Chronic kidney disease: a new look at pathogenetic mechanisms and treatment options

Study on the mechanism of hirudin multi target delaying renal function decline in chronic kidney disease based on the "gut-kidney axis" theory

The disorder of the "gut-kidney axis" exacerbates renal function decline in chronic kidney disease (CKD), and current CKD therapy is insufficient to address this issue. Hirudin has a palliative effect on the decline of renal function. However, whether hirudin can delay CKD by regulating the "intestinal renal axis" disorder remains unclear. Unilateral ureteral ligation (UUO) induced CKD rat model, and the rats were treated with bifidobacterium and hirudin for 36 days. After 14 and 36 days of modeling, kidney and colon tissues were collected for pathology, western blot (WB) assay, and quantitative real-time PCR (qPCR) detection. Serum samples were collected for renal function testing. Fecal samples were used for 16S rRNA sequencing and research on fecal bacterial transplantation. Lipopolysaccharide combine with adenosine 5'-triphosphate (LPS + ATP)-induced intestinal epithelial cell injury was treated with a nod-like receptor pyrin domain-associated protein 3 (NLRP3) inhibitor and hirudin. Protein expression was detected using WB and qPCR. The kidneys and colons of the CKD rats exhibited varying degrees of lesions. Creatinine (CRE), blood urea nitrogen (BUN), N-acetyl-β-D-glucosidase (NAG) enzyme, and serum uremic toxins were elevated. The expression of claudin-1 and occludin was decreased, NLRP3 inflammatory-related proteins were increased, and the gut microbiota was disrupted. These pathological changes were more pronounced after 36 days of modeling. Meanwhile, high-dose hirudin treatment significantly improved these lesions and restored the intestinal flora to homeostasis in CKD rats. In vitro, hirudin demonstrated comparable effects to NLRP3 inhibitors by upregulating claudin-1 and occludin expression, and downregulating NLRP3 inflammatory-related proteins expression. The dysbiosis of the gut microbiota and impaired intestinal epithelial barrier function in CKD are associated with renal dysfunction in CKD. Hirudin delays the progression of CKD by regulating the disorder of the "gut-kidney axis" and inhibiting the activation of the NLRP3-ASC-caspase-1 pathway.

Dioscorea nipponica Makino: A comprehensive review of its chemical composition and pharmacology on chronic kidney disease

Chronic kidney disease (CKD) is a widespread ailment that significantly impacts global health. It is characterized by high prevalence, poor prognosis, and substantial healthcare costs, making it a major public health concern. The current clinical treatments for CKD are not entirely satisfactory, leading to a high demand for alternative therapeutic options. Chinese herbal medicine, with its long history, diverse varieties, and proven efficacy, offers a promising avenue for exploration. One such Chinese herbal medicine, Dioscorea nipponica Makino (DNM), is frequently used to treat kidney diseases. In this review, we have compiled studies examining the mechanisms of action of DNM in the context of CKD, focusing on five primary areas: improvement of oxidative stress, inhibition of renal fibrosis, regulation of metabolism, reduction of inflammatory response, and regulation of autophagy.

Chronic Kidney Disease as a Risk Factor for Heart Failure With Preserved Ejection Fraction: A Focus on Microcirculatory Factors and Therapeutic Targets

Heart failure (HF) and chronic kidney disease (CKD) co-exist, and it is estimated that about 50% of HF patients suffer from CKD. Although studies have been performed on the association between CKD and HF with reduced ejection fraction (HFrEF), less is known about the link between CKD and heart failure with preserved ejection fraction (HFpEF). Approximately, 50% of all patients with HF suffer from HFpEF, and this percentage is projected to rise in the coming years. Therapies for HFrEF are long established and considered quite successful. In contrast, clinical trials for treatment of HFpEF have all shown negative or disputable results. This is likely due to the multifactorial character and the lack of pathophysiological knowledge of HFpEF. The typical co-existence of HFpEF and CKD is partially due to common underlying comorbidities, such as hypertension, dyslipidemia and diabetes. Macrovascular changes accompanying CKD, such as hypertension and arterial stiffening, have been described to contribute to HFpEF development. Furthermore, several renal factors have a direct impact on the heart and/or coronary microvasculature and may underlie the association between CKD and HFpEF. These factors include: (1) activation of the renin-angiotensin-aldosterone system, (2) anemia, (3) hypercalcemia, hyperphosphatemia and increased levels of FGF-23, and (4) uremic toxins. This review critically discusses the above factors, focusing on their potential contribution to coronary dysfunction, left ventricular stiffening, and delayed left ventricular relaxation. We further summarize the directions of novel treatment options for HFpEF based on the contribution of these renal drivers.

