Comparison of human adipose stromal vascular fraction and adipose-derived mesenchymal stem cells for the attenuation of acute renal ischemia/reperfusion injury

Enriched human embryonic stem cells-derived CD133+, CD24+ renal progenitors engraft and restore function in a gentamicin-induced kidney injury in mice

Introduction

Acute kidney injury (AKI) is a common health problem that leads to high morbidity and potential mortality. The failure of conventional treatments to improve forms of this condition highlights the need for innovative and effective treatment approaches. Regenerative therapies with Renal Progenitor Cells (RPCs) have been proposed as a promising new strategy. A growing body of evidence suggests that progenitor cells differentiated from different sources, including human embryonic stem cells (hESCs), can effectively treat AKI.

Methods

Here, we describe a method for generating RPCs and directed human Embryoid Bodies (EBs) towards CD133+CD24+ renal progenitor cells and evaluate their functional activity in alleviating AKI.

Results

The obtained results show that hESCs-derived CD133+CD24+ RPCs can engraft into damaged renal tubules and restore renal function and structure in mice with gentamicin-induced kidney injury, and significantly decrease blood urea nitrogen levels, suppress oxidative stress and inflammation, and attenuate histopathological disturbances, including tubular necrosis, tubular dilation, urinary casts, and interstitial fibrosis.

Conclusion

The results suggest that RPCs have a promising regenerative potential in improving renal disease and can lay the foundation for future cell therapy and disease modeling.

Toward transplantation tolerance with adipose tissue-derived therapeutics

Solid organ and composite tissue allotransplanation have been widely applied to treat end-stage organ failure and massive tissue defects, respectively. Currently there are a lot of research endeavors focusing on induction of transplantation tolerance, to relieve the burden derived from long-term immunosuppressant uptake. The mesenchymal stromal cells (MSCs) have been demonstrated with potent immunomodulatory capacities and applied as promising cellular therapeutics to promote allograft survival and induce tolerance. As a rich source of adult MSCs, adipose tissue provides additional advantages of easy accessibility and good safety profile. In recent years, the stromal vascular fraction (SVF) isolated from adipose tissues following enzymatic or mechanical processing without in vitro culture and expansion has demonstrated immunomodulatory and proangiogenic properties. Furthermore, the secretome of AD-MSCs has been utilized in transplantation field as a potential "cell-free" therapeutics. This article reviews recent studies that employ these adipose-derived therapeutics, including AD-MSCs, SVF, and secretome, in various aspects of organ and tissue allotransplantation. Most reports validate their efficacies in prolonging allograft survival. Specifically, the SVF and secretome have performed well for graft preservation and pretreatment, potentially through their proangiogenic and antioxidative capacities. In contrast, AD-MSCs were suitable for peri-transplantation immunosuppression. The proper combination of AD-MSCs, lymphodepletion and conventional immunosuppressants could consistently induce donor-specific tolerance to vascularized composite allotransplants (VCA). For each type of transplantation, optimizing the choice of therapeutics, timing, dose, and frequency of administration may be required. Future progress in the application of adipose-derived therapeutics to induce transplantation tolerance will be further benefited by continued research into their mechanisms of action and the development of standardized protocols for isolation methodologies, cell culture, and efficacy evaluation.

Clinical applications of adipose-derived stromal vascular fraction in veterinary practice

Adipose tissue-derived stromal vascular fraction (AdSVF) comprises a heterogeneous cell population, including the multipotent mesenchymal stem cells, hematopoietic stem cells, immune cells, endothelial cells, fibroblasts, and pericytes. As such, multipotent adipose tissue-derived mesenchymal stem cells (AdMSCs), are one of the important components of AdSVF. Commonly used techniques to harvest AdSVF involve enzymatic or non-enzymatic methods. The enzymatic method is considered to be the gold standard technique due to its higher yield. The cellular components of AdSVF can be resuspended in normal saline, platelet-rich plasma, or phosphate-buffered saline