Complement involvement in kidney diseases: From physiopathology to therapeutical targeting

Complement cascade is involved in several renal diseases and in renal transplantation. The different components of the complement cascade might represent an optimal target for innovative therapies. In the first section of the paper the authors review the physiopathology of complement involvement in renal diseases and transplantation. In some cases this led to a reclassification of renal diseases moving from a histopathological to a physiopathological classification. The principal issues afforded are: renal diseases with complement over activation, renal diseases with complement dysregulation, progression of renal diseases and renal transplantation. In the second section the authors discuss the several complement components that could represent a therapeutic target. Even if only the anti C5 monoclonal antibody is on the market, many targets as C1, C3, C5a and C5aR are the object of national or international trials. In addition, many molecules proved to be effective in vitro or in preclinical trials and are waiting to move to human trials in the future.

Is there a role for systemic targeted therapy after surgical treatment for metastases of renal cell carcinoma?

Metastatic renal cell carcinoma (mRCC) is a challenging disease. Despite the new targeted therapies, complete remissions occur only in 1%-3% of the cases, and the most effective first-line treatment drugs have reached a ceiling in overall survival (ranging from 9 to 49 mo). Metastasectomy remains to be the only curative option in most patients with mRCC. Prognostic nomograms have been recently published, so we have tools to classify patients in risk groups, allowing us to detect the cases with the higher risk of recurrence after metastasectomy. Although sparse, there is some evidence of effectiveness of neoadjuvant targeted therapy before metastasectomy; but with an increase in surgical complications due to the effects of these new drugs in tissue healing. We have aimed to answer the question: Is there a role for systemic targeted therapy after surgical treatment for metastases of renal cell carcinoma? We have made a search in Pubmed database. As far as we know, evidence is low and it’s based in case reports and small series of patients treated with adjuvant drugs after neoadjuvant therapy plus metastasectomy in cases of partial response to initial systemic treatment. Despite the limitations and high risk of bias, promising results and cases with long-term survival with this approach have been described. Two ongoing clinical trials may answer the question that concerns us.

Oxidative stress as a potential causal factor for autoimmune hemolytic anemia and systemic lupus erythematosus

The kidneys and the blood system mutually exert influence in maintaining homeostasis in the body. Because the kidneys control erythropoiesis by producing erythropoietin and by supporting hematopoiesis, anemia is associated with kidney diseases. Anemia is the most prevalent genetic disorder, and it is caused by a deficiency of glucose 6-phosphate dehydrogenase (G6PD), for which sulfhydryl oxidation due to an insufficient supply of NADPH is a likely direct cause. Elevated reactive oxygen species (ROS) result in the sulfhydryl oxidation and hence are another potential cause for anemia. ROS are elevated in red blood cells (RBCs) under superoxide dismutase (SOD1) deficiency in C57BL/6 mice. SOD1 deficient mice exhibit characteristics similar to autoimmune hemolytic anemia (AIHA) and systemic lupus erythematosus (SLE) at the gerontic stage. An examination of AIHA-prone New Zealand Black (NZB) mice, which have normal SOD1 and G6PD genes, indicated that ROS levels in RBCs are originally high and further elevated during aging. Transgenic overexpression of human SOD1 in erythroid cells effectively suppresses ROS elevation and ameliorates AIHA symptoms such as elevated anti-RBC antibodies and premature death in NZB mice. These results support the hypothesis that names oxidative stress as a risk factor for AIHA and other autoimmune diseases such as SLE. Herein we discuss the association between oxidative stress and SLE pathogenesis based mainly on the genetic and phenotypic characteristics of NZB and New Zealand white mice and provide insight into the mechanism of SLE pathogenesis.

Primary and secondary hyperoxaluria: Understanding the enigma

Hyperoxaluria is characterized by an increased urinary excretion of oxalate. Primary and secondary hyperoxaluria are two distinct clinical expressions of hyperoxaluria. Primary hyperoxaluria is an inherited error of metabolism due to defective enzyme activity. In contrast, secondary hyperoxaluria is caused by increased dietary ingestion of oxalate, precursors of oxalate or alteration in intestinal microflora. The disease spectrum extends from recurrent kidney stones, nephrocalcinosis and urinary tract infections to chronic kidney disease and end stage renal disease. When calcium oxalate burden exceeds the renal excretory ability, calcium oxalate starts to deposit in various organ systems in a process called systemic oxalosis. Increased urinary oxalate levels help to make the diagnosis while plasma oxalate levels are likely to be more accurate when patients develop chronic kidney disease. Definitive diagnosis of primary hyperoxaluria is achieved by genetic studies and if genetic studies prove inconclusive, liver biopsy is undertaken to establish diagnosis. Diagnostic clues pointing towards secondary hyperoxaluria are a supportive dietary history and tests to detect increased intestinal absorption of oxalate. Conservative treatment for both types of hyperoxaluria includes vigorous hydration and crystallization inhibitors to decrease calcium oxalate precipitation. Pyridoxine is also found to be helpful in approximately 30% patients with primary hyperoxaluria type 1. Liver-kidney and isolated kidney transplantation are the treatment of choice in primary hyperoxaluria type 1 and type 2 respectively. Data is scarce on role of transplantation in primary hyperoxaluria type 3 where there are no reports of end stage renal disease so far. There are ongoing investigations into newer modalities of diagnosis and treatment of hyperoxaluria. Clinical differentiation between primary and secondary hyperoxaluria and further between the types of primary hyperoxaluria is very important because of implications in treatment and diagnosis. Hyperoxaluria continues to be a challenging disease and a high index of clinical suspicion is often the first step on the path to accurate diagnosis and management.

Renal dopaminergic system: Pathophysiological implications and clinical perspectives

Fluid homeostasis, blood pressure and redox balance in the kidney are regulated by an intricate interaction between local and systemic anti-natriuretic and natriuretic systems. Intrarenal dopamine plays a central role on this interactive network. By activating specific receptors, dopamine promotes sodium excretion and stimulates anti-oxidant and anti-inflammatory pathways. Different pathological scenarios where renal sodium excretion is dysregulated, as in nephrotic syndrome, hypertension and renal inflammation, can be associated with impaired action of renal dopamine including alteration in biosynthesis, dopamine receptor expression and signal transduction. Given its properties on the regulation of renal blood flow and sodium excretion, exogenous dopamine has been postulated as a potential therapeutic strategy to prevent renal failure in critically ill patients. The aim of this review is to update and discuss on the most recent findings about renal dopaminergic system and its role in several diseases involving the kidneys and the potential use of dopamine as a nephroprotective agent.

Histopathology of renal asphyxia in newborn piglets: Individual susceptibility to tubular changes

AIM: To analyze the effects on the kidney of hypoxia-reoxygenation in an experimental model of normocapnic asphyxia.

METHODS: To this end, 40 newborn Landrace/Large-White piglets aged 1-4 d were studied in this work. Hypoxia was induced by decreasing the inspired fiO2 to 0.06-0.08. Animals were resuscitated with different fiO₂ and subdivided into 4 groups: group 1, 2, 3 and 4 received 18%, 21%, 40% and 100% O₂ respectively. Macroscopic examination was carried out to evidence possible pathological features. Tissue sample were obtained from both kidneys. Four or five micron paraffin sections were stained with H-E and PAS stain and examined under an optical microscope.