Chronic kidney disease and urological disorders: systematic use of uroflowmetry in nephropathic patients

Background

Chronic kidney disease (CKD) is a highly prevalent condition. Urologic disorders are known causes of CKD, but often remain undiagnosed and underestimated also for their insidious onset and slow progression. We aimed to evaluate the prevalence of urological unrecognized diseases in CKD patients by uroflowmetry.

Methods

We enrolled consecutive stable CKD outpatients. The patients carried out two questionnaires, the International Prostate Symptom Score and Incontinence Questionnaire-Short Form, and they also underwent uroflowmetry, evaluating max flow rate (Q_max), voiding time and voided volume values.

Results

A total of 83 patients (43 males, mean age of 59.8 ± 13.3 years) were enrolled. Our study showed 28 males and 10 females with a significant reduction of Q_max (P < 0.001) while 21 females reported a significant increase of Q_max (P < 0.001) with a prevalence of 49.5% of functional urological disease. Moreover, we showed a significant association between Q_max and creatinine (P = 0.013), estimated glomerular filtration rate (P = 0.029) and voiding volume (P = 0.05). We have not shown significant associations with age (P = 0.215), body mass index (P = 0.793), systolic blood pressure (P = 0.642) or diastolic blood pressure (P = 0.305). Moreover, Pearson’s chi-squared test showed a significant association between Q_max altered with CKD (χ²  = 1.885, P = 0.170) and recurrent infection (χ² = 8.886, P = 0.012), while we have not shown an association with proteinuria (χ² = 0.484, P = 0.785), diabetes (χ² = 0.334, P = 0.563) or hypertension (χ² = 1.885, P = 0.170).

Conclusions

We showed an elevated prevalence of urological diseases in nephropathic patients; therefore, we suggest to include uroflowmetry in CKD patient assessment, considering the non-invasiveness, repeatability and low cost of examination. Uroflowmetry could be used to identify previously unrecognized urological diseases, which may prevent the onset of CKD or progression to end-stage renal disease and reduce the costs of management.

Fisetin and telmisartan each alone or in low-dose combination alleviate OVA-induced food allergy in mice

BACKGROUND

Food allergy (FA) is a worldwide health problem, affecting nearly 10% of all populations, with no prophylactic options or regulatory treatment available until now. Fisetin, a biologically active flavonoid, and telmisartan, the highly selective competitive AT1 receptor antagonist, recently exhibited potent anti-inflammatory and immunomodulatory activities. In the present study, we have evaluated the possible anti-inflammatory and immunomodulatory activities of fisetin and telmisartan each alone or in low-dose combination in a mouse model of FA.

METHODS

For induction of FA, eight-week-old BALB/c mice, sensitized by two ip injection of 50 μg ovalbumin (OVA) and 1 mg alum at day 0 and 7. Then, each mouse challenged with 10 mg OVA at days 14, 16, 18, and 21. On the 28^th day, the fifth challenge carried out by oral administration of 50 mg OVA. Either fisetin (1 or 3 mg/kg/d), telmisartan (1 or 3 mg/kg/d) or a combination of fisetin 1 mg/kg/d and telmisartan 1 mg/kg/d received orally from the 13^th day till 28^th day. In challenge days, the treatments received one-hour before the challenge.

RESULTS

Our data showed that fisetin and telmisartan each alone or in low-dose combination attenuated the anaphylactic manifestation, decreased blood eosinophilic count, serum OVA-specific IgE, and IL-4 levels, the intestinal total and degranulated mast cells count, and CD4⁺ immunohistochemical expression. Furthermore, they enhanced the serum IFN-γ level and abrogated the intestinal histopathological changes induced by OVA in mice.

CONCLUSION

Either fisetin, telmisartan or their low-dose combination could be promising in the management of FA.

