Acute Kidney Injury in Kidney Transplant Patients in Intensive Care Unit: From Pathogenesis to Clinical Management

Identification of ALDH2 as a novel target for the treatment of acute kidney injury in kidney transplantation based on WGCNA and machine learning algorithms and exploration of its potential mechanism of action using animal experiments

Background

Acute kidney injury (AKI) after kidney transplantation is one of the main causes of graft loss and poor patient prognosis, and it is important to explore new targets for treating AKI in kidney transplantation.

Methods

Based on the kidney transplantation AKI-related dataset GSE30718, the most relevant modular genes for AKI among them were firstly screened using WGCNA and intersected with the DEGs, and the intersected genes were used as candidate genes for kidney transplantation AKI. Second, machine learning algorithms were utilized to identify the key genes among them, and the HPA database was used to explore the expression landscape. Next, we constructed a rat renal IRI model and explored the role of key genes in renal IRI. Finally, we combined ssGSEA enrichment analysis with animal experiments to further validate the potential mechanism of action of key genes.

Results

In total, we identified 98 of the most relevant modular genes for AKI and 417 DEGs, which intersected to yield a total of 24 AKI candidate genes. Next, we intersected the key genes identified by three types of machine learning, namely, Random Forest, LASSO regression analysis and SVM, and obtained a total of 1 intersected gene as ALDH2, which we used as a key gene in kidney transplantation AKI. Using the HPA database, we found that ALDH2 has a high expression level in renal tissues and is mainly located in renal tubular epithelial cells. Next, we found in a rat renal IRI model that increasing the expression of ALDH2 alleviated the impairment of renal function and decreased the expression of NGAL, a marker of tubular injury, and BAX, an apoptotic protein, as well as reducing the expression of the inflammatory factors IL1β and IL6. Finally, using ssGSEA enrichment analysis and animal experiments, we further found that ALDH2 was able to inhibit the activation of the MAPK signaling pathway.

Conclusion

ALDH2 may serve as a novel target for the treatment of kidney transplantation AKI, and increasing the expression level of ALDH2 has a protective effect on renal IRI, and this protective effect may be achieved by inhibiting the MAPK signaling pathway.

Frequency and Outcomes of Acute Kidney Injury in the First Month Post-transplant: A Study on Renal Transplant Recipients in a Resource-Limited Country

Objective The study aimed to determine the incidence of acute kidney injury (AKI) in renal transplant recipients in the first month after transplant. The number of AKI episodes per patient and their outcome on renal graft function were also determined. Material and methods It is a retrospective study that took place in the Nephrology Department of Pakistan Kidney and Liver Institute and Research Center (PKLI & RC), Lahore, Pakistan. A total of 195 patients aged 18-70 years who underwent kidney transplant surgery at PKLI & RC, Lahore, were selected in this cohort that underwent renal transplants from 31st January 2024 to 31st December 2024. One month post-transplant course was followed by obtaining serum creatinine level values. Data was analyzed using Microsoft Excel (Microsoft® Corp., Redmond, WA, USA). Results A total of 81 out of 195 patients (41.5%) had AKI within the first 30 days following a renal transplant. Seventy patients experienced AKI once (86.4%), meanwhile, 11 patients (13.5%) had two episodes of AKI within the first 30 days. Staging done as per Kidney Disease Improving Global Outcomes (KDIGO) guidelines showed that 73 patients had stage I AKI (90.1%). Three patients had stage II AKI (3.7%), while five patients had stage III AKI (6.2%). The most common cause was found to be pre-renal (dehydration) in 24 patients out of 81 (29.6%) and followed by a urinary tract infection in 23 patients (28.3%). Twenty patients (24.6%) had drug-induced AKI; there was calcineurin inhibitor (CNI) toxicity in 8.6% and acute tubular necrosis (ATN) in 7.4% of patients. One patient had acute antibody-mediated rejection (ABMR). Most cases of AKI were found to be self-limiting, with complete resolution to baseline renal allograft function. Conclusion Even though most episodes of AKI completely resolved to baseline creatinine, it is pivotal to timely diagnose and treat AKI in post-renal transplant patients. If left untreated, there can be a worsening of graft function and overall outcome of the transplant.

BK Polyomavirus and acute kidney injury in transplant recipients: signaling pathways and molecular mechanisms

Acute kidney injury (AKI) is a condition that can result in changes in both urine production and creatinine levels in the bloodstream, complicating the treatment process and worsening outcomes for many hospitalized patients. BK polyomavirus (BKPyV), a member of the Polyomaviridae family, is prevalent in the population and remains latent in the body. It can reactivate in individuals with a compromised immune system, particularly post-kidney transplant, and can activate various transcription factors and immune mediators. Although reactivation is often asymptomatic, it can present as AKI, which is a risk factor for early loss of the transplanted organ. The immune response to BKPyV is crucial in controlling the virus and safeguarding organs from damage during infection. Understanding BKPyV pathways may offer novel opportunities for effectively treating BKPyV-associated complications. This review seeks to elucidate the potential mechanisms by which BKPyV reactivation can lead to AKI by analyzing various signaling pathways, as well as the identification of molecular mechanisms that BKPyV may utilize to induce AKI.

