Transplantation of bone marrow-derived MSCs improves renal function and Na++K+-ATPase activity in rats with renovascular hypertension

Anti-Na+/K+-ATPase DR antibody attenuates UUO-induced renal fibrosis through inhibition of Na+/K+-ATPase α1-dependent HMGB1 release

Reduced Na⁺/K⁺-ATPase (NKA) activity and NKAα1 expression are engaged in the pathologies of renal diseases. NKA-mediated Src activation is not the only reason for NKA-related renal fibrosis. In this study, we found that genetic reduction of NKAα1 exhibited exacerbated tubulointerstitial lesions and fibrosis in the UUO mice model. Activation of NKAα1 with an antibody against the extracellular DR region of the NKAα1 subunit (DRm217) prevented UUO-induced tubulointerstitial lesions, preserved kidney function, and decrease renal fibrosis. Further studies revealed that NKAα1 deficiency mice exhibited high inflammation factors expression when they suffered UUO surgery, compared with NKAα1^+/+ (WT) mice. DRm217 alleviated inflammatory cell infiltration, suppress NF-κB phosphorylation, and decreased inflammatory factors expression in the UUO mice model. Released HMGB1 can trigger the inflammatory response and contribute to renal fibrosis. Knockdown of NKA in renal tubular cells or in NKAα1^+/- mice was associated with more susceptibility to HMGB1 release in the UUO mice model. DRm217 exerted its antifibrotic effect via inhibiting HMGB1 release. Furthermore, AMPK activation participates in the effect of DRm217 on inhibiting HMGB1 release. Our findings suggest that NKAα1 is a regulator of renal fibrosis and its DR-region is a novel target on it.

Development of Cell Therapies for Renal Disease and Regenerative Medicine

The incidence of renal disease is gradually increasing worldwide, and this condition has become a major public health problem because it is a trigger for many other chronic diseases. Cell therapies using multipotent mesenchymal stromal cells, hematopoietic stem cells, macrophages, and other cell types have been used to induce regeneration and provide a cure for acute and chronic kidney disease in experimental models. This review describes the advances in cell therapy protocols applied to acute and chronic kidney injuries and the attempts to apply these treatments in a clinical setting.

Effects of mesenchymal stem cells in renovascular disease of preclinical and clinical studies: a systematic review and meta-analysis

Renal artery stenosis (RAS) causes severe renovascular hypertension, worsening kidney function, and increased cardiovascular morbidity. According to recent studies, mesenchymal stem cells (MSCs) administration is a promising therapy for the improvement of RAS outcomes. The meta-analysis aims to evaluate the therapeutic effects of MSC therapy on RAS. We performed a search in MEDLINE, Web of Science, Embase, and Cochrane Library from inception to 5, October 2022. We included 16 preclinical and 3 clinical studies in this meta-analysis. In preclinical studies, the pooled results indicated that animals treated with MSCs had lower levels of systolic blood pressure (SBP) (SMD = - 1.019, 95% CI - 1.434 to - 0.604, I² = 37.2%, P = 0.000), serum creatinine (Scr) (SMD = - 1.112, 95% CI - 1.932 to - 0.293, I² = 72.0%, P = 0.008), and plasma renin activity (PRA) (SMD = - 0.477, 95% CI - 0.913 to 0.042, I² = 43.4%, P = 0.032). The studies also revealed increased levels of renal blood flow (RBF) in stenotic kidney (STK) (SMD = 0.774, 95% CI - 0.351 to 1.197, I² = 0%, P = 0.000) and the glomerular filtration rate (GFR) of STK (SMD = 1.825, 95% CI 0.963 to 2.688, I² = 72.6%, P = 0.000). In clinical studies, the cortical perfusion and fractional hypoxia of the contralateral kidney (CLK) were alleviated by MSC therapy. Taken together, this meta-analysis revealed that MSCs therapy might be a promising treatment for RAS. However, due to the discrepancy between preclinical studies and early clinical trials outcomes, MSC therapy couldn't be recommended in clinical care for the moment, more high-quality randomized controlled clinical trials are needed to validate our conclusions and standardize MSCs protocols.

