Amyloidosis refers to the extracellular tissue deposition of fibrils composed of lowmolecular-weight subunits of a variety of proteins. These deposits may result in a wide range of clinical manifestations depending upon their type, location, and the amount of deposition. Dialysis-related amyloidosis is a serious complication of long-term dialysis therapy and is characterized by the deposition of amyloid fibrils, principally composed of b2 microglobulins (b2M), in the osteoarticular structures and viscera. Most of the b2M is eliminated through glomerular filtration and subsequent reabsorption and catabolism by the proximal tubules. As a consequence, the serum levels of b2M are inversely related to the glomerular filtration rate; therefore, in end-stage renal disease patients, b2M levels increase up to 60-fold. Serum levels of b2M are also elevated in several pathological conditions such as chronic inflammation, liver disease, and above all, in renal dysfunction. Retention of amyloidogenic protein has been attributed to several factors including type of dialysis membrane, prolonged uremic state and/or decreased diuresis, advanced glycation end products, elevated levels of cytokines and dialysate. Dialysis treatment per se has been considered to be an inflammatory stimulus, inducing cytokine production (such as interleukin-1, tumor necrosis factor-α, interleukin-6) and complement activation. The released cytokines are thought to stimulate the synthesis and release of b2M by the macrophages and/or augment the expression of human leukocyte antigens (class I), increasing b2M expression. Residual renal function is probably the best determinant of b2M levels. Therefore, it has to be maintained as long as possible. In this article, we will focus our attention on the etiology of dialysis-related amyloidosis, its prevention, therapy, and future solutions.

The release of proinflammatory cytokines during inflammation represents an attempt to respond to injury, but it may produce detrimental effects. The inflammasome is a large, multiprotein complex that drives proinflammatory cytokine production in response to infection and tissue injury; the best-characterized inflammasome is the nod-like receptor protein-3 (NLRP3). Once activated, inflammasome leads to the active form of caspase-1, the enzyme required for the maturation of interleukin-1beta. Additional mechanisms bringing to renal inflammatory, systemic diseases and fibrotic processes were recently reported, via the activation of the inflammasome that consists of NLRP3, apoptosis associated speck-like protein and caspase-1. Several manuscripts seem to identify NLRP3 inflammasome as a possible therapeutic target in the treatment of progressive chronic kidney disease. Serum amyloid A (SAA), as acute-phase protein with also proinflammatory properties, has been shown to induce the secretion of cathepsin B and inflammasome components from human macrophages. SAA is a well recognised potent activator of the NLRP3. Here we will address our description on the involvement of the kidney in autoinflammatory diseases driven mainly by secondary, or reactive, AA amyloidosis with a particular attention on novel therapeutic approach which has to be addressed in suppressing underlying inflammatory disease and reducing the SAA concentration.

Several cardiovascular (CV) risk factors may explain the high rate of CV death among patients with chronic kidney disease (CKD). Among them both traditional and uremia-related risk factors are implicated and, moreover, the presence of kidney disease represents "per se" a multiplier of CV risk. Plasma lipid and lipoprotein profiles are changed in quantitative, but above all in qualitative, structural, and functional ways, and lipoprotein metabolism is influenced by the progressive loss of renal function. Statin therapy significantly reduces cholesterol synthesis and both CV morbidity and mortality either directly, by reducing the lipid profile, or via pleiotropic effects; it is supposed to be able to reduce both the progression of CKD and also proteinuria. These observations derive from a post-hoc analysis of large trials conducted in the general population, but not in CKD patients. However, the recently published SHARP trial, including over 9200 patients, either on dialysis or pre-dialysis, showed that simvastatin plus ezetimibe, compared with placebo, was associated with a significant low-density lipoprotein cholesterol reduction and a 17% reduction in major atherosclerotic events. However, no benefit was observed in overall survival nor in preserving renal function in patients treated. These recent data reinforce the conviction among nephrologists to consider their patients at high CV risk and that lipid lowering drugs such as statins may represent an important tool in reducing atheromatous coronary disease which, however, represents only a third of CV deaths in patients with CKD. Therefore, statins have no protective effect among the remaining two-thirds of patients who suffer from sudden cardiac death due to arrhythmia or heart failure, prevalent among CKD patients. The safety of statins is demonstrated in CKD by several trials and recently confirmed by the largest SHARP trial, in terms of no increase in cancer incidence, muscle pain, creatine kinase levels, severe rhabdomyolysis, hepatitis, gallstones and pancreatitis; thus confirming the handiness of statins in CKD patients. Here we will review the latest data available concerning the effectiveness and safety of statin therapy in CKD patients.

Muckle-Wells syndrome (MWS) is a rare hereditary autoinflammatory disorder characterized by recurrent urticaria-like skin rashes, arthralgias, conjunctivitis, hypoacusia, and risk of reactive AA amyloidosis due to the progressive accumulation of amyloid fibrils in different organs. Its genetic defect lies in mutations in the NLRP3 gene, encoding the cryopyrin protein, and resulting in interleukin (IL)-1β oversecretion. Renal involvement, in terms of proteinuria or renal insufficiency, can be observed in up to 25% of patients. Herein, we describe our experience with two Caucasian patients, father and son, aged 52 and 26 years, respectively, heterozygous for both V198M and R260W NLRP3 mutations who had AA amyloid deposits on renal biopsy. The fully human monoclonal antibody canakinumab, providing selective and prolonged IL-1β blockade, was administered in both patients every 60 days over a period of 18 months. This treatment allowed to obtain amazing results: a rapid disappearance of any clinical symptoms, the stable normalization of serum amyloid-A and, furthermore, a marked improvement of glomerular filtration rate and proteinuria with no adverse events. Our data, though limited to only two patients, emphasize that therapeutic intervention with canakinumab, suppressing both inflammation and IL-1β-mediated manifestations, can contribute to improve kidney function in MWS with overt renal amyloidosis.

Introduction Acute respiratory failure (ARF) is the main clinical sign of coronavirus disease-2019 (COVID-19), but little is known about the outcome of acute kidney injury (AKI) associated with ARF. Study design Retrospective cohort study on clinical features of adult patients hospitalized with COVID-19 between March 1st and April 30th, 2020 in the district of Piacenza (Italy). Results Among 1894 hospitalized patients, 1701 affected by COVID-19 underwent at least two serum creatinine evaluations. According to KDIGO definitions, 233 of 1,701 patients (13.7%) developed AKI: 159, 34, and 40 had stage 1, 2 and 3 AKI, respectively. Patients with AKI were older (mean age 73.5 ± 14 years, range 24–95) than those without AKI (72 ± 14 years, range 20–102). In-hospital mortality was high in COVID patients (567/1701 patients, 33%), which almost doubled among AKI patients (132/233 patients, 57%), compared with those without AKI ( p < 0.01). Risk factors for AKI included older age, male gender, diabetes and need for ventilation. Fourteen patients with stage 3 AKI underwent renal replacement therapy (RRT). Conclusions Hospitalized COVID-19 patients with AKI associated with ARF have poor chances of survival. Diagnosing and preventing the progression of renal damage is fundamental in order to delay initiating RRT, especially when resources are limited.