Myeloma – new approaches to combined nephrological–haematological management

The role of cystatin C as a proteasome inhibitor in multiple myeloma

Objectives: Bone destruction and renal impairment are two frequent complications of multiple myeloma (MM). Cystatin C, an extracellular cysteine proteinase inhibitor, is encoded by the housekeeping gene CST3 and associated with human tumors. The role of cystatin C in multiple myeloma has been revealed recently. The purpose of this study was to explore the role of cystatin C as a proteasome inhibitor in multiple myeloma. Methods : A comprehensive literature review was conducted through Pubmed to summarize the published evidence on cystatin C in multiple myeloma. English literature sources since 1999 were searched, using the terms cystatin C, multiple myeloma. Results: cystatin C is a sensitive indicator for the diagnosis of myeloma nephropathy and has a dual role in myeloma bone disease. Also, cystatin C reflects tumor burden and is strongly associated with prognosis in patients with multiple myeloma. Conclusion: Cystatin C have great diagnostic and prognostic value in multiple myeloma. It can provide a new treatment direction for MM by designing and searching for antagonists of cystatin C or cysteine protease agonists using cystatin C as a therapeutic target.

Multiple Myeloma-Associated Light Chain Amyloidosis and a Proposed Approach to Monoclonal Immunoglobulin-Associated Renal Disease

Many challenges remain in diagnosing monoclonal immunoglobulin-associated renal disease, despite widespread application of immunofluorescence (IF) and immunohistochemistry. Here, we report a newly diagnosed case of multiple myeloma with clinical suspicion of renal amyloidosis, which had negative IF staining for kappa and lambda light chains in the glomeruli. Although laser microdissection and mass spectrometry-based proteomic analysis have emerged as important tools for amyloid typing in the literature, such facilities are still not widely available in Asia. We propose that a clinicopathological algorithm for the evaluation of organized monoclonal renal deposits, together with a combined nephrological-haematological approach, will still be adequate to generate an unequivocal diagnosis in the majority of cases.

The pathogenesis and diagnosis of acute kidney injury in multiple myeloma

Renal failure remains a principal cause of morbidity for patients with multiple myeloma. Once reversible factors such as hypercalcemia have been corrected, the most common cause of severe renal failure in these patients is a tubulointerstitial pathology that results from the very high circulating concentrations of monoclonal immunoglobulin free light chains. These endogenous proteins can result in isolated proximal tubule cell cytotoxicity, tubulointerstitial nephritis and cast nephropathy (myeloma kidney). Less frequently, high levels of free light chains can lead to immunoglobulin light chain amyloidosis and light chain deposition disease, although these conditions are usually associated with insidious progression of renal failure rather than acute kidney injury. Unless there is rapid intervention, progressive and irreversible damage occurs, particularly interstitial fibrosis and tubular atrophy. Despite advances in our understanding of the pathogenesis of these processes there has been a gap in translating these achievements into improved patient outcomes. The International Kidney and Monoclonal Gammopathy Research Group was formed to address this need. In this Review, we discuss the mechanisms of disease and diagnostic approaches to patients with acute kidney injury complicating multiple myeloma.

Intravenous infusion of pituitary adenylate cyclase-activating polypeptide (PACAP) in a patient with multiple myeloma and myeloma kidney: a case study

We have recently shown significant renoprotective effects with the administration of pituitary adenylate cyclase-activating polypeptide (PACAP) in models of myeloma kidney. PACAP markedly inhibited the production of proinflammatory cytokines stimulated by immunoglobulin light chains in human renal proximal tubule epithelial cells and in the kidneys of rats infused with myeloma light chains. PACAP was also shown to suppress the proliferation of human kappa and lambda light chain-secreting multiple myeloma-derived cells. In this case study, an 81-year-old male patient with active multiple myeloma and myeloma kidney was infused intravenously with synthetic human PACAP38 at a rate of 4 pmol/kg/min for 120 min. The continuous infusion increased the level of PACAP38 in blood, with a plateau at about 0.2 nM during the infusion. The level of PACAP in the blood rapidly declined after the cessation of administration with a half-life of about 5-10 min. The continuous infusion did not significantly alter the basal glucose level, blood gases or blood pressure. There was a large reduction in free lambda light chains in urine after the start of the treatment with PACAP. These studies show that PACAP can be safely used in humans and suggest that it could be used as a novel therapeutic agent for the treatment of multiple myeloma and myeloma kidney.

Multiple myeloma-associated AL amyloidosis: is a distinctive therapeutic approach warranted?

The natural history of multiple myeloma (MM) was revolutionized by the introduction of haematopoietic stem cell transplantation to the treatment armamentarium of this disease. Defined subgroups of MM patients (such as the elderly or dialysis-dependent) have required an individualized approach in order to minimize the transplant-related mortality. Little, however, is known about the management of 12-30% of MM patients with coexistent AL amyloidosis as the amyloidopathy is often overlooked and when recognized these patients commonly are excluded from clinical trials. While occult amyloidosis appears to have no impact on the toxicity and outcome of MM patients, the presence of symptomatic amyloidopathy clearly worsens their prognosis. Use of induction chemotherapy drugs that can cause further damage to the heart (Adriamycin), nervous system (Vincristine) or kidneys should be avoided as should lengthy delays in proceeding to autograft. Further, refining the transplant eligibility criteria for this subgroup of patients with co-existent amyloidopathy to include the number of organs involved and the degree of cardiac involvement (NYHA class, Troponins and NT-pro-BNP levels) along with melphalan dose-adjustment will minimize the treatment-related toxicity and mortality and possibly allow a reversal of the organ damage induced by the amyloidogenic light chain.

Extramedular plasmacytoma in the urinary bladder: Unusual localization

Background. Multiple myeloma is a plasmaproliferative disease characterized by the uncontrolled proliferation of a pathogenic plasma cell clone engaged in the production of monoclonal immunoglobulin. This condition affects the bone marrow, but it can be manifested in any other organ or tissue. The urinary bladder involvement is extremely rare. Case report. We reported a 70-year-old male with the history of multiple myeloma, receiving chemotherapy containing melphalan and prednisone (MP). Two years after the treatment, there was a renal failure associated with oligoanuria, hematuria and bilateral hydronephrosis. The urine cytology tests revealed the atypical cells, so was suspected obstructive uropathy to be caused by urothelium cancer. However, only upon the cystoscopy and biopsy performed on the urinary bladder mass, plasmacytoid infiltration diagnosis was confirmed. This extremely rare variant was presented throughout the illness period and proved to be resistant to the administered chemotherapy. Conclusion. When renal failure associated with hematuria and bilateral hydronephrosis is presented in a patient with multiple myeloma, this unusual and rare extramedular localization should be also considered.