Dosing Limitation for Intra-Renal Arterial Infusion of Mesenchymal Stromal Cells

The immunomodulatory and regenerative properties of mesenchymal stromal cells (MSCs) make MSC therapy a promising therapeutic strategy in kidney disease. A targeted MSC administration via the renal artery offers an efficient delivery method with limited spillover to other organs. Although local administration alleviates safety issues with MSCs in systemic circulation, it introduces new safety concerns in the kidneys. In a porcine model, we employed intra-renal arterial infusion of ten million allogenic adipose tissue-derived MSCs. In order to trigger any potential adverse events, a higher dose (hundred million MSCs) was also included. The kidney function was studied by magnetic resonance imaging after the MSC infusion and again at two weeks post-treatment. The kidneys were assessed by single kidney glomerular filtration rate (skGFR) measurements, histology and inflammation, and fibrosis-related gene expression. None of the measured parameters were affected immediately after the administration of ten million MSCs, but the administration of one hundred million MSCs induced severe adverse events. Renal perfusion was reduced immediately after MSC administration which coincided with the presence of microthrombi in the glomeruli and signs of an instant blood-mediated inflammatory reaction. At two weeks post-treatment, the kidneys that were treated with one hundred million MSCs showed reduced skGFR, signs of tissue inflammation, and glomerular and tubular damage. In conclusions, the intra-renal administration of ten million MSCs is well-tolerated by the porcine kidney. However, higher concentrations (one hundred million MSCs) caused severe kidney damage, implying that very high doses of intra-renally administered MSCs should be undertaken with caution.

Enhancing the Therapeutic Potential of Mesenchymal Stromal Cell-Based Therapies with an Anti-Fibrotic Agent for the Treatment of Chronic Kidney Disease

Chronic kidney disease (CKD) affects 1 in 10 members of the general population, placing these patients at an increasingly high risk of kidney failure. Despite the significant burden of CKD on various healthcare systems, there are no effective cures that reverse or even halt its progression. In recent years, human bone-marrow-derived mesenchymal stromal cells (BM-MSCs) have been recognised as a novel therapy for CKDs, owing to their well-established immunomodulatory and tissue-reparative properties in preclinical settings, and their promising safety profile that has been demonstrated in patients with CKDs from several clinical trials. However, renal fibrosis (scarring), a hallmark of CKD, has been shown to impair the viability and functionality of BM-MSCs post-transplantation. This has suggested that BM-MSCs might require a pre-treatment or adjunct therapy that can enhance the viability and therapeutic efficacy of these stromal cells in chronic disease settings. To address this, recent studies that have combined BM-MSCs with the anti-fibrotic drug serelaxin (RLX), have demonstrated the enhanced therapeutic potential of this combination therapy in normotensive and hypertensive preclinical models of CKD. In this review, a critical appraisal of the preclinical data available on the anti-fibrotic and renoprotective actions of BM-MSCs or RLX alone and when combined, as a treatment option for normotensive vs. hypertensive CKD, is discussed.

Perspective on Stem Cell Therapy in Organ Fibrosis: Animal Models and Human Studies

Tissue fibrosis is characterized by excessive deposition of extracellular matrix (ECM) components that result from the disruption of regulatory processes responsible for ECM synthesis, deposition, and remodeling. Fibrosis develops in response to a trigger or injury and can occur in nearly all organs of the body. Thus, fibrosis leads to severe pathological conditions that disrupt organ architecture and cause loss of function. It has been estimated that severe fibrotic disorders are responsible for up to one-third of deaths worldwide. Although intensive research on the development of new strategies for fibrosis treatment has been carried out, therapeutic approaches remain limited. Since stem cells, especially mesenchymal stem cells (MSCs), show remarkable self-renewal, differentiation, and immunomodulatory capacity, they have been intensively tested in preclinical studies and clinical trials as a potential tool to slow down the progression of fibrosis and improve the quality of life of patients with fibrotic disorders. In this review, we summarize in vitro studies, preclinical studies performed on animal models of human fibrotic diseases, and recent clinical trials on the efficacy of allogeneic and autologous stem cell applications in severe types of fibrosis that develop in lungs, liver, heart, kidney, uterus, and skin. Although the results of the studies seem to be encouraging, there are many aspects of cell-based therapy, including the cell source, dose, administration route and frequency, timing of delivery, and long-term safety, that remain open areas for future investigation. We also discuss the contemporary status, challenges, and future perspectives of stem cell transplantation for therapeutic options in fibrotic diseases as well as we present recent patents for stem cell-based therapies in organ fibrosis.

