, Farmington, Connecticut, USA. FSGS incidence decreases in old age where as MGUS incidence increases with old age. It is unusual to find both conditions together. A 72 year old Caucasian male with PMH for atrial fibrillation, HTN, hyperlipidemia and BPH, was electively admitted for evaluation of AKI. A week prior to hospitalization, he had presented to his PCP with chief complaints of malaise and worsening fatigue, and was found to have elevated serum Cr of 5.0 mg/dL (increased from 1.1 mg/dL 4 months ago). He was diagnosed with MGUS incidentally 2 years ago. Further work up revealed nephrotic range proteinuria with a spot urine sample showing protein: creatinine ratio of 4.8 g/mg. Renal US showed mildly increased echogenicity in both kidneys. Serum IgM level was 1.6g/dL. Otherwise immunoglobulin profile was normal. ANA, ANCA, Anti-GBM antibody, Hepatitis panel and HIV were negative. Renal biopsy showed severe collapsing-variant of FSGS. Cr continued to increase, with Cr = 6.4mg/dL on discharge. The incidence of MGUS increases with age, affecting 3% of the adults > 50 years. FSGS, collapsing variant has been predominantly linked to African American ethnicity, HIV status and exposure to uncommon chemicals. MGUS has been associated with Cryoglobulinemic glomerulonephritis, Immunoglobulin deposition disease, light chain nephropathy and amyloidosis AJKD 2003; 42(1):87-95. MGUS and collapsing-variant of FSGS are seldom seen to occur simultaneously. It may be related to the increased screening of protein electrophoresis in serum and/or urine in renal failure patients. Although, there has been one case report by Dingli et al showing an epidemiological as well as temporal relationship between MGUS and FSGS AJKD 46:278-282. The study proposed that they may be linked at the level of molecular pathogenesis. MGUS molecular basis and FSGS pathogenesis are unclear. Both conditions may be found together due to the increased number of patients screened for protein electrophoresis routinely for renal failure.

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RENAL TRANSPLANTATION AFTER SUCCESSFUL TREATMENT OF CALCIPHYLAXIS WITH SODIUM THIOSULFATE Deepika Jain, Preethi Yerram, Ramesh Khanna Calciphylaxis or Calcific Uremic Arteriolopathy (CUA) is a almost fatal condition characterized by mural calcification of small vessels resulting in severe ischemia and tissue necrosis with skin ulceration, and secondary infection. With the exception of one case report, data on renal transplantation after treatment of CUA, and the outcomes in such patients is lacking. Here in, we report a case of CUA that was successfully treated with intravenous (IV) sodium thiosulfate (STS), and went on to receive a successful cadaveric renal transplantation, (CRT) without recurrence of CUA 2 years post transplantation. 42 year old Caucasian female with CRT in 2002 (ESRD of uncertain etiology), presented with subcutaneous nodules and skin ulcerations on the abdomen, back, and buttocks with severe pain in early 2004. Skin biopsy confirmed the diagnosis of CUA. Pt was treated with IV STS for 5 months along with aggressive wound care with complete resolution of her skin lesions. In the interim, patient was noted to have worsening allograft dysfunction with no clear pathology identified. Pt was evaluated for retransplantation, and received a CRT in October 2007. After transplantation, patient did well, and has not had any recurrence of CUA since stopping the STS. Pt has had near normal creatinine until November 2008, when she had a sudden increase in her creatininewhich was proven to be secondary tonephropathy on renal biopsy, and is currently being treated for the same.. At the time of submitting this abstract, no particular etiology for this increase could be found. Patient did not respond to empiric treatment with increased doses of prednisone, ruling down the possibility of acute rejection. A renal biopsy among other things is being planned at this time. Also of note, p We feel that our case report provides valuable information in an area where data is lacking. This case is unique since the patient not only recovered from CUA after treatment with IV STS, but also went on to receive a second renal transplant, without any evidence of recurrence of CUA after stopping STS therapy. This demonstrates that IV STS successfully treats CUA, and once treated, these patients should potentially be considered for renal transplantation. The above being said, data on long term outcomes in these patients are lacking, and this needs to be studied further.

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A 57 YEAR OLD KIDNEY TRANSPLANT RECIPIENT WITH SKIN LESIONS, POLYNEUROPATHY AND DIFFICULTY WALKING Rabih Kalakeche, M.D. Michael Sheehan,M.D., Muhammad S. Yaqub, M.D. Division of Nephrology, Indiana University, Indianapolis, IN. Multiple nutritional deficiencies with skin lesions and neurologic manifestation is a rare disorder. A 57 year old African American male who underwent deceased donor kidney transplant 10 years ago, presented with diffuse skin lesions, polyneuropathy, difficulty walking, memory deficits, weight loss and diarrhea of 4 month duration. His graft function so far has remained stable while maintained on cyclosporine, mycophenolate and prednisone. His exam was significant for exfoliative dermatitis of the hands and finger tips in addition to a psoriasiform dermatitis of the trunk and bilateral lower extremities.

He was diagnosed with acute on chronic pancreatitis. Skin biopsy was consistent with nutritional deficiencies vs. necrolytic migratory erythema. Work for neuroendocrine tumors was negative. However, he was found to have multiple vitamin and mineral deficiencies: vit A <0.06mg/l(0.3-1.2), vit B1 66 nmol/l (70-180), vit B6=1.4 ng/ml (5-30), 25 hydroxy vitD <6 ng/ml (25-80), and zinc 35 mcg/dl (60-150). He was subsequently placed on vit A, B1, B6, vit D and zinc in addition to multivitamins, vit C and pancreatic enzymes. He was able to walk again, and 4 months later, there was a dramatic improvement of his skin lesions with complete resolution. Multivitamin deficiencies causing neurological deficits has been commonly described in the medical literature but it is uncommon to encounter extensive skin manifestations of vitamin deficiency combined with neurological symptoms in a transplant patient. Early recognition and prompt treatment may prevent the progression to potentially irreversible neurological and skin disorders.

NKF 2010 Spring Clinical Meetings AbstractsA66