Orphan kidney diseases

Risk factors analysis and construction of predictive models for acute kidney injury in overweight patients receiving vancomycin treatment

BACKGROUND

Vancomycin-induced acute kidney injury (VI-AKI) is one of its serious adverse reactions. The purpose of this study is to discuss the risk factors for VI-AKI in overweight patients and construct a clinical prediction model based on the results of the analysis.

METHODS

Multivariable logistic regression analysis was used to identify risk factors for VI-AKI and constructed nomogram models. The performance of the nomogram was evaluated based on the area under the receiver operating characteristic curve (AUC), calibration curves, and decision curve analysis (DCA).

RESULT

Cancer (OR 4.186, 95% CI 1.473-11.896), vancomycin trough concentration >20.0 μg/mL (OR 6.251, 95% CI 2.275-17.180), concomitant furosemide (OR 2.722, 95% CI 1.071-6.919) and vasoactive agent (OR 2.824, 95% CI 1.086-7.340) were independent risk factors for VI-AKI. The AUC of the nomogram validation cohorts were 0.807 (95% CI 0.785-0.846). The calibration curve revealed that the predicted outcome was in agreement with the actual observations. Finally, the DCA curves showed that the nomogram had a good clinical applicability value.

CONCLUSION

There are four independent risk factors for the occurrence of VI-AKI in overweight patients, and the nomogram prediction model has good predictive ability, which can provide reference for clinical decision-making.

Prediction of acute kidney injury after cardiac surgery with fibrinogen-to-albumin ratio: a prospective observational study

Background

The occurrence of acute kidney injury (AKI) following cardiac surgery is common and linked to unfavorable consequences while identifying it in its early stages remains a challenge. The aim of this research was to examine whether the fibrinogen-to-albumin ratio (FAR), an innovative inflammation-related risk indicator, has the ability to predict the development of AKI in individuals after cardiac surgery.

Methods

Patients who underwent cardiac surgery from February 2023 to March 2023 and were admitted to the Cardiac Surgery Intensive Care Unit of a tertiary teaching hospital were included in this prospective observational study. AKI was defined according to the KDIGO criteria. To assess the diagnostic value of the FAR in predicting AKI, calculations were performed for the area under the receiver operating characteristic curve (AUC), continuous net reclassification improvement (NRI), and integrated discrimination improvement (IDI).

Results

Of the 260 enrolled patients, 85 developed AKI with an incidence of 32.7%. Based on the multivariate logistic analyses, FAR at admission [odds ratio (OR), 1.197; 95% confidence interval (CI), 1.064-1.347, p = 0.003] was an independent risk factor for AKI. The receiver operating characteristic (ROC) curve indicated that FAR on admission was a significant predictor of AKI [AUC, 0.685, 95% CI: 0.616-0.754]. Although the AUC-ROC of the prediction model was not substantially improved by adding FAR, continuous NRI and IDI were significantly improved.

Conclusions

FAR is independently associated with the occurrence of AKI after cardiac surgery and can significantly improve AKI prediction over the clinical prediction model.

Brown-Norway chromosome 1 mitigates the upregulation of proinflammatory pathways in mTAL cells and subsequent age-related CKD in Dahl SS/JrHsdMcwi rats

