Kidney regeneration: Where we are and future perspectives

In 2012, about 16487 people received kidney transplants in the United States, whereas 95022 candidates were on the waiting list by the end of the year. Despite advances in renal transplant immunology, approximately 40% of recipients will die or lose graft within 10 years. The limitations of current therapies for renal failure have led researchers to explore the development of modalities that could improve, restore, or replace the renal function. The aim of this paper is to describe a reasonable approach for kidney regeneration and review the current literature regarding cell sources and mechanisms to develop a bioengineering kidney. Due to kidneys peculiar anatomy, extracellular matrix based scaffolds are rational starting point for their regeneration. The perfusion of detergents through the kidney vasculature is an effcient method for delivering decel-lularizing agents to cells and for removing of cellular material from the tissue. Many efforts have focused on the search of a reliable cell source to provide enrichment for achieving stable renal cell systems. For an effcient bioengineered kidney, these cells must be attached to the organ and then maturated into the bio-ractors, which simulates the human body environment.A functional bioengineered kidney is still a big challenge for scientists. In the last ten years we have got many improvements on the feld of solid organ regeneration; however, we are still far away from the main target. Currently, regenerative centers worldwide have been striving to find feasible strategies to develop bioengi-neered kidneys. Cell-scaffold technology gives hope to end-stage renal disease patients who struggle with morbidity and mortality due to extended periods on dialysis or immunosupression. The potential of bioengi-neered organ is to provide a reliable source of organs, which can be refunctionalized and transplanted.

Clinical trial with traditional Chinese medicine intervention ''tonifying the kidney to promote liver regeneration and repair by affecting stem cells and their microenvironment'' for chronic hepatitis B-associated liver failure

AIM:To study the clinical efficacy of traditional Chinese medicine(TCM)intervention"tonifying the kidney to promote liver regeneration and repair by affecting stem cells and their microenvironment"("TTK")for treating liver failure due to chronic hepatitis B.METHODS:We designed the study as a randomized controlled clinical trial.Registration number of Chinese Clinical Trial Registry is Chi CTR-TRC-12002961.A total of 144 patients with liver failure due to infection with chronic hepatitis B virus were enrolled in this randomized controlled clinical study.Participants were randomly assigned to the following three groups:(1)a modern medicine control group(MMC group,36patients);(2)a"tonifying qi and detoxification"("TQD")group(72 patients);and(3)a"tonifying the kidney to promote liver regeneration and repair by affecting stem cells and their microenvironment"("TTK")group(36patients).Patients in the MMC group received general internal medicine treatment;patients in the"TQD"group were given a TCM formula"tonifying qi and detoxification"and general internal medicine treatment;patients in the"TTK"group were given a TCM formula of"TTK"and general internal medicine treatment.All participants were treated for 8 wk and then followed at 48 wk following their final treatment.The primaryefficacy end point was the patient fatality rate in each group.Measurements of various virological and biochemical indicators served as secondary endpoints.The one-way analysis of variance and the t-test were used to compare patient outcomes in the different treatment groups.RESULTS:At the 48-wk post-treatment time point,the patient fatality rates in the MMC,"TQD",and"TTK"groups were 51.61%,35.38%,and 16.67%,respectively,and the differences between groups were statistically significant(P<0.05).However,there were no significant differences in the levels of hepatitis B virus DNA or prothrombin activity among the three groups(P>0.05).Patients in the"TTK"group had significantly higher levels of serum total bilirubin compared to MMC subjects(339.40μmol/L±270.09μmol/L vs 176.13μmol/L±185.70μmol/L,P=0.014).Serum albumin levels were significantly increased in both the"TQD"group and"TTK"group as compared with the MMC group(31.30 g/L±4.77g/L,30.72 g/L±2.89 g/L vs 28.57 g/L±4.56 g/L,P<0.05).There were no significant differences in levels of alanine transaminase among the three groups(P>0.05).Safety data showed that there was one case of stomachache in the"TQD"group and one case of gastrointestinal side effect in the"TTK"group.CONCLUSION:Treatment with"TTK"improved the survival rates of patients with liver failure due to chronic hepatitis B.Additionally,liver tissue was regenerated and liver function was restored.

Current advances of stem cell-based therapy for kidney diseases

Kidney diseases are a prevalent health problem around the world.Multidrug therapy used in the current routine treatment for kidney diseases can only delay disease progression.None of these drugs or treatments can reverse the progression to an end-stage of the disease.Therefore,it is crucial to explore novel therapeutics to improve patients’quality of life and possibly cure,reverse,or alleviate the kidney disease.Stem cells have promising potentials as a form of regenerative medicine for kidney diseases due to their unlimited replication and their ability to differentiate into kidney cells in vitro.Mounting evidences from the administration of stem cells in an experimental kidney disease model suggested that stem cell-based therapy has therapeutic or renoprotective effects to attenuate kidney damage while improving the function and structure of both glomerular and tubular compartments.This review summarises the current stem cell-based therapeutic approaches to treat kidney diseases,including the various cell sources,animal models or in vitro studies.The challenges of progressing from proof-of-principle in the laboratory to widespread clinical application and the human clinical trial outcomes reported to date are also highlighted.The success of cell-based therapy could widen the scope of regenerative medicine in the future.

Microenvironment of Liver Regeneration in Liver Cancer

The occurrence and development of liver cancer are essentially the most serious outcomes of uncontrolled liver regeneration. The progression of liver cancer is inevitably related to the abnormal microenvironment of liver regeneration. The deterioration observed in the microenvironment of liver regeneration is a necessary condition for the occurrence, development and metastasis of cancer. Therefore, the use of a technique to prevent and treat liver cancer via changes in the microenvironment of liver regeneration is a novel strategy. This strategy would be an effective way to delay, prevent or even reverse cancer occurrence, development and metastasis through an improvement in the liver regeneration microenvironment along with the integrated regulation of multiple components, targets, levels, channels and time sequences. In addition, the treatment of ＂tonifying Shen（Kidney） to regulate liver regeneration and repair by affecting stem cells and their microenvironment＂ can regulate ＂the dynamic imbalance between the normal liver regeneration and the abnormal liver regeneration＂; this would improve the microenvironment of liver regeneration, which is also a mechanism by which liver cancer may be prevented or treated.

Role of adult resident renal progenitor cells in tubular repair after acute kidney injury

Acute kidney injury is a serious global health problem and determinant of morbidity and mortality. Recent advancements in the fi eld of stem cell research raise hopes for stem cell-based regenerative approaches to treat acute kidney diseases. In this review, the authors summarized the latest research advances of the adult resident renal progenitor cells（ARPCs） on kidney repair, the role of ARPCs on tubular regeneration after acute kidney injury, the current understanding of the mechanisms rela ted to ARPC activation and modulation, as well as the challenges that remain to be faced.