Mesenchymal Stem Cells Contribute to Improvement of Renal Function in a Canine Kidney Injury Model

Mesenchymal stem cell-derived cell-free technologies: a patent landscape

Mesenchymal stem/stromal cells (MSC) play a pivotal role in regenerative therapies. Recent studies show that factors secreted by MSC can replicate their biological activity, driving the emergence of cell-free therapy, likely to surpass stem cell therapy. Patents are an objective measure of R&D and innovation activities, and patent mapping allows us to verify the state of the art and technology, anticipate trends, and identify emerging lines of research. This review performed a search on Derwent World Patents Index™ and retrieved 269 patent families related to the MSC-derived cell-free products. Analysis reveals an exponential increase in patents from the mid-2010s, primarily focusing on exosomes. The patent's contents offer a great diversity of applications and associated technologies by using the products as medicinal agents or drug delivery systems. Nevertheless, numerous application branches remain unexplored, suggesting vast potential for cell-free technologies alone or combined with other approaches.

Body fluid-derived stem cells - an untapped stem cell source in genitourinary regeneration

Somatic stem cells have been obtained from solid organs and tissues, including the bone marrow, placenta, corneal stroma, periosteum, adipose tissue, dental pulp and skeletal muscle. These solid tissue-derived stem cells are often used for tissue repair, disease modelling and new drug development. In the past two decades, stem cells have also been identified in various body fluids, including urine, peripheral blood, umbilical cord blood, amniotic fluid, synovial fluid, breastmilk and menstrual blood. These body fluid-derived stem cells (BFSCs) have stemness properties comparable to those of other adult stem cells and, similarly to tissue-derived stem cells, show cell surface markers, multi-differentiation potential and immunomodulatory effects. However, BFSCs are more easily accessible through non-invasive or minimally invasive approaches than solid tissue-derived stem cells and can be isolated without enzymatic tissue digestion. Additionally, BFSCs have shown good versatility in repairing genitourinary abnormalities in preclinical models through direct differentiation or paracrine mechanisms such as pro-angiogenic, anti-apoptotic, antifibrotic, anti-oxidant and anti-inflammatory effects. However, optimization of protocols is needed to improve the efficacy and safety of BFSC therapy before therapeutic translation.

Immunomodulatory effects of canine mesenchymal stem cells in an experimental atopic dermatitis model

Mesenchymal stem cells (MSCs) have the potential to differentiate into multi-lineage cells, suggesting their future applicability in regenerative medicine and biotechnology. The immunomodulatory properties of MSCs make them a promising replacement therapy in various fields of animal research including in canine atopic dermatitis (AD), a skin disease with 10-15% prevalence. We investigated the immunomodulatory effects of MSCs in an experimental canine AD model induced by Dermatophagoides farinae extract ointment. Canine adipose tissue-derived MSCs (cAT-MSCs) were differentiated into mesodermal cell lineages at the third passage. Alterations in immunomodulatory factors in control, AD, and MSC-treated AD groups were evaluated using flow cytometric analysis, enzyme-linked immunosorbent assay, and quantitative reverse transcription PCR. In the MSC-treated AD group, the number of eosinophils decreased, and the number of regulatory T cells (Tregs) increased compared to those in the AD group. In addition, the immunoglobulin E (IgE) and prostaglandin E₂ levels were reduced in the MSC-treated AD group compared to those in the AD group. Furthermore, the filaggrin, vascular endothelial growth factor, and interleukin-5 gene expression levels were relatively higher in the MSC-treated AD group than in the AD group, however, not significantly. cAT-MSCs exerted immunomodulatory effects in an AD canine model via a rebalancing of type-1 and -2 T helper cells that correlated with increased levels of Tregs, IgE, and various cytokines.

Combination of immunosuppressive drugs and allogeneic stem cell treatment in a dog with suspected nephrotic syndrome

The case study aims to describe the nephrotic syndrome (NS) in a castrated 3-year-old male Cocker Spaniel dog. The patient arrived at the hospital with a loss of appetite and weakness. Skin oedema with ascites was observed along with hypoalbuminaemia, hypoproteinaemia, hyperlipidaemia, hypercholesterolaemia, and proteinuria (urine protein to creatinine ratio = 22.4). Based on these findings, the patient was diagnosed with NS, although a renal biopsy was not conducted. Prednisolone (1 mg/kg, p.o. q12 h) and mycophenolate mofetil (10 mg/kg, p.o. q12 h) were prescribed as the immunosuppressive drugs, and previously cryopreserved allogeneic adipose tissue-derived mesenchymal stem cells (2 × 107 cells/kg) were injected intravenously. After several weeks of treatment, the patient recovered from NS. This is the first case report on immunosuppressive drugs and allogeneic mesenchymal stem cells being used to treat a dog with NS.