Hematuria and Proteinuria in Children

Practice Gap

Pediatricians must be aware of screening indications and the evaluation

and management of a child with hematuria and/or proteinuria.

Objectives

After completing this article, readers should be able to:

1. Understand the common causes of proteinuria and hematuria and be able to differentiate between benign and serious causes.

2. Describe screening techniques for initial evaluation of hematuria and proteinuria.

3. Recognize the criteria for diagnosis of proteinuria and hematuria.

4. Plan the appropriate initial evaluation for hematuria and proteinuria and interpret laboratory findings essential for diagnosis.

5. Recognize serious causes of hematuria and proteinuria that warrant immediate referral.

Prospective cohort analyzing risk factors for chronic kidney disease progression in children

OBJECTIVE

To identify risk factors for chronic kidney disease progression in Brazilian children and to evaluate the interactions between factors.

METHODS

This was a multicenter prospective cohort in São Paulo, involving 209 children with CKD stages 3-4. The study outcome included: (a) death, (b) start of kidney replacement therapy, (c) eGFR decrease >50% during the followup. Thirteen risk factors were tested using univariate regression models, followed by multivariable Cox regression models. The terms of interaction between the variables showing significant association with the outcome were then introduced to the model.

RESULTS

After a median follow-up of 2.5 years (IQR=1.4-3.0), the outcome occurred in 44 cases (21%): 22 started dialysis, 12 had >50% eGFR decrease, seven underwent transplantation, and three died. Advanced CKD stage at onset (HR=2.16, CI=1.14-4.09), nephrotic proteinuria (HR=2.89, CI=1.49-5.62), age (HR=1.10, CI=1.01-1.17), systolic blood pressure Z score (HR=1.36, CI=1.08-1.70), and anemia (HR=2.60, CI=1.41-4.77) were associated with the outcome. An interaction between anemia and nephrotic proteinuria at V1 (HR=0.25, CI=0.06-1.00) was detected.

CONCLUSIONS

As the first CKD cohort in the southern hemisphere, this study supports the main factors reported in developed countries with regards to CKD progression, affirming the potential role of treatments to slow CKD evolution. The detected interaction suggests that anemia may be more deleterious for CKD progression in patients without proteinuria and should be further studied.

Protective effects of probucol on Ox-LDL-induced epithelial-mesenchymal transition in human renal proximal tubular epithelial cells via LOX‑1/ROS/MAPK signaling

Oxidized low-density lipoprotein (Ox-LDL), as a strong oxidant, results in renal injury through multiple mechanisms. The aim of the present study was to determine the injury effects of Ox‑LDL and the potential protective effects of the antioxidant reagent probucol on epithelial‑mesenchymal transition (EMT) in human renal proximal tubular epithelial cells (HK‑2) and to further explore the role and interrelation of lectin‑like oxidized low‑density lipoprotein receptor‑1 (LOX‑1), reactive oxygen species (ROS) and mitogen‑activated protein kinase (MAPK) pathway. In the present study, concentrations of 0‑100 µg/ml Ox‑LDL were used to induce HK‑2 cell EMT. Then, probucol (20 µmol/l) and the LOX‑1 inhibitor, polyinosinic acid (250 µg/ml), were also used to pretreat HK‑2 cells. Intracellular ROS activity was evaluated using the specific probe 2',7'‑dichlorodihydrofluorescein diacetate (DCFH‑DA). Concentration of nitric oxide (NO) was determined using a biochemical colorimetric method. Expression of E‑cadherin, α‑smooth muscle actin (SMA), LOX‑1, NADPH oxidase 4 (NOX4), cytochrome b‑245 α chain (p22phox), extracellular signal‑regulated kinase (ERK), and p38 MAPK protein levels were examined by western blotting. The results revealed that Ox‑LDL induced the expression of LOX‑1 and α‑SMA and reduced the expression of E‑cadherin in a dose‑dependent manner, and these effects were inhibited by polyinosinic acid or probucol pretreatment. Stimulation with 50 µg/ml Ox‑LDL induced the expression of NOX4 and p22phox and increased intracellular ROS activity, but NO production in the cell supernatants was not affected. The Ox‑LDL‑mediated increases in Nox4 and p22phox expression and in ROS activity were inhibited by probucol pretreatment. Further investigations into the underlying molecular pathways demonstrated that ERK and p38 MAPK were activated by Ox‑LDL stimulation and then inhibited by probucol pretreatment. The findings of the present study therefore suggest that Ox‑LDL induced EMT in HK‑2 cells, the mechanism of which may be associated with LOX‑1‑related oxidative stress via the ERK and p38 MAPK pathways. Notably, pretreatment with probucol inhibited the Ox‑LDL‑induced oxidative stress by reducing the expression of LOX‑1, and blocked the progression of EMT.

