Luca Visconti

Renal biopsy: Still a landmark for the nephrologist

Renal biopsy was performed for the first time more than one century ago, but its clinical use was routinely introduced in the 1950s. It is still an essential tool for diagnosis and choice of treatment of several primary or secondary kidney diseases. Moreover, it may help to know the expected time of end stage renal disease. The indications are represented by nephritic and/or nephrotic syndrome and rapidly progressive acute renal failure of unknown origin. Nowadays, it is performed mainly by nephrologists and radiologists using a 14-18 gauges needle with automated spring-loaded biopsy device, under real-time ultrasound guidance. Bleeding is the major primary complication that in rare cases may lead to retroperitoneal haemorrhage and need for surgical intervention and/or death. For this reason, careful evaluation of risks and benefits must be taken into account, and all procedures to minimize the risk of complications must be observed. After biopsy, an observation time of 12-24 h is necessary, whilst a prolonged observation may be needed rarely. In some cases it could be safer to use different techniques to reduce the risk of complications, such as laparoscopic or transjugular renal biopsy in patients with coagulopathy or alternative approaches in obese patients. Despite progress in medicine over the years with the introduction of more advanced molecular biology techniques, renal biopsy is still an irreplaceable tool for nephrologists.

Phosphate binders for the treatment of chronic kidney disease: role of iron oxyhydroxide

Chronic kidney disease-mineral bone disorder is frequent in patients with renal failure. It is characterized by abnormalities in mineral and bone metabolism with resulting hyperphosphatemia, low serum vitamin D, secondary hyperparathyroidism, altered bone morphology and strength, higher risk of bone fractures, and development of vascular or other soft tissue calcifications. Besides the recommendation to reduce phosphorus dietary intake, many drugs are currently available for the treatment of calcium/phosphate imbalance. Among them, phosphate binders represent a milestone. Calcium-based binders (calcium carbonate, calcium acetate) are effective in lowering serum phosphate, but their use has been associated with an increased risk of hypercalcemia and calcifications. Calcium-free binders (sevelamer hydrochloride, sevelamer carbonate, and lanthanum carbonate) are equally or slightly less effective than calcium-containing compounds. They would not induce an increase in calcium levels but may have relevant side effects, including gastrointestinal symptoms for sevelamer and risk of tissue accumulation for lanthanum. Accordingly, new phosphate binders are under investigation and some of them have already been approved. A promising option is sucroferric oxyhydroxide (Velphoro®, PA21), an iron-based phosphate binder consisting of a mixture of polynuclear iron(III)-oxyhydroxide, sucrose, and starches. The present review is focused on pharmacology, mode of action, and pharmacokinetics of sucroferric oxyhydroxide, with a discussion on comparative efficacy, safety, and tolerability studies of this drug in chronic kidney disease and patient perspectives such as quality of life, satisfaction, and acceptability. Sucroferric oxyhydroxide has proven to be as effective as sevelamer in reducing phosphatemia with a similar safety profile and lower pill burden. Experimental and clinical studies have documented a minimal percentage of iron absorption without inducing toxicity. In conclusion, the overall benefit–risk balance of sucroferric oxyhydroxide is deemed to be positive, and this new drug may therefore represent a good alternative to traditional phosphate binders for the treatment of hyperphosphatemia in dialysis patients.

Metformin-related lactic acidosis: is it a myth or an underestimated reality?

Abstract Metformin, belonging to a class of drugs called biguanides, is the recommended first-line treatment for overweight patients with type 2 diabetes mellitus. It has multiple mechanisms of action, such as reduction of gluconeogenesis, increases peripheral uptake of glucose, and decreases fatty acid oxidation. However, a potential serious complication, defined metformin-associated lactic acidosis (MALA), is related to increased plasma lactate levels, linked to an elevated plasma metformin concentrations and/or a coexistent condition altering lactate production or clearance. The mortality rate for MALA approaches 50% and metformin has been contraindicated in moderate and severe renal impairment, to minimize its potential toxic levels. Nevertheless, metformin prescription or administration, despite the presence of contraindications or precipitating factors for MALA, was a common topic highlighted in all reviewed papers. Routine assessment of metformin plasma concentration is not easily available in all laboratories, but plasma metformin concentrations measured in the emergency room could ensure the correct diagnosis, eliminating metformin as the cause of lactic acidosis if low plasma levels occurred. Renal replacement therapies have been successfully employed to achieve the correction of metabolic acidosis and rapidly remove metformin and lactate, but the optimal treatment modality for MALA is still controversial.