The therapeutic potential of Camel Wharton jelly mesenchymal stem cells (CWJ-MSCs) in canine chronic kidney disease model

Background

Chronic kidney disease (CKD) is a worldwide health problem that its incidence increases nowadays with the increase in the risk of environmental pollution. CKD can progress to end-stage renal disease (ESRD) which usually ends fatally. This study aimed to examine the therapeutic potential of Camel Wharton jelly-mesenchymal stem cells (CWJ-MSCs) in chronic kidney disease model induced in dogs.

Methods

CWJ-MSCs were injected directed to the kidney with ultrasonographic guidance in dogs with 5/6 nephrectomy to evaluate its therapeutic potency in such cases. Analysis of variance was applied in normally distributed quantitative variables while a non-parametric Mann–Whitney test was used for non-normally distributed quantitative variables.

Results

The serum urea and creatinine in the treated group were significantly decreased transferring dogs in the treated group from stage 3 to stage 2 CKD according to the IRIS staging system. Histopathology of renal tissue revealed improving CKD lesions by increasing regeneration of degenerated tubules, maintaining the integrity of glomeruli. New vascularization with blood vessels remodeling were common findings. Periodic acid Schiff stain of renal tissue showed the integrity of renal tubules and thickness of the glomerular basement membrane. Fibrosis of cortex and medulla was lower in the treated group than in the CKD model as monitored by Mallory’s trichrome stain (MTC). NGAL and KIM-1 genes expression were decreased while VEGF and EGF genes expression were increased indicating renal tissue repair.

Conclusions

CWJ-MSCs have a therapeutic potential in the CKD model induced in dogs.

Current Status on Canine Foetal Fluid and Adnexa Derived Mesenchymal Stem Cells

Effective standards of care treatment guidelines have been developed for many canine diseases. However, a subpopulation of patients is partially or completely refractory to these protocols, so their owners seek novel therapies such as treatments with MSCs. Although in dogs, as with human medicine, the most studied MSCs sources have been bone marrow and adipose tissue, in recent years, many researchers have drawn attention towards alternative sources, such as foetal adnexa and fluid, since they possess many advantages over bone marrow and adipose tissue. Foetal adnexa and fluid could be considered as discarded material; therefore, sampling is non-invasive, inexpensive and free from ethical considerations. Furthermore, MSCs derived from foetal adnexa and fluid preserve some of the characteristics of the primitive embryonic layers from which they originate and seem to present immune-modulatory properties that make them a good candidate for allo- and xenotransplantation. The aim of the present review is to offer an update on the state of the art on canine MSCs derived from foetal adnexa and fluid focusing on the findings in their clinical setting.

Large animal models for translational research in acute kidney injury

While extensive research using animal models has improved the understanding of acute kidney injury (AKI), this knowledge has not been translated into effective treatments. Many promising interventions for AKI identified in mice and rats have not been validated in subsequent clinical trials. As a result, the mortality rate of AKI patients remains high. Inflammation plays a fundamental role in the pathogenesis of AKI, and one reason for the failure to translate promising therapeutics may lie in the profound difference between the immune systems of rodents and humans. The immune systems of large animals such as swine, nonhuman primates, sheep, dogs and cats, more closely resemble the human immune system. Therefore, in the absence of a basic understanding of the pathophysiology of human AKI, large animals are attractive models to test novel interventions. However, there is a lack of reviews on large animal models for AKI in the literature. In this review, we will first highlight differences in innate and adaptive immunities among rodents, large animals, and humans in relation to AKI. After illustrating the potential merits of large animals in testing therapies for AKI, we will summarize the current state of the evidence in terms of what therapeutics have been tested in large animal models. The aim of this review is not to suggest that murine models are not valid to study AKI. Instead, our objective is to demonstrate that large animal models can serve as valuable and complementary tools in translating potential therapeutics into clinical practice.

Mesenchymal Stem Cell Therapy for Diabetic Kidney Disease: A Review of the Studies Using Syngeneic, Autologous, Allogeneic, and Xenogeneic Cells