In Vitro Selection of Cell-Internalizing DNA Aptamers in a Model System of Inflammatory Kidney Disease

Chronic kidney disease (CKD) is a progressive pathological condition marked by a gradual loss of kidney function. Treatment of CKD is most effective when diagnosed at an early stage and patients are still asymptomatic. However, current diagnostic biomarkers (e.g., serum creatinine and urine albumin) are insufficient for prediction of the pathogenesis of the disease. To address this need, we applied a cell-SELEX (systematic evolution of ligands by exponential enrichment) approach and identified a series of DNA aptamers, which exhibit high affinity and selectivity for cytokine-stimulated cells, resembling some aspects of a CKD phenotype. The cell-SELEX approach was driven toward the enrichment of aptamers that internalize via the endosomal pathway by isolating the endosomal fractions in each selection cycle. Indeed, we demonstrated co-localization of selected aptamers with lysosomal-associated membrane protein 1 (LAMP-1), a late endosomal and lysosomal marker protein, by fluorescence in situ hybridization. These findings are consistent with binding and subsequent internalization of the aptamers into cytokine-stimulated cells. Thus, our study sets the stage for applying selected DNA aptamers as theragnostic reagents for the development of targeted therapies to combat CKD.

Hypertension in pediatric patients with chronic kidney disease: management challenges

In contrast to adults where hypertension is a leading cause of chronic kidney disease, in pediatrics, hypertension is predominantly a sequela, however, an important one that, like in adults, is likely associated with a more rapid decline in kidney function or progression of chronic kidney disease to end stage. There is a significant issue with unrecognized, or masked, hypertension in childhood chronic kidney disease. Recent evidence and, therefore, guidelines now suggest targeting a blood pressure of <50th percentile for age, sex, and height in children with proteinuria and chronic kidney disease. This often cannot be achieved by monotherapy and additional agents need to be added. Blockade of the renin angiotensin aldosterone system represents the mainstay of therapy, although often limited by the side effect of hyperkalemia. The addition of a diuretic, at least in the earlier stages of chronic kidney disease, might help mitigate this problem.

Pericytes and immune cells contribute to complement activation in tubulointerstitial fibrosis

We have examined the pathogenic role of increased complement expression and activation during kidney fibrosis. Here, we show that PDGFRβ-positive pericytes isolated from mice subjected to obstructive or folic acid injury secrete C1q. This was associated with increased production of proinflammatory cytokines, extracellular matrix components, collagens, and increased Wnt3a-mediated activation of Wnt/β-catenin signaling, which are hallmarks of myofibroblast activation. Real-time PCR, immunoblots, immunohistochemistry, and flow cytometry analysis performed in whole kidney tissue confirmed increased expression of C1q, C1r, and C1s as well as complement activation, which is measured as increased synthesis of C3 fragments predominantly in the interstitial compartment. Flow studies localized increased C1q expression to PDGFRβ-positive pericytes as well as to CD45-positive cells. Although deletion of C1qA did not prevent kidney fibrosis, global deletion of C3 reduced macrophage infiltration, reduced synthesis of C3 fragments, and reduced fibrosis. Clodronate mediated depletion of CD11bF4/80 high macrophages in UUO mice also reduced complement gene expression and reduced fibrosis. Our studies demonstrate local synthesis of complement by both PDGFRβ-positive pericytes and CD45-positive cells in kidney fibrosis. Inhibition of complement activation represents a novel therapeutic target to ameliorate fibrosis and progression of chronic kidney disease.

Astaxanthin in cardiovascular health and disease: mechanisms of action, therapeutic merits, and knowledge gaps

Cardiovascular disease is the main contributor to morbidity and mortality worldwide.