RESULTS: Pathological changes, mainly affecting tubular cells, were observed in the vast majority of kidneys of asphyxiated piglets. The most frequent tubular changes were: tubular casts (95%), tubular dilatation (87.5%), tubular vacuolization (70%), tubular eosinophilia (52.5%), sloughing (50%), fragmentation of the brush border (50%), oedema (32.5%), apoptosis (15%) and glomerular changes (meningeal cell proliferation, capsular adhesion between the flocculus and Bowman’s capsule, glomerulosclerosis and fibrous or cellular crescents associated with collapse of the glomerular tuft). Statistical analysis was carried out on changes observed when the animals were allocated in the 4 groups (χ²-test 0.05). The statistical analysis showed no evidence of differences regarding kidney lesions among the animals groups.

CONCLUSION: Our data show that renal pathology in newborn piglets is characterized by interindividual variability to hypoxia and is not associated with oxygen concentration.

Primary glomerular diseases in the elderly

Primary glomerular diseases in the elderly population are a frustrating topic due to difficulties in both the diagnosis and decision making about treatment. The most frequent type of primary glomerular disease in elderly is membranous nephropathy; while its counterpart in younger population is IgA nephropathy. The most frequent cause of nephrotic syndrome in the elderly is also membranous nephropathy. Pauci-immune crescentic glomerulonephritis (GN) rate increases both in elderly and very elderly population. Pauci-immune crescentic GNs should be regarded as urgencies in elderly patients as in their younger counterparts due to potential for causing end-stage renal disease in case of delayed diagnosis and treatment, and also causing mortality due to alveolar hemorrhage in patients with pulmonary involvement. Renal biopsy is the inevitable diagnostic method in the elderly as in all other age groups. Renal biopsy prevents unnecessary treatments and provides prognostic data. So advanced age should not be the sole contraindication for renal biopsy. The course of primary glomerular diseases may differ in the elderly population. Acute kidney injury is more frequent in the course and renal functions may be worse at presentation. These patients are more prone to be hypertensive. The decision about adding immune suppressive therapies to conservative methods should be made considering many factors like co-morbidities, drug side effects and potential drug interactions, risk of infection, patient preference, life expectancy and renal functions at the time of diagnosis.

Impact of obesity on kidney function and blood pressure in children

In recent years, obesity has become an increasingly important epidemic health problem in children and adolescents. The prevalence of the overweight status in children grew from 5% to 11% from 1960s to 1990s. The epidemic of obesity has been paralleled by an increase in the incidence of chronic kidney disease (CKD) and hypertension. Results of several studies have demonstrated that obesity and metabolic syndrome were independent predictors of renal injury. The pathophysiology of obesity related hypertension is complex, including activation of sympathetic nervous system, renin angiotensin aldosterone system, hyperinsulinemia and inflammation. These same mechanisms likely contribute to the development of increased blood pressure in children. This review summarizes the recent epidemiologic data linking obesity with CKD and hypertension in children, as well as the potential mechanisms.

Evidence-based medicine: An update on treatments for peritoneal dialysis-related peritonitis

Peritonitis continues to be a major complication of peritoneal dialysis (PD), and adequate treatment is crucial for a favorable outcome. There is no consensus regarding the optimal therapeutic regimen, and few prospective controlled studies have been published. The objective of this manuscript is to review the results of PD peritonitis treatment reported in narrative reviews, systematic reviews, and proportional meta-analyses. Two narrative reviews, the only existing systematic review and its update published between 1991 and 2014 were included. In addition, we reported the results of a proportional meta-analysis published by our group. Results from systematic reviews of randomized control trials (RCT) and quasi-RCT were not able to identify any optimal antimicrobial treatment, but glycopeptide regimens were more likely to achieve a complete cure than a first generation cephalosporin. Compared to urokinase, simultaneous catheter removal and replacement resulted in better outcomes. Continuous and intermittent IP antibiotic use had similar outcomes. Intraperitoneal antibiotics were superior to intravenous antibiotics in reducing treatment failure. In the proportional meta-analysis of RCTs and the case series, the resolution rate (86%) of ceftazidime plus glycopeptide as initial treatment was significantly higher than first generation cephalosporin plus aminoglycosides (66%) and glycopeptides plus aminoglycosides (75%). Other comparisons of regimens used for either initial treatment or treatment of gram-positive rods or gram-negative rods did not show statistically significant differences. The superiority of a combination of a glycopeptide and a third generation cephalosporin was also reported by a narrative review study published in 1991, which reported an 88% resolution rate.

African origins and chronic kidney disease susceptibility in the human immunodeficiency virus era

Chronic kidney disease (CKD) is a major public health problem worldwide with the estimated incidence growing by approximately 6% annually. There are striking ethnic differences in the prevalence of CKD such that, in the United States, African Americans have the highest prevalence of CKD, four times the incidence of end stage renal disease when compared to Americans of European ancestry suggestive of genetic predisposition. Diabetes mellitus, hypertension and human immunodeficiency virus (HIV) infection are the major causes of CKD. HIV-associated nephropathy (HIVAN) is an irreversible form of CKD with considerable morbidity and mortality and is present predominantly in people of African ancestry. The APOL1 G1 and G2 alleles were more strongly associated with the risk for CKD than the previously examined MYH9 E1 risk haplotype in individuals of African ancestry. A strong association was reported in HIVAN, suggesting that 50% of African Americans with two APOL1 risk alleles, if untreated, would develop HIVAN. However these two variants are not enough to cause disease. The prevailing belief is that modifying factors or second hits (including genetic hits) underlie the pathogenesis of kidney disease. This work reviews the history of genetic susceptibility of CKD and outlines current theories regarding the role for APOL1 in CKD in the HIV era.

Treatment of hypogonadotropic male hypogonadism: Case-based scenarios

The aim of this study is to review four case-based scenarios regarding the treatment of symptomatic hypogonadism in men. The article is designed as a review of published literature. We conducted a PubMed literature search for the time period of 1989-2014, concentrating on 26 studies investigating the efficacy of various therapeutic options on semen analysis, pregnancy outcomes, time to recovery of spermatogenesis, as well as serum and intratesticular testosterone levels. Our results demonstrated that exogenous testosterone suppresses intratesticular testosterone production, which is an absolute prerequisite for normal spermatogenesis. Cessation of exogenous testosterone should be recommended for men desiring to maintain their fertility. Therapies that protect the testis involve human chorionic gonadotropin (hCG) therapy or selective estrogen receptor modulators (SERMs), but may also include low dose hCG with exogenous testosterone. Off-label use of SERMs, such as clomiphene citrate, are effective for maintaining testosterone production long-term and offer the convenience of representing a safe, oral therapy. At present, routine use of aromatase inhibitors is not recommended based on a lack of long-term data. We concluded that exogenous testosterone supplementation decreases sperm production. It was determined that clomiphene citrate is a safe and effective therapy for men who desire to maintain fertility. Although less frequently used in the general population, hCG therapy with or without testosterone supplementation represents an alternative treatment.

Effect of urinary stone disease and its treatment on renal function

Urolithiasis is a common disease that affects urinary tract in all age groups. Both in adults and in children, stone size, location, renal anatomy, and other factors, can influence the success of treatment modalities. Recently, there has been a great advancement in technology for minimally invasive management of urinary stones. The epoch of open treatment modalities has passed and currently there are much less invasive treatment approaches, such as percutaneous nephrolithotomy, ureteroscopy, shockwave lithotripsy, and retrograde internal Surgery. Furthermore, advancement in imaging technics ensures substantial knowledge that permit physician to decide the most convenient treatment method for the patient. Thus, effective and rapid treatment of urinary tract stones is substantial for the preservation of the renal function. In this review, the effects of the treatment options for urinary stones on renal function have been reviewed.

