Role of insulin resistance in uric acid nephrolithiasis

Metabolic syndrome has been implicated in the pathogenesis of uric acid stones. Although not completely understood, its role is supported by many studies demonstrating increased prevalence of uric acid stones in patients with metabolic syndrome and in particular insulin resistance, a major component of metabolic syndrome. This review presents epidemiologic studies demonstrating the association between metabolic syndrome and nephrolithiasis in general as well as the relationship between insulin resistance and uric acid stone formation, in particular. We also review studies that explore the pathophysiologic relationship between insulin resistance and uric acid nephrolithiasis.

Regulatory roles of nitric oxide and angiotensin II on renal tubular transport

Renal tubules regulate blood pressure and humoral homeostasis. Mediators that play a significant role in regulating the transport of solutes and water include angiotensin II (AngII) and nitric oxide (NO). AngIIcan significantly raise blood pressure via effects on the heart, vasculature, and renal tubules. AngII generally stimulates sodium reabsorption by triggering sodium and fluid retention in almost all segments of renal tubules. Stimulation of renal proximal tubule (PT) transport is thought to be essential for AngII-mediated hypertension. However, AngII has a biphasic effect on in vitro PT transport in mice, rats, and rabbits: stimulation at low concentrations and inhibition at high concentrations. On the other hand, NO is generally thought to inhibit renal tubular transport. In PTs, NO seems to be involved in the inhibitory effect of AngII. A recent study reports a surprising finding: AngII has a monophasic stimulatory effect on human PT transport. Detailed analysis of signalling mechanisms indicates that in contrast to other species, the human NO/guanosine 3’,5’-cyclic monophosphate/extracellular signal-regulated kinase pathway seems to mediate this effect of Ang II on PT transport. In this review we will discuss recent progress in understanding the effects of AngII and NO on renal tubular transport.

Why do young people with chronic kidney disease die early?

Cardiovascular disease poses the greatest risk of premature death seen among patients with chronic kidney disease (CKD). Up to 50% of mortality risk in the dialysis population is attributable to cardiovascular disease and the largest relative excess mortality is observed in younger patients. In early CKD, occlusive thrombotic coronary disease is common, but those who survive to reach end-stage renal failure requiring dialysis are more prone to sudden death attributable mostly to sudden arrhythmic events and heart failure related to left ventricular hypertrophy, coronary vascular calcification and electrolyte disturbances. In this review, we discuss the basis of the interaction of traditional risk factors for cardiovascular disease with various pathological processes such as endothelial dysfunction, oxidative stress, low grade chronic inflammation, neurohormonal changes and vascular calcification and stiffness which account for the structural and functional cardiac changes that predispose to excess morbidity and mortality in young people with CKD.

From crystalluria to kidney stones, some physicochemical aspects of calcium nephrolithiasis

Nephrolithiasis seems to be the result of crystal formation, aggregation and retention in the kidney during crystalluria. These processes have to occur within the short urinary transit time through the kidney being in the order of few minutes. Recently much work was done on rather qualitative aspects of nephrolithiasis like genetics, metabolism and morphology. In this review we try to provide some quantitative information on urinary supersaturation with respect to stone minerals, especially Ca oxalate (CaOx), on the formation and aggregation of CaOx crystals and on crystal retention in the kidney. The paper is centered on idiopathic Ca nephrolithiasis being the most frequent stone disease with only partially known pathogenesis. New aspects of the role of urinary macromolecules in stone formation and of the mechanism of crystal aggregation are provided.

T-cell ageing in end-stage renal disease patients: Assessment and clinical relevance

End-stage renal disease (ESRD) patients have a defective T-cell-mediated immune system which is related to excessive premature ageing of the T-cell compartment. This is likely to be caused by the uremia-associated pro-inflammatory milieu, created by loss of renal function. Therefore, ESRD patients are highly susceptible for infections, have an increased risk for virus-associated cancers, respond poorly to vaccination and have an increased risk for atherosclerotic diseases. Three ageing parameters can be used to assess an immunological T-cell age. First, thymic output can be determined by assessing the T-cell receptor excision circles-content together with CD31 expression within the naïve T cells. Second, the telomere length of T cells and third the T-cell differentiation status are also indicators of T-cell ageing. Analyses based on these parameters in ESRD patients revealed that the immunological T-cell age is increased by on average 20 years compared to the chronological age. After kidney transplantation (KTx) the aged T-cell phenotype persists although the pro-inflammatory milieu is diminished. This might be explained by epigenetic modifications at hematopoietic stem cells level. Assessment of an immunological T-cell age could be an important tool to identify KTx recipients who are at risk for allograft rejection or to prevent over-immunosuppression.

Gait speed and hospitalization among ambulatory hemodialysis patients: USRDS special study data

AIM: To assess the association of measured gait speed with hemodialysis (HD) patients’ hospitalization, in conjunction with, and apart from, recent fall history.

METHODS: Gait speed was measured by a standard protocol and falls during the past 12 mo were ascertained for a prevalent multi-center HD cohort (n = 668) aged 20-92. Hospitalization during the past 12 mo was identified in the patient’s clinic records, and the first hospitalization after gait speed assessment (or the competing event of death) was identified in the 2013 United States Renal Data System Standard Analysis Files.

RESULTS: Slow gait speed, defined as < 0.8 m/s, characterized 34.7% of the patients, and 27.1% had experienced a recent fall. Patients with slow gait speed but without a history of recent falls were 1.79 times more likely to have been hospitalized during the past 12 mo (OR = 1.79, 95%CI: 1.11-2.88, P = 0.02), and patients with slow gait speed and a history of recent falls were over two times more likely to have been hospitalized (OR = 2.10, 95%CI: 1.19-3.73, P = 0.01), compared with patients having faster gait speed and no recent fall history. Prospective examination of gait speed/fall history status in relation to first hospitalization (or death) incurred by the end of follow-up December 31, 2011 also showed that slow gait speed was associated with these events in conjunction with a history of falls (HR = 1.54, 95%CI: 1.04-2.30, P = 0.03).

CONCLUSION: The International Task Force on Nutrition and Aging reported that gait speed is a powerful predictor for older adults of adverse outcomes such as hospitalization. In our data, gait speed--apart from, as well as in conjunction with, recent fall history--was associated with HD patients’ hospitalization for multiple causes. Gait speed may be a sensitive health indicator among HD patients across the age spectrum.

Therapeutic target for nephrotic syndrome: Identification of novel slit diaphragm associated molecules

The slit diaphragm bridging the neighboring foot processes functions as a final barrier of glomerular capillary wall for preventing the leak of plasma proteins into primary urine. It is now accepted that the dysfunction of the sit diaphragm contributes to the development of proteinuria in several glomerular diseases. Nephrin, a gene product of NPHS1, a gene for a congenital nephrotic syndrome of Finnish type, constitutes an extracellular domain of the slit diaphragm. Podocin was identified as a gene product of NPHS2, a gene for a familial steroid-resistant nephrotic syndrome of French. Podocin binds the cytoplasmic domain of nephrin. After then, CD2 associated protein, NEPH1 and transient receptor potential-6 were also found as crucial molecules of the slit diaphragm. In order to explore other novel molecules contributing to the development of proteinuria, we performed a subtraction hybridization assay with a normal rat glomerular RNA and a glomerular RNA of rats with a puromycin aminonucleoside nephropathy, a mimic of a human minimal change type nephrotic syndrome. Then we have found that synaptic vesicle protein 2B, ephrin-B1 and neurexin were already downregulated at the early stage of puromycin aminonucleoside nephropathy, and that these molecules were localized close to nephrin. It is conceivable that these molecules are the slit diaphragm associated molecules, which participate in the regulation of the barrier function. These molecules could be targets to establish a novel therapy for nephrotic syndrome.

