A novel pharmacodynamic assay to evaluate the effects of crystallization inhibitors on calcium phosphate crystallization in human plasma.

Cardiovascular calcification (CVC) is a progressive complication of chronic kidney disease and a predictor of CV events and mortality. The use of biomarkers to predict CV risk and activities of potential or current treatment drugs in these patients could have a crucial impact on therapeutic approaches. Our aim was to develop a novel assay for measurement of the rate of calcium phosphate crystallization in human plasma and provide a tool to evaluate the effects of crystallization inhibitors. The efficacy of inhibitors was determined by adding inhibitory compounds (polyphosphates, fetuin-A, sodium thiosulfate or citrate) to control samples. The assay was additionally validated for SNF472, an experimental formulation of phytate being developed for the treatment of calciphylaxis and CVC in patients with end-stage renal disease (ESRD) undergoing hemodialysis (HD). The method was repeatable and reproducible. The plasma crystallization rate was reduced up to 80% in a concentration-dependent manner following treatment with inhibitors in vitro, among which SNF472 was the most potent. This method appears beneficial in evaluating and discriminating between inhibitory activities of compounds such as polyphosphates on calcium phosphate crystallization, which present a novel therapeutic approach to treat CVC in ESRD patients.

Calciphylaxis in a dialysis patient diagnosed by muscle biopsy.

Calciphylaxis is a rare condition seen mostly in patients with chronic renal disease and secondary hyperparathyroidism who develop painful skin lesions and myopathy secondary to extensive small vessel calcification, which leads to tissue ischemia. It is typically diagnosed by a biopsy of prominent skin lesions. Here, we report a 49-year-old man with end-stage renal disease on chronic peritoneal dialysis who presented with weakness, myalgias, and necrotic skin lesions. Multiple skin biopsies were nondiagnostic because of severe extensive necrosis, and the diagnosis of systemic calciphylaxis was eventually made by a muscle biopsy. This case demonstrates the significant muscle involvement in calciphylaxis and highlights the importance of maintaining a high clinical suspicion for patients with risk factors for calciphylaxis, even when skin biopsy does not confirm it.

LDL-apheresis dramatically improves generalized calciphylaxis in a patient undergoing hemodialysis.

We present the first documented case of generalized calciphylaxis that dramatically improved after low-density lipoprotein-apheresis (LA) in a patient undergoing long-term hemodialysis. Calciphylaxis was diagnosed by skin biopsy and was manifest as painful ulcers on the right leg, left buttock, and glans penis. Skin perfusion pressure (SPP), which has recently been used as an indicator of impaired capillary perfusion in distal lesions of the lower extremities, was markedly reduced. The ulcers continued to worsen despite general wound care, correction of levels of calcium × phosphate product, hyperbaric oxygen therapy, and use of bisphosphonate, antiplatelet therapy, and vasodilators. Because LA is known to exert favorable effects on peripheral arterial disease through improved hemorheology, anti-inflammatory action, vasodilation, and angiogenesis, we introduced LA to produce the same effects on calciphylaxis. LA dramatically increased SPP and promoted ulcer healing, demonstrating that LA can be a useful treatment option for calciphylaxis.

Successful treatment of calcific uraemic arteriolopathy with bisphosphonates.

BACKGROUND AND OBJECTIVES: Calcific uraemic arteriolopathy (CUA), also known as calciphylaxis, is a rare but life-threatening condition that almost exclusively affects patients with chronic kidney disease. Several therapies have been employed to treat this disease but with irregular results. We report a prospective case series of eight patients diagnosed with CUA in our unit between 2002 and 2010. MATERIAL AND METHOD: The series consisted of eight patients with CUA (including 4 men, 5 dialysis patients and 3 with functioning allografts) who were treated with bisphosphonates. The diagnosis was by clinical suspicion and a confirmatory biopsy. Five patients had a previous history of high calcium-phosphorus product, 6 had a history of high parathyroid hormone levels (>800pg/ml), 4 had undergone parathyroidectomy, 5 had a history of high cumulative doses of steroids, and 6 patients were under dicoumarin treatment. None of the patients were obese or had diabetes mellitus. RESULTS: In all patients, progression of skin lesions stopped between 2 to 4 weeks after starting bisphosphonate therapy, with no changes in blood levels of calcium and phosphate. Improvement in pain and lesions was faster in patients receiving intravenous ibandronate. All of these patients remained on bisphosphonate treatment for at least 6 months until the wounds healed completely. No recurrences have been observed after follow-up periods between 1 and 9 years. Renal function remained stable in transplant recipients. The treatment was well tolerated and no adverse effects were observed. CONCLUSIONS: Bisphosphonates could be a new and attractive alternative to treat CUA.