Chronic kidney disease (CKD) has a strong genetic component; however, the underlying pathways are not well understood. Dahl salt-sensitive (SS)/Jr rats spontaneously develop CKD with age and are used to investigate the genetic determinants of CKD. However, there are currently several genetically diverse Dahl SS rats maintained at various institutions and the extent to which some exhibit age-related CKD is unclear. We assessed glomerulosclerosis (GS) and tubulointerstitial fibrosis (TIF) in 3- and 6-mo-old male and female SS/JrHsdMcwi, BN/NHsd/Mcwi [Brown-Norway (BN)], and consomic SS-Chr 1BN/Mcwi (SS.BN1) rats, in which chromosome 1 from the BN rat was introgressed into the genome of the SS/JrHsdMcwi rat. Rats were fed a 0.4% NaCl diet. GS (31 ± 3% vs. 7 ± 1%) and TIF (2.3 ± 0.2 vs. 0.5 ± 0.1) were significantly greater in 6-mo-old compared with 3-mo-old SS/JrHsdMcwi rats, and CKD was exacerbated in males. GS was minimal in 6- and 3-mo-old BN (3.9 ± 0.6% vs. 1.2 ± 0.4%) and SS.BN1 (2.4 ± 0.5% vs. 1.0 ± 0.3%) rats, and neither exhibited TIF. In SS/JrHsdMcwi and SS.BN1 rats, mean arterial blood pressure was significantly greater in 6-mo-old compared with 3-mo-old SS/JrHsdMcwi (162 ± 4 vs. 131 ± 2 mmHg) but not SS.BN1 (115 ± 2 vs. 116 ± 1 mmHg) rats. In 6-mo-old SS/JrHsdMcwi rats, blood pressure was significantly greater in females. RNA-sequencing analysis revealed that inflammatory pathways were upregulated in isolated medullary thick ascending tubules in 7-wk-old SS/JrHsdMcwi rats, before the development of tubule pathology, compared with SS.BN1 rats. In summary, SS/JrHsdMcwi rats exhibit robust age-related progression of medullary thick ascending limb abnormalities, CKD, and hypertension, and gene(s) on chromosome 1 have a major pathogenic role in such changes.NEW & NOTEWORTHY This study shows that the robust age-related progression of kidney disease in Dahl SS/JrHsdMcw rats maintained on a normal-salt diet is abolished in consomic SS.BN1 rats. Evidence that medullary thick ascending limb segments of SS/JrHsdMcw rats are structurally abnormal and enriched in proinflammatory pathways before the development of protein casts provides new insights into the pathogenesis of kidney disease in this model.

The potential of RNA-based therapy for kidney diseases

Inherited kidney diseases (IKDs) are a large group of disorders affecting different nephron segments, many of which progress towards kidney failure due to the absence of curative therapies. With the current advances in genetic testing, the understanding of the molecular basis and pathophysiology of these disorders is increasing and reveals new potential therapeutic targets. RNA has revolutionized the world of molecular therapy and RNA-based therapeutics have started to emerge in the kidney field. To apply these therapies for inherited kidney disorders, several aspects require attention. First, the mRNA must be combined with a delivery vehicle that protects the oligonucleotides from degradation in the blood stream. Several types of delivery vehicles have been investigated, including lipid-based, peptide-based, and polymer-based ones. Currently, lipid nanoparticles are the most frequently used formulation for systemic siRNA and mRNA delivery. Second, while the glomerulus and tubules can be reached by charge- and/or size-selectivity, delivery vehicles can also be equipped with antibodies, antibody fragments, targeting peptides, carbohydrates or small molecules to actively target receptors on the proximal tubule epithelial cells, podocytes, mesangial cells or the glomerular endothelium. Furthermore, local injection strategies can circumvent the sequestration of RNA formulations in the liver and physical triggers can also enhance kidney-specific uptake. In this review, we provide an overview of current and potential future RNA-based therapies and targeting strategies that are in development for kidney diseases, with particular interest in inherited kidney disorders.

Phytochemical Classification of Medicinal Plants Used in the Treatment of Kidney Disease Based on Traditional Persian Medicine

Methods

This review was focused on studying the various secondary metabolites in model plants of Iranian herbal medicine known as treatment of kidney diseases in traditional Persian medicine textbooks including Makhzan-ol-Advieh, The Canon of Medicine, and Taghvim al-Abdan fi Tadbir al-Ensan.

Results

Secondary metabolites of 94 medical plants belonging to 42 families were reported with their scientific and family name.

Conclusion

Although herbal medicines are gaining rapid popularity among people and the pharmaceutical industry, the understandings of the phytochemical and therapeutic properties of medicinal plant are important for developing effective nephroprotective medicines. Therefore, the relationship between traditional uses and biological properties should be clearly verified through further studies.