Kidney regeneration: Where we are and future perspectives

In 2012, about 16487 people received kidney transplants in the United States, whereas 95022 candidates were on the waiting list by the end of the year. Despite advances in renal transplant immunology, approximately 40% of recipients will die or lose graft within 10 years. The limitations of current therapies for renal failure have led researchers to explore the development of modalities that could improve, restore, or replace the renal function. The aim of this paper is to describe a reasonable approach for kidney regeneration and review the current literature regarding cell sources and mechanisms to develop a bioengineering kidney. Due to kidneys peculiar anatomy, extracellular matrix based scaffolds are rational starting point for their regeneration. The perfusion of detergents through the kidney vasculature is an efficient method for delivering decellularizing agents to cells and for removing of cellular material from the tissue. Many efforts have focused on the search of a reliable cell source to provide enrichment for achieving stable renal cell systems. For an efficient bioengineered kidney, these cells must be attached to the organ and then maturated into the bioractors, which simulates the human body environment. A functional bioengineered kidney is still a big challenge for scientists. In the last ten years we have got many improvements on the field of solid organ regeneration; however, we are still far away from the main target. Currently, regenerative centers worldwide have been striving to find feasible strategies to develop bioengineered kidneys. Cell-scaffold technology gives hope to end-stage renal disease patients who struggle with morbidity and mortality due to extended periods on dialysis or immunosupression. The potential of bioengineered organ is to provide a reliable source of organs, which can be refunctionalized and transplanted.

Long-term outcome of ketoconazole and tacrolimus co-administration in kidney transplant patients

AIM: To study the long-term outcome of ketoconazole and tacrolimus combination in kidney transplant recipients.

METHODS: From 2006 to 2010, ketoconazole was given in 199 patients and was continued for at least 1 year or until graft failure (Group 1), while 149 patients did not receive any ketoconazole (Group 2). A combination of tacrolimus, mycophenolate and steroid was used as maintenance therapy. High risk patients received basiliximab induction.

RESULTS: Basic demographic data was similar between the 2 groups. The 5-year cumulative incidence of biopsy-confirmed and clinically-treated acute rejection was significantly higher in Group 1 than in Group 2 (34% vs 18%, P = 0.01). The 5-year Kaplan-Meier estimated graft survival (74.3% vs 76.4%, P = 0.58) and patient survival (87.8% vs 87.5%, P = 0.93) were not different between the 2 groups. Multivariable analyses identified ketoconazole usage as an independent risk of acute rejection (HR = 2.33, 95%CI: 1.33-4.07; P = 0.003) while tacrolimus dose in the 2^nd month was protective (HR = 0.89, 95%CI: 0.75-0.96; P = 0.041).

CONCLUSION: Co-administration of ketoconazole and tacrolimus is associated with significantly higher incidence of acute rejection in kidney transplant recipients.

Innocuous-looking skin scab over an arteriovenous fistula: Case report and literature review

Little is written on the management of an innocuous-looking skin scab over an autogenous arteriovenous fistula (AVF) used for haemodialysis. The seriousness of the underlying pathology can be under-estimated, and this may lead to early loss of the AVF, and major-life-threatening haemorrhage. We describe the management of a 78-year-old patient presenting with an innocuous-looking scab over an AVF and review the pertinent literature on this subject.

Role of endoscopic ultrasound fine-needle aspiration evaluating adrenal gland enlargement or mass

AIM: To report the clinical impact of adrenal endoscopic ultrasound fine-needle aspiration (EUS-FNA) in the evaluation of patients with adrenal gland enlargement or mass.

METHODS: In a retrospective single-center case-series, patients undergoing EUS-FNA of either adrenal gland from 1997-2011 in our tertiary care center were included. Medical records were reviewed and results of EUS, cytology, adrenal size change on follow-up imaging ≥ 6 mo after EUS and any repeat EUS or surgery were abstracted. A lesion was considered benign if: (1) EUS-FNA cytology was benign and the lesion remained < 1 cm from its original size on follow-up computed tomography (CT), magnetic resonance imaging or repeat EUS ≥ 6 mo after EUS-FNA; or (2) subsequent adrenalectomy and surgical pathology was benign.

RESULTS: Ninety-four patients had left (n = 90) and/or right (n = 5) adrenal EUS-FNA without adverse events. EUS indications included: cancer staging or suspected recurrence (n = 31), pancreatic (n = 20), mediastinal (n = 10), adrenal (n = 7), lung (n = 7) mass or other indication (n = 19). Diagnoses after adrenal EUS-FNA included metastatic lung (n = 10), esophageal (n= 5), colon (n = 2), or other cancer (n = 8); benign primary adrenal mass or benign tissue (n = 60); or was non-diagnostic (n = 9). Available follow-up confirmed a benign lesion in 5/9 non-diagnostic aspirates and 32/60 benign aspirates. Four of the 60 benign aspirates were later confirmed as malignant by repeat biopsy, follow-up CT, or adrenalectomy. Adrenal EUS-FNA diagnosed metastatic cancer in 24, and ruled out metastasis in 10 patients. For the diagnosis of malignancy, EUS-FNA of either adrenal had sensitivity, specificity, positive predictive value and negative predictive value of 86%, 97%, 96% and 89%, respectively.

CONCLUSION: Adrenal gland EUS-FNA is safe, minimally invasive and a sensitive technique with significant impact in the management of adrenal gland mass or enlargement.

Kinin B2 receptor does not exert renoprotective effects on mice with glycerol-induced rhabdomyolysis

AIM: To investigate a potential protective role of the kinin B₂ receptor in a glycerol-induced rhabdomyolysis mouse model.

METHODS: We separated 28 C57Bl/6 male mice into 4 groups: untreated WT animals, untreated B₂ knockout mice, glycerol-treated WT and glycerol-treated B₂ knockout mice. Glycerol-treated animals received one intramuscular injections of glycerol solution (50% v/v, 7 mL/kg). After 48 h, urine and blood samples were collected to measure creatinine and urea levels. Additionally, kidney samples were extracted for histological evaluation, and the mRNA expression levels of kinin B1 and B2 receptors and inflammatory mediators were measured by real-time polymerase chain reaction.

RESULTS: Serum creatinine and urea levels showed differences between untreated wild-type and glycerol-treated wild-type mice (0.66 ± 0.04 vs 2.61 ± 0.53 mg/dL, P < 0.01; and 33.51 ± 2.08 vs 330.2 ± 77.7 mg/dL, P < 0.005), and between untreated B₂ knockout mice and glycerol-treated knockout mice (0.56 ± 0.03 vs 2.23 ± 0.87 mg/dL, P < 0.05; and 42.49 ± 3.2 vs 327.2 ± 58.4 mg/dL, P < 0.01), but there was no difference between the glycerol-treated wild-type and glycerol-treated knockout mice. Glycerol was able to induce a striking increase in kinin B₂ receptor expression (> 30 times, 31.34 ± 8.9) in kidney. Animals injected with glycerol had a higher degree of tubular injury than untreated animals. Wild-type and knockout mice treated with glycerol intramuscularly present kidney injury, with impairment in renal function. However, B₂ knockout mice treated with glycerol did not show a different phenotype regarding kidney injury markers, when compared to the wild-type glycerol-treated group.

CONCLUSION: We conclude that the kinin B₂ receptor does not have a protective role in renal injury.