Diabetic kidney disease (DKD) is a microvascular complication of diabetes mellitus (DM) and comprises multifactorial pathophysiologic mechanisms. Despite current treatment, around 30-40% of individuals with type 1 and type 2 DM (DM1 and DM2) have progressive DKD, which is the most common cause of end-stage chronic kidney disease worldwide. Mesenchymal stem cell- (MSC-) based therapy has important biological and therapeutic implications for curtailing DKD progression. As a chronic disease, DM may impair MSC microenvironment, but there is compelling evidence that MSC derived from DM1 individuals maintain their cardinal properties, such as potency, secretion of trophic factors, and modulation of immune cells, so that both autologous and allogeneic MSCs are safe and effective. Conversely, MSCs derived from DM2 individuals are usually dysfunctional, exhibiting higher rates of senescence and apoptosis and a decrease in clonogenicity, proliferation, and angiogenesis potential. Therefore, more studies in humans are needed to reach a conclusion if autologous MSCs from DM2 individuals are effective for treatment of DM-related complications. Importantly, the bench to bedside pathway has been constructed in the last decade for assessing the therapeutic potential of MSCs in the DM setting. Laboratory research set the basis for establishing further translation research including preclinical development and proof of concept in model systems. Phase I clinical trials have evaluated the safety profile of MSC-based therapy in humans, and phase II clinical trials (proof of concept in trial participants) still need to answer important questions for treating DKD, yet metabolic control has already been documented. Therefore, randomized and controlled trials considering the source, optimal cell number, and route of delivery in DM patients are further required to advance MSC-based therapy. Future directions include strategies to reduce MSC heterogeneity, standardized protocols for isolation and expansion of those cells, and the development of well-designed large-scale trials to show significant efficacy during a long follow-up, mainly in individuals with DKD.

Autologous Adipose Tissue-Derived Mesenchymal Stem Cells Introduced by Biliary Stents or Local Immersion in Porcine Bile Duct Anastomoses

Biliary complications (strictures and leaks) represent major limitations in living donor liver transplantation. Mesenchymal stem cells (MSCs) are a promising modality to prevent biliary complications because of immunosuppressive and angiogenic properties. Our goal was to evaluate the safety of adipose-derived MSC delivery to biliary anastomoses in a porcine model. Secondary objectives were defining the optimal method of delivery (intraluminal versus extraluminal) and to investigate MSC engraftment, angiogenesis, and fibrosis. Pigs were divided into 3 groups. Animals underwent adipose collection, MSC isolation, and expansion. Two weeks later, animals underwent bile duct transection, reanastomosis, and stent insertion. Group 1 received plastic stents wrapped in unseeded Vicryl mesh. Group 2 received stents wrapped in MSC-seeded mesh. Group 3 received unwrapped stents with the anastomosis immersed in an MSC suspension. Animals were killed 1 month after stent insertion when cholangiograms and biliary tissue were obtained. Serum was collected for liver biochemistries. Tissue was used for hematoxylin-eosin and trichrome staining and immunohistochemistry for MSC markers (CD44 and CD34) and for a marker of neoangiogenesis (CD31). There were no intraoperative complications. One pig died on postoperative day 3 due to acute cholangitis. All others recovered without complications. Cholangiography demonstrated no biliary leaks and minimal luminal narrowing. Surviving animals exhibited no symptoms, abnormal liver biochemistries, or clinically significant biliary stricturing. Group 3 showed significantly greater CD44 and CD34 staining, indicating MSC engraftment. Fibrosis was reduced at the anastomotic site in group 3 based on trichrome stain. CD31 staining of group 3 was more pronounced, supporting enhanced neoangiogenesis. In conclusion, adipose-derived MSCs were safely applied to biliary anastomoses. MSCs were locally engrafted within the bile duct and may have beneficial effects in terms of fibrosis and angiogenesis.

Therapeutic Effects of Human Urine-Derived Stem Cells in a Rat Model of Cisplatin-Induced Acute Kidney Injury In Vivo and In Vitro

Acute kidney injury (AKI) is an extremely dangerous clinical syndrome with high morbidity and mortality. Stem cell-based therapies have shown great promise for AKI treatment. Urine-derived stem cells (USCs) are a novel cell source in tissue engineering and cell therapy which provide advantages of simple, noninvasive, and low-cost harvest methods, efficient proliferation, and multi-differentiation potential. Here, we described the therapeutic effects of USCs in a rat model of cisplatin-induced AKI as a novel therapy. In vivo, the intravenous administration of USCs alleviated the renal functional damage in AKI rats, for the levels of blood urea nitrogen (BUN) and serum creatinine (SCr) were significantly decreased. The USCs-treated group also exhibited improved histological and ultrastructural changes, promoted proliferation, and inhibited apoptosis in renal tissues. After the USC therapy, the expression levels of proinflammatory cytokines (TNF-α and IL-6) and apoptosis-related proteins (BAX and cleaved caspase-3) were downregulated. In addition, the presence of a few GFP-labeled USCs was confirmed in rat renal tissues. In vitro, rat tubular epithelial (NRK-52E) cells were incubated with cisplatin to induce cell damage and then cocultured with USCs. After coculture with USCs, the cisplatin-induced NRK-52E cells showed higher cell viability and a lower apoptosis ratio than those of the control group, and cell cycle arrest was improved. In conclusion, our results demonstrated that USC therapy significantly improved the renal function and histological damage, inhibited the inflammation and apoptosis processes in the kidney, and promoted tubular epithelial proliferation. Our study exhibited the potential of USCs in the treatment of AKI, representing a new clinical therapeutic strategy.