Tumoral calcinosis, calciphylaxis, hyperparathyroidism and tuberculosis in a dialysis patient.

Tumoral calcinosis and calciphylaxis are uncommon but severe complications in uremic patients. They occur generally after long-term hemodialysis (HD) treatment explained by advanced secondary hyperparathyroidism and longstanding high calcium phosphorus product (Ca × P). Other factors such granulomatous diseases may worsen the calcium phosphate homeostasis alterations. We report a young male patient treated by HD for 6 years who developed tuberculosis in addition to tumoral calcinosis and calciphylaxis.

Suspected systemic calcinosis and calciphylaxis in 5 horses.

Five horses were presented with signs of myopathy along with systemic malaise, hyperfibrinogenemia, hyperphosphatemia, and an elevated calcium phosphorus product (Ca*P). Postmortem findings were consistent with systemic calcinosis, a syndrome of calcium deposition in the tissue of organs including lungs, kidneys, muscle, and heart that has not been previously described in horses.

Calcinosis cutis: a rare reaction to subcutaneous injections of calcium-containing heparin in patients with renal failure.

Calcinosis of the cutis and the subcutis is a rare complication of calcium-containing heparin cutaneous injections, mostly occurring in a context of severe renal failure. We report 2 cases. The first patient developed firm erythematous nodules on his thighs and right arm, in a context of disseminated tuberculosis and acute severe renal failure related to human immunodeficiency virus nephropathy. Cutaneous location of tuberculosis was suspected. Histological features allowed to establish the diagnosis of calcinosis of the cutis and the subcutis, showing violaceous and crackled von Kossa-positive calcium deposits in the whole reticular dermis and in thin collagenous septa of subcutaneous tissue. A retrospective inquiry confirmed that subcutaneous injections of calcium-containing heparin had been performed on the sites where lesions occurred. The second patient developed similar lesions at injection sites of calcium-containing heparin, in a context of non-Hodgkin lymphoma and end-stage renal failure. Similar histological features were observed. Calcinosis of the cutis and the subcutis after subcutaneous injections of calcium-containing heparin is rare. It always occurs in a context of elevated calcium-phosphate product, a situation mostly encountered in severe renal failure. Early cutaneous lesions do not bear specific clinical features.

Determinants of survival in patients with calciphylaxis: a multivariate analysis.

BACKGROUND: Our study aims to assess the factors affecting survival in patients with calciphylaxis. METHODS: We identified 26 patients with biopsy-proven calciphylaxis treated between 1995 and 2007. Clinical and follow-up data were obtained from medical records. Cox proportional hazards models were used to assess the factors affecting survival. RESULTS: The study group consisted of 23 women and 3 men with a mean age of 56.4 +/- 12.9 years. All patients had multiple comorbidities/risk factors including coronary artery disease (58%), diabetes mellitus (58%), and peripheral vascular disease (23%). Mean laboratory values were: calcium, 9.0 mg/dL (range, 6.8-11.6); albumin, 2.8 mg/dL; phosphate, 4.5 mg/dL (range, 2.5-7.5); Ca *phosphate, 35.9; and parathyroid hormone, 320.9 pg/mL (range, 4.6-2,419). Parathyroidectomy was performed in 9 of 26 patients (35%). Of our patients, 19% underwent revascularization procedures and 58% underwent debridement. In multivariate analyses, factors associated with poor survival were female gender ( P = .01), increased weight ( P = .01), and need for vascular procedures ( P = .06). Improved survival was associated with operative debridement ( P = .01). Parathyroidectomy alone did not emerge as a determinant of patient survival, although there was a trend to improved survival when debridement and parathyroidectomy were combined ( P = .09). CONCLUSION: Rather than a single intervention such as parathyroidectomy, a multidisciplinary approach involving early diagnosis, aggressive medical management, operative debridement, and parathyroidectomy may improve survival in calciphylaxis.

Calciphylaxis: a case report.

Calciphylaxis or calcific uremic arteriolopathy is characterized by the involvement of the tunica elastica of the reticular or deep subcutaneous dermis, with extravascular and vascular thrombosis calcifications that lead to tissular ischemia. The torso muscles, the lumbar region, and lower limbs are more frequently affected. The pathogenesis is unknown. Calciphylaxis is associated to hyperparathyroidism, chronic renal failure, and diabetes mellitus. The best therapy to date is prevention: early treatment of renal failure, performing a partial parathyroidectomy where necessary, surgical debridement of the necrotic tissue, as well as avoiding the trigger factors such as systemic corticosteroids.