Obesity in kidney disease: A heavyweight opponent

Obesity is an important worldwide challenge that must be faced in most developed and developing countries because of unhealthy nutritional habits. The consequences of obesity and being overweight are observed in different organs, but the kidney is one of the most affected. Excess adipose tissue causes hemodynamic alterations in the kidney that can result in renal disease. However, obesity is also commonly associated with other comorbidities such as chronic inflammation, hypertension and diabetes. This association of several aggravating factors is still a matter of concern in clinical and basic research because the pathophysiologic mechanisms surrounding chronic kidney disease development in obese patients remain unclear. This review will discuss the consequences of obesity in the context of renal injury.

Chronic kidney disease prediction is an inexact science: The concept of “progressors” and “nonprogressors”

In 2002, the National Kidney Foundation Kidney Disease Outcomes Quality Initiative (NKF KDOQI) instituted new guidelines that established a novel chronic kidney disease (CKD) staging paradigm. This set of guidelines, since updated, is now very widely accepted around the world. Nevertheless, the authoritative United States Preventative Task Force had in August 2012 acknowledged that we know surprisingly little about whether screening adults with no signs or symptoms of CKD improve health outcomes and that we deserve better information on CKD. More recently, the American Society of Nephrology and the American College of Physicians, two very well respected United States professional physician organizations were strongly at odds coming out with exactly opposite recommendations regarding the need or otherwise for ”CKD screening” among the asymptomatic population. In this review, we revisit the various angles and perspectives of these conflicting arguments, raise unanswered questions regarding the validity and veracity of the NKF KDOQI CKD staging model, and raise even more questions about the soundness of its evidence-base. We show clinical evidence, from a Mayo Clinic Health System Renal Unit in Northwestern Wisconsin, United States, of the pitfalls of the current CKD staging model, show the inexactitude and unpredictable vagaries of current CKD prediction models and call for a more cautious and guarded application of CKD staging paradigms in clinical practice. The impacts of acute kidney injury on CKD initiation and CKD propagation and progression, the effects of such phenomenon as the syndrome of late onset renal failure from angiotensin blockade and the syndrome of rapid onset end stage renal disease on CKD initiation, CKD propagation and CKD progression to end stage renal disease all demand further study and analysis. Yet more research on CKD staging, CKD prognostication and CKD predictions is warranted. Finally and most importantly, cognizant of the very serious limitations and drawbacks of the NKF K/DOQI CKD staging model, the need to individualize CKD care, both in terms of patient care and prognostication, cannot be overemphasized.

Renin-angiotensin system in the kidney: What is new?

The renin-angiotensin system (RAS) has been known for more than a century as a cascade that regulates body fluid balance and blood pressure. Angiotensin II(Ang II) has many functions in different tissues; however it is on the kidney that this peptide exerts its main functions. New enzymes, alternative routes for Ang IIformation or even active Ang II-derived peptides have now been described acting on Ang II AT₁ or AT₂ receptors, or in receptors which have recently been cloned, such as Mas and AT₄. Another interesting observation was that old members of the RAS, such as angiotensin converting enzyme (ACE), renin and prorenin, well known by its enzymatic activity, can also activate intracellular signaling pathways, acting as an outside-in signal transduction molecule or on the renin/(Pro)renin receptor. Moreover, the endocrine RAS, now is also known to have paracrine, autocrine and intracrine action on different tissues, expressing necessary components for local Ang II formation. This in situ formation, especially in the kidney, increases Ang II levels to regulate blood pressure and renal functions. These discoveries, such as the ACE2/Ang-(1-7)/Mas axis and its antangonistic effect rather than classical deleterious Ang II effects, improves the development of new drugs for treating hypertension and cardiovascular diseases.

Recurrent epiploic appendagitis and peritoneal dialysis: A case report and literature review

Epiploic appendagitis (EA) is rare cause of acute or subacute abdominal pain in patients on peritoneal dialysis (PD), where the diagnosis can be challenging as the clinical features, laboratory markers and imaging characteristics have not been described previously in this group of patients. Here, we present the management of a case of EA in a patient on PD and review published literature pertinent to the subject. The importance of establishing the diagnosis early by laparoscopy is emphasised.

Pediatric lupus nephritis: Management update

Childhood-onset systemic lupus erythematosus (cSLE) is a severe multisystem autoimmune disease. Renal involvement occurs in the majority of cSLE patients and is often fatal. Renal biopsy is an important investigation in the management of lupus nephritis. Treatment of renal lupus consists of an induction phase and maintenance phase. Treatment of childhood lupus nephritis using steroids is associated with poor outcome and excess side-effects. The addition of cyclophosphamide to the treatment schedule has improved disease control. In view of treatment failure using these drugs and a tendency for non-adherence, many newer agents such as immune-modulators and monoclonal antibodies are being tried in patients with cSLE. Trials of these novel agents in the pediatric population are still lacking making a consensus in the management protocol of pediatric lupus nephritis difficult.

Frequent office visits of patients with chronic kidney disease: Is a prelude to prevention of dialysis

This study is an excerpt of broad-based office practice which is designed to treat patients with diabetes and hypertension, the two most common causes of chronic kidney disease (CKD), as well as CKD of unknown etiology. This model of office practice is dedicated to evaluating patients with CKD for their complete well-being; blood pressure control, fluid control and maintenance of acid-base status and hemoglobin. Frequent office visits, every four to six weeks, confer a healthy life style year after year associated with a feeling of good well-being and a positive outlook. Having gained that, such patients remain compliant to their medication and diet, and scheduled laboratory and office visits which are determinant of a dialysis-free life.

Silent diabetic nephropathy

AIM: To examine the risk of renal events in patients with biopsy-proven diabetic nephropathy (DN) and its possible associated factors.

METHODS: Clinical and histological data of 60 patients diagnosed with diabetic nephropathy were retrospectively collected. Patients with evidence or suspicion of other nephropathies were excluded from the study. The final event was defined as renal replacement therapy (RRT) initiation or progression of chronic kidney disease (CKD), according to the KDIGO 2012 definition of a decrease in CKD category and a decrease in GFR of 25% or more.

RESULTS: A total of 45 patients with a follow-up of at least 3 mo were included. Most of the patients presented type 2 DM, with a mean age of 58.3 years old. The time of evolution of DM was 9.6 ± 7.8 years, although in 13 patients, it was less than 5 years. A total of 62% of patients reached the final event in a median period of 3.4 years (95%CI: 2.1-4.7), with 21 of them requiring dialysis. The factors that were independently associated with renal survival were estimated glomerular filtration rate (eGFR) at the time of biopsy, cardiovascular disease (CVD) history and HbA1c less than 7%. Therefore, for each 10 mL/min per 1.73 m² reduction in eGFR, we obtained a DN progression risk of HR = 2 (1.3-3.0) (P = 0.001); patients with CVD were at greater risk for DN progression (HR = 2.8, 1.1-7.1, P = 0.032), and CKD patients with HbA1c < 7% demonstrated greater renal risk than patients with HbA1c ≥ 7%, with an HR of 2.9 (1.0-8.4) (P = 0.054).

CONCLUSION: A past history of CVD is a risk factor for DN progression. Levels of HbA1c less than 7% could favor an eGFR decrease in these patients.

