Complications and Their Prevention in Experimental Renal Transplantation in Rats.

Objectives: Experimental rat models of renal transplant have played a pivotal role in renal transplant research. Both intraoperative and postoperative complications during donor nephrectomy and implantation in the recipient can be associated with significant morbidity and mortality. The aim of this paper is to discuss the incidence, pathophysiology, and prevention of complications that occurred in the process of establishment of a rat model of chronic allograft injury at our institution.

Surgical Anatomy and Microvascular Surgical Technique Relevant to Experimental Renal Transplant in Rat Employing Aortic and Inferior Venacaval Conduits.

Objectives: Rat models of renal transplant are used to investigate immunologic processes and responses to therapeutic agents before their translation into routine clinical practice. In this study, we have described details of rat surgical anatomy and our experiences with the microvascular surgical technique relevant to renal transplant by employing donor inferior vena cava and aortic conduits.

Materials And Methods: For this study, 175 rats (151 Lewis and 24 Fisher) were used to establish the Fisher-Lewis rat model of chronic allograft injury at our institution.

Review of Surgical Techniques of Experimental Renal Transplantation in Rats.

Microvascular surgical techniques of renal transplant in rats have evolved over the past 5 decades to achieve successful rat renal transplant; these modifications have included surgical techniques to address the anatomic variations in the renal blood vessels and those to reduce ischemic and operation durations. Here, we review the surgical techniques of renal transplant in rats and evaluate the advantages and disadvantages of individual techniques of vascular and ureteric anastomoses. For this review, we performed a systematic literature search using relevant medical subject heading terms and included appropriate publications in the review.

Evolution of the Concept and Pathogenesis of Chronic Renal Allograft Injury: An Updated Review.

The advantages conferred by renal transplant, such as the improved quality of life and survival, are compromised by the reduced half-life of the transplanted kidney to a decade because of chronic allograft injury, which is the leading cause of transplant loss. There has been a significant evolution in the concept of the nomenclature, grading of histologic changes, diagnostic markers, and the theories of the pathogenesis of chronic allograft injury in the past decade. This review sought to consolidate the published literature that contributes toward understanding the changing concepts and pathogenesis of the chronic allograft injury, which has implications to managing and preventing chronic allograft injury in experimental and clinical settings.

Inhibiting ERK Activation with CI-1040 Leads to Compensatory Upregulation of Alternate MAPKs and Plasminogen Activator Inhibitor-1 following Subtotal Nephrectomy with No Impact on Kidney Fibrosis.

Extracellular-signal regulated kinase (ERK) activation by MEK plays a key role in many of the cellular processes that underlie progressive kidney fibrosis including cell proliferation, apoptosis and transforming growth factor β1-mediated epithelial to mesenchymal transition. We therefore assessed the therapeutic impact of ERK1/2 inhibition using a MEK inhibitor in the rat 5/6 subtotal nephrectomy (SNx) model of kidney fibrosis. There was a twentyfold upregulation in phospho-ERK1/2 expression in the kidney after SNx in Male Wistar rats.

Historical perspectives in kidney transplantation: an updated review.

The present state of success in kidney transplantation, including its benefits to patients with end-stage renal failure, was achieved through relentless research, both in experimental animal models and human volunteers. Kidney transplantation has evolved during the past century thanks to various milestones in surgical techniques, immunology, immunosuppressive drugs, expansion of donor sources, organ preservation, transplant against immunological barriers (ABO blood group-incompatible and positive crossmatch transplants), and research on induction of tolerance, xenotransplants, and stem cell technology. Despite significant improvements in graft and patient survival, several issues still must be addressed to reduce the growing number of patients with kidney failure waiting to receive organs.

Upregulation of transglutaminase and ε (γ-glutamyl)-lysine in the Fisher-Lewis rat model of chronic allograft nephropathy.

Background: Tissue transglutaminase (TG2), a cross-linking enzyme, modulates deposition of extracellular matrix protein in renal fibrosis. This study aimed to examine TG2 and its cross-link product ε(γ-glutamyl)-lysine in the Fisher-Lewis rat renal transplantation (RTx) model of chronic allograft nephropathy (CAN).

Materials And Methods: Left renal grafts from male Fisher and Lewis were transplanted into Lewis rats, generating allografts and isografts, respectively.

Experimental rat models of chronic allograft nephropathy: a review.