Prolonged hypernatremia triggered by hyperglycemic hyperosmolar state with coma: A case report

A man with past lithium use for more than 15 years, but off lithium for two years and not carrying the diagnosis of diabetes mellitus or nephrogenic diabetes insipidus (NDI), presented with coma and hyperglycemic hyperosmolar state (HHS). Following correction of HHS, he developed persistent hypernatremia accompanied by large volumes of urine with low osmolality and no response to desmopressin injections. Urine osmolality remained < 300 mOsm/kg after injection of vasopressin. Improvement in serum sodium concentration followed the intake of large volumes of water plus administration of amiloride and hydrochlorothiazide. Severe hyperglycemia may trigger symptomatic lithium-induced NDI years after cessation of lithium therapy. Patients with new-onset diabetes mellitus who had been on prolonged lithium therapy in the past require monitoring of their serum sodium concentration after hyperglycemic episodes regardless of whether they do or do not carry the diagnosis of NDI.

Novel biomarkers of acute kidney injury: Evaluation and evidence in urologic surgery

Patients undergoing urologic surgery are at risk of acute kidney injury (AKI) and consequently long-term deterioration in renal function. AKI is further associated with significantly higher odds of perioperative complications, prolonged hospital stay, higher mortality and costs. Therefore, better awareness and detection of AKI, as well as identification of AKI determinants in the urological surgery setting is warranted to pre-empt and mitigate further deterioration of renal function in patients at special risk. New consensus criteria provide precise definitions of diagnosis and description of the severity of AKI. However, they rely on serum creatinine (SCr), which is known to be an inaccurate marker of early changes in renal function. Therefore, several new urinary and serum biomarkers promise to address the gap associated with the use of SCr. Novel biomarkers may complement SCr measurement or most likely improve the diagnostic accuracy of AKI when used in combinations. However, novel biomarkers have to prove their clinical applicability, accuracy, and cost effectiveness prior to implementation into clinical practice. Most preferably, novel biomarkers should help to positively improve a patient’s long-term renal functional outcomes. The purpose of this review is to discuss currently available biomarkers and to review their clinical evidence within urologic surgery settings.

Management of hepatorenal syndrome

Hepatorenal syndrome (HRS) is defined as development of renal dysfunction in patients with chronic liver diseases due to decreased effective arterial blood volume. It is the most severe complication of cirrhosis because of its very poor prognosis. In spite of several hypotheses and research, the pathogenesis of HRS is still poorly understood. The onset of HRS is a progressive process rather than a suddenly arising phenomenon. Since there are no specific tests for HRS diagnosis, it is diagnosed by the exclusion of other causes of acute kidney injury in cirrhotic patients. There are two types of HRS with different characteristics and prognostics. Type 1 HRS is characterized by a sudden onset acute renal failure and a rapid deterioration of other organ functions. It may develop spontaneously or be due to some precipitating factors. Type 2 HRS is characterized by slow and progressive worsening of renal functions due to cirrhosis and portal hypertension and it is accompanied by refractory ascites. The only definitive treatment for both Type 1 and Type 2 HRS is liver transplantation. The most suitable bridge treatment or treatment for patients who are not eligible for transplantation is a combination of terlipressin and albumin. For the same purpose, it is possible to try hemodialysis or renal replacement therapies in the form of continuous veno-venous hemofiltration. Artificial hepatic support systems are important for patients who do not respond to medical treatment. Transjugular intrahepatic portosystemic shunt may be considered as a treatment modality for unresponsive patients to medical treatment. The main goal of clinical surveillance in a cirrhotic patient is prevention of HRS before it develops. The aim of this article is to provide an updated review about the physiopathology of HRS and its treatment.

Pathogenesis of glomerular haematuria

Haematuria was known as a benign hallmark of some glomerular diseases, but over the last decade, new evidences pointed its negative implications on kidney disease progression. Cytotoxic effects of oxidative stress induced by hemoglobin, heme, or iron released from red blood cells may account for the tubular injury observed in human biopsy specimens. However, the precise mechanisms responsible for haematuria remain unclear. The presence of red blood cells (RBCs) with irregular contours and shape in the urine indicates RBCs egression from the glomerular capillary into the urinary space. Therefore glomerular haematuria may be a marker of glomerular filtration barrier dysfunction or damage. In this review we describe some key issues regarding epidemiology and pathogenesis of haematuric diseases as well as their renal morphological findings.

Species differences in regulation of renal proximal tubule transport by certain molecules

Renal proximal tubules (PTs) play important roles in the regulation of acid/base, plasma volume and blood pressure. Recent studies suggest that there are substantial species differences in the regulation of PT transport. For example, thiazolidinediones (TZDs) are widely used for the treatment of type 2 diabetes mellitus, but the use of TZDs is associated with fluid overload. In addition to the transcriptional enhancement of sodium transport in distal nephrons, TZDs rapidly stimulate PT sodium transport via a non-genomic mechanism depending on peroxisome proliferator activated receptor γ/Src/epidermal growth factor receptor (EGFR)/MEK/ERK. In mouse PTs, however, TZDs fail to stimulate PT transport probably due to constitutive activation of Src/EGFR/ERK pathway. This unique activation of Src/ERK may also affect the effect of high concentrations of insulin on mouse PT transport. On the other hand, the effect of angiotensin II (Ang II) on PT transport is known to be biphasic in rabbits, rats, and mice. However, Ang II induces a concentration-dependent, monophasic transport stimulation in human PTs. The contrasting responses to nitric oxide/guanosine 3’,5’-cyclic monophosphate pathway may largely explain these different effects of Ang II on PT transport. In this review, we focus on the recent findings on the species differences in the regulation of PT transport, which may help understand the species-specific mechanisms underlying edema formation and/or hypertension occurrence.

Strategies to optimize shock wave lithotripsy outcome: Patient selection and treatment parameters

Shock wave lithotripsy (SWL) was introduced in 1980, modernizing the treatment of upper urinary tract stones, and quickly became the most commonly utilized technique to treat kidney stones. Over the past 5-10 years, however, use of SWL has been declining because it is not as reliably effective as more modern technology. SWL success rates vary considerably and there is abundant literature predicting outcome based on patient- and stone-specific parameters. Herein we discuss the ways to optimize SWL outcomes by reviewing proper patient selection utilizing stone characteristics and patient features. Stone size, number, location, density, composition, and patient body habitus and renal anatomy are all discussed. We also review the technical parameters during SWL that can be controlled to improve results further, including type of anesthesia, coupling, shock wave rate, focal zones, pressures, and active monitoring. Following these basic principles and selection criteria will help maximize success rate.

