Single-Cell RNA Sequencing Identifies Response of Renal Lymphatic Endothelial Cells to Acute Kidney Injury

Adding insult to injury: the spectrum of tubulointerstitial responses in acute kidney injury

Acute kidney injury (AKI) encompasses pathophysiology ranging from glomerular hypofiltration to tubular cell injury and outflow obstruction. This Review will focus on the tubulointerstitial processes that underlie most cases of AKI. Tubular epithelial cell (TEC) injury can occur via distinct insults, including ischemia, nephrotoxins, sepsis, and primary immune-mediated processes. Following these initial insults, tubular cells can activate survival and repair responses or they can develop mitochondrial dysfunction and metabolic reprogramming, cell-cycle arrest, and programmed cell death. Developing evidence suggests that the fate of individual tubular cells to survive and proliferate or undergo cell death or senescence is frequently determined by a biphasic immune response with initial proinflammatory macrophage, neutrophil, and lymphocyte infiltration exacerbating injury and activating programmed cell death, while alternatively activated macrophages and specific lymphocyte subsets subsequently modulate inflammation and promote repair. Functional recovery requires that this reparative phase supports proteolytic degradation of tubular casts, proliferation of surviving TECs, and restoration of TEC differentiation. Incomplete resolution or persistence of inflammation can lead to failed tubular repair, fibrosis, and chronic kidney disease. Despite extensive research in animal models, translating preclinical findings to therapies remains challenging, emphasizing the need for integrated multiomic approaches to advance AKI understanding and treatment.

Moving toward a better understanding of renal lymphatics: challenges and opportunities

The development of lymphatic-specific markers has enabled detailed visualization of the lymphatic vascular network that has greatly enhanced our ability to explore this often-overlooked system. Lymphatics remove fluid, solutes, macromolecules, and cells from the interstitium and return them to circulation. The kidneys have lymphatics. As in other organs, the kidney lymphatic vessels are highly sensitive to changes in the local microenvironment. The sensitivity to its milieu may be especially relevant in kidneys because they are central in regulating fluid homeostasis and clearance of metabolites delivered into and eliminated from the renal interstitial compartment. Numerous physiologic conditions and diseases modify the renal interstitial volume, pressure, and composition that can, in turn, influence the growth and function of the renal lymphatics. The impact of the renal microenvironment is further heightened by the fact that kidneys are encapsulated. This review considers the development, structure, and function of the renal lymphatic vessels and explores how factors within the kidney interstitial compartment modify their structure and functionality. Moreover, although currently there are no pharmaceutical agents that specifically target the lymphatic network, we highlight several medications currently used in children with kidney disease and hypertension that have significant but underappreciated effects on lymphatics.

Bibliometric and visual analysis of immunisation associated with acute kidney injury from 2003 to 2023

Objective

This study aims to conduct a detailed bibliometric and visual analysis of acute kidney injury (AKI) and immune-related research conducted over the past two decades, focusing on identifying emerging trends and key areas of interest.

Methods

The Web of Science Core Collection (WoSCC) was utilised for the meticulous examination of various parameters including publication volume, authorship, geographic distribution, institutional contributions, journal sources, prevalent keywords and citation frequencies. Data were intricately visualised and interpreted using VOSviewer, CiteSpace and Excel 365 software.

Results

Analysis of the WoSCC database revealed 3,537 articles on AKI and immunisation, originating from 94 countries and regions, involving 3,552 institutions and authored by 18,243 individuals. Notably, the top five countries contributing to this field were the United States, China, Germany, Italy and the United Kingdom, with the United States leading with 35.76% of total publications. Among the 3,552 contributing institutions, those in the United States were predominant, with Harvard University leading with 134 papers and 3,906 citations. Key journals driving productivity included Frontiers in Immunology, Kidney International, Journal of the American Society of Nephrology and International Journal of Molecular Sciences, with Kidney International being the most cited, followed by Journal of the American Society of Nephrology and New England Journal of Medicine. Prominent authors in the field included Ronco Claudio, Okusa Mark D and Anders, Hans-Joachim. Co-citation clustering and timeline analysis highlighted recent research foci such as COVID-19, immune checkpoint inhibitors, regulated necrosis, cirrhosis and AKI. Keyword analysis identified "inflammation," "ischaemia-reperfusion injury," "sepsis," "covid-19," and "oxidative stress" as prevalent terms.

Conclusion

This study provides the first bibliometric analysis of AKI and immune research, offering a comprehensive overview of research hotspots and evolving trends within the field.