Klomjit, Nattawat

Chronic kidney disease is a global health care burden, yet clinically-proven treatments are limited. Low-intensity shockwave, which utilizes ≈10% of the energy levels used in clinically indicated shockwave lithotripsy, is a promising technique to ameliorate ischemia and regenerate tissues. It has been demonstrated to improve healing in tissues such as bone, muscle, myocardium, and kidney via several mechanisms, particularly through promoting neovascularization. Low-intensity shockwave stimulates mechanoreceptors located primarily in endothelial and proximal tubular cells and subsequently upregulates vascular endothelial growth factors. This, in turn, promotes angiogenesis and ameliorates renal hypoxia, inflammation, and fibrosis, and ultimately preserves renal function. Furthermore, low-intensity shockwave can stimulate release of homing factors to attract endothelial progenitor or stem cells into injured kidneys for tissue repair. These effects may be beneficial in several kidney disease models, including renal artery stenosis, diabetic kidney disease, and various chronic kidney diseases, although most studies reported to date have been performed in animal models. Because of its low energy intensity, the procedure is relatively tolerable and safe, yet, more clinical studies are needed to establish its efficacy beyond currently existing strategies. Therefore, low-intensity shockwave therapy emerges as an alternative therapeutic approach that may offer a promising noninvasive intervention for treating renal diseases. Registration— URL: https://www.clinicaltrials.gov ; Unique identifier: NCT02515461; NCT03602807; and NCT03445247.

Significance Statement It is not known how frequently a kidney biopsy specimen reveals monoclonal gammopathy (MG) of renal significance (MGRS) in patients with MG or what factors predict this finding. In a review of medical records of 6300 patients with MG, the authors found that only 160 (2.5%) had a biopsy. Of those, 96 (60%) had lesions unrelated to MG, with arteriosclerosis and diabetic nephropathy accounting for most cases. Among 64 patients with MGRS, amyloid light chain amyloidosis and proliferative GN with monoclonal Ig deposition were the most common lesions. An elevated serum free light chain ratio, proteinuria ≥1.5 g/d, and hematuria were the strongest independent predictors of finding MGRS on biopsy specimens. These findings will assist nephrologists in determining which patients with MG and CKD would be at high risk of having MGRS. Background Little is known about the rate and predictors of finding lesions of monoclonal gammopathy (MG) of renal significance (MGRS) on kidney biopsy specimens among patients with MG. Methods We reviewed the medical records from 2013 to 2018 at the Mayo Clinic in Rochester, Minnesota, to identify patients with MG and whether they had undergone a kidney biopsy. In a more select group of patients with MG from 2017 to 2018, we conducted a review of records to determine how many had underlying CKD, which of those with CKD had undergone a kidney biopsy, and reasons for deferring a kidney biopsy. Results Between 2013 and 2018, we identified 6300 patients who had MG, 160 (2.5%) of whom had undergone a kidney biopsy. Of the 160 patients, 64 (40%) had an MGRS lesion; amyloid light chain amyloidosis, the most common finding, accounted for nearly half of these lesions. In the non-MGRS group comprising 96 patients, 23 had arteriosclerosis, the most common finding. In multivariate analysis, strong predictors of finding an MGRS lesion included the presence of an elevated free light chain ratio, proteinuria, and hematuria. Among 596 patients with CKD and MG from 2017 to 2018, 62 (10.4%) underwent a kidney biopsy. Kidney biopsy was deferred for 70 patients (20%); for 62 of the 70, the diagnosis was already known, and eight were not candidates for therapy. Younger age and higher proteinuria and serum creatinine levels increased the likelihood that the patient would undergo a kidney biopsy. Conclusions Proteinuria ≥1.5 g/d, hematuria, and an elevated free light chain ratio increase the likelihood of finding MGRS, and a kidney biopsy should be highly considered in such patients.

Fibrillary GN (FGN) is a rare glomerular disease that is diagnosed based on the presence of fibrils in glomeruli. The fibrils are typically noncongophilic, randomly oriented, and measure 12–24 nm. Traditionally, electron microscopy (EM) has been an important tool to aid in the diagnosis of FGN by identifying the fibrils and to distinguish it from other entities that could mimic FGN. However, recently DnaJ homolog subfamily B member 9 (DNAJB9) has emerged as both a specific and sensitive biomarker in patients with FGN. It allows prompt diagnosis and alleviates reliance on EM. DNAJB9 is a cochaperone of heat shock protein 70 and is involved in endoplasmic reticulum protein-folding pathways. But its role in the pathogenesis of FGN remains elusive. DNAJB9 may act as a putative antigen or alternatively it may secondarily bind to misfolded IgG in the glomeruli. These hypotheses need future studies to elucidate the role of DNAJB9 in the pathogenesis of FGN. The treatment regimen for FGN has been limited due to paucity of studies. Most patients receive combination immunosuppressive regimens. Rituximab has been studied the most in FGN and it may delay disease progression. Prognosis of FGN remains poor and 50% require dialysis within 2 years of diagnosis. Despite its poor prognosis in native kidneys, the rate of recurrence post-transplantation is low (20%) and patient as well as allograft outcomes are similar to patients without FGN.

Although peritoneal dialysis (PD)-associated peritonitis secondary to mycobacterium is rare, the treatment is challenging and outcomes remain poor. We report the first case of PD-associated peritonitis secondary to Mycobacterium septicum. The patient is a 53-year-old Caucasian man who developed end-stage kidney disease due to systemic sclerosis. He was initially started on intermittent hemodialysis and was then switched to PD 10 months later. He presented with generalized abdominal pain and an increase in the number of nucleated cells and neutrophils in the dialysate effluent sample (854 total nucleated cells/µL and 512 neutrophils/µL). Ten days later, the fluid grew M. septicum, a rapidly growing nontuberculous mycobacterium (NTM). Once the organism was identified, he was treated with moxifloxacin and doxycycline, and the PD catheter was removed. Antibiotics were adjusted due to sensitivities profile and side effects, and he completed 4 months of antibiotic treatment with decreasing cell counts and negative PD fluid cultures. This case highlights the growing list of organisms responsible for NTM peritonitis and complexity of care in the patient with NTM peritonitis.

Abstract BACKGROUND New onset resistant hypertension in a previously stable patient with chronic hypertension should lead to consideration of secondary causes. Electrolyte abnormalities are useful clues for identifying some common causes, especially mineralocorticoid excess. CASE PRESENTATION We report the case of a 69-year-old man who developed severe resistant hypertension despite the use of 6 antihypertensive medications, including diuretics. He had metabolic alkalosis and hypokalemia with suppressed plasma renin activity and serum aldosterone. Concurrently, he was diagnosed with small cell neuroendocrine carcinoma of the prostate gland, a rare form of prostate cancer. Despite absence of typical Cushingoid features, investigation confirmed the diagnosis of ectopic adrenocorticotropic hormone (ACTH) syndrome from neuroendocrine prostate cancer. Because of the severity of his hypercortisolism, he underwent urgent bilateral adrenalectomy for hormonal and symptomatic control. Blood pressure improved significantly and he was dismissed with a single antihypertensive agent. Unfortunately, the patient died from his cancer 1 month later. CONCLUSION Primary and secondary hyperaldosteronism are usually diagnosed based on measurements of aldosterone and plasma renin activity. However, if plasma renin activity and aldosterone are both low, rare causes of mineralocorticoid excess such as ectopic ACTH syndrome should be entertained.