Cystinosis as a lysosomal storage disease with multiple mutant alleles: Phenotypic-genotypic correlations

Cystinosis is an autosomal recessive lysosomal storage disease with an unclear enzymatic defect causing lysosomal cystine accumulation with no corresponding elevation of plasma cystine levels leading to multisystemic dysfunction. The systemic manifestations include a proximal renal tubular defect (Fanconi-like), endocrinal disturbances, eye involvements, with corneal, conjunctival and retinal depositions, and neurological manifestations in the form of brain and muscle dysfunction. Most of the long-term ill effects of cystinosis are observed particularly in patients with long survival as a result of a renal transplant. Its responsible CTNS gene that encodes the lysosomal cystine carrier protein (cystinosin) has been mapped on the short arm of chromosome 17 (Ch17 p13). There are three clinical forms based on the onset of main symptoms: nephropathic infantile form, nephropathic juvenile form and non-nephropathic adult form with predominant ocular manifestations. Avoidance of eye damage from sun exposure, use of cystine chelators (cysteamine) and finally renal transplantation are the main treatment lines. Pre-implantation genetic diagnosis for carrier parents is pivotal in the prevention of recurrence.

Primary focal and segmental glomerulosclerosis and soluble factor urokinase-type plasminogen activator receptor

Primary focal and segmental glomerulosclerosis (FSGS) may be due to genetic or acquired etiologies and is a common cause of nephrotic syndrome with high morbidity that often leads to end-stage renal failure. The different available therapeutic approaches are unsuccessful, in part due to partially deciphered heterogeneous and complex pathophysiological mechanisms. Moreover, the term FSGS, even in its primary form, comprises a histological description shared by a number of different causes with completely different molecular pathways of disease. This review focuses on the latest developments regarding the pathophysiology of primary acquired FSGS caused by soluble factor urokinase type plasminogen activator receptor, a circulating permeability factor involved in proteinuria and edema formation, and describes recent advances with potential success in therapy.

Vascular response to vasodilator treatment in microalbuminuric diabetic kidney disease

Under common practice, the conventional diagnostic marker such as microalbuminuria determination does not recognized early stage of diabetic kidney disease (normoalbuminuria, chronic kidney disease stage 1, 2); due to the insensitiveness of the available marker. Treatment at later stage (microalbuminuria) simply slows the renal disease progression, but is rather difficult to restore the renal perfusion. Intrarenal hemodynamic study in these patients revealed an impaired renal perfusion and abnormally elevated renal arteriolar resistances. Treatment with vasodilators such as angiotensin converting enzyme inhibitor and angiotensin receptor blocker fails to correct the renal ischemia. Recent study on vascular homeostasis revealed a defective mechanism associated with an impaired nitric oxide production which would explain the therapeutic resistance to vasodilator treatment in microalbuminuric diabetic kidney disease. This study implies that the appropriate therapeutic strategy should be implemented at earlier stage before the appearance of microalbuminuria.

A retrospective Aliskiren and Losartan study in non-diabetic chronic kidney disease

AIM: To assess the efficacy of combined Aliskiren and Losartan vs high dose Losartan and Aliskiren alone in chronic kidney disease (CKD).

METHODS: This is a retrospective study of 143 patients with non-diabetic CKD comparing combined Aliskiren (150 mg/d) with Losartan (100 mg/d) therapy vs High dose Angiotensin receptor blockers (ARB) (Losartan 200 mg/d) and the third group Aliskiren (150 mg/d) alone. This study involved only patient medical records. Entry criteria included those patients who had been treated with the above drugs for at least 36 mo within the 5 years period; other criteria included proteinuria of 1 g or more and or CKD Stage 3 at the start of the 36 mo period. The study utilised primary renal end points of estimated Glomerular Filtration Rate (eGFR) < 15 mL/min or end stage renal failure.

RESULTS: Patients treated with high dose ARB compared to the other two treatment groups had significantly less proteinuria at the end of 36 mo (P < 0.007). All 3 groups had significant reduction of proteinuria (P < 0.043, P < 0.001). Total urinary protein was significantly different between the 3 groups over the 3-year study period (P = 0.008), but not eGFR. The changes in eGFR from baseline to each year were not significantly different between the 3 therapeutic groups (P < 0.119). There were no significant differences in the systolic and diastolic blood pressure between the 3 drug groups throughout the 3 years. The incidence of hyperkalemia (> 5.5 mmol/L) was 14.2% (7/49) in the Combined Aliskiren and ARB group, 8.7% (4/46) in the Aliskiren alone group and 6.3% (3/48) in the High dose ARB group (P < 0.001).

CONCLUSION: This study in non-diabetic CKD patients showed that Combination therapy with Aliskiren and ARB was effective but was not safe as it was associated with a high prevalence of hyperkalaemia.

Vitamin E and diabetic nephropathy in mice model and humans

Diabetes mellitus (DM) is associated with increased oxidative stress due to elevated glucose levels in the plasma. Glucose promotes glycosylation of both plasma and cellular proteins with increased risk for vascular events. Diabetic patients suffer from a higher incidence of cardiovascular complications such as diabetic nephropathy. Haptoglobin (Hp) is an antioxidant plasma protein which binds free hemoglobin, thus preventing heme-iron mediated oxidation. Two alleles exist at the Hp gene locus (1 and 2) encoding three possible Hp genotypes that differ in their antioxidant ability, and may respond differently to vitamin E treatment. Several clinical studies to have shown that Hp 1-1 genotype is a superior antioxidant to the Hp 2-2 genotype and Hp 2-2 genotype is associated with a higher incidence of cardiovascular disease. Vitamin E was found to have beneficial effect in patient and mice with Hp 2-2 genotype. In this review we have summarized the results of our studies in patients with diabetic nephropathy treated with vitamin E and in diabetic mice with different haptoglobin genotypes.

Update on hemolytic uremic syndrome: Diagnostic and therapeutic recommendations

Hemolytic uremic syndrome (HUS) is a rare disease. In this work the authors review the recent findings on HUS, considering the different etiologic and pathogenetic classifications. New findings in genetics and, in particular, mutations of genes that encode the complement-regulatory proteins have improved our understanding of atypical HUS. Similarly, the complement proteins are clearly involved in all types of thrombotic microangiopathy: typical HUS, atypical HUS and thrombotic thrombocytopenic purpura (TTP). Furthermore, several secondary HUS appear to be related to abnormalities in complement genes in predisposed patients. The authors highlight the therapeutic aspects of this rare disease, examining both "traditional therapy" (including plasma therapy, kidney and kidney-liver transplantation) and "new therapies". The latter include anti-Shiga-toxin antibodies and anti-C5 monoclonal antibody "eculizumab". Eculizumab has been recently launched for the treatment of the atypical HUS, but it appears to be effective in the treatment of typical HUS and in TTP. Future therapies are in phases I and II. They include anti-C5 antibodies, which are more purified, less immunogenic and absorbed orally and, anti-C3 antibodies, which are more powerful, but potentially less safe. Additionally, infusions of recombinant complement-regulatory proteins are a potential future therapy.

Matrix metalloproteinases contribute to kidney fibrosis in chronic kidney diseases

Matrix metalloproteinases (MMPs) are members of the neutral proteinase family. They were previously thought to be anti-fibrotic because of their ability to degrade and remodel of extracellular matrix. However, recent studies have shown that MMPs are implicated in initiation and progression of kidney fibrosis through tubular cell epithelial–mesenchymal transition (EMT) as well as activation of resident fibroblasts, endothelial-mesenchymal transition (EndoMT) and pericyte-myofibroblast transdifferentiation. Interstitial macrophage infiltration has also been shown to correlate with the severity of kidney fibrosis in various chronic kidney diseases. MMPs secreted by macrophages, especially MMP-9, has been shown by us to be profibrotic by induction of tubular cells EMT. EMT is mainly induced by transforming growth factor-β (TGF-β). However, MMP-9 was found by us and others to be up-regulated by TGF-β1 in kidney tubular epithelial cells and secreted by activated macrophages, resulting in EMT and ultimately kidney fibrosis. Therefore, MMP-9 may serve as a potential therapeutic target to prevent kidney fibrosis in chronic kidney disease. This review, by a particular focus on EMT, seeks to provide a comprehensive understanding of MMPs, especially MMP-9, in kidney fibrosis.