Chronic allograft nephropathy (CAN) is the leading cause of late allograft loss after renal transplantation (RT), which continues to remain an unresolved problem. A rat model of CAN was first described in 1969 by White et al. Although the rat model of RT can be technically challenging, it is attractive because the pathogenesis of CAN is similar to that following human RT and the pathological features of CAN develop within months as compared with years in human RT.

Biological pathways and potential targets for prevention and therapy of chronic allograft nephropathy.

Renal transplantation (RT) is the best option for patients with end-stage renal disease, but the half-life is limited to a decade due to progressive deterioration of renal function and transplant failure from chronic allograft nephropathy (CAN), which is the leading cause of transplant loss. Extensive research has been done to understand the pathogenesis, the biological pathways of fibrogenesis, and potential therapeutic targets for the prevention and treatment of CAN. Despite the advancements in the immunosuppressive agents and patient care, CAN continues to remain an unresolved problem in renal transplantation.

Inhibition of collagen I accumulation reduces glomerulosclerosis by a Hic-5-dependent mechanism in experimental diabetic nephropathy.

Glomerulosclerosis of any cause is characterized by loss of functional glomerular cells and deposition of excessive amounts of interstitial collagens including collagen I. We have previously reported that mesangial cell attachment to collagen I leads to upregulation of Hic-5 in vitro, which mediates mesangial cell apoptosis. Furthermore, glomerular Hic-5 expression was increased during the progression of experimental glomerulosclerosis.

Inflammatory lymphangiogenesis in a rat transplant model of interstitial fibrosis and tubular atrophy.

We have previously reported de novo lymphangiogenesis in human renal allograft nephrectomy specimens that exhibited interstitial fibrosis and tubular atrophy (IFTA). This study examined whether a similar pathology developed in an experimental model of renal transplantation in the rat. Renal transplants were carried out in rats comprising both isografts (Lewis kidneys → Lewis rats) and allografts (Fisher kidneys → Lewis rats).

Skin gadolinium following use of MR contrast agents in a rat model of nephrogenic systemic fibrosis.

Purpose: To detect the ultrastructural site of gadolinium retention in skin by using an animal model of nephrogenic systemic fibrosis and compare a linear, low-stability gadolinium chelate (formulated gadodiamide) with a macrocylic, high-stability gadolinium chelate (gadoterate meglumine).

Materials And Methods: Experimental procedures were performed according to rules and regulations laid down by the UK Home Office (Animal Procedures Act of 1986). Male Wistar rats were subjected to 5/6 subtotal nephrectomy (creatinine clearance, 25% normal).

Atorvastatin improving renal ischemia reperfusion injury via direct inhibition of active caspase-3 in rats.

Caspase-3 is a key molecule involved in the inflammation and apoptosis of ischemia reperfusion (IR) injury. Statins are known to inhibit IR injury, but the mechanism of action remains uncertain. In the present study, the effect and underlying mechanism of ischemia alone, and reperfusion with or without atorvastatin (AT) as a timed intervention were examined, since clinically the kidney is only exposed to drug delivery during reperfusion.

Pathophysiology of nephrogenic systemic fibrosis: A review of experimental data.

Since the association between nephrogenic systemic fibrosis (NSF) and gadolinium contrast agents (Gd-CAs) was suggested in 2006, several experimental studies have been published to elucidate the role of these agents in the pathogenesis of NSF. Low stability Gd-CAs have a stimulant effect on human skin and fibroblasts in culture and modulate the production of collagen by these cells. Low stability agents have also induced NSF-like skin changes in a rat model with normal renal function after multiple repeat administrations.

Nephrogenic gadolinium biodistribution and skin cellularity following a single injection of Omniscan in the rat.

Objectives: The development of nephrogenic systemic fibrosis (NSF) following MRI contrast examination has been associated with gadolinium (Gd) toxicity. Animal models should show the key features of NSF in man where, the only immutable epidemiological feature is renal impairment. A rat model of chronic renal insufficiency has been employed to establish whether tissue gadolinium retention and increased skin cellularity following a gadolinium based contrast agent (GBCA) can be correlated with a reduction in renal function.

Do changes in transglutaminase activity alter latent transforming growth factor beta activation in experimental diabetic nephropathy?

Background: Diabetic nephropathy is the leading cause of end-stage kidney failure worldwide. It is characterized by excessive extracellular matrix accumulation. Transforming growth factor beta 1 (TGF-β1) is a fibrogenic cytokine playing a major role in the healing process and scarring by regulating extracellular matrix turnover, cell proliferation and epithelial mesanchymal transdifferentiation.