Monoclonal antibodies for renal diseases: current concepts and ongoing treatments

Introduction: In recent years, technological innovations in the field of molecular biology have provided new therapeutic options. In particular, human monoclonal antibodies (mAbs), initially used in the treatment of malignancies, have become a therapeutic tool for many other diseases. Most of the application of mAbs revealed encouraging findings to treat patients with immune-mediated glomerular diseases, for whom the standard protocols based on corticosteroids and non-specific immunosuppressants with heavy side effects have for decades been the only therapies. Area covered: Rituximab, an mAb directed against a specific antigen expressed on B lymphocytes, CD20 antigen, inducing a premature cell apoptosis became very important in the treatment of membranous glomerulonephritis, steroid-resistant nephrotic syndromes and membranoproliferative glomerulonephritis (MPGN). Another important mAb, eculizumab, is used successfully for treatment of atypical hemolytic uremic syndrome, C3 nephropathy and MPGN. Many other mAbs are now under premarketing investigation, such as adalimumab, daclizumab, fresolimumab, belimumab, tocilizumab, although some of these mAbs are already approved for different medical applications. Expert opinion: The availability of novel mAb may therefore constitute the basis for a revolution in the treatment of immune-mediated renal diseases. However, the cost for this therapy remains very high and represents a barrier for its widespread use.

An overview of experimental and early investigational therapies for the treatment of polycystic kidney disease

Introduction: At present, treatment of autosomal dominant polycystic kidney disease (ADPKD) is essentially supportive as there is still no specific therapy. However, recent advances with ADPKD pathophysiology have stimulated research for new therapeutic strategies. Areas covered: The aim of this systematic review is to analyze the experimental and early investigational therapies currently under evaluation in this field. Data from completed clinical trials were retrieved from the currently available scientific literature and from the ClinicalTrials.gov website. Expert opinion: Among the drugs currently being explored, mammalian target of rapamycin inhibitors reduce kidney volume enlargement but their role remains uncertain. The most promising drug is the V2 receptor antagonist tolvaptan, which reduces the increased rate of total kidney volume and slows down glomerular filtration rate decline. The main candidates for the treatment of cysts growth, both in the kidney and in the liver whenever present, are the somatostatin analogues, such as lanreotide and octreotide and more recently pasireotide. As for other therapies, some favorable results have been achieved but data are still not sufficient to establish if these approaches may be beneficial in slowing ADPKD progression in the future.

Kidney disease and psoriasis: novel evidences beyond old concepts.

Psoriasis is an immune-mediated inflammatory disease for a long time considered as a type of pathology characterized by an exclusive skin involvement. Recently it has been shown that patients affected by this disease have a higher risk of developing comorbidities such as cardiovascular diseases, arterial hypertension, diabetes mellitus, and metabolic syndrome. Even the kidneys can be affected by psoriasis through three different mechanisms: immune-mediated renal damage, drug-related renal damage and chronic renal damage. Renal function should be monitored periodically to minimize the risk of renal adverse events.

Novel avenues for treating diabetic nephropathy: new investigational drugs

ABSTRACT Introduction: At present, treatment of diabetic kidney disease (DKD) is still mainly based on drugs acting on glycemic and blood pressure control, as there is no validated therapy able to halt the progression of renal failure. Because of the high incidence of DKD, due to the increase of diabetes mellitus in general population, new therapeutic strategies are needed. Areas covered: We analysed ongoing and already completed clinical trials, from clinicaltrials.gov and PubMed, dealing with new therapies for DKD. Expert opinion: Among the drugs currently being explored, the most promising molecules are those that interfere with glucose-dependent pathways, in particular polyol, protein kinase, hexosamine and AGEs metabolic pathways, and impaired renal vascular regulation. One of the recent goals achieved by molecular biology is the development of monoclonal antibodies able to interfere with extracellular matrix accumulation and fibrosis. Other interesting therapies are under investigation and further studies with a greater number of patients will establish a better approach for diabetic nephropathy.