Combined functional and anatomical diagnostic endpoints for assessing arteriovenous fistula dysfunction

Failure of arteriovenous fistulas (AVF) to mature and thrombosis in matured fistulas have been the major causes of morbidity and mortality in hemodialysis patients. Stenosis, which occurs due to adverse remodeling in AVFs, is one of the major underlying factors under both scenarios. Early diagnosis of a stenosis in an AVF can provide an opportunity to intervene in a timely manner for either assisting the maturation process or avoiding the thrombosis. The goal of surveillance strategies was to supplement the clinical evaluation (i.e., physical examination) of the AVF for better and earlier diagnosis of a developing stenosis. Surveillance strategies were mainly based on measurement of functional hemodynamic endpoints, including blood flow (Q_a) to the vascular access and venous access pressure (VAP). As the changes in arterial pressure (MAP) affects the level of VAP, the ratio of VAP to MAP (VAPR = VAP/MAP) was used for diagnosis. A Q_a < 400-500 mL/min or a VAPR > 0.55 is considered sign of significant stenosis, which requires immediate intervention. However, due to the complex nature of AVFs, the surveillance strategies have failed to consistently detect stenosis under different scenarios. VAPR has been primarily developed to detect outflow stenosis in arteriovenous grafts, and it hasn’t been successful in accurate diagnosis of outflow lesions in AVFs. Similarly, AVFs can maintain relatively high blood flow despite the presence of a significant outflow stenosis and thus, Q_a has been found to be a better predictor of only inflow lesions. Similar shortcomings have been reported in the detection of functional severity of coronary stenosis using diagnostic endpoints that were based on either flow or pressure. This limitation has been associated with the fact that both pressure and flow change in the presence of a stenosis and thus, hemodynamic diagnostic endpoints that employ only one of these parameters are inherently prone to inaccuracies. Recent attempts have resulted in development of new diagnostic endpoints that can combine the effects of pressure and flow. These new hemodynamic diagnostic endpoints have shown to be better predictors of functional severity of lesions as compared to either flow or pressure based counterparts. In this review article, we discussed the advantages and limitations of current functional and anatomical diagnostic endpoints in AVFs.

Complement activation in progressive renal disease

Chronic kidney disease (CKD) is common and the cause of significant morbidity and mortality. The replacement of functioning nephrons by fibrosis is characteristic of progressive disease. The pathways that lead to fibrosis are not fully understood, although chronic non-resolving inflammation in the kidney is likely to drive the fibrotic response that occurs. In patients with progressive CKD there is histological evidence of inflammation in the interstitium and strategies that reduce inflammation reduce renal injury in pre-clinical models of CKD. The complement system is an integral part of the innate immune system but also augments adaptive immune responses. Complement activation is known to occur in many diverse renal diseases, including glomerulonephritis, thrombotic microangiopathies and transplant rejection. In this review we discuss current evidence that complement activation contributes to progression of CKD, how complement could cause renal inflammation and whether complement inhibition would slow progression of renal disease.

Nephroprevention in the oldest old with chronic kidney disease: Special considerations

Nephroprevention strategies are crucial for handling chronic kidney disease (CKD) complications, and slowing its progression. However, these preventative measures should be guided by major geriatrics principles in order to help nephrologists to adequately handle the oldest old with CKD. These geriatric concepts consist of taking into account the relevance of choosing an individualized therapy, handling clinical frailty, and keeping a geriatric perspective which means that a good quality of life is sometimes a more important therapeutic objective in octogenarians than merely prolonging life. Even though nephroprevention strategies for treating the oldest old with CKD are basically similar to those applied to younger patients such as low sodium and protein diet, optimized hemoglobin levels, blood pressure and metabolic control, the treating physician or care provider must at all times be ready to make fundamental adjustments and tweak patient care paradigms and objectives if and when the initial therapeutic options applied have caused unintended clinical consequences and complications. Additionally, the sarcopenia status should also be evaluated and treated in very old CKD patients.

Increasing the use of biocompatible, glucose-free peritoneal dialysis solutions

A major concern inhibiting some clinicians from embracing peritoneal dialysis (PD) as the preferred first modality of dialysis is the effects of PD solutions on the peritoneal membrane. These anatomical and functional changes predispose to complications like peritonitis, encapsulating peritoneal sclerosis and ultrafiltration failure. In recent years, “biocompatible” and glucose-sparing PD regimens have been developed to minimize damage to the peritoneal membrane. Can the use of these more expensive solutions be justified on current evidence? In this review of the literature, we explore how we may individualize the prescription of biocompatible PD fluid.

Review on renal recovery after anatrophic nephrolithotomy: Are we really healing our patients?

The main goals for urinary stone treatment are to preserve renal function, reduce or avoid complications related to calculi, and to render the patient free of calculi as soon as possible. Anatrophic nephrolithotomy (ANL) is a valid and useful alternative for conventional staghorn calculi excision. Although excellent stone free rates can be achieved with ANL there are some drawbacks that may be of concern. Morbidity related to intraoperative and postoperative complications is one of them. Another, great concern is the possibility of reduction on renal function related to the procedure itself. This may be related to nephron injury during nephrotomy and parenchymal closure or to ischemic injury. In this review we assess functional results after anatrophic nephrolithotomy.

Appropriate kidney stone size for ureteroscopic lithotripsy: When to switch to a percutaneous approach

Flexible ureteroscopy (fURS) has become a more effective and safer treatment for whole upper urinary tract stones. Percutaneous nephrolithotomy (PNL) is currently the first-line recommended treatment for large kidney stones ≥ 20 mm and it has an excellent stone-free rate for large kidney stones. However, its invasiveness is not negligible considering its major complication rates. Staged fURS is a practical treatment for such large kidney stones because fURS has a minimal blood transfusion risk, short hospitalization and few restrictions on daily routines. However, as the stone size becomes larger, the stone-free rate decreases, and the number of operations required increases. Therefore, in our opinion, staged fURS is a practical option for kidney stones 20 to 40 mm. Miniaturized PNL combined with fURS should be considered to be a preferred option for stones larger than 40 mm. Moreover, URS is an effective treatment for multiple upper urinary tract stones. Especially for patients with a stone burden < 20 mm, URS is a favorable option that promises a high stone-free rate after a single session either unilaterally or bilaterally. However, for patients with a stone burden ≥ 20 mm, a staged operation should be considered to achieve stone-free status.

Time to re-evaluate effects of renin-angiotensin system inhibitors on renal and cardiovascular outcomes in diabetic nephropathy

The use of renin-angiotensin system (RAS) inhibitors, such angiotensin converting enzyme inhibitors/angiotensin-II receptor blockers, to slow progression of chronic kidney disease (CKD) in a large group dominated by elderly people in the real world is not supported by available evidence. Large-scale clinical trials had many faults, among them a lack of focus on the elderly. However, it would be difficult to conduct clinical trials of a similar scale in elderly CKD patients. Besides, progression of kidney disease is often slow in elderly persons, and the vast majority of older adults with CKD will die before reaching end stage renal disease. Moreover, since it is not clear that progression of kidney disease, and even of proteinuric diabetic nephropathy, is not inhibited through the use of RAS inhibitors, the most patient-centric goal of therapy for many elderly individuals should be individualized.

Relationship of MTHFR gene polymorphisms with renal and cardiac disease

AIM: To investigate the effects of different methylenetetrahydrofolate reductase (MTHFR) 677C>T gene polymorphism and hyperhomocysteinemia for the development of renal failure and cardiovascular events, which are controversial.

METHODS: We challenged the relationship, if any, of MTHFR 677C>T and MTHFR 1298A>C polymorphisms with renal and heart function. The present article is a reappraisal of these concepts, investigating within a larger population, and including a subgroup of dialysis patients, if the two most common MTHFR polymorphisms, C677T and A1298C, as homozygous, heterozygous or with a compound heterozygous state, show different association with chronic renal failure requiring hemodialysis. MTHFR polymorphism could be a favorable evolutionary factor, i.e., a protective factor for many ominous conditions, like cancer and renal failure. A similar finding was reported in fatty liver disease in which it is suggested that MTHFR polymorphisms could have maintained and maintain their persistence by an heterozygosis advantage mechanism. We studied a total of 630 Italian Caucasian subject aged 54.60 ± 16.35 years, addressing to the increased hazard of hemodialysis, if any, according to the studied MTHFR genetic polymorphisms.