Update on hemolytic uremic syndrome: Diagnostic and therapeutic recommendations

Hemolytic uremic syndrome (HUS) is a rare disease. In this work the authors review the recent findings on HUS, considering the different etiologic and pathogenetic classifications. New findings in genetics and, in particular, mutations of genes that encode the complement-regulatory proteins have improved our understanding of atypical HUS. Similarly, the complement proteins are clearly involved in all types of thrombotic microangiopathy: typical HUS, atypical HUS and thrombotic thrombocytopenic purpura (TTP). Furthermore, several secondary HUS appear to be related to abnormalities in complement genes in predisposed patients. The authors highlight the therapeutic aspects of this rare disease, examining both “traditional therapy” (including plasma therapy, kidney and kidney-liver transplantation) and “new therapies”. The latter include anti-Shiga-toxin antibodies and anti-C5 monoclonal antibody “eculizumab”. Eculizumab has been recently launched for the treatment of the atypical HUS, but it appears to be effective in the treatment of typical HUS and in TTP. Future therapies are in phases I and II. They include anti-C5 antibodies, which are more purified, less immunogenic and absorbed orally and, anti-C3 antibodies, which are more powerful, but potentially less safe. Additionally, infusions of recombinant complement-regulatory proteins are a potential future therapy.

Acute renal artery occlusion following infliximab infusion

We report the case of a 44-year-old male patient who presented with acute renal artery occlusion, 3 d after first injection of infliximab for steroid refractory attack of ulcerative colitis. Extensive work-up provided no evidence of predisposing factors for arterial thrombosis. Infliximab was thus suspected in the genesis of thrombosis, based on both intrinsic and extrinsic criteria. At month 3 after thrombosis with ongoing anticoagulation, angio-tomodensitometry showed complete revascularization of the left renal artery with renal atrophy. Renal function remained normal and the patient was still in steroid free remission on mercaptopurin monotherapy at maximal follow-up. Few thromboembolic events have been described with anti- tumor necrosis factor (TNF) agents, but it is the first case reported of renal artery thrombosis after infliximab infusion. In addition, we review thrombosis associated with anti-TNF agents.

Lowering vascular calcification burden in chronic kidney disease: Is it possible?

High prevalence of atherosclerosis and arterial calcification in chronic kidney disease is far beyond the explanation by common cardiovascular risk factors such as aging diabetes, hypertension and dyslipidemia. The magnitude of coronary artery calcification is independently and inversely associated with renal function. In addition to cardiovascular risk factors, other chronic kidney disease-related risks such as phosphate retention, excess of calcium and prolonged dialysis vintage also contribute to the development of vascular calcification. Strategies to lower vascular calcification burden in chronic kidney disease population should include minimizing chronic kidney disease and atherosclerotic risk factors. Current therapies available are non-calcium containing phosphate binders, low dose active vitamin D and calcimimetic agent. The role of bisphosphonates in vascular calcification in chronic kidney disease population remains unclear. Preliminary data on sodium thiosulfate are promising, however, larger studies on efficacy and patient outcomes are necessary. Several large randomized controlled trials have confirmed the lack of benefit of statin in attenuating the progression of vascular calcification.

Evaluation of microvascular reactivity with laser Doppler flowmetry in chronic kidney disease

Cardiovascular diseases are the major causes of mortality in patients with chronic kidney disease (CKD). The complex process of accelerated athero- and arteriosclerosis in CKD is associated with this phenomenon, where endothelial dysfunction (ED) is one of the initial steps. Hence, the early diagnosis of ED can potentially lead to early interventions which could result in a better outcome for these patients. Several methodologies have been developed for the diagnosis of ED. Laser Doppler flowmetry (LDF) enables us to study the microcirculation continuously in a non-invasive manner. In our review we would like to focus on different tests developed for LDF, like postocclusive reactive hyperaemia, local heating, iontophoresis, microdialysis or analysis of flowmotion. We would also like to summarize the available data in CKD with these methodologies to enlighten their perspectives in the clinical use on this patient population.

Arteriovenous fistulas and digital hypoperfusion ischemic syndrome in patients on hemodialysis

AIM: To determine survival parameters as well as characteristics of patients with this syndrome.

METHODS: The investigation was conducted over a period of eight years, as a prospective, non-randomized, clinical study which included 204 patients, treated by chronic hemodialysis. Most patients received hemodialysis 12 h per week. As vascular access for hemodialysis all subjects had an arteriovenous fistulae. Based on surveys the respondents were divided into groups of patients with and without digital hypoperfusion ischemic syndrome. Gender, demographic and anthropometric characteristics, together with comorbidity and certain habits, were recorded. During this period 34.8% patients died.

RESULTS: Patients with digital hypoperfusion ischemic syndrome were older than those without ischemia (P = 0.01). Hemodialysis treatment lasted significantly longer in the patients with digital hypoperfusion ischemic syndrome (P = 0.02). The incidence of cardiovascular disease (P < 0.001) and diabetes mellitus (P = 0.01), as well as blood flow through the arteriovenous fistula (P = 0.036), were higher in patients with digital hypoperfusion ischemic syndrome. Statistically significant differences also existed in relation to oxygen saturation (P = 0.04). Predictive parameters of survival for patients with digital hypoperfusion ischemic syndrome were: adequacy of hemodialysis (B = -3.604, P < 0.001), hypertension (B = -0.920, P = 0.018), smoking (B = -0.901, P = 0.049), diabetes mellitus (B = 1.227, P = 0.005), erythropoietin therapy (B = 1.274, P = 0.002) and hemodiafiltration (B = -1.242, P = 0.033). Kaplan-Meier survival analysis indicated that subjects with and without digital hypoperfusion ischemic syndrome differed regarding the length of survival (P < 0.001), i.e., patients with confirmed digital hypoperfusion ischemic syndrome died earlier.

CONCLUSION: Survival was significantly longer in the patients without digital hypoperfusion ischemic syndrome.

Hepcidin-25 negatively predicts left ventricular mass index in chronic kidney disease patients

AIM: To assess the correlation between the serum hepcidin-25 level and left ventricular mass index.

METHODS: This study was a cross-sectional study conducted between March 2009 and April 2010. Demographic and biochemical data, including the serum hepcidin-25 level, were collected for chronic kidney disease (CKD) patients. Two-dimensional echocardiography was performed to determine the left ventricle mass (LVM), left ventricular mass index (LVMI), interventricular septum thickness (IVSd), left ventricle posterior wall thickness (LVPW), right ventricular dimension (RVD), left atrium (LA) and ejection fraction (EF).

