Currently used measures to assess kidney function and injury are largely inadequate. Markers such as serum creatinine, formulas to estimate glomerular filtration rate, cystatin C, and proteinuria largely identify an underlying disease process that is well established. Thus, there has been a recent effort to identify new biomarkers that reflect kidney function, early injury, and/or repair that ultimately can relate to progression or regression of damage. Several biomarkers emerged recently that are able to detect kidney damage earlier than is currently possible with traditional biomarkers such as serum creatinine and proteinuria. Identification of urine biomarkers has proven to be beneficial in recent years because of ease of handling, stability, and the ability to standardize the various markers to creatinine or other peptides generally already present in the urine. Recent markers such as neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), and podocin have garnered a lot of attention. The emergence of these and other biomarkers is largely because of the evolution of novel genomic and proteomic applications in investigations of acute kidney injury and chronic kidney disease. In this article, we focus on the applications of these biomarkers in disease.

Intravitreal Vascular Endothelial Growth Factor (VEGF) Receptor blockade is used for a variety of retinal pathologies. These include age related macular degeneration (AMD), diabetic macular edema (DME), and central retinal vein obstruction (CRVO). Reports of absorption of intravitreal agents into systemic circulation have increased in number, and confirmation of depletion of VEGF has been confirmed. Increasingly there are studies and case reports showing worsening hypertension, proteinuria, renal dysfunction, and glomerular disease. The pathognomonic findings of systemic VEGF blockade, thrombotic microangiopathies (TMAs) are also being increasingly reported. One variant of TMAs that has been described is collapsing focal and segmental glomerulosclerosis (cFSGS). CFSGS has been postulated to occur due to TMA induced chronic glomerular hypoxia. In this updated review, we discuss the mechanistic, pharmacological, epidemiological, and clinical evidence of intravitreal VEGF toxicity. We review cases of biopsy proven toxicity presented by our group and other investigators. We also present the third reported case of cFSGS in the setting of intravitreal VEGF blockade, a chronic TMA component was crucially found on biopsy. This patient is a 74-year-old non-diabetic male receiving aflibercept for AMD. Of the two prior cases of cFSGS in setting of VEGF blockade, one had AMD and the other had DME. This case solidifies the finding of cFSGS and its association with chronic TMA as a lesion that may be frequently encountered in patients receiving intravitreal VEGF inhibitors.

We report a case of a patient who developed dialysis-requiring acute kidney injury (AKI) after the use of canagliflozin. A 66-year-old man with type 2 diabetes who was recovering from left knee septic arthritis at a rehabilitation facility was admitted with oliguric AKI 5 days after starting treatment with canagliflozin, an inhibitor of sodium/glucose cotransporter 2 (SGLT2). The patient presented with hematuria, non-nephrotic-range proteinuria, and serum creatinine level of 6.8 (baseline, 1.1-1.3) mg/dL. There was no recent use of radiocontrast agents or exposure to other nephrotoxins. The patient subsequently required hemodialysis. Due to recent antibiotic use (ampicillin-sulbactam), acute interstitial nephritis was considered in the differential diagnosis. Kidney biopsy was performed, which showed the presence of osmotic nephropathy. The patient's kidney function returned to baseline after 2 weeks of hemodialysis. This case provides evidence of an association of osmotic nephropathy with the use of canagliflozin and discusses potential mechanisms. We recommend kidney biopsy for cases of severe AKI associated with SGLT2 inhibitors to better understand the relationship of this complication with the use of this class of medications. Complete author and article information provided before references.

Multiple myeloma complicated by acute renal failure is a diagnosis often encountered by the practicing nephrologist. The role of plasmapheresis in such patients has been of interest for decades. Three randomized controlled trials (RCTs) and multiple observational trials have evaluated the potential role of plasmapheresis in the management of this condition. This systematic review presents the results of these trials regarding survival benefits, recovery from dialysis, and improvement in renal function. A comprehensive search revealed 56 articles. Of these, only 8 articles met our inclusion criteria (3 RCTs, 1 correction of results, and 4 observational trials). Two of the 3 RCTs showed no difference in survival benefit. Two of the 3 RCTs showed a greater percentage of patients stopping dialysis in the intervention group; however, these results were not reproduced in the largest trial. All the studies showed an improvement in renal function for patients receiving plasmapheresis; however, only 2 RCTs and 1 retrospective study showed a statistically significant improvement in renal function among patients who received plasmapheresis in comparison with a control group. Our systematic review does not suggest a benefit of plasmapheresis independent of chemotherapy for multiple myeloma patients with acute renal failure in terms of overall survival, recovery from dialysis, or improvement in renal function.