In Situ Identification of Unknown Crystals in Acute Kidney Injury Using Raman Spectroscopy

Raman spectroscopy is a well-established and powerful tool for in situ biomolecular evaluation. Type 2 crystal nephropathies are characterized by the deposition of crystalline materials in the tubular lumen, resulting in rapid onset of acute kidney injury without specific symptoms. Timely crystal identification is essential for its diagnosis, mechanism exploration and therapy, but remains challenging. This study aims to develop a Raman spectroscopy-based method to assist pathological diagnosis of type 2 crystal nephropathies. Unknown crystals in renal tissue slides from a victim suffered extensive burn injury were detected by Raman spectroscopy, and the inclusion of crystals was determined by comparing Raman data with established database. Multiple crystals were scanned to verify the reproducibility of crystal in situ. Raman data of 20 random crystals were obtained, and the distribution and uniformity of substances in crystals were investigated by Raman imaging. A mouse model was established to mimic the crystal nephropathy to verify the availability of Raman spectroscopy in frozen biopsy. All crystals on the human slides were identified to be calcium oxalate dihydrate, and the distribution and content of calcium oxalate dihydrate on a single crystal were uneven. Raman spectroscopy was further validated to be available in identification of calcium oxalate dihydrate crystals in the biopsy specimens. Here, a Raman spectroscopy-based method for in situ identification of unknown crystals in both paraffin-embedded tissues and biopsy specimens was established, providing an effective and promising method to analyze unknown crystals in tissues and assist the precise pathological diagnosis in both clinical and forensic medicine.

The utility of a genetic kidney disease clinic employing a broad range of genomic testing platforms: experience of the Irish Kidney Gene Project

BACKGROUND AND AIMS

Genetic testing presents a unique opportunity for diagnosis and management of genetic kidney diseases (GKD). Here, we describe the clinical utility and valuable impact of a specialized GKD clinic, which uses a variety of genomic sequencing strategies.

METHODS

In this prospective cohort study, we undertook genetic testing in adults with suspected GKD according to prespecified criteria. Over 7 years, patients were referred from tertiary centres across Ireland to an academic medical centre as part of the Irish Kidney Gene Project.

RESULTS

Among 677 patients, the mean age was of 37.2 ± 13 years, and 73.9% of the patients had family history of chronic kidney disease (CKD). We achieved a molecular diagnostic rate of 50.9%. Four genes accounted for more than 70% of identified pathogenic variants: PKD1 and PKD2 (n = 186, 53.4%), MUC1 (8.9%), and COL4A5 (8.3%). In 162 patients with a genetic diagnosis, excluding PKD1/PKD2, the a priori diagnosis was confirmed in 58% and in 13% the diagnosis was reclassified. A genetic diagnosis was established in 22 (29.7%) patients with CKD of uncertain aetiology. Based on genetic testing, a diagnostic kidney biopsy was unnecessary in 13 (8%) patients. Presence of family history of CKD and the underlying a priori diagnosis were independent predictors (P < 0.001) of a positive genetic diagnosis.

CONCLUSIONS

A dedicated GKD clinic is a valuable resource, and its implementation of various genomic strategies has resulted in a direct, demonstrable clinical and therapeutic benefits to affected patients.

Rare inherited kidney diseases: an evolving field in Nephrology

There are more than 150 different rare genetic kidney diseases. They can be classified according to diagnostic findings as (i) disorders of growth and structure, (ii) glomerular diseases, (iii) tubular, and (iv) metabolic diseases. In recent years, there has been a shift of paradigm in this field. Molecular testing has become more accessible, our understanding of the underlying pathophysiologic mechanisms of these diseases has evolved, and new therapeutic strategies have become more available. Therefore, the role of nephrologists has progressively shifted from a mere spectator to an active player, part of a multidisciplinary team in the diagnosis and treatment of these disorders. This article provides an overview of the recent advances in rare hereditary kidney disorders by discussing the genetic aspects, clinical manifestations, diagnostic, and therapeutic approaches of some of these disorders, named familial focal and segmental glomerulosclerosis, tuberous sclerosis complex, Fabry nephropathy, and MYH-9 related disorder.