RESULTS: A total of 146 patients with stage 1 to 5 CKD were enrolled. Serum hepcidin-25 levels were 16.51 ± 5.2, 17.59 ± 5.32, 17.38 ± 6.47, 19.98 ± 4.98 and 22.03 ± 4.8 ng/mL for stage 1 to 5 CKD patients, respectively. Hepcidin-25 level was independently predicted by the serum ferritin level (β = 0.6, P = 0.002) and the estimated glomerular filtration rate (β = -0.48, P = 0.04). There were negative correlations between the serum hepcidin level and the LVM and LVMI (P = 0.04 and P = 0.005, respectively). Systolic blood pressure (BP) was positively correlated with the LVMI (P = 0.005). In the multivariate analysis, a decreased serum hepcidin-25 level was independently associated with a higher LVMI (β = -0.28, 95%CI: -0.48 - -0.02, P = 0.006) after adjusting for body mass index, age and systolic BP.

CONCLUSION: A lower serum hepcidin level is associated with a higher LVMI in CKD patients. Low hepcidin levels may be independently correlated with unfavorable cardiovascular outcomes in this population.

Inflammatory status in chronic renal failure: The role of homocysteinemia and pro-inflammatory cytokines

AIM: To evaluate determinants of inflammatory markers in chronic renal failure patients according to the level of glomerular filtration rate.

METHODS: One hundred fifty four patients (Age: 44 ± 06 years; male/female: 66/88) with chronic renal failure (CRF) were divided into 6 groups according to the National Kidney Foundation (NKF) classification. They included 28 primary stage renal failure patients (CRF 1), 28 moderate stage renal failure patients (CRF 2), 28 severe stage renal failure patients (CRF 3), 18 end-stage renal failure patients (CRF 4), 40 hemodialysis (HD) patients, and 12 peritoneal dialysis (PD) patients. Tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6) and C-reactive protein (CRP) were analyzed by immunosorbent assay kit (ELISA) (Cayman Chemical’s ACETM EIA kit). Immunoassay methods were used for total homocysteine (tHcy) (fluorescence polarization immunoanalysis HPLC, PerkinEmer 200 series), transferrin (MININEPHTM human transferin kit: ZK070.R), ferritin (ADVIA Centaur) and fibrinogen analysis (ACL 200). Differences between groups were performed using SPSS 20.0 and data are expressed as the mean ± SD.

RESULTS: Results showed that in comparison with CRF 1 group and other groups, TNF-α and IL-6 levels were respectively more elevated in HD (16.38 ± 5.52 pg/mL vs 0.39 ± 0.03 pg/mL, 11.05 ± 3.59 pg/mL vs 8.20 ± 0.22 pg/mL, P < 0.001) and PD (14.04 ± 3.40 pg/mL vs 0.39 ± 0.03 pg/mL, 10.15 ± 1.66 pg/mL vs 8.20 ± 0.22 pg/mL, P < 0.001). IL-1β levels were increased in HD (9.63 ± 3.50 pg/mL vs 3.24 ± 0.10 pg/mL, P < 0.001) and CRF 4 (7.76 ± 0.66 pg/mL vs 3.24 ± 0.10 pg/mL, P < 0.001) patients than in CRF 1 and in the other groups. Plasma tHcy levels were higher in HD (32.27 ± 12.08 μmol/L) and PD (28.37 ± 4.98 μmol/L) patients compared to the other groups of CRF (P < 0.001). The serum CRP level was significantly increased in HD (18.17 ± 6.38 mg/L) and PD (17.97 ± 4.85 mg/L) patients compared to the other groups of CRF patients (P < 0.001). The plasma fibrinogen level was more elevated in HD (6.86 ± 1.06 g/L) and CRF 4 (6.05 ± 0.57 g/L) than in the other groups (P < 0.001). Furthermore; the ferritin level was higher in HD (169.90 ± 62.16 ng/mL) and PD (90.08 ± 22.09 ng/mL) patients compared to the other groups of CRF (P < 0.001). The serum transferrin value was significantly decreased especially in PD (1.78 ± 0.21 g/L) compared to the other groups (P < 0.001). We found a negative correlation between glomerular filtration rate (GFR), TNF-α levels (r = -0.75, P < 0.001), and tHcy levels (r = -0.68, P < 0.001). We observed a positive correlation between GFR and transferrin levels (r = 0.60, P < 0.001).

CONCLUSION: CRF was associated with elevated inflammatory markers. The inflammation was observed at the severe stage of CRF and increases with progression of renal failure.

Calcitriol-induced hypercalcemia in a patient with granulomatous mycosis fungoides and end-stage renal disease

An 86-year-old man, diagnosed as having mycosis fungoides in May 2008 and treated with repeated radiation therapy, was admitted to our hospital for initiation of hemodialysis due to end-stage renal disease (ESRD) in April 2012. On admission, his corrected serum calcium level was 9.3 mg/dL, and his intact parathyroid hormone level was 121.9 pg/mL (normal range 13.9-78.5 pg/mL), indicating secondary hyperparathyroidism due to ESRD. After starting hemodialysis, urinary volume diminished rapidly. The serum calcium level increased (12.7 mg/dL), and the intact parathyroid hormone level was suppressed (< 5 pg/mL), while the 1,25-dihydroxyvitamin D₃ (calcitriol) level increased (114 pg/mL, normal range: 20.0-60.0 pg/mL) in June 2012. The possibilities of sarcoidosis and tuberculosis were ruled out. Skin biopsies from tumorous lesions revealed a diagnosis of granulomatous mycosis fungoides. The serum soluble interleukin-2 receptor levels and the degrees of skin lesions went in parallel with the increased serum calcium and calcitriol levels. Therefore, the patient was diagnosed as having calcitriol-induced hypercalcemia possibly associated with granulomatous mycosis fungoides. Granulomatous mycosis fungoides is rare, and its association with calcitriol-induced hypercalcemia has not been reported. Careful attention to calcium metabolism is needed in patients with granulomatous mycosis fungoides, especially in patients with ESRD.

Uric acid and chronic kidney disease: A time to act?

A role for uric acid in the pathogenesis and progression of renal disease had been proposed almost a century ago, but, too hastily dismissed in the early eighties. A body of evidence, mostly accumulated during the last decade, has led to a reappraisal of the influence of uric acid on hypertension, cardiovascular, and renal disease. The focus of this review will be solely on the relationship between serum uric acid and renal function and disease. We will review experimental evidence derived from animal and human studies, evidence gathered from a number of epidemiological studies, and from the few (up to now) studies of uric-acid-lowering therapy. Some space will be also devoted to the effects of uric acid in special populations, such as diabetics and recipients of kidney allografts. Finally we will briefly discuss the challenges of a trial of uric-acid-lowering treatment, and the recent suggestions on how to conduct such a trial.

Roles of adaptor proteins in podocyte biology

Podocytes covering the glomerular basement membrane over the glomerular capillary consist of three morphologically and functionally different segments, the cell body, major processes and extending finger-like foot processes (FPs). The FPs of neighboring podocytes are connected by a continuous adherent junction structure named the slit diaphragm (SD). The extracellular SD is linked to the intracellular, a highly dynamic, cytoskeleton through adaptor proteins. These adaptor proteins, such as CD2-associated protein, zonula occludens 1, β-catenin, Nck and p130Cas, located at the intracellular SD insertion area near lipid rafts, have important structural and functional roles. Adaptor proteins in podocytes play important roles as a structural component of the podocyte structure, linking the SD to the cytoskeletal structure and as a signaling platform sending signals from the SD to the actin cytoskeleton. This review discusses the roles of adaptor proteins in the podocyte cytoskeletal structure and signaling from the SD to the actin cytoskeleton.

Pericytes synthesize renin

AIM: To investigate renin expression in pericytes during normal kidney development and after deletion of angiotensinogen, the precursor for all angiotensins.