RESULTS: A favorable association with normal renal function of MTHFR polymorphisms, and notably of MTHFR C677T is present independently of the negative effects of left ventricular hypertrophy, increased Intra-Renal arterial Resistance and hyperparathyroidism.

CONCLUSION: MTHFR gene polymorphisms could have a protective role on renal function as suggested by their lower frequency among our dialysis patients in end-stage renal failure; differently, the association with left ventricular hypertrophy and reduced left ventricular relaxation suggest some type of indirect, or concurrent mechanism.

Role of β2-microglobulin in uremic patients may be greater than originally suspected

The role of beta2-microglobulin (β₂M) in dialysis-related amyloidosis as a specific amyloid precursor was defined in the 1980s. Studies in those years were largely related to β₂M amyloidosis. In 2005, for what was probably the first time in the available literature, we provided data about the association between β₂M and early-onset atherosclerosis in hemodialysis patients without co-morbidities. In recent years, the role of uremic toxins in uremic atherosclerosis and the interest in β₂M as a marker of cardiovascular (CV) and/or mortality risk have grown. In the current literature, clinical studies suggest that β₂M is an independent, significant predictor of mortality, not only in dialysis patients, but also in predialysis patients and in the high-risk portion of the general population, and it seems to be a factor strongly linked to the presence and severity of CV disease. It is still unknown whether β₂M is only a uremic toxin marker or if it also has an active role in vascular damage, but data support that it may reflect an increased burden of systemic atherosclerosis in a setting of underlying chronic kidney disease. Thus, although there have been some inconsistencies among the various analyses relating to β₂M, it promises to be a novel risk marker of kidney function in the awareness and detection of high-risk patients. However, more research is required to establish the pathophysiological relationships between retained uremic toxins and further biochemical modifications in the uremic milieu to get answers to the questions of why and how. In this review, the recent literature about the changing role of β₂M in uremic patients will be examined.

Are phosphodiesterase type 5 inhibitors effective for the management of lower urinary symptoms suggestive of benign prostatic hyperplasia?

AIM: To review the efficacy of phosphodiesterase type 5 inhibitors (PDE5-Is) in lower urinary tract symptoms (LUTS) suggestive of benign prostate hyperplasia (LUTS/BPH).

METHODS: A comprehensive research was conducted to identify all publications relating to benign prostate hyperplasia and treatment with sildenafil, vardenafil and tadalafil. To assess the efficacy, the changes in total international prostate symptom score (IPSS), IPSS subscore including voiding, storage and quality of life (QoL), Benign prostatic hyperplasia Impact Index (BII), maximum urinary flow rate (Qmax) and the International Index of Erectile Function (IIEF) were extracted. A meta-analytical technique was used for the analysis of integrated data from the included studies to evaluate the mean difference in the results.

RESULTS: Total IPSS score, IIEF and BII showed a significant improvement in trials in which LUTS/BPH with or without erectile dysfunction (ED) were compared with the placebo. For LUTS/BPH, the mean differences of total IPSS score, IIEF and BII are -2.17, 4.88 and -0.43, P < 0.00001, respectively. For LUTS/BPH with comorbid ED, the mean difference are -1.97, 4.54 and -0.52, P < 0.00001, respectively. PDE5-Is appear to improve IPSS storage, voiding and QoL subscore (mean difference = -0.71, -1.23 and -0.33, P < 0.00001, respectively). Although four doses of tadalafil (2.5, 5, 10 and 20 mg) failed to reach significance in Qmax (mean difference = 0.22, P = 0.10), the 5 mg dose of tadalafil significantly improved the Qmax (mean difference = 0.33, P = 0.03).

CONCLUSION: PED5-Is demonstrated efficacy for improving LUTS in BPH patients with or without ED and could be considered to be the first line treatment for LUTS/BPH.

ACE and ACE2 in kidney disease

Renin angiotensin system (RAS) activation has a significant influence on renal disease progression. The classical angiotensin-converting enzyme (ACE)-angiotensin II (Ang II)-Ang II type 1 (AT1) axis is considered to control the effects of RAS activation on renal disease. However, since its discovery in 2000 ACE2 has also been demonstrated to have a significant impact on the RAS. The synthesis and catabolism of Ang II are regulated via a complex series of interactions, which involve ACE and ACE2. In the kidneys, ACE2 is expressed in the proximal tubules and less strongly in the glomeruli. The synthesis of inactive Ang 1-9 from Ang I and the catabolism of Ang II to produce Ang 1-7 are the main functions of ACE2. Ang 1-7 reduces vasoconstriction, water retention, salt intake, cell proliferation, and reactive oxygen stress, and also has a renoprotective effect. Thus, in the non-classical RAS the ACE2-Ang 1-7-Mas axis counteracts the ACE-Ang II-AT1 axis. This review examines recent human and animal studies about renal ACE and ACE2.

Lipid abnormalities in kidney disease and management strategies

Patients with kidney diseases continue to experience significant cardiovascular disease (CVD) morbidity and mortality. Although there are many important risk factors playing a role in the pathogenesis of CVD in chronic kidney disease (CKD) patients, dyslipidemia (elevated triglycerides, elevated oxidized low-density lipoprotein and low/dysfunctional low high-density) represents one of the modifiable risk factors. Renal failure patients have unique lipid abnormalities which not only have complex role in pathogenesis of CVD but also cause relative resistance to usual interventions. Most of the randomized trials have been in hemodialysis population and data from CKD non-dialysis, peritoneal dialysis and renal transplant populations is extremely limited. Compared to general population, evidence of mortality benefit of lipid lowering medications in CKD population is scarce. Future research should be directed towards establishing long term benefits and side effects of lipid lowering medications, through randomized trials, in CKD population.

Biomarkers in chronic kidney disease, from kidney function to kidney damage

Chronic kidney disease (CKD) typically evolves over many years, with a long latent period when the disease is clinically silent and therefore diagnosis, evaluation and treatment is based mainly on biomarkers that assess kidney function. Glomerular filtration rate (GFR) remains the ideal marker of kidney function. Unfortunately measuring GFR is time consuming and therefore GFR is usually estimated from equations that take into account endogenous filtration markers like serum creatinine (SCr) and cystatin C (CysC). Other biomarkers such as albuminuria may precede kidney function decline and have demonstrated to have strong associations with disease progression and outcomes. New potential biomarkers have arisen with the promise of detecting kidney damage prior to the currently used markers. The aim of this review is to discuss the utility of the GFR estimating equations and biomarkers in CKD and the different clinical settings where these should be applied. The CKD-Epidemiology Collaboration equation performs better than the modification of diet in renal disease equation, especially at GFR above 60 mL/min per 1.73 m². Equations combining CysC and SCr perform better than the equations using either CysC or SCr alone and are recommended in situations where CKD needs to be confirmed. Combining creatinine, CysC and urine albumin to creatinine ratio improves risk stratification for kidney disease progression and mortality. Kidney injury molecule and neutrophil gelatinase-associated lipocalin are considered reasonable biomarkers in urine and plasma to determine severity and prognosis of CKD.

Aging and uremia: Is there cellular and molecular crossover?