Megalin-targeting and ROS-responsive elamipretide-conjugated polymeric prodrug for treatment of acute kidney injury

Acute kidney injury (AKI) is associated with both kidney function loss and increased mortality. In the pathological progression of ischemia-reperfusion-induced AKI, the surge of reactive oxygen species (ROS) plays a crucial role. To combat this, mitochondrial-targeted antioxidant therapy shows great promise as mitochondria are the primary source of ROS in AKI. However, most strategies aiming to target mitochondria directly result in nanodrugs that are too large to pass through the glomerular system and reach the renal tubules, which are the main site of damage in AKI. This study focused on synthesizing a Megalin receptor-targeted polymeric prodrug, low molecular weight chitosan-thioketal-elamipretide (LMWC/TK/Ela), to mitigate excessive ROS in renal tubular epithelial cells for AKI. This soluble polymeric prodrug has the ability to successfully reach the tubular site by crossing the glomerular barrier. Once there, it can responsively release elamipretide, which possesses excellent antioxidative properties. Therefore, this research offers a novel approach to actively target renal tubular epithelial cells and intracellular mitochondria for the relief of AKI.

Immunosuppressants against acute kidney injury: what to prefer or to avoid?

BACKGROUND

Acute kidney injury (AKI) is a critical global health issue associated with high mortality rates, particularly in patients undergoing renal transplants and major surgeries. These individuals often receive immunosuppressants to dampen immune responses, but the impact of these drugs on AKI remains unclear.

OBJECTIVE

This review aims to provide a detailed understanding of the effects of different classes of immunosuppressants against AKI, elucidating their role in either exacerbating or mitigating the occurrence or progression of AKI.

METHODS

Several preclinical and clinical reports were analyzed to evaluate the impact of various immunosuppressants on AKI. Relevant preclinical and clinical studies were reviewed through different databases such as Scopus, PubMed, Google Scholar, and ScienceDirect, and official websites like https://clinicaltrials.gov to understand the mechanisms underlying the effects of immunosuppressants on kidney function.

RESULTS AND DISCUSSION

Specific immunosuppressants have been linked to the progression of AKI, while others demonstrate renoprotective effects. However, there is no consensus on the preferred or avoided immunosuppressants for AKI patients. This review outlines the classes of immunosuppressants commonly used and their impact on AKI, providing guidance for physicians in selecting appropriate drugs to prevent or ameliorate AKI.

CONCLUSION

Understanding the effects of immunosuppressants on AKI is crucial for optimizing patient care. This review highlights the need for further research to determine the most suitable immunosuppressants for AKI patients, considering both their efficacy and potential side effects.

Allograft function predicts mortality in kidney transplant recipients with severe COVID-19: a paradoxical risk factor

Introduction

Kidney transplant recipients (KTRs) are at a higher risk of severe coronavirus disease (COVID-19) because of their immunocompromised status. However, the effect of allograft function on the prognosis of severe COVID-19 in KTRs is unclear. In this study, we aimed to analyze the correlation between pre-infection allograft function and the prognosis of severe COVID-19 in KTRs.

Methods

This retrospective cohort study included 82 patients who underwent kidney transplantation at the Sichuan Provincial Peoples Hospital between October 1, 2014 and December 1, 2022 and were diagnosed with severe COVID-19. The patients were divided into decreased eGFR and normal eGFR groups based on the allograft function before COVID-19 diagnosis (n=32 [decreased eGFR group], mean age: 43.00 years; n=50 [normal eGFR group, mean age: 41.88 years). We performed logistic regression analysis to identify risk factors for death in patients with severe COVID-19. The nomogram was used to visualize the logistic regression model results.

Results

The mortality rate of KTRs with pre-infection allograft function insufficiency in the decreased eGFR group was significantly higher than that of KTRs in the normal eGFR group (31.25% [10/32] vs. 8.00% [4/50], P=0.006). Pre-infection allograft function insufficiency (OR=6.96, 95% CI: 1.4633.18, P=0.015) and maintenance of a mycophenolic acid dose >1500 mg/day before infection (OR=7.59, 95% CI: 1.0853.20, P=0.041) were independent risk factors, and the use of nirmatrelvir/ritonavir before severe COVID-19 (OR=0.15, 95% CI: 0.030.72, P=0.018) was a protective factor against death in severe COVID-19.