METHODS: We examined the distribution of renin expressing cells by immunoshistochemistry in the interstitial compartment of wild type (WT) and angiotensinogen deficient (AGT -/-) mice at different developmental stages from embryonic day 18 (E18: WT, n = 4; AGT -/-, n = 5) and at day 1 (P1: WT, n = 5; AGT -/-, n = 5), 5 (P5: WT, n = 7; AGT -/-, n = 8), 10 (P10: WT, n = 3; AGT -/-, n = 5), 21 (P21: WT, n = 7; AGT -/-, n = 5), 45 (P45: WT, n = 3; AGT -/-, n = 3), and 70 (P70: WT, n = 2; AGT -/-, n = 2) of postnatal life. We quantified the number of pericytes positive for renin at all the developmental stages mentioned above and compared the results of AGT -/- mice to their WT counterparts.

RESULTS: In WT mice, renal interstitial pericytes synthesize renin in early life supporting a lineage relationship with renin cells in the vasculature. The number of pericytes positive for renin per area of 0.32 mm² (density) in WT mice was maintained from fetal life till weaning age (E18 = 4.25 ± 0.63, P1 = 3.75 ± 0.48, P5 = 3.75 ± 0.48, P10 = 4 ± 0.71, P21 = 3.8 ± 0.58) and markedly decreased in adult life (P45 = 1.2 ± 0.37, P70 = 0.8 ± 0.20). On the other hand, in AGT -/- mice the density of pericytes expressing renin was not significantly different from WT mice at E18 and P1: E18 = 5.75 ± 0.50 vs 4.25 ± 0.63 (P = 0.106), P1 = 9.25 ± 3.50 vs 3.75 ± 0.48 (P = 0.175) but significantly increased from P5 till P70: P5 = 38.25 ± 5 vs 3.75 ± 0.48 (P = 0.0004), P10 = 173 ± 7.50 vs 4 ± 0.70 (P = 5.24567 × 10^-7), P21 = 83 ± 6.70 vs 3.8 ± 0.58 (P = 2.97358 × 10^-6), P45 = 49 ± 3.50 vs 1.2 ± 0.37 (P = 8.18274 x 10^-7) and P70 = 17.8 ± 2.30 vs 0.8 ± 0.20 (P = 3.51151 × 10^-5). The AGT -/- mice showed a marked increase in the number of pericytes per field studied starting from P5, reaching its peak at P10, and then a gradually decreasing until P70.

CONCLUSION: Interstitial pericytes synthesize renin during development and the number of renin-expressing pericytes increases in response to a homeostatic threat imposed early in life such as lack of angiotensinogen.

Erectile dysfunction in hemodialysis: A systematic review

Men with chronic renal failure (CRF) on hemodialysis have been frequently associated with erectile dysfunction (ED), with an of between 20% to 87.7%. As a result of the multi-system disease processes present in many uremic men, it is apparent that the pathogenesis of ED is most probably multifactorial. Factors to be considered include peripheral vascular disease, neurogenic abnormalities, hormonal disturbances and medications used for treatment of conditions associated with CRF. These physiological abnormalities may be supplemented by significant psychological stresses and abnormalities resulting from chronic illness. Treatment must start with the determination and treatment of the underlying causes. In addition to psychological treatment, further lines of treatment of ED in CRF can be classified as 1st line (medical treatment which includes oral phosphodiesterase-5 inhibitors and hormone regulation), 2nd line (intracavernosal injection, vacuum constriction devices and alprostadil urethral suppositories) or 3rd line (surgical treatment). Renal transplantation improves the quality of life for some patients with CRF and subsequently it may improve erectile function in a significant number of them, however still there is high incidence of ED after transplantation.

Urgent call for reconsideration of chronic kidney disease

Circulating toxins namely: free radicals, cytokines and metabolic products induce glomerular endothelial dysfunction, hemodynamic maladjustment and chronic ischemic state;this leads to tubulointerstitial fibrosis in chronic kidney disease (CKD). Altered vascular homeostasis observed in late stage CKD revealed defective angiogenesis and impaired nitric oxide production explaining therapeutic resistance to vasodilator treatment in late stage CKD. Under current practice, CKD patients are diagnosed and treated at a rather late stage due to the lack of sensitivity of the diagnostic markers available. This suggests the need for an alternative therapeutic strategy implementing the therapeutic approach at an early stage. This view is supported by the normal or mildly impaired vascular homeostasis observed in early stage CKD. Treatment at this early stage can potentially enhance renal perfusion, correct the renal ischemic state and restore renal function. Thus, this alternative therapeutic approach would effectively prevent end-stage renal disease.

Proton pump inhibitor-induced hypomagnesemia: A new challenge

Proton pump inhibitors (PPIs) are commonly used in clinical practice for the prevention and treatment of peptic ulcer, gastritis, esophagitis and gastroesophageal reflux. Hypomagnesemia has recently been recognized as a side effect of PPIs. Low magnesium levels may cause symptoms from several systems, some of which being potentially serious, such as tetany, seizures and arrhythmias. It seems that PPIs affect the gastrointestinal absorption of magnesium. Clinicians should be vigilant in order to timely consider and prevent or reverse hypomagnesemia in patients who take PPIs, especially if they are prone to this electrolyte disorder.

Treatment of young patients with lupus nephritis using calcineurin inhibitors

Recent advances in the management of lupus nephritis, together with earlier renal biopsy and selective use of aggressive immunosuppressive therapy, have contributed to a favorable outcome in children and adolescents with systemic lupus erythematosus (SLE). Nevertheless, we believe that a more effective and less toxic treatment is needed to attain an optimal control of the activity of lupus nephritis. Recent published papers and our experiences regarding treatment of young patients with lupus nephritis using calcineurin inhibitors are reviewed. Although it has been reported that intermittent monthly pulses of intravenous cyclophosphamide (IVCY) are effective for preserving renal function in adult patients, CPA is a potent immunosuppressive agent that induces severe toxicity, including myelo- and gonadal toxicity, and increases the risk of secondary malignancy. Thus, treatment for controlling lupus nephritis activity, especially in children and adolescents, remains challenging. Cyclosporine A (CsA) and tacrolimus (Tac) are T-cell-specific calcineurin inhibitors that prevent the activation of helper T cells, thereby inhibiting the transcription of the early activation genes of interleukin (IL)-2 and suppressing T cell-induced activation of tumor necrosis factor-α, IL-1β and IL-6. Therefore, both drugs, which we believe may be less cytotoxic, are attractive therapeutic options for young patients with lupus nephritis. Recently, a multidrug regimen of prednisolone (PDN), Tac, and mycophenolate mofetile (MMF) has been found effective and relatively safe in adult lupus nephritis. Since the mechanisms of action of MMF and Tac are probably complementary, multidrug therapy for lupus nephritis may be useful. We propose as an alternative to IVCY, a multidrug therapy with mizoribine, which acts very similarly to MMF, and Tac, which has a different mode of action, combined with PDN for pediatric-onset lupus nephritis. We also believe that a multidrug therapy including CsA and Tac may be an attractive option for young patients with SLE and lupus nephritis.

Treatment of dyslipidemia in chronic kidney disease: Effectiveness and safety of statins

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.