Many observers have noted that the morphological changes that occur in chronic kidney disease (CKD) patients resemble those seen in the geriatric population, with strikingly similar morbidity and mortality profiles and rates of frailty in the two groups, and shared characteristics at a pathophysiological level especially in respect to the changes seen in their vascular and immune systems. However, whilst much has been documented about the shared physical characteristics of aging and uremia, the molecular and cellular similarities between the two have received less attention. In order to bridge this perceived gap we have reviewed published research concerning the common molecular processes seen in aging subjects and CKD patients, with specific attention to altered proteostasis, mitochondrial dysfunction, post-translational protein modification, and senescence and telomere attrition. We have also sought to illustrate how the cell death and survival pathways apoptosis, necroptosis and autophagy are closely interrelated, and how an understanding of these overlapping pathways is helpful in order to appreciate the shared molecular basis behind the pathophysiology of aging and uremia. This analysis revealed many common molecular characteristics and showed similar patterns of cellular dysfunction. We conclude that the accelerated aging seen in patients with CKD is underpinned at the molecular level, and that a greater understanding of these molecular processes might eventually lead to new much needed therapeutic strategies of benefit to patients with renal disease.

Immune profiling and cancer post transplantation

Half of all long-term (> 10 year) australian kidney transplant recipients (KTR) will develop squamous cell carcinoma (SCC) or solid organ cancer (SOC), making cancer the leading cause of death with a functioning graft. At least 30% of KTR with a history of SCC or SOC will develop a subsequent SCC or SOC lesion. Pharmacological immunosuppression is a major contributor of the increased risk of cancer for KTR, with the cancer lesions themselves further adding to systemic immunosuppression and could explain, in part, these phenomena. Immune profiling includes; measuring immunosuppressive drug levels and pharmacokinetics, enumerating leucocytes and leucocyte subsets as well as testing leucocyte function in either an antigen specific or non-specific manner. Outputs can vary from assay to assay according to methods used. In this review we define the rationale behind post-transplant immune monitoring assays and focus on assays that associate and/or have the ability to predict cancer and rejection in the KTR. We find that immune monitoring can identify those KTR of developing multiple SCC lesions and provide evidence they may benefit from pharmacological immunosuppressive drug dose reductions. In these KTR risk of rejection needs to be assessed to determine if reduction of immunosuppression will not harm the graft.

Preeclampsia from a renal point of view: Insides into disease models, biomarkers and therapy

Proteinuria is a frequently detected symptom, found in 20% of pregnancies. A common reason for proteinuria in pregnancy is preeclampsia. To diagnose preeclampsia clinically and to get new insights into the pathophysiology of the disease it is at first essential to be familiar with conditions in normal pregnancy. Animal models and biomarkers can help to learn more about disease conditions and to find new treatment strategies. In this article we review the changes in kidney function during normal pregnancy and the differential diagnosis of proteinuria in pregnancy. We summarize different pathophysiological theories of preeclampsia with a special focus on the renal facets of the disease. We describe the current animal models and give a broad overview of different biomarkers that were reported to predict preeclampsia or have a prognostic value in preeclampsia cases. We end with a summary of treatment options for preeclampsia related symptoms including the use of plasmapheresis as a rescue therapy for so far refractory preeclampsia. Most of these novel biomarkers for preeclampsia are not yet implemented in clinical use. Therefore, we recommend using proteinuria (measured by UPC ratio) as a screening parameter for preeclampsia. Delivery is the only curative treatment for preeclampsia. In early preeclampsia the primary therapy goal is to prolong pregnancy until a state were the child has an acceptable chance of survival after delivery.

Searching for a treatment for Alport syndrome using mouse models

Alport syndrome (AS) is a hereditary nephritis caused by mutations in COL4A3, COL4A4 or COL4A5 encoding the type IV collagen α3, α4, and α5 chains, which are major components of the glomerular basement membrane. About 20 years have passed since COL4A3, COL4A4, and COL4A5 were identified and the first Alport mouse model was developed using a knockout approach. The phenotype of Alport mice is similar to that of Alport patients, including characteristic thickening and splitting of the glomerular basement membrane. Alport mice have been widely used to study the pathogenesis of AS and to develop effective therapies. In this review, the newer therapies for AS, such as pharmacological interventions, genetic approaches and stem cell therapies, are discussed. Although some stem cell therapies have been demonstrated to slow the renal disease progression in Alport mice, these therapies demand continual refinement as research advances. In terms of the pharmacological drugs, angiotensin-converting enzyme inhibitors have been shown to be effective in Alport mice. Novel therapies that can provide a better outcome or lead to a cure are still awaited.

Renal biopsy practice: What is the gold standard?

Renal biopsy (RB) is useful for diagnosis and therapy guidance of renal diseases but incurs a risk of bleeding complications of variable severity, from transitory haematuria or asymptomatic hematoma to life-threatening hemorrhage. Several risk factors for complications after RB have been identified, including high blood pressure, age, decreased renal function, obesity, anemia, low platelet count and hemostasis disorders. These should be carefully assessed and, whenever possible, corrected before the procedure. The incidence of serious complications has become low with the use of automated biopsy devices and ultrasound guidance, which is currently the “gold standard” procedure for percutaneous RB. An outpatient biopsy may be considered in a carefully selected population with no risk factor for bleeding. However, controversies persist on the duration of observation after biopsy, especially for native kidney biopsy. Transjugular RB and laparoscopic RB represent reliable alternatives to conventional percutaneous biopsy in patients at high risk of bleeding, although some factors limit their use. This aim of this review is to summarize the issues of complications after RB, assessment of hemorrhagic risk factors, optimal biopsy procedure and strategies aimed to minimize the risk of bleeding.

Nutcracker syndrome

The nutcracker phenomenon [left renal vein (LRV) entrapment syndrome] refers to compression of the LRV most commonly between abdominal aorta and superior mesenteric artery. Term of nutcracker syndrome (NCS) is used for patients with clinical symptoms associated with nutcracker anatomy. LRV entrapment divided into 2 types: anterior and posterior. Posterior and right-sided NCSs are rare conditions. The symptoms vary from asymptomatic hematuria to severe pelvic congestion. Symptoms include hematuria, orthostatic proteinuria, flank pain, abdominal pain, varicocele, dyspareunia, dysmenorrhea, fatigue and orthostatic intolerance. Existence of the clinical features constitutes a basis for the diagnosis. Several imaging methods such as Doppler ultrasonography, computed tomography angiography, magnetic resonance angiography and retrograde venography are used to diagnose NCS. The management of NCS depends upon the clinical presentation and the severity of the LRV hypertension. The treatment options are ranged from surveillance to nephrectomy. Treatment decision should be based on the severity of symptoms and their expected reversibility with regard to patient’s age and the stage of the syndrome.

Cardiovascular co-morbidity in chronic kidney disease: Current knowledge and future research needs

Chronic kidney disease (CKD) is recognised as a health concern globally and leads to high rates of morbidity, mortality and healthcare expenditure. CKD is itself an independent risk factor for unfavorable health outcomes that include cardiovascular disease (CVD). Coronary artery disease is the primary type of CVD in CKD patients and a significant cause of death among renal transplant patients. Traditional and non-traditional risk factors for CVD exist in patients with CKD. Traditional factors include smoking, hypertension, dyslipidemia and diabetes which are highly prevalent in CKD patients. Non-traditional risk factors of CKD are mainly uraemia-specific and increase in prevalence as kidney function declines. Some examples of uraemia-specific risk factors that have been well documented include low levels of haemoglobin, albuminuria, and abnormal bone and mineral metabolism. Therapeutic interventions targeted at more traditional risk factors which contribute to CVD, have not had the desired effect on lowering CVD events and mortality in those suffering with CKD. Future research is warranted to delineate clear evidence to the benefit of modifying non-traditional risk factors.