Predicting Risk of Chronic Kidney Disease in Infants and Young Children at Diagnosis of Posterior Urethral Valves: Initial Ultrasound Kidney Characteristics and Validation of Parenchymal Area as Forecasters of Renal Reserve

PURPOSE

There is paucity of validated objective early imaging markers to help predict future renal deterioration in infants with posterior urethral valves. We evaluated the prognostic value of total renal parenchymal area, renal echogenicity and corticomedullary differentiation regarding future development of chronic kidney disease.

MATERIALS AND METHODS

We analyzed initial postnatal ultrasonographic images from serial posterior urethral valve cases seen at a single tertiary referral center using National Institutes of Health sponsored image processing software. Echogenicity and corticomedullary differentiation were objectively measured as ratios relative to the adjacent liver or spleen and between cortex and medulla. The primary study outcome, renal function at last followup, was dichotomized based on glomerular filtration rate and/or need for renal replacement therapy (dialysis or renal transplantation, stage 5 chronic kidney disease).

RESULTS

A total of 75 patients were evaluated, of whom 16 had progression to stage 5 chronic kidney disease after a mean ± SD followup of 64.2 ± 38.9 months. Mean renal parenchymal area was 21.41 cm(2) in patients without and 16 cm(2) in patients with stage 5 chronic kidney disease (p <0.001), and mean corticomedullary differentiation was 1.77 and 1.21, respectively (p <0.001). Bilateral echogenic kidneys were significantly associated with development of stage 5 chronic kidney disease (p = 0.004). The performance of corticomedullary differentiation in predicting stage 5 chronic kidney disease was statistically significant (AUROC 0.881, 95% CI 0.776-0.987, p <0.001).

CONCLUSIONS

Estimates of renal parenchyma quantity (total renal parenchymal area) and quality (corticomedullary differentiation and renal echogenicity) measured on initial postnatal ultrasound carry prognostic value in determining future risk of stage 5 chronic kidney disease in patients with posterior urethral valves. These data are promising for developing tools to risk stratify patients, counsel parents and customize monitoring protocols.

Comparison of Efficacy of Long-term Oral Treatment with Telmisartan and Benazepril in Cats with Chronic Kidney Disease

Background

The efficacy and benefits of telmisartan in cats with chronic kidney disease (CKD) have not previously been reported.

Hypothesis

Long‐term treatment of cats with CKD using telmisartan decreases urine protein‐to‐creatinine ratio (UP/C) similar to benazepril.

Animals

Two‐hundred and twenty‐four client‐owned adult cats with CKD.

Methods

Prospective, multicenter, controlled, randomized, parallel group, blinded clinical trial with noninferiority design. Cats were allocated in a 1 : 1 ratio to either telmisartan (1 mg/kg; n = 112) or benazepril (0.5–1.0 mg/kg; n = 112) PO q24 h. The primary endpoint was prospectively defined as the change in proteinuria (benazepril:telmisartan) based on a log transformed weighted average of UP/C change from baseline (AUC 0→t/t) as a percentage compared using a confidence interval (CI) approach. Changes of UP/C from baseline were assessed on all study days and corrected for multiple comparisons.

Results

Telmisartan proved noninferior to benazepril in controlling proteinuria (CI, −0.035 to 0.268). At Day 180, UP/C compared to baseline in the telmisartan group was significantly lower (−0.05 ± 0.31; P = .016), whereas in the benazepril group the change (−0.02 ± 0.48) was not statistically significant (P = .136). Similar results were obtained at all assessment points with significant decrease in UP/C occurring with telmisartan but not benazepril.

Conclusion and Clinical Importance

Both telmisartan and benazepril were well tolerated and safe. Telmisartan proved to be noninferior to benazepril and significantly decreased proteinuria relative to baseline at all assessment points whereas benazepril did not.

The impact of small kidneys

BACKGROUND

Small kidneys due to renal hypodysplasia (RHD) result from a decrease in nephron number. The objectives of this study were to identify clinical variables that determine long-term renal outcome in children with RHD and to define the role of kidney size as a predictor of developing end-stage renal disease (ESRD).

METHODS

This was a single-center retrospective cohort analysis. The primary outcome was development of ESRD. We identified 202 RHD cases, with 25 (12%) reaching ESRD at mean age of 8.9 (±6.6) years.