Hepcidin and HFE protein: Iron metabolism as a target for the anemia of chronic kidney disease

The anemia of chronic kidney disease and hemodialysis is characterized by chronic inflammation and release of cytokines, resulting in the upregulation of the iron hormone hepcidin, also increased by iron therapy and reduced glomerular filtration, with consequent reduction in iron absorption, recycling, and availability to the erythron. This response proves advantageous in the short-term to restrain iron availability to pathogens, but ultimately leads to severe anemia, and impairs the response to erythropoietin (Epo) and iron. Homozygosity for the common C282Y and H63D HFE polymorphisms influence iron metabolism by hampering hepcidin release by hepatocytes in response to increased iron stores, thereby resulting in inadequate inhibition of the activity of Ferroportin-1, inappropriately high iron absorption and recycling, and iron overload. However, in hemodialysis patients, carriage of HFE mutations may confer an adaptive benefit by decreasing hepcidin release in response to iron infusion and inflammation, thereby improving iron availability to erythropoiesis, anemia control, the response to Epo, and possibly survival. Therefore, anti-hepcidin therapies may improve anemia management in hemodialysis. However, HFE mutations directly favor hemoglobinization independently of hepcidin, and reduce macrophages activation in response to inflammation, whereas hepcidin might also play a beneficial anti-inflammatory and anti-microbic action during sepsis, so that direct inhibition of HFE-mediated regulation of iron metabolism may represent a valuable alternative therapeutic target. Genetic studies may offer a valuable tool to test these hypotheses and guide the research of new therapies.

Chronic kidney disease in acute coronary syndromes

Chronic kidney disease (CKD) is associated with a high burden of coronary artery disease. In patients with acute coronary syndromes (ACS), CKD is highly prevalent and associated with poor short- and long-term outcomes. Management of patients with CKD presenting with ACS is more complex than in the general population because of the lack of well-designed randomized trials assessing therapeutic strategies in such patients. The almost uniform exclusion of patients with CKD from randomized studies evaluating new targeted therapies for ACS, coupled with concerns about further deterioration of renal function and therapy-related toxic effects, may explain the less frequent use of proven medical therapies in this subgroup of high-risk patients. However, these patients potentially have much to gain from conventional revascularization strategies used in the general population. The objective of this review is to summarize the current evidence regarding the epidemiology and the clinical and prognostic relevance of CKD in ACS patients, in particular with respect to unresolved issues and uncertainties regarding recommended medical therapies and coronary revascularization strategies.

Role of renal proximal tubule transport in thiazolidinedione-induced volume expansion

Thiazolidinediones (TZDs), pharmacological activators of peroxisome-proliferator-activated receptors γ (PPARγ), significantly improve insulin resistance and lower plasma glucose concentrations. However, the use of TZDs is associated with plasma volume expansion, the mechanism of which has been a matter of controversy. Originally, PPARγ-mediated enhanced transcription of the epithelial Na channel (ENaC) γ subunit was thought to play a central role in TZD-induced volume expansion. However, later studies suggested that the activation of ENaC alone could not explain TZD-induced volume expansion. We have recently shown that TZDs rapidly stimulate sodium-coupled bicarbonate absorption from renal proximal tubule (PT) in vitro and in vivo. TZD-induced transport stimulation was dependent on PPARγ/Src/EGFR/ERK, and observed in rat, rabbit and human. However, this stimulation was not observed in mouse PTs where Src/EGFR is constitutively activated. Analysis in mouse embryonic fibroblast cells confirmed the existence of PPARγ/Src-dependent non-genomic signaling, which requires the ligand binding ability but not the transcriptional activity of PPARγ. The TZD-induced enhancement of association between PPARγ and Src supports an obligatory role for Src in this signaling. These results support the view that TZD-induced volume expansion is multifactorial. In addition to the PPARγ-dependent enhanced expression of the sodium transport system(s) in distal nephrons, the PPARγ-dependent non-genomic stimulation of renal proximal transport may be also involved in TZD-induced volume expansion.

Metabolic bone diseases in kidney transplant recipients

Metabolic bone disease after kidney transplantation has a complex pathophysiology and heterogeneous histology. Pre-existing renal osteodystrophy may not resolve completely, but continue or evolve into a different osteodystrophy. Rapid bone loss immediately after transplant can persist, at a lower rate, for years to come. These greatly increase the risk of bone fracture and vertebral collapse. Each patient may have multiple risk factors of bone loss, such as steroids usage, hypogonadism, persistent hyperparathyroidism (HPT), poor allograft function, metabolic acidosis, hypophosphatemia, vitamin D deficiency, aging, immobility and chronic disease. Clinical management requires a comprehensive approach to address the underlying and ongoing disease processes. Successful prevention of bone loss has been shown with vitamin D, bisphosphonates, calcitonin as well as treatment of hypogonadism and HPT. Novel approach to restore the normal bone remodeling and improve the bone quality may be needed in order to effectively decrease bone fracture rate in kidney transplant recipients.

Creatinine, urea, uric acid, water and electrolytes renal handling in the healthy oldest old

Renal physiology in the healthy oldest old has the following characteristics, in comparison with the renal physiology in the young: a reduced creatinine clearance, tubular pattern of creatinine back-filtration, preserved proximal tubule sodium reabsorption and uric acid secretion, reduced sodium reabsorption in the thick ascending loop of Henle, reduced free water clearance, increased urea excretion, presence of medulla hypotonicity, reduced urinary dilution and concentration capabilities, and finally a reduced collecting tubules response to furosemide which expresses a reduced potassium excretion in this segment due to a sort of aldosterone resistance. All physiological changes of the aged kidney are the same in both genders.

Peritoneal dialysis associated infections: An update on diagnosis and management

Peritoneal dialysis (PD) is associated with a high risk of infection of the peritoneum, subcutaneous tunnel and catheter exit site. Although quality standards demand an infection rate < 0.67 episodes/patient/year on dialysis, the reported overall rate of PD associated infection is 0.24-1.66 episodes/patient/year. It is estimated that for every 0.5-per-year increase in peritonitis rate, the risk of death increases by 4% and 18% of the episodes resulted in removal of the PD catheter and 3.5% resulted in death. Improved diagnosis, increased awareness of causative agents in addition to other measures will facilitate prompt management of PD associated infection and salvage of PD modality. The aims of this review are to determine the magnitude of the infection problem, identify possible risk factors and provide an update on the diagnosis and management of PD associated infection. Gram-positive cocci such as Staphylococcus epidermidis, other coagulase negative staphylococcoci, and Staphylococcus aureus (S. aureus) are the most frequent aetiological agents of PD-associated peritonitis worldwide. Empiric antibiotic therapy must cover both gram-positive and gram-negative organisms. However, use of systemic vancomycin and ciprofloxacin administration for example, is a simple and efficient first-line protocol antibiotic therapy for PD peritonitis - success rate of 77%. However, for fungal PD peritonitis, it is now standard practice to remove PD catheters in addition to antifungal treatment for a minimum of 3 wk and subsequent transfer to hemodialysis. To prevent PD associated infections, prophylactic antibiotic administration before catheter placement, adequate patient training, exit-site care, and treatment for S. aureus nasal carriage should be employed. Mupirocin treatment can reduce the risk of exit site infection by 46% but it cannot decrease the risk of peritonitis due to all organisms.

Vitamin E-derived copolymers continue the challenge to hemodialysis biomaterials

Improving material biocompatibility has been a continuous effort and remains a major goal of dialysis therapy. In this respect, vitamin E-modified copolymers have been used to produce a generation of biomaterials that has offered new clinical challenges and the chance of further improving the quality of synthetic hemodialyser membranes. This mini review article describes the evolution of these copolymers that only recently have been adopted to develop new vitamin E-modified polysulfone hemodialysers. Biomaterial characteristics and clinical aspects of these membranes are discussed, starting from the most recent contributions that have appeared in the literature that are of interest for the community of nephrology and dialysis specialists, as well as biomaterial scientists.