Nephropathy in dietary hyperoxaluria: A potentially preventable acute or chronic kidney disease

Hyperoxaluria can cause not only nephrolithiasis and nephrocalcinosis, but also renal parenchymal disease histologically characterized by deposition of calcium oxalate crystals throughout the renal parenchyma, profound tubular damage and interstitial inflammation and fibrosis. Hyperoxaluric nephropathy presents clinically as acute or chronic renal failure that may progress to end-stage renal disease (ESRD). This sequence of events, well recognized in the past in primary and enteric hyperoxalurias, has also been documented in a few cases of dietary hyperoxaluria. Estimates of oxalate intake in patients with chronic dietary hyperoxaluria who developed chronic kidney disease or ESRD were comparable to the reported average oxalate content of the diets of certain populations worldwide, thus raising the question whether dietary hyperoxaluria is a primary cause of ESRD in these regions. Studies addressing this question have the potential of improving population health and should be undertaken, alongside ongoing studies which are yielding fresh insights into the mechanisms of intestinal absorption and renal excretion of oxalate, and into the mechanisms of development of oxalate-induced renal parenchymal disease. Novel preventive and therapeutic strategies for treating all types of hyperoxaluria are expected to develop from these studies.

Residual urinary output in high body mass index individuals on chronic hemodialysis: A disregarded life vest?

AIM: To assess residual diuresis and diverse variables according to body mass index (BMI).

METHODS: Cross-sectional study (n = 57), with 3 groups. Group A: BMI < 25, n = 22; Group B: BMI 25-30, n = 15; Group C: BMI > 30, n = 20. Diuresis, hematocrit, albumin, C-reactive protein, Malnutrition inflammatory score, Pro-BNP, Troponin T, leptin and insulin levels are expressed as median and ranges (r).

RESULTS: Albumin (g/dL): GA vs GC, 3.70 (r2.20-4.90) vs 3.85 (r3.40-4.90), P = 0.02. Diuresis (mL/d): GA 690 (r0-1780); GB 660 (r60-1800); GC 840 (r40-2840). Diuresis GA vs GC, P = 0.01. Leptin (ng/mL): GA vs GC, 3.81 (r0.78-69.60) vs GC, 32.80 (r0.78-124.50), P < 0.001. Insulin (µU/mL): GA vs GB, 7 (r2-44) vs 11.50 (r4-38), P = 0.02; GA vs GC, 7 (r2-44) vs 19.5 (r5-155), P = 0.0001. Troponin T and Pro-BNP levels were not different. Significant correlations: GC, Insulin-UF: ρ = 0.53; P = 0.03; TroponinT-diuresis: ρ = -0.48, P < 0.05; Pro-BNP-diuresis: ρ = -0.39, P < 0.01; Troponin T-ProBNP: ρ = 0.77, P < 0.0001; albumin-Troponin T: ρ = -0.66, P < 0.0001; albumin-ProBNP: ρ = -0.44, P < 0.05.

CONCLUSION: High BMI associated positively with higher diuresis and albuminemia, and negatively with TropT and Pro-BNP. High BMI-associated better survival may be explained by better urinary output, lowering cardiovascular stress.

Metabolic syndrome and chronic kidney disease: Current status and future directions

Metabolic syndrome (MetS) is a term used to denote a combination of selected, widely prevalent cardiovascular disease (CVD)-related risk factors. Despite the ambiguous definition of MetS, it has been clearly associated with chronic kidney disease markers including reduced glomerular filtration rate, proteinuria and/or microalbuminuria, and histopathological markers such as tubular atrophy and interstitial fibrosis. However, the etiological role of MetS in chronic kidney disease (CKD) is less clear. The relationship between MetS and CKD is complex and bidirectional, and so is best understood when CKD is viewed as a common progressive illness along the course of which MetS, another common disease, may intervene and contribute. Possible mechanisms of renal injury include insulin resistance and oxidative stress, increased proinflammatory cytokine production, increased connective tissue growth and profibrotic factor production, increased microvascular injury, and renal ischemia. MetS also portends a higher CVD risk at all stages of CKD from early renal insufficiency to end-stage renal disease. Clinical interventions for MetS in the presence of CKD should include a combination of weight reduction, appropriate dietary modification and increase physical activity, plus targeting of individual CVD-related risk factors such as dysglycemia, hypertension, and dyslipidemia while conforming to relevant national societal guidelines.

Quality of life in end stage renal disease patients

AIM: To understand factors associated with quality of life (QOL), examine types of QOL instruments, and determine need for further improvements in QOL assessment.

METHODS: The method used databases (Pubmed, Google scholar) and a bibliographic search using key words QOL, end stage renal disease, Hemodialysis, Peritoneal dialysis, instruments to measure QOL, patients and qualitative/quantitative analysis published during 1990 to June 2014. Each article was assessed for sample size, demographics of participants, study design and type of QOL instruments used. We used WHO definition of QOL.

RESULTS: For this review, 109 articles were screened, out of which 65 articles were selected. Out of 65 articles, there were 19 reports/reviews and 12 questionnaire manuals. Of the 34 studies, 82% were quantitative while only 18% were qualitative. QOL instruments measured several phenomenon such as physical/psychological health, effects and burdens of kidney disease, social support etc. those are associated with QOL. Few studies looked at spiritual beliefs, cultural beliefs, personal concerns, as per the WHO definition. Telemedicine and Palliative care have now been successfully used however QOL instruments seldom addressed those in the articles reviewed. Also noticed was that longitudinal studies were rarely conducted. Existing QOL instruments only partially measure QOL. This may limit validity of predictive power of QOL.

CONCLUSION: Culture and disease specific QOL instruments that assess patients’ objective and subjective experiences covering most aspects of QOL are urgently needed.

Acute kidney injury due to bilateral ureteral obstruction in children

Bilateral ureteral obstruction in children is a rare condition arising from several medical or surgical pictures. It needs to be promptly suspected in order to attempt a quick renal function recovery. In this paper we concentrated on uncommon causes of obstruction, with the aim of giving a summary of such multiple, rare and heterogeneous conditions joint together by the common denominator of sudden bilateral ureteral obstruction, difficult to be suspected at times. Conversely, typical and well-known diseases have been just run over. We considered pediatric cases of ureteral obstruction presenting as bilateral, along with some cases which truly appeared as single-sided, because of their potential bilateral presentation. We performed a review of the literature by a search on PubMed, CrossRef Metadata Search, internet and reference lists of single articles updated to May 2014, with no time limits in the past. Given that we deal with rare conditions, we decided to include also papers in non-English languages, published with an English abstract. For the sake of clearness, we divided our research results into 8 categories: (1) urolithiasis; (2) congenital urinary tract malformations; (3) immuno-rheumatologic causes of ureteral obstruction; (4) ureteral localization of infections; (5) other systemic infective causes of ureteral obstructions; (6) neoplastic intrinsic ureteral obstructions; (7) extrinsic ureteral obstructions; and (8) iatrogenic trigonal obstruction or inflammation. Of course, different pathogenic mechanisms underlay those clinical pictures, partly well-known and partly not completely understood.