Kidney-lung connections in acute and chronic diseases: current perspectives

Lung and kidney functions are intimately related in both health and disease. The regulation of acid–base equilibrium, modification of partial pressure of carbon dioxide and bicarbonate concentration, and the control of blood pressure and fluid homeostasis all closely depend on renal and pulmonary activities. These interactions begin in fetal age and are often responsible for the genesis and progression of diseases. In gestational age, urine is a fundamental component of the amniotic fluid, acting on pulmonary maturation and growth. Moreover, in the first trimester of pregnancy, kidney is the main source of proline, contributing to collagen synthesis and lung parenchyma maturation. Pathologically speaking, the kidneys could become damaged by mediators of inflammation or immuno-mediated factors related to a primary lung pathology or, on the contrary, it could be the renal disease that determines a consecutive pulmonary damage. Furthermore, non immunological mechanisms are frequently involved in renal and pulmonary diseases, as observed in chronic pathologies such as sleep apnea syndrome, pulmonary hypertension, progressive renal disease and hemodialysis. Kidney damage has also been related to mechanical ventilation. The aim of this review is to describe pulmonary-renal interactions and their related pathologies, underscoring the need for a close collaboration between intensivists, pneumologists and nephrologists.

Acute kidney injury in cirrhotic patients undergoing contrast-enhanced computed tomography

AbstractContrast medium administration is one of the leading causes of acute kidney injury (AKI) in different clinical settings. The aim of the study was to investigate occurrence and predisposing factors of AKI in cirrhotic patients undergoing contrast-enhanced computed tomography (CECT).Datasets of 1279 consecutively hospitalized cirrhotic patients were retrospectively analyzed. Two hundred forty-nine of 1279 patients (mean age 64 ± 11 years, 165 male) who had undergone CECT were selected on the basis of the availability of serum creatinine (sCr) values evaluated before and after CECT (CECT group). In analogy, 203/1279 cases (mean age 66 ± 10 years, 132 male) who had not undergone CECT and had been tested twice for sCr in 7 days were also included as controls (Control group). AKI network criteria were employed to assess contrast-induced AKI (CI-AKI) development. Apart from lack of narrowed double sCr measurements, additional exclusion criteria were active bacterial infections, nephrotoxic drugs intake, and estimated glomerular filtration rate <30 mL/min.AKI developed in 22/249 (8.8%) and in 6/203 (3%) of the CECT and the Control groups, respectively (P = 0.01). The multivariate logistic regression analysis showed that AKI was significantly associated with contrast medium administration (odds ratio [OR]: 3.242, 95% confidence interval [CI]: 1.255–8.375; P = 0.015), female sex (OR: 0.339, 95% CI: 0.139–0.827; P = 0.017), and sCr values (OR: 0.124, 95% CI: 0.016–0.975; P = 0.047). In the CECT group, presence of ascites (OR: 2.796, 95% CI: 1.109–7.052; P = 0.029), female sex (OR: 0.192, 95% CI: 0.073–0.510; P = 0.001), and hyperazotemia (OR: 1.018, 95% CI: 1.001–1.037; P = 0.043) correlated with CI-AKI development at multivariate analysis.CI-AKI is a quite frequent occurrence in cirrhotic patients with female sex, presence of ascites, and hyperazotemia being the predisposing factors.

Lipid disorders in patients with renal failure: Role in cardiovascular events and progression of chronic kidney disease

The spectrum of lipid disorders in chronic kidney disease (CKD) is usually characterized by high triglycerides and reduced high dense lipoprotein (HDL), associated with normal or slightly reduced low dense lipoprotein (LDL)-cholesterol. This dyslipidemia is associated with an increased risk for atherosclerotic cardiovascular disease. Keys for the cardiovascular risk reduction in these patients are lowering the number and modifying the composition of the cholesterol-carrying atherogenic lipoprotein particles. Statins have an important role in primary prevention of cardiovascular events and mortality in non-hemodialyzed CKD patients. The benefits in terms of progression of renal failure are contradictory. Patient education regarding dietary regimen should be part of the CKD clinical management.