Conclusions

Pre-infection allograft function is a good predictor of death in patients with severe COVID-19. Allograft function was improved after treatment for severe COVID-19, which was not observed in patients with non-severe COVID-19.

Global Scientific Trends in Continuous Renal Replacement Therapy from 2000 to 2023: A Bibliometric and Visual Analysis

INTRODUCTION

Continuous renal replacement therapy (CRRT) is one of the most widely used blood purification and organ support methods in the ICU. However, the development process, the current status, hotspots, and future trends of CRRT remain unclear.

METHOD

The WoSCC database was used to analyze CRRT research evolution and theme trends. VOSviewer was used to construct coauthorship, co-occurrence, co-citation, and network visualizations. CiteSpace is used to detect bursts for co-occurrence items. Several important subtopics were reviewed and discussed in more detail.

RESULTS

Global publications increased from 56 in 2000 to 398 in 2023, a 710.71% increase. Blood Purification published the most manuscripts, followed by the International Journal of Artificial Organs. The USA, the San Bortolo Hospital, and Bellomo were the most productive and impactful institution, country, and author, respectively. Based on co-occurrence cluster analysis, five clusters emerged: (1) clinical applications and management of CRRT; (2) sepsis and CRRT; (3) CRRT anticoagulant management; (4) CRRT and antibiotic pharmacokinetics and pharmacodynamics; and (5) comparison of CRRT and intermittent hemodialysis. COVID-19, initiation, ECOMO, cefepime, guidelines, cardiogenic shock, biomarker, and outcome were the latest high-frequency keywords or strongest bursts, indicating the emerging frontiers of CRRT.

CONCLUSIONS

There has been widespread publication and citation of CRRT research in the past 2 decades. We provide an overview of current trends, global collaboration patterns, basic knowledge, research hotspots, and emerging frontiers.

Management of the kidney transplant recipient in the intensive care unit

PURPOSE OF REVIEW

Kidney transplantation is the ideal treatment for patients with chronic kidney disease and end stage renal disease. While centers are performing more transplants every year, the need for organ transplantation outpaces the supply of organ donors. Due to a growing population of patients with advanced kidney disease and a scarcity of kidneys from deceased donors, patients face extended wait times. By the time patients approach transplantation they have multiple comorbidities, in particular cardiovascular complications. Their risk of complications is further compounded by exposure to immunosuppression post kidney transplantation. Kidney transplant recipients (KTRs) are medically complex and may require acute management in the intensive care unit (ICU), as a result of cardiovascular complications, infections, and/or respiratory compromise from lung infections and/or acute pulmonary edema. Acute complication of immunosuppression, such as thrombotic microangiopathy and posterior reversible encephalopathy syndrome may also warrant ICU admission. This review will cover assessment of high-risk complications and management strategies following kidney transplantation.

RECENT FINDINGS

For intensivists caring for KTRs, it is imperative to understand anatomical considerations of the transplanted kidney, unique infectious risks faced by this population, and appropriate modulation of immunosuppression.

SUMMARY

Recognizing potential complications and implementing appropriate management strategies for KTRs admitted to the ICU will improve kidney allograft and patient survival outcomes.

COVID-19 Outcomes in Kidney Transplant Recipients in a German Transplant Center

Kidney transplant recipients (KTRs) show higher morbidity and mortality from COVID-19 than the general population and have an impaired response to vaccination. We analyzed COVID-19 incidence and clinical outcomes in a single-center cohort of approximately 2500 KTRs. Between 1 February 2020 and 1 July 2022, 578 KTRs were infected with SARS-CoV-2, with 25 (4%) recurrent infections. In total, 208 KTRs (36%) were hospitalized, and 39 (7%) died. Among vaccinated patients, infection with the Omicron variant had a mortality of 2%. Unvaccinated patients infected with the Omicron variant showed mortality (9% vs. 11%) and morbidity (hospitalization 52% vs. 54%, ICU admission 12% vs. 18%) comparable to the pre-Omicron era. Multivariable analysis revealed that being unvaccinated (OR = 2.15, 95% CI [1.38, 3.35]), infection in the pre-Omicron era (OR = 3.06, 95% CI [1.92, 4.87]), and higher patient age (OR = 1.04, 95% CI [1.03, 1.06]) are independent risk factors for COVID-19 hospitalization, whereas a steroid-free immunosuppressive regimen was found to reduce the risk of COVID-19 hospitalization (OR = 0.51, 95% CI [0.33, 0.79]). This suggests that both virological changes in the Omicron variant and vaccination reduce the risk for morbidity and mortality from COVID-19 in KTRs. Our data extend the knowledge from the general population to KTRs and provide important insights into outcomes during the Omicron era.