Roles of the (pro)renin receptor in the kidney

Prorenin receptor (PRR) is a multi-functioning protein possessing at least four different roles: (1) working as a receptor for renin and prorenin producing angiotensin I from angiotensinogen thus enhancing the tissue renin-angiotensin system; (2) inducing intracellular signals when a ligand binds to PRR; (3) participating in the functions of vacuolar proton ATPase; and (4) constituting the Wnt signaling receptor complex. Here, the roles of PRR in kidney physiology and diabetic conditions as well as recent findings regarding a soluble form of PRR are discussed. We also propose the possible mechanism concerning diabetic nephropathy as “trade-off hypothesis” from a PRR point of view. In brief, under hyperglycemic conditions, injured podocytes degrade degenerated proteins and intracellular organelles which require V-ATPase and PRR for vesicle internal acidification. Sustained hyperglycemia overproduces PRR molecules, which are transported to the transmembrane and bind to increased serum prorenin in the diabetic condition. This enhances tissue renin-angiotensin system and PRR-mediated mitogen-activated protein kinase signals, resulting in increased injurious molecules such as transforming growth factor-β, cyclooxygenase2, interleukin-1β, and tumor necrosis factor-α ending in diabetic nephropathy progression. Although many findings led us to better PRR understanding, future works should elucidate which PRR functions, of the four discussed here, are dominant in each cell and kidney disease context.

Retrograde intrarenal surgery in pediatric patients

Urinary tract stone disease is seen at a level of 1%-2% in childhood (< 18 years). In recent years, however, there has been a marked increased in pediatric stone disease, particularly in adolescence. A carbohydrate- and salt-heavy diet and a more sedentary lifestyle are implicated in this increase. Although stone disease is rare in childhood, its presence is frequently associated with metabolic or anatomical disorders or infectious conditions, for which reason there is a high possibility of post-therapeutic recurrence. Factors such as a high possibility of recurrence and increasing incidence further enhance the importance of minimally invasive therapeutic options in children, with their expectations of a long life. In children in whom active stone removal is decided on, the way to achieve the highest level of success with the least morbidity is to select the most appropriate treatment modality. Thanks to today’s advanced technology, renal stones that were once treated only by surgery can now be treated with minimally invasive techniques, from invasion of the urinary system in an antegrade (percutaneous nephrolithotomy) or retrograde (retrograde intrarenal surgery) manner or shock wave lithotripsy to laparoscopic stone surgery. This compilation study examined studies involving the RIRS procedure, the latest minimally invasive technique, in children and compared the results of those studies with those from other techniques.

Prostatic surgery associated acute kidney injury

Acute kidney injury (AKI) is associated with extended hospital stays, high risks of in-hospital and long-term mortality, and increased risk of incident and progressive chronic kidney disease. Patients with urological diseases are a high-risk group for AKI owing to the coexistence of obstructive uropathy, older age, and preexistent chronic kidney disease. Nonetheless, precise data on the incidence and outcomes of postoperative AKI in urological procedures are lacking. Benign prostatic hyperplasia and prostate cancer are common diagnoses in older men and are frequently treated with surgical procedures. Whereas severe AKI after prostate surgery in general appears to be unusual, AKI associated with transurethral resection of the prostate (TURP) syndrome and with rhabdomyolysis (RM) after radical prostatectomy have been frequently described. The purpose of this review is to discuss the current knowledge regarding the epidemiology, risk factors, outcomes, prevention, and treatment of AKI associated with prostatic surgery. The mechanisms of TURP syndrome and RM following prostatic surgeries will be emphasized.

Usefulness of hounsfield unit and density in the assessment and treatment of urinary stones

Computed tomography (CT) is widely used to examine stones in the urinary system. In addition to the size and location of the stone and the overall health of the kidney, CT can also assess the density of the stone in Hounsfield units (HU). The HU, or Hounsfield density, measured by CT, is related to the density of the tissue or stone. A number of studies have assessed the use of HU in urology. HUs have been used to predict the type and opacity of stones during diagnosis, and the efficacy has been assessed using methods including extracorporeal shock wave lithotripsy (ESWL), percutaneous nephrolithotomy (PCNL), ureterorenoscopic ureterolithotripsy (URSL), and medical expulsive treatment (MET). Previous studies have focused on the success rate of HU for predicting the type of stone and of ESWL treatment. Understanding the composition of the stone plays a key role in determining the most appropriate treatment modality. The most recent reports have suggested that the HU value and its variants facilitate prediction of stone composition. However, the inclusion of data regarding urine, such as pH and presence of crystals, increases the predictive accuracy. HUs, which now form part of the clinical guidelines, allow us to predict the success of ESWL; therefore, they should be taken into account when ESWL is considered as a treatment option. However, there are currently insufficient data available regarding the value of HU for assessing the efficacy of PCNL, URSL, and MET. Studies performed to date suggest that these values would make a significant contribution to the diagnosis and treatment of urinary system stones. However, more data are required to assess this further.

Clinical audit, a valuable tool to improve quality of care: General methodology and applications in nephrology

Evaluation and improvement of quality of care provided to the patients are of crucial importance in the daily clinical practice and in the health policy planning and financing. Different tools have been developed, including incident analysis, health technology assessment and clinical audit. The clinical audit consist of measuring a clinical outcome or a process, against well-defined standards set on the principles of evidence-based medicine in order to identify the changes needed to improve the quality of care. In particular, patients suffering from chronic renal diseases, present many problems that have been set as topics for clinical audit projects, such as hypertension, anaemia and mineral metabolism management. Although the results of these studies have been encouraging, demonstrating the effectiveness of audit, overall the present evidence is not clearly in favour of clinical audit. These findings call attention to the need to further studies to validate this methodology in different operating scenarios. This review examines the principle of clinical audit, focusing on experiences performed in nephrology settings.

Ureteroscopy and stones: Current status and future expectations

Urolithaisis is becoming an ever increasing urological, nephrological and primary care problem. With a lifetime prevalence approaching 10% and increasing morbidity due to stone disease, the role of ureteroscopy and stone removal is becoming more important. We discuss the current status of stone disease and review the ever increasing role that ureteroscopy has to play in its management. We discuss technological advances that have been made in stone management and give you an overview of when, how and why ureteroscopy is the most common treatment option for stone management. We touch on the role of robotic ureteroscopy and the future of ureteroscopy in the next 10 years.

Chronic kidney disease and erectile dysfunction

Erectile dysfunction (ED) is a common condition among male chronic kidney disease (CKD) patients. Its prevalence is estimated to be approximately 80% among these patients. It has been well established that the production of nitric oxide from the cavernous nerve and vascular endothelium and the subsequent production of cyclic GMP are critically important in initiating and maintaining erection. Factors affecting these pathways can induce ED. The etiology of ED in CKD patients is multifactorial. Factors including abnormalities in gonadal-pituitary system, disturbance in autonomic nervous system, endothelial dysfunction, anemia (and erythropoietin deficiency), secondary hyperparathyroidism, drugs, zinc deficiency, and psychological problems are implicated in the occurrence of ED. An improvement of general conditions is the first step of treatment. Sufficient dialysis and adequate nutritional intake are necessary. In addition, control of anemia and secondary hyperparathyroidism is required. Changes of drugs that potentially affect erectile function may be necessary. Further, zinc supplementation may be necessary when zinc deficiency is suspected. Phosphodiesterase type 5 inhibitors (PDE5Is) are commonly used for treating ED in CKD patients, and their efficacy was confirmed by many studies. Testosterone replacement therapy in addition to PDE5Is may be useful, particularly for CKD patients with hypogonadism. Renal transplantation may restore erectile function. ED is an early marker of cardiovascular disease (CVD), which it frequently precedes; therefore, it is crucial to examine the presence of ED in CKD patients not only for the improvement of the quality of life but also for the prevention of CVD attack.