RESULTS

Children with RHD with a known genetic syndrome had the smallest kidneys while those with posterior urethral valves (PUV) had the largest kidneys at diagnosis. Cases with bilateral RHD were most likely to develop ESRD. Younger gestational age (OR 0.8, CI 0.69-0.99, p = 0.05), smaller kidney size at diagnosis (OR 0.13, CI 0.03-0.47, p = 0.002), lower best-estimated glomerular filtration rate (eGFR) (OR 0.74, CI 0.58-0.93, p = 0.01), proteinuria (OR 1.03, CI 1.01-1.05, p < 0.001) and high blood pressure (OR 1.02, CI 1.01-1.04, p = 0.01) were associated with development of ESRD, while kidney size at diagnosis was independently associated with ESRD (HR 0.03, CI 0.01-0.72, p = 0.043).

CONCLUSIONS

In children with RHD, kidney size at diagnosis predicts the likelihood of developing ESRD.

Renal function in patients with Wilms tumor

Survival in patients with Wilms tumor (WT) is excellent compared with other pediatric malignancies and adult renal tumors. Treatment-related long-term morbidity and mortality in WT survivors is an area of increasing concern. Renal dysfunction is an example of one of the most feared long-term issues observed in these survivors. Direct toxicity from chemotherapy and radiation as well as direct nephron ablation from surgical treatment (nephrectomy) renders the kidney susceptible to a multitude of problems over time in patients with WT. In this article, we review the existing literature pertaining to renal function in these patients. Incidence rates, causes, and methods to mitigate renal dysfunction are presented in 3 distinct clinical situations: sporadic unilateral WT, syndromic unilateral WT, and bilateral WT. We also offer a critical lens on the current role of nephron-sparing surgery as a means to preserve renal function in these patients. Finally, we discuss potential avenues for refining renal function preservation in patients with WT in the future. We conclude that: (1) renal function in pediatric cancer survivors must be carefully ascertained prospectively using methods that allow diagnosis of mild cases (rather than focus solely on extreme cases represented by the development of end-stage renal disease), (2) every effort should be made to recognize subtle features of predisposition syndromes to avoid syndromic cases from being misclassified and treated as sporadic, (3) molecular stratification for disease aggressiveness as well as multifocality and renal dysfunction will be very important to tailor treatment and balance survival with preservation of renal function, and (4) the role and potential benefits of nephron-sparing surgery deserves careful exploration under well-designed protocols.

Predictors of Rapid Progression of Glomerular and Nonglomerular Kidney Disease in Children and Adolescents: The Chronic Kidney Disease in Children (CKiD) Cohort

BACKGROUND

Few studies have prospectively evaluated the progression of chronic kidney disease (CKD) in children and adolescents, as well as factors associated with progression.

STUDY DESIGN

Prospective multicenter observational cohort study.

SETTING & PARTICIPANTS

496 children and adolescents with CKD enrolled in the Chronic Kidney Disease in Children (CKiD) Study.

PREDICTORS

Proteinuria, hypoalbuminemia, blood pressure, dyslipidemia, and anemia.

OUTCOMES

Parametric failure-time models were used to characterize adjusted associations between baseline levels and changes in predictors and time to a composite event of renal replacement therapy or 50% decline in glomerular filtration rate (GFR).

RESULTS

398 patients had nonglomerular disease and 98 had glomerular disease; of these, 29% and 41%, respectively, progressed to the composite event after median follow-ups of 5.2 and 3.7 years, respectively. Demographic and clinical characteristics and outcomes differed substantially according to the underlying diagnosis; hence, risk factors for progression were assessed in stratified analyses, and formal interactions by diagnosis were performed. Among patients with nonglomerular disease and after adjusting for baseline GFR, times to the composite event were significantly shorter with urinary protein-creatinine ratio > 2mg/mg, hypoalbuminemia, elevated blood pressure, dyslipidemia, male sex, and anemia, by 79%, 69%, 38%, 40%, 38%, and 45%, respectively. Among patients with glomerular disease, urinary protein-creatinine ratio >2mg/mg, hypoalbuminemia, and elevated blood pressure were associated with significantly reduced times to the composite event by 94%, 71%, and 67%, respectively. Variables expressing change in patient clinical status over the initial year of the study contributed significantly to the model, which was cross-validated internally.

LIMITATIONS

Small number of events in glomerular patients and use of internal cross-validation.