Differential methylation as a diagnostic biomarker of rare renal diseases: a systematic review

BACKGROUND

The challenges in diagnosis of rare renal conditions can negatively impact patient prognosis, quality of life and result in significant healthcare costs. Differential methylation is emerging as an important biomarker for rare diseases and should be evaluated for rare renal conditions.

METHODS

A comprehensive systematic review of methylation and rare renal disorders was conducted by searching the electronic databases MEDLINE, EMBASE, PubMed, Cochrane Library, alongside grey literature from GreyLit and OpenGrey databases, for publications published before September 2018. Additionally, the reference lists of the included papers were searched. Data was extracted and appraised including the primary focus, measurement and methodological rigour of the source. Eligibility criteria were adapted using the inclusion criteria from 'The 100,000 Genomes Project' and The National Registry of Rare Kidney Diseases, with additional focus on methylation.

RESULTS

Thirteen full text articles were included in the review. Diseases analysed for differential methylation included glomerular disease, IgA nephropathy, ADPKD, rare causes of proteinuria, congenital renal agenesis, and membranous nephropathy.

CONCLUSIONS

Differential methylation has been observed for several rare renal diseases, highlighting its potential for improving molecular characterisation of these disorders. Further investigation of methylation following a standardised reporting structure is necessary to improve research quality. Multi-omic data will provide insights for improved diagnosis, prognosis and support for individuals living and working with rare renal diseases.

Rare Renal Disease in Macedonia - An Update

Rare renal diseases (RRD) are an important category of rare disease (RD) as they can do great damage to the patients, families and society. The patient may undergo years even decades of numerous investigations including invasive procedures and yet not have definitive and precise diagnose and therefore, no opportunity for appropriate treatment. The great progress in molecular genetic techniques characterized many Mendelian diseases on molecular level. This gave the possibility for appropriate prevention and treatment interventions, genetic counseling and prenatal diagnosis. Herein, we summarize the current status of RRD in Macedonia. The research interest of Macedonian clinicians and scientists is focused on the genetics of congenital anomalies of the kidney and urinary tract (CAKUT), steroid resistant nephrotic syndrome, nephrolithiasis and nephrocalcinosis, cystic diseases and cilliopathies with collaborations with eminent laboratories in Unites States and Europe. This collaboration resulted in detection of new genes and pathophysiological pathways published in The New England Journal of Medicine and in other high impact journals. Macedonian health professionals have knowledge and equipment for diagnosis of RRD. Unfortunately the lack of finances is great obstacle for early and appropriate diagnosis. Participation in the international registries, studies and trials should be encouraged. This would result in significant benefit for the patients, health professionals and science.

Rare diseases, rare presentations: recognizing atypical inherited kidney disease phenotypes in the age of genomics

A significant percentage of adults (10%) and children (20%) on renal replacement therapy have an inherited kidney disease (IKD). The new genomic era, ushered in by the next generation sequencing techniques, has contributed to the identification of new genes and facilitated the genetic diagnosis of the highly heterogeneous IKDs. Consequently, it has also allowed the reclassification of diseases and has broadened the phenotypic spectrum of many classical IKDs. Various genetic, epigenetic and environmental factors may explain ‘atypical’ phenotypes. In this article, we examine different mechanisms that may contribute to phenotypic variability and also provide case examples that illustrate them. The aim of the article is to raise awareness, among nephrologists and geneticists, of rare presentations that IKDs may show, to facilitate diagnosis.

Good-quality research in rare diseases: trials and tribulations

Despite the fact that rare diseases affecting the kidney are not as uncommon as generally believed, proper clinical guidelines for guiding therapeutic management are scarce or absent owing to the overall lack of reliable scientific evidence. Although the randomized controlled trial (RCT) is the best study design for dealing with questions of intervention, RCTs under low-prevalence conditions are extremely challenging because of the limited number of patients, the variable phenotypic expression, and the long course of these disorders. In this brief review, we aimed to summarize the main alternative methods to traditional RCTs designed with the intent of minimizing the number of subjects needed for recruitment or maximizing the statistical efficiency of study analyses. Most of these approaches have not yet been extensively employed, may denote crucial limitations to wide applicability, or still lack proper validation in the field of rare diseases. Nevertheless, the growing number of proposed strategies is indicative of the perceived necessity by the scientific community to fill the quality gap between clinical guidelines for common and rare pathological conditions.