Pkd2 dosage influences cellular repair responses following ischemia-reperfusion injury.

Autosomal dominant polycystic kidney disease (ADPKD) results from mutations in either PKD1 or PKD2 and accounts for 10% of all patients on renal replacement therapy. The kidney disease phenotype is primarily characterized by cyst formation, but there are also prominent interstitial changes (inflammation, apoptosis, proliferation, and fibrosis). Using a model of unilateral ischemia-reperfusion injury, we tested the hypothesis that Pkd2 heterozygous kidneys are more sensitive to injury and that this could lead to interstitial inflammation and fibrosis.

Transglutaminase inhibition ameliorates experimental diabetic nephropathy.

Diabetic nephropathy is characterized by excessive extracellular matrix accumulation resulting in renal scarring and end-stage renal disease. Previous studies have suggested that transglutaminase type 2, by formation of its protein crosslink product epsilon-(gamma-glutamyl)lysine, alters extracellular matrix homeostasis, causing basement membrane thickening and expansion of the mesangium and interstitium. To determine whether transglutaminase inhibition can slow the progression of chronic experimental diabetic nephropathy over an extended treatment period, the inhibitor NTU281 was given to uninephrectomized streptozotocin-induced diabetic rats for up to 8 months.

Lack of effect of IGF-I on the glomerular filtration rate in non-diabetic patients with advanced chronic kidney disease.

Recombinant human insulin-like growth factor I (rhIGF-I) acutely increases the glomerular filtration rate (GFR) in human volunteers and patients with advanced chronic kidney disease (CKD). However, on chronic administration, rhIGF-I induces tolerance to its renal effects attributed to a fall in serum IGF-binding protein 3 (IGFBP-3) enhancing its systemic clearance. Tolerance may be avoided by the use of an intermittent dosage regimen of rhIGF-I.

Modulation of tissue transglutaminase in tubular epithelial cells alters extracellular matrix levels: a potential mechanism of tissue scarring.

The up-regulation and trafficking of tissue transglutaminase (TG2) by tubular epithelial cells (TEC) has been implicated in the development of kidney scarring. TG2 catalyses the crosslinking of proteins via the formation of highly stable epsilon(gamma-glutamyl) lysine bonds. We have proposed that TG2 may contribute to kidney scarring by accelerating extracellular matrix (ECM) deposition and by stabilising the ECM against proteolytic decay.

(-)-Epigallocatechin 3-O-gallate (EGCG)-induced apoptosis in normal rat kidney interstitial fibroblast (NRK-49F) cells.

(-)-Epigallocatechin 3-O-gallate (EGCG), a major catechin in green tea, suppresses renal failure in animals, and inhibits the growth of mesangial cells and opossum kidney proximal tubular cells. In addition, gallic acid, a structural constituent of this catechin, induces apoptosis in tumor cell lines. However, the effects of catechins on renal fibroblastic cells have not been investigated.

Reduction of ischemia-reperfusion injury in the rat kidney by FTY720, a synthetic derivative of sphingosine.

Background: The current shortage of organ donors has led many centers to use marginal and nonheart-beating donors (NHBDs). Recent research has implicated the infiltration of lymphocytes as an important mediator of ischemia-reperfusion injury (IRI). FTY720 is an immunosuppressant that promotes lymphocyte sequestration into lymph nodes.

Endothelin B receptor blockade accelerates disease progression in a murine model of autosomal dominant polycystic kidney disease.

Autosomal dominant polycystic kidney disease (ADPKD) is the most common genetic disease that causes kidney failure and accounts for 10% of all patients who are on renal replacement therapy. However, the marked phenotypic variation between patients who carry the same PKD1 or PKD2 mutation suggests that nonallelic factors may have a greater influence on the cystic phenotype. Endothelin-1 (ET-1) transgenic mice have been reported to develop profound renal cystic disease and interstitial fibrosis without hypertension.

Haploinsufficiency of Pkd2 is associated with increased tubular cell proliferation and interstitial fibrosis in two murine Pkd2 models.

Background: Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited human kidney disease and is caused by germline mutations in PKD1 (85%) or PKD2 (15%). It has been estimated that around 1% of tubular cells give rise to cysts, and cell hyperproliferation has been noted to be a cardinal feature of cystic epithelium. Nevertheless, it is uncertain whether the increase in proliferative index observed is an early or late feature of the cystic ADPKD kidney.