Systemic calciphylaxis.

An 11-year-old male developed systemic calciphylaxis during induction therapy for acute lymphoblastic leukemia. His predisposing conditions were hypercalcemia, supplements for pamidronate-induced hypocalcemia and hypophosphatemia and renal insufficiency. He died of cardiorespiratory arrest on the 20th day of induction treatment. Autopsy revealed extensive calcium deposits in the heart, lungs and kidneys. He had diffused alveolar damage, acute tubular necrosis, chronic pancreatitis and marked hepatic steatosis. Systemic calcium deposition may progress rapidly in children with hypercalcemia of malignancy. Since pamidronate reduces mineral resorption from tissues, calcium and phosphate replacements increase systemic mineral deposits. Thus, mineral supplements should be considered only to combat symptoms.

Calciphylaxis from nonuremic causes: a systematic review.

BACKGROUND AND OBJECTIVES: Calciphylaxis, or calcific uremic arteriolopathy, is a well-described entity in end-stage kidney disease and renal transplant patients; however, little systematic information is available on calciphylaxis from nonuremic causes. This systematic review was designed to characterize etiologies, clinical features, laboratory abnormalities, and prognosis of nonuremic calciphylaxis. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: A systematic review of literature for case reports and case series of nonuremic calciphylaxis was performed. Cases included met the operational definition of nonuremic calciphylaxis-histopathologic diagnosis of calciphylaxis in the absence of end-stage kidney disease, renal transplantation, or acute kidney injury requiring renal replacement therapy. RESULTS: We found 36 cases (75% women, 63% Caucasian, aged 15 to 82 yr) of nonuremic calciphylaxis. Primary hyperparathyroidism, malignancy, alcoholic liver disease, and connective tissue disease were the most common reported causes. Preceding corticosteroid use was reported for 61% patients. Protein C and S deficiencies were seen in 11% of patients. Skin lesions were morphologically similar to calcific uremic arteriolopathy. Mortality rate was 52%, with sepsis being the leading cause of death. CONCLUSION: Calciphylaxis should be considered while evaluating skin lesions in patients with predisposing conditions even in the absence of end-stage kidney disease and renal transplantation. Nonuremic calciphylaxis is reported most often in white women. Mineral abnormalities that are invoked as potential causes in calcific uremic arteriolopathy are often absent, suggesting that heterogeneous mechanisms may contribute to its pathogenesis. Nonuremic calciphylaxis is associated with high mortality, and there is no known effective treatment.

Calciphylaxis-associated second renal graft failure and patient loss: a case report and review of the literature.

OBJECTIVES: Calciphylaxis is a small vessel disease that affects 1% to 4% of patients undergoing dialysis. Only 21 cases of postrenal transplant calciphylaxis have been reported, but none has been associated with primary graft failure or has occurred in a second graft. We present the first case of second renal graft calciphylaxis leading to primary graft failure and death. MATERIALS AND METHODS: We reviewed the 22 cases, including ours, and assessed risk factors, management, and mortality for these cases. RESULTS: The mean age was 34.2 -/+ 10.6 years, 11 patients were males (50%), and 13 (57.9%) underwent a deceased-donor renal transplant. The mean pretransplant dialysis period was 35.7 -/+ 39.3 months, 22 patients (100%) were on steroid therapy, 8 (36.4%) had a rejection, 18 (81.8%) underwent postcalciphylaxis parathyroidectomy, and 11 patients died (50%). Acute graft rejection and its management in the presence of high parathormone and divalent ion levels may be associated with postrenal transplant calciphylaxis. CONCLUSIONS: If the high parathormone levels are not adequately suppressed with medical treatment, prerenal transplant preparation should include parathyroidectomy. In addition, steroids and other immunosuppressive medications should be tapered quickly in calciphylaxis patients, especially if a patient's life is at risk.

Calcifying panniculitis following subcutaneous injections of nadroparin-calcium in a patient with osteomalacia.