The pooling of manpower and resources through the establishment of European reference networks and rare disease patient registries is a necessary area of collaboration for rare renal disorders

This review aims to provide guidance on emerging concepts and policy related to European reference networks (ERNs) for rare diseases (RDs) and the development and management of RD patient registries. A major problem facing many RDs including rare renal disorders is that patients do not have a specialist centre that they can attend where clinicians, working as a multidisciplinary team, are experts in the particular disease. Furthermore, for most RDs, no single centre, and in many cases no single country, has sufficient numbers of patients and resources to fully understand the natural history or to conduct clinical and translational research. Therefore, the pooling of manpower and resources through the establishment of ERN and RD patient registries is a common and necessary area of collaboration. The concept of European networks for RDs dates back to the early 2000s and the Commission launch of a call for European pilot reference networks for RDs. These networks of expert centres have been brought together through the desire for further knowledge and innovation in RD areas. Networks demand a holistic approach and long-term vision with close collaboration between clinicians, diagnostic laboratories, scientists, patients and their families. The development of legal measures for ERNs is in progress at the Commission and these networks will be a shared responsibility of the Commission and member states. In the context of ERNs, an essential activity is the patient registries. Patient registries are organized databases where patient information, including demographic, medical and family history, are collected, stored and available for retrieval via standardized and secure methods. Patient registries are increasingly recognized as crucial tools for RD research for which international collaboration is absolutely essential to understand the pathogenesis of rare genotypes, achieve a unified collection of phenotypic data, foster natural history studies providing the foundation for successful orphan drug development, facilitate studies to identify appropriate clinical endpoints or biomarkers, identify participants for research and clinical trials and support discussions with regulators including the safety and efficacy evaluation of potential therapies. Furthermore, patient registries are often used as part of regulatory decisions and post-marketing surveillance requirements. Data can be entered into a registry by patients, clinicians, researchers or directly imported from patient's health records. The major concern in maintaining the dynamic of these networks and registries is sustainability, as the infrastructures and coordination have a cost.

Rare inherited kidney diseases: challenges, opportunities, and perspectives

At least 10% of adults and nearly all children who receive renal-replacement therapy have an inherited kidney disease. These patients rarely die when their disease progresses and can remain alive for many years because of advances in organ-replacement therapy. However, these disorders substantially decrease their quality of life and have a large effect on health-care systems. Since the kidneys regulate essential homoeostatic processes, inherited kidney disorders have multisystem complications, which add to the usual challenges for rare disorders. In this review, we discuss the nature of rare inherited kidney diseases, the challenges they pose, and opportunities from technological advances, which are well suited to target the kidney. Mechanistic insights from rare disorders are relevant for common disorders such as hypertension, kidney stones, cardiovascular disease, and progression of chronic kidney disease.

Clinical and ultrasonographical characterization of childhood cystic kidney diseases in Egypt

BACKGROUND

Renal cystic disorders (RCD) constitute an important and leading cause of end-stage renal disease (ESRD) in children. It can be acquired or inherited; isolated or associated with extrarenal manifestations. The precise diagnosis represents a difficult clinical challenge.

METHODS

The aim of this study was to define the pattern of clinical phenotypes of children with renal cystic diseases in Pediatric Nephrology Center, Cairo University. We have studied the clinical phenotypes of 105 children with RCD [45 (43%) of them had extrarenal manifestations].

RESULTS

The most common disorders were the presumably inherited renal cystic diseases (65.7%) mainly nephronophthisis and related ciliopathies (36.2%), as well as polycystic kidney diseases (29.5%). Moreover, multicystic dysplastic kidneys accounted for 18% of study cases. Interestingly, eight syndromic cases are described, yet unclassified as none had been previously reported in the literature.

CONCLUSION

RCD in this study had an expanded and complex spectrum and were largely due to presumably inherited/genetic disorders (65.7%). Moreover, we propose a modified algorithm for clinical and diagnostic approach to patients with RCD.