Pathophysiology of Acute Kidney Injury, Repair, and Regeneration

Author(s):  
Ching-Wei Tsai ◽  
Sanjeev Noel ◽  
Hamid Rabb

Acute kidney injury (AKI), regardless of its aetiology, can elicit persistent or permanent kidney tissue changes that are associated with progression to end-stage renal disease and a greater risk of chronic kidney disease (CKD). In other cases, AKI may result in complete repair and restoration of normal kidney function. The pathophysiological mechanisms of renal injury and repair include vascular, tubular, and inflammatory factors. The initial injury phase is characterized by rarefaction of peritubular vessels and engagement of the immune response via Toll-like receptor binding, activation of macrophages, dendritic cells, natural killer cells, and T and B lymphocytes. During the recovery phase, cell adhesion molecules as well as cytokines and chemokines may be instrumental by directing the migration, differentiation, and proliferation of renal epithelial cells; recent data also suggest a critical role of M2 macrophage and regulatory T cell in the recovery period. Other processes contributing to renal regeneration include renal stem cells and the expression of growth hormones and trophic factors. Subtle deviations in the normal repair process can lead to maladaptive fibrotic kidney disease. Further elucidation of these mechanisms will help discover new therapeutic interventions aimed at limiting the extent of AKI and halting its progression to CKD or ESRD.

2021 ◽  
Author(s):  
Weifeng Li ◽  
Qiuxia Huang ◽  
Jinjin Yu ◽  
Jiabao Yu ◽  
Yajie Yang ◽  
...  

Abstract Schisandrin (Sch) is a main bioactive component of Schisandra sphenanthera Rehd.et Wils. It has been reported that Sch could regulate inflammatory disease. This study evaluated the anti-inflammatory and anti-oxidant effects effect of Sch on lipopolysaccharide (LPS)-induced macrophages activation and acute kidney injury mice. Male Kunming mice were intraperitoneally injected with LPS (15 mg/kg) after administration of Sch (12.5, 25, 50 mg/kg) seven days for developing acute kidney injury vivo model. RAW264.7 macrophages were pretreatment Sch (10, 20, 40 µM) and administrated LPS (1 µg/ml) to create an in vitro injury model. ELISA results found that Sch administration reduced the production of inflammatory factors induced by LPS in kidney tissues and RAW264.7 macrophages. It has been observed that Sch alleviated oxidative stress by reducing the levels of reactive oxygen species, myeloperoxidase and malondialdehyde, and increasing the activity of superoxide dismutase and glutathione peroxidase. Hematoxylin-eosin staining data suggested that Sch administration significantly reduced inflammatory cell infiltration and the kidney tissue damage induced by LPS. The blood urea nitrogen and creatinine levels were also reduced by Sch treatment. In addition, Western blot and immunohistochemical analysis showed that Sch up-regulated the expression of Nrf2 and HO-1, and decreased the expression of p-p38, p-JNK, p-ERK1/2, p-IκBα, p-NF-κBp65 and TLR4. The current research showed that Sch reduced LPS-induced acute kidney injury by inhibiting inflammation and oxidative stress, and provided insights into potential ways to treat AKI.


Physiology ◽  
2015 ◽  
Vol 30 (3) ◽  
pp. 183-194 ◽  
Author(s):  
Qi Cao ◽  
David C. H. Harris ◽  
Yiping Wang

Macrophages are found in normal kidney and in increased numbers in diseased kidney, where they act as key players in renal injury, inflammation, and fibrosis. Macrophages are highly heterogeneous cells and exhibit distinct phenotypic and functional characteristics in response to various stimuli in the local microenvironment in different types of kidney disease. In kidney tissue necrosis and/or infection, damage- and/or pathogen-associated molecular patterns induce pro-inflammatory macrophages, which contribute to further tissue injury, inflammation, and subsequent fibrosis. Apoptotic cells and anti-inflammatory factors in post-inflammatory tissues induced anti-inflammatory macrophages, which can mediate kidney repair and regeneration. This review summarizes the role of macrophages with different phenotypes in kidney injury, inflammation, and fibrosis in various acute and chronic kidney diseases. Understanding alterations of kidney microenvironment and the factors that control the phenotype and functions of macrophages may offer an avenue for the development of new cellular and cytokine/growth factor-based therapies as alternative treatment options for patients with kidney disease.