Calcifying panniculitis is a rare form of calcinosis cutis belonging to the spectrum of calciphylaxis that has almost invariably been described in patients with severe renal disturbances. We report a patient with osteomalacia without chronic renal failure, who developed calcifying panniculitis following subcutaneous administration of nadroparin-calcium. Light microscopy studies of biopsy specimens revealed multiple foci of microcalcification within the adipose lobules, in the interadipocyte spaces, in connective tissue septa and in the media of small arteries in the subcutis. The patient had an elevated level of intact parathyroid hormone, whereas the calcium-phosphorus product was normal. The lesions slowly resolved upon discontinuation of nadroparin. We conclude that calcifying panniculitis is a rare complication associated with the subcutaneous administration of nadroparin-calcium that may rarely also occur in the absence of renal disturbances. Low molecular weight calcium-containing heparins should probably be used with caution in the presence of hyperparathyroidism.

Calciphylaxis in a patient with POEMS syndrome without renal failure and/or hyperparathyroidism. A case report.

POEMS (Crow-Fukase) syndrome is a rare plasma cell lymphoproliferative disorder associated with polyneuropathy (P), organomegaly (O), endocrinopathy (E), monoclonal (M) gammopathy and skin (S) abnormalities. The latter are usually not specific and include hyperpigmentation, hypertrichosis, cutaneous angioma and skin-thickening. A 45-year-old Italian woman was admitted to hospital because of muscle weakness, marked fatigue and paresthesia of the upper and lower extremities. Two and a half years earlier, a POEMS syndrome had been diagnosed on the basis of a history of organomegaly and mild lymphadenopathy, IgA-lambda monoclonal gammopathy, hypothyroidism, severe lower and upper limb sensory-motor peripheral neuropathy and a single osteosclerotic lesion in the left humerus. Eight weeks later, she developed skin lesions bioptically shown to be due to calciphylaxis-induced cutaneous vasculitis. To our knowledge, this is the first case of POEMS syndrome with this peculiar type of vasculitis. The absence of predisposing conditions, namely renal failure, hyperparathyroidism or clotting disorders renders the pathogenetic mechanism(s) of this severe type of vasculitis more intriguing.

The serum protein alpha 2-Heremans-Schmid glycoprotein/fetuin-A is a systemically acting inhibitor of ectopic calcification.

Ectopic calcification is a frequent complication of many degenerative diseases. Here we identify the serum protein alpha2-Heremans-Schmid glycoprotein (Ahsg, also known as fetuin-A) as an important inhibitor of ectopic calcification acting on the systemic level. Ahsg-deficient mice are phenotypically normal, but develop severe calcification of various organs on a mineral and vitamin D-rich diet and on a normal diet when the deficiency is combined with a DBA/2 genetic background. This phenotype is not associated with apparent changes in calcium and phosphate homeostasis, but with a decreased inhibitory activity of the Ahsg-deficient extracellular fluid on mineral formation. The same underlying principle may contribute to many calcifying disorders including calciphylaxis, a syndrome of severe systemic calcification in patients with chronic renal failure. Taken together, our data demonstrate a critical role of Ahsg as an inhibitor of unwanted mineralization and provide a novel therapeutic concept to prevent ectopic calcification accompanying various diseases.

Calciphylaxis is associated with hyperphosphatemia and increased osteopontin expression by vascular smooth muscle cells.

Calciphylaxis or calcific uremic arteriolopathy (CUA) is a fatal disease in dialysis patients due to calcification of cutaneous blood vessels. The pathogenesis has been attributed to elevated parathyroid hormone (PTH). However, recent studies evaluating vascular calcification in nondialysis patients have found that the smooth muscle cells play an active role, including production of the bone matrix protein osteopontin. To examine the involvement of various clinical parameters and smooth muscle cells of CUA, we performed a case-control analysis comparing 10 CUA patients with our current dialysis patients. Available histologic sections were immunostained for osteopontin, markers of smooth muscle cells, endothelial cells, and macrophages. Compared with our current dialysis population, patients with CUA were more likely to be obese, white, and female (P < 0.02). Comparison of laboratory values found CUA patients with lower serum albumin, greater serum phosphorus, and greater calcium X phosphorus product (P < 0.01). In contrast, there was no difference in the concentration of PTH or calcium between the 2 groups. Immunostaining of calcified blood vessels showed that all calcified vessels stained positive for osteopontin, whereas all the noncalcifed vessels showed no osteopontin localization. Staining for smooth muscle alpha-actin decreased in the medial layer with calcification, with cells appearing to be sloughed off, leading to near occlusion of the vessel lumen. Our case-control study demonstrates that hyperphosphatemia and an elevated calcium X phosphorus product is associated with CUA. Histologic examination suggests that the calcification is associated with increased expression of osteopontin by smooth muscle cells.