CONCLUSIONS

Characterization and modeling of risk factors for CKD progression can be used to predict the extent to which these factors, either alone or in combination, would shorten the time to renal replacement therapy or 50% decline in GFR in children with CKD.

Anthropometric and biochemical profile of children and adolescents with chronic kidney disease in a predialysis pediatric interdisciplinary program

This is longitudinal retrospective observational cohort study that evaluated anthropometric and biochemical variables of children and adolescents admitted to a Predialysis Interdisciplinary Management Program (PDIMP) responsible for the follow-up of children and adolescents at stages 2 to 4 of chronic kidney disease (CKD) at a tertiary center. One hundred thirty-eight patients with CKD on predialysis treatment with median age at admission of 9 years and the median follow-up time of 5 years were evaluated. Seventy-four (53%) had CKD stage 3 at admission and 70 (51%) reached CKD stage 5 at the end of the follow-up. There was no significant difference between the mean initial and final hemoglobin and serum albumin. However, the final serum bicarbonate presented a significant improvement. Analyses stratified according to clinical variables of interest showed a significant improvement in body mass index (BMI) Z score, especially in the subgroup of children admitted under two years of age. In relation to stature-for-age Z score, data show a significant improvement in stature SD at the end of the study. In conclusion, the present study showed improvement of nutritional status of CKD patients and that the deterioration of renal function was not correlated with BMI-for-age Z score.

Multicentre prospective validation of a urinary peptidome-based classifier for the diagnosis of type 2 diabetic nephropathy

BACKGROUND

Diabetic nephropathy (DN) is one of the major late complications of diabetes. Treatment aimed at slowing down the progression of DN is available but methods for early and definitive detection of DN progression are currently lacking. The 'Proteomic prediction and Renin angiotensin aldosterone system Inhibition prevention Of early diabetic nephRopathy In TYpe 2 diabetic patients with normoalbuminuria trial' (PRIORITY) aims to evaluate the early detection of DN in patients with type 2 diabetes (T2D) using a urinary proteome-based classifier (CKD273).

METHODS

In this ancillary study of the recently initiated PRIORITY trial we aimed to validate for the first time the CKD273 classifier in a multicentre (9 different institutions providing samples from 165 T2D patients) prospective setting. In addition we also investigated the influence of sample containers, age and gender on the CKD273 classifier.

RESULTS

We observed a high consistency of the CKD273 classification scores across the different centres with areas under the curves ranging from 0.95 to 1.00. The classifier was independent of age (range tested 16-89 years) and gender. Furthermore, the use of different urine storage containers did not affect the classification scores. Analysis of the distribution of the individual peptides of the classifier over the nine different centres showed that fragments of blood-derived and extracellular matrix proteins were the most consistently found.

CONCLUSION

We provide for the first time validation of this urinary proteome-based classifier in a multicentre prospective setting and show the suitability of the CKD273 classifier to be used in the PRIORITY trial.

Mammalian tribbles homologs at the crossroads of endoplasmic reticulum stress and Mammalian target of rapamycin pathways

In 2000, investigators discovered Tribbles, a Drosophila protein that coordinates morphogenesis by inhibiting mitosis. Further work has delineated Xenopus (Xtrb2), Nematode (Nipi-3), and mammalian homologs of Drosophila tribbles, which include TRB1, TRB2, and TRB3. The sequences of tribbles homologs are highly conserved, and despite their protein kinase structure, to date they have not been shown to have kinase activity. TRB family members play a role in the differentiation of macrophages, lymphocytes, muscle cells, adipocytes, and osteoblasts. TRB isoforms also coordinate a number of critical cellular processes including glucose and lipid metabolism, inflammation, cellular stress, survival, apoptosis, and tumorigenesis. TRB family members modulate multiple complex signaling networks including mitogen activated protein kinase cascades, protein kinase B/AKT signaling, mammalian target of rapamycin, and inflammatory pathways. The following review will discuss metazoan homologs of Drosophila tribbles, their structure, expression patterns, and functions. In particular, we will focus on TRB3 function in the kidney in podocytes. This review will also discuss the key signaling pathways with which tribbles proteins interact and provide a rationale for developing novel therapeutics that exploit these interactions to provide better treatment options for both acute and chronic kidney disease.