Progenitor/Stem Cell Delivery by Suprarenal Aorta Route in Acute Kidney Injury

Progenitor/stem cell-based kidney regenerative strategies are a key step towards the development of novel therapeutic regimens for kidney disease treatment. However, the route of cell delivery, e.g., intravenous, intra-arterial, or intra-parenchymal, may affect the efficiency for kidney repair in different models of acute and chronic injury. Here, we describe a protocol of intra-aorta progenitor/stem cell injection in rats following either acute ischemia-reperfusion injury or acute proteinuria induced by puromycin aminonucleoside (PAN) – the experimental prototype of human minimal change disease and early stages of focal and segmental glomerulosclerosis. Vascular clips were applied across both renal pedicles for 35 min, or a single dose of PAN was injected via intra-peritoneal route, respectively. Subsequently, 2 x 10⁶ stem cells [green fluorescent protein (GFP)-labeled c-Kit+ progenitor/stem cells or GFP-mesenchymal stem cells] or saline were injected into the suprarenal aorta, above the renal arteries, after application of a vascular clip to the abdominal aorta below the renal arteries. This approach contributed to engraftment rates of ∼10% at day 8 post ischemia-reperfusion injury, when c-Kit+ progenitor/stem cells were injected, which accelerated kidney recovery. Similar rates of engraftment were found after PAN-induced podocyte damage at day 21. With practice and gentle surgical technique, 100% of the rats could be injected successfully, and, in the week following injection, ∼ 85% of the injected rats will recover completely. Given the similarities in mammals, much of the data obtained from intra-arterial delivery of progenitor/stem cells in rodents can be tested in translational research and clinical trials with endovascular catheters in humans.

miRNA‑mRNA regulatory network analysis of mesenchymal stem cell treatment in cisplatin‑induced acute kidney injury identifies roles for miR‑210/Serpine1 and miR‑378/Fos in regulating inflammation

The present study aimed to identify microRNAs (miRNAs) that may be crucial for the mechanism of mesenchymal stem cell (MSC) treatment in cisplatin-induced acute kidney injury (AKI) and to investigate other potential drugs that may have a similar function. Transcriptomics (GSE85957) and miRNA expression (GSE66761) datasets were downloaded from the Gene Expression Omnibus database. Differentially expressed genes (DEGs) and differentially expressed miRNAs (DEMs) were identified using the linear models for microarray data method and mRNA targets of DEMs were predicted using the miRWalk2.0 database. The crucial DEGs were screened by constructing a protein-protein interaction (PPI) network and module analysis. Functions of target genes were analyzed using the database for annotation, visualization and integrated discovery. Small molecule drugs were predicted using the connectivity map database. As a result, 5 DEMs were identified to be shared and oppositely expressed in comparisons between AKI model and control groups, and between MSC treatment and AKI model groups. The 103 DEGs were overlapped with the target genes of 5 common DEMs, and the resulting list was used for constructing the miRNA-mRNA regulatory network, including rno-miR-210/Serpine1 and rno-miR-378/Fos. Serpine1 (degree=17) and Fos (degree=42) were predicted to be hub genes according to the topological characteristic of degree in the PPI network. Function analysis indicated Serpine1 and Fos may be inflammation-related. Furthermore, gliclazide was suggested to be a potential drug for the treatment of AKI because the enrichment score was the closest to −1 (−0.9). In conclusion, it can be speculated that gliclazide may have a similar mechanism to MSC as a potential therapeutic agent for cisplatin-induced AKI, by regulating miR-210/Serpine1 and miR-378-/Fos-mediated inflammation and cell apoptosis.

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.

Concise Reviews: Stem Cells and Kidney Regeneration: An Update

Significant progress has been made to advance stem cell products as potential therapies for kidney diseases: various kinds of stem cells can restore renal function in preclinical models of acute and chronic kidney injury. Nonetheless this literature contains contradictory results, and for this reason, we focus this review on reasons for apparent discrepancies in the literature, because they contribute to difficulty in translating renal regenerative therapies. Differences in methodologies used to derive and culture stem cells, even those from the same source, in addition to the lack of standardized renal disease animal models (both acute and chronic), are important considerations underlying contradictory results in the literature. We propose that harmonized rigorous protocols for characterization, handling, and delivery of stem cells in vivo could significantly advance the field, and present details of some suggested approaches to foster translation in the field of renal regeneration. Our goal is to encourage coordination of methodologies (standardization) and long‐lasting collaborations to improve protocols and models to lead to reproducible, interpretable, high‐quality preclinical data. This approach will certainly increase our chance to 1 day offer stem cell therapeutic options for patients with all‐too‐common renal diseases. Stem Cells Translational Medicine2019;8:82–92