2021 ◽  
Author(s):  
Qiming Gong ◽  
Yan Jiang ◽  
Xiuhong Pan ◽  
Yanwu You

Abstract Background: Fractalkine(CX3CL1, FKN),a CX3C gene sequence inflammatory chemokine, has been found to have pro-inflammatory and pro-adhesion effects. Macrophages are immune cells with a critical role in regulate inflammatory response. The imbalance of M1/M2 macrophage polarization can lead to aggravated inflammation. This study takes an attempt to investigate the mechanisms through which FKN regulates the macrophage activation and the acute kidney injury (AKI) involved in the inflammatory response induced by lipopolysaccharide (LPS) by using FKN-knockout (FKN-KO) mice and cultured macrophages.Results: In this study, we found that FKN and Wnt/β-catenin signaling have a positive interaction in macrophages. FKN-overexpression inhibited LPS-induced macrophage apoptosis. However, it enhanced the cell viability and transformed them into M2 type. The effects of FKN-overexpression were accelerated by activation of Wnt/β-catenin signaling. In the in vivo experiments, FKN deficiency suppressed the macrophage activation and reduced AKI induced by LPS. Inhibition of Wnt/β-catenin signaling and FKN deficiency further mitigated the pathologic process of AKI. Conclusions: We provide a novel mechanism underlying activation of macrophage in LPS-induced AKI. The positive interaction between FKN and Wnt/β-catenin signaling pathway may be the therapeutic target in kidney injury.


Diabetes ◽  
2018 ◽  
Vol 67 (Supplement 1) ◽  
pp. 1737-P
Author(s):  
LYNN M. FRYDRYCH ◽  
GUOWU BIAN ◽  
PETER A. WARD ◽  
MARKUS BITZER ◽  
MATTHEW DELANO

Author(s):  
John R. Prowle ◽  
Lui G. Forni ◽  
Max Bell ◽  
Michelle S. Chew ◽  
Mark Edwards ◽  
...  

AbstractPostoperative acute kidney injury (PO-AKI) is a common complication of major surgery that is strongly associated with short-term surgical complications and long-term adverse outcomes, including increased risk of chronic kidney disease, cardiovascular events and death. Risk factors for PO-AKI include older age and comorbid diseases such as chronic kidney disease and diabetes mellitus. PO-AKI is best defined as AKI occurring within 7 days of an operative intervention using the Kidney Disease Improving Global Outcomes (KDIGO) definition of AKI; however, additional prognostic information may be gained from detailed clinical assessment and other diagnostic investigations in the form of a focused kidney health assessment (KHA). Prevention of PO-AKI is largely based on identification of high baseline risk, monitoring and reduction of nephrotoxic insults, whereas treatment involves the application of a bundle of interventions to avoid secondary kidney injury and mitigate the severity of AKI. As PO-AKI is strongly associated with long-term adverse outcomes, some form of follow-up KHA is essential; however, the form and location of this will be dictated by the nature and severity of the AKI. In this Consensus Statement, we provide graded recommendations for AKI after non-cardiac surgery and highlight priorities for future research.


2021 ◽  
Vol 10 (6) ◽  
pp. 1175
Author(s):  
Emaad M. Abdel-Rahman ◽  
Faruk Turgut ◽  
Jitendra K. Gautam ◽  
Samir C. Gautam

Acute kidney injury (AKI) is a common clinical syndrome characterized by rapid impairment of kidney function. The incidence of AKI and its severe form AKI requiring dialysis (AKI-D) has been increasing over the years. AKI etiology may be multifactorial and is substantially associated with increased morbidity and mortality. The outcome of AKI-D can vary from partial or complete recovery to transitioning to chronic kidney disease, end stage kidney disease, or even death. Predicting outcomes of patients with AKI is crucial as it may allow clinicians to guide policy regarding adequate management of this problem and offer the best long-term options to their patients in advance. In this manuscript, we will review the current evidence regarding the determinants of AKI outcomes, focusing on AKI-D.


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