Bone marrow-derived mesenchymal stem cells transplantation ameliorates renal injury through anti-fibrotic and anti-inflammatory effects in chronic experimental renovascular disease

Background

Progressive renal fibrosis is an underlying pathological process of chronic kidney disease (CKD) evolution. This study aimed to evaluate the roles of bone-marrow-derived mesenchymal stem cells (MSC) in the remodeling of fibrotic kidney parenchyma in the two kidneys-one clip (2K1C) CKD animal model.

Methods

Wistar rats were allocated into three groups: Sham, 2K1C, and 2K1C þ MSC. MSCs (106) were transplanted into the renal subcapsular region two weeks after clipping the left renal artery. Six weeks after clipping, left kidney samples were analyzed using histological and western blotting techniques. ANOVA tests were performed and differences between groups were considered statistically significant if p < 0.05.

Results

Clipped kidneys of 2K1C rats displayed renal fibrosis, with excessive collagen deposition, glomerulosclerosis and renal basement membrane disruption. Clipped kidneys of 2K1C þ MSC rats showed preserved Bowman's capsule and tubular basement membranes, medullary tubules morphological reconstitution and reduced collagen deposits. Expression levels of matrix metalloproteinase (MMP)-2 and MMP-9 were elevated, whereas tissue inhibitor of MMPs (TIMP)-1 and TIMP-2 levels were decreased in clipped kidneys of 2K1C rats. MSCs transplantation restored these expression levels. Moreover, MSCs suppressed macrophages and myofibroblasts accumulation, as well as TNF-a expression in clipped kidneys of 2K1C animals. MSCs transplantation significantly increased IL-10 expression.

Conclusions

Transplanted MSCs orchestrate anti-fibrotic and anti-inflammatory events, which reverse renal fibrosis and promote renal morphological restoration. This study supports the notion that only one MSCs delivery into the renal subcapsular region represents a possible therapeutic strategy against renal fibrosis for CKD treatment.

Insulin-like growth factor-1 short-period therapy stimulates bone marrow cells in obese swiss mice

Bone marrow cells (BMCs) from obese Swiss mice fed with Western diet show mitochondrial dysfunction. Obesity interferes with BMCs disrupting energetic metabolism, stimulating apoptosis, and reducing cell proliferation since adipose tissue releases inflammatory adipokines into the medullar microenvironment. These changes lead to reduction of BMC differentiation capacity and hematopoiesis impairment, a process responsible for blood cell continuous production through hematopoietic stem cells (HSCs). This work aimed to analyze the effects of IGF-1 therapy on BMC viability in Western diet-induced obesity, in vivo. We observed that after only 1 week of treatment, obese Swiss mice presented reduced body weight and visceral fat and increased mitochondrial oxidative capacity and coupling, indicating mitochondrial function improvement. In addition, IGF-1 was able to reduce apoptosis of total BMCs, stem cell subpopulations (hematopoietic and mesenchymal), and leukocytes, restoring all progenitor hematopoietic lineages. The treatment also contributed to increase proliferative capacity of hematopoietic stem cells and leukocytes, keeping the hematopoietic and immune systems balanced. Therefore, we conclude that IGF-1 short period therapy improved BMC survival, proliferation, and differentiation capacity in obese Swiss mice.

Therapeutic potential of mesenchymal stem cells in multiple organs affected by COVID-19

Currently, the world has been devastated by an unprecedented pandemic in this century. The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the agent of coronavirus disease 2019 (COVID-19), has been causing disorders, dysfunction and morphophysiological alterations in multiple organs as the disease evolves. There is a great scientific community effort to obtain a therapy capable of reaching the multiple affected organs in order to contribute for tissue repair and regeneration. In this regard, mesenchymal stem cells (MSCs) have emerged as potential candidates concerning the promotion of beneficial actions at different stages of COVID-19. MSCs are promising due to the observed therapeutic effects in respiratory preclinical models, as well as in cardiac, vascular, renal and nervous system models. Their immunomodulatory properties and secretion of paracrine mediators, such as cytokines, chemokines, growth factors and extracellular vesicles allow for long range tissue modulation and, particularly, blood-brain barrier crossing. This review focuses on SARS-CoV-2 impact to lungs, kidneys, heart, vasculature and central nervous system while discussing promising MSC's therapeutic mechanisms in each tissue. In addition, MSC's therapeutic effects in high-risk groups for COVID-19, such as obese, diabetic and hypertensive patients are also explored.

Stem/progenitor cell in kidney: characteristics, homing, coordination, and maintenance

Renal failure has a high prevalence and is becoming a public health problem worldwide. However, the renal replacement therapies such as dialysis are not yet satisfactory for its multiple complications. While stem/progenitor cell-mediated tissue repair and regenerative medicine show there is light at the end of tunnel. Hence, a better understanding of the characteristics of stem/progenitor cells in kidney and their homing capacity would greatly promote the development of stem cell research and therapy in the kidney field and open a new route to explore new strategies of kidney protection. In this review, we generally summarize the main stem/progenitor cells derived from kidney in situ or originating from the circulation, especially bone marrow. We also elaborate on the kidney-specific microenvironment that allows stem/progenitor cell growth and chemotaxis, and comment on their interaction. Finally, we highlight potential strategies for improving the therapeutic effects of stem/progenitor cell-based therapy. Our review provides important clues to better understand and control the growth of stem cells in kidneys and develop new therapeutic strategies.

Novel therapeutic strategies for renovascular disease

PURPOSE OF REVIEW

Renovascular disease (RVD) remains an important cause of hypertension and renal dysfunction. Given the failure of renal revascularization to provide consistent clinical benefit in the Cardiovascular Outcomes for Renal Artery Lesions trial among others, further research has underscored the need for mechanistically targeted interventions to improve renal outcomes in patients in RVD. This review discusses novel therapeutic approaches for RVD in the post-Cardiovascular Outcomes for Renal Artery Lesions era.

RECENT FINDINGS

Emerging evidence indicates that renal inflammation, microvascular remodeling, and mitochondrial damage accelerate progression of renal injury and are important determinants of the response to revascularization. Experimental studies have identified interventions capable of ameliorating renal inflammation (e.g., cytokine inhibitors, mesenchymal stem cells), microvascular remodeling (proangiogenic interventions), and mitochondrial injury (mito-protective drugs), alone or combined with renal revascularization, to preserve the structure and function of the poststenotic kidney. Recent prospective pilot studies in patients with atherosclerotic RVD demonstrate the safety and feasibility of some of such interventions to protect the kidney.

SUMMARY

Experimental studies and pilot clinical trials suggest that therapies targeting renal inflammation, microvascular remodeling, and mitochondrial damage have the potential to preserve the structure and function of the stenotic kidney. Further studies in larger cohorts are needed to confirm their renoprotective effects and clinical role in human RVD.

Treatment with Mesenchymal Stem Cells Improves Renovascular Hypertension and Preserves the Ability of the Contralateral Kidney to Excrete Sodium

BACKGROUND

Mesenchymal stem cells (MSC) improve renal function and renovascular hypertension in the 2-kidney 1-clip model (2K-1C). While MSC play an immunomodulatory role, induce neoangiogenesis, and reduce fibrosis, they do not correct sodium loss by the contra-lateral kidney.

OBJECTIVES

We investigated the tubular function of both stenotic and contralateral kidneys and the effect of MSC treatment by evaluating diuresis, natriuresis, and the expression of the main water and sodium transporters.

METHOD

Adult Wistar rats were allocated into four groups: control (CT), CT+MSC, 2K-1C, and 2K-1C+MSC. MSC (2 × 105) were infused through the tail vein 3 and 5 weeks after clipping. Systolic blood pressure (SBP) was monitored weekly by plethysmography. Six weeks after clipping, 24-hour urine and blood samples were collected for biochemical analysis. Gene expression of the Na/H exchanger-3, epithelial sodium channel, Na/K-ATPase, Na/K/2Cl cotransporter, and aquaporins 1 and 2 (AQP1 and AQP2) were analyzed by RT-PCR. Intrarenal distribution of AQP1 and AQP2 was analyzed by immunohistochemistry.

RESULTS

In hypertensive 2K-1C animals, MSC prevented additional increases in BP. AQP1, but not AQP2, was suppressed in the contralateral kidney, resulting in significant increase in urinary flow rate and sodium excretion. Gene expressions of sodium transporters were similar in both kidneys, suggesting that the high perfusing pressure in the contralateral kidney was responsible for increased natriuresis. Contralateral hypertensive kidney showed signs of renal deterioration with lower GFR in spite of normal RPF levels.

CONCLUSIONS

MSC treatment improved renal function and enhanced the ability of the contralateral kidney to excrete sodium through a tubular independent mechanism contributing to reduce SBP.

Potential and Therapeutic Efficacy of Cell-based Therapy Using Mesenchymal Stem Cells for Acute/chronic Kidney Disease

Kidney disease can be either acute kidney injury (AKI) or chronic kidney disease (CKD) and it can lead to the development of functional organ failure. Mesenchymal stem cells (MSCs) are derived from a diverse range of human tissues. They are multipotent and have immunomodulatory effects to assist in the recovery from tissue injury and the inhibition of inflammation. Numerous studies have investigated the feasibility, safety, and efficacy of MSC-based therapies for kidney disease. Although the exact mechanism of MSC-based therapy remains uncertain, their therapeutic value in the treatment of a diverse range of kidney diseases has been studied in clinical trials. The use of MSCs is a promising therapeutic strategy for both acute and chronic kidney disease. The mechanism underlying the effects of MSCs on survival rate after transplantation and functional repair of damaged tissue is still ambiguous. The paracrine effects of MSCs on renal recovery, optimization of the microenvironment for cell survival, and control of inflammatory responses are thought to be related to their interaction with the damaged kidney environment. This review discusses recent experimental and clinical findings related to kidney disease, with a focus on the role of MSCs in kidney disease recovery, differentiation, and microenvironment. The therapeutic efficacy and current applications of MSC-based kidney disease therapies are also discussed.

DR region specific antibody ameliorated but ouabain worsened renal injury in nephrectomized rats through regulating Na,K-ATPase mediated signaling pathways

Reduced Na⁺-K⁺-ATPase function is reported in various renal diseases. This implies that increase of Na⁺-K⁺-ATPase function may be a new target in treatment of renal injury. We previously reported that Na⁺-K⁺-ATPase was stabilized by DRm217, a specific antibody against DR region of Na⁺-K⁺-ATPase. In this study, we compared the protective effect of DRm217 and ouabain on kidney in a chronic kidney disease rat model and investigated the mechanism under it. We found that DRm217 improved renal function, alleviated glomerulus atrophy, inhibited renal tubular cells apoptosis, tubulointerstitial injury and renal fibrosis in 5/6 nephrectomized rats. Contrary to DRm217, ouabain worsened renal damage. Activated Na⁺-K⁺-ATPase /Src signaling pathway, increased oxidant stress and activated inflammasome were responsible for nephrectomized or ouabain-induced renal injury. DRm217 inhibited Na⁺-K⁺-ATPase /Src signaling pathway, retarded oxidant stress, suppressed inflammasome activation, and improved renal function, suggesting a novel approach to prevent renal damage.

Are cell-based therapies for kidney disease safe? A systematic review of preclinical evidence

The number of individuals affected by acute kidney injury (AKI) and chronic kidney disease (CKD) is constantly rising. In light of the limited availability of treatment options and their relative inefficacy, cell based therapeutic modalities have been studied. However, not many efforts are put into safety evaluation of such applications. The aim of this study was to review the existing published literature on adverse events reported in studies with genetically modified cells for treatment of kidney disease. A systematic review was conducted by searching PubMed and EMBASE for relevant articles published until June 2018. The search results were screened and relevant articles selected using pre-defined criteria, by two researchers independently. After initial screening of 6894 abstracts, a total number of 97 preclinical studies was finally included for full assessment. Of these, 61 (63%) presented an inappropriate study design for the evaluation of safety parameters. Only 4 studies (4%) had the optimal study design, while 32 (33%) showed sub-optimal study design with either direct or indirect evidence of adverse events. The high heterogeneity of studies included regarding cell type and number, genetic modification, administration route, and kidney disease model applied, combined with the consistent lack of appropriate control groups, makes a reliable safety evaluation of kidney cell-based therapies impossible. Only a limited number of relevant studies included looked into essential safety-related outcomes, such as inflammatory (48%), tumorigenic and teratogenic potential (12%), cell biodistribution (82%), microbiological safety with respect to microorganism contamination and latent viruses' reactivation (1%), as well as overall well-being and animal survival (19%). In conclusion, for benign cell-based therapies, well-designed pre-clinical studies, including all control groups required and good manufacturing processes securing safety, need to be done early in development. Preferably, this should be performed side by side with efficacy evaluation and according to the official guidelines of leading health organizations.

The use of unlicensed bone marrow-derived platelet lysate-expanded mesenchymal stromal cells in colitis: a pre-clinical study

BACKGROUND

Mesenchymal stromal cells (MSCs) are a promising candidate for treatment of inflammatory disorders, but their efficacy in human inflammatory bowel diseases (IBDs) has been inconsistent. Comparing the results from various pre-clinical and clinical IBD studies is also challenging due to a large variation in study designs.

METHODS

In this comparative pre-clinical study, we compared two administration routes and investigated the safety and feasibility of both fresh and cryopreserved platelet-lysate-expanded human bone marrow-derived MSCs without additional licensing in a dextran sodium sulfate (DSS) colitis mouse model both in the acute and regenerative phases of colitis. Body weight, macroscopic score for inflammation and colonic interleukin (IL)-1β and tumor necrosis factor (TNF)α concentrations were determined in both phases of colitis. Additionally, histopathology was assessed and Il-1β and Agtr1a messenger RNA (mRNA) levels and angiotensin-converting enzyme (ACE) protein levels were measured in the colon in the regenerative phase of colitis.

RESULTS

Intravenously administered MSCs exhibited modest anti-inflammatory capacity in the acute phase of colitis by reducing IL-1β protein levels in the inflamed colon. There were no clear improvements in mice treated with fresh or cryopreserved unlicensed MSCs according to weight monitoring results, histopathology and macroscopic score results. Pro-inflammatory ACE protein expression and shedding were reduced by cryopreserved MSCs in the colon.

CONCLUSIONS

In conclusion, we observed a good safety profile for bone marrow-derived platelet lysate-expanded MSCs in a mouse pre-clinical colitis model, but the therapeutic effect of MSCs prepared without additional licensing (i.e. such as MSCs are administered in graft-versus-host disease) was modest in the chosen in vivo model system and limited to biochemical improvements in cytokines without a clear benefit in histopathology or body weight development.

The use of hydrogels for cell-based treatment of chronic kidney disease

Chronic kidney disease (CKD) is a major and growing public health concern with increasing incidence and prevalence worldwide. The therapeutic potential of stem cell therapy, including mesenchymal stem cells (MSCs) and endothelial progenitor cells (EPCs) holds great promise for treatment of CKD. However, there are significant bottlenecks in the clinical translation due to the reduced number of transplanted cells and the duration of their presence at the site of tissue damage. Bioengineered hydrogels may provide a route of cell delivery to enhance treatment efficacy and optimise the targeting effectiveness while minimising any loss of cell function. In this review, we highlight the advances in stem cell therapy targeting kidney disease and discuss the emerging role of hydrogel delivery systems to fully realise the potential of adult stem cells as a regenerative therapy for CKD in humans. MSCs and EPCs mediate kidney repair through distinct paracrine effects. As a delivery system, hydrogels can prolong these paracrine effects by improving retention at the site of injury and protecting the transplanted cells from the harsh inflammatory microenvironment. We also discuss the features of a hydrogel, which may be tuned to optimise the therapeutic potential of encapsulated stem cells, including cell-adhesive epitopes, material stiffness, nanotopography, modes of gelation and degradation and the inclusion of bioactive molecules. This review concludes with a discussion of the challenges to be met for the widespread clinical use of hydrogel delivery system of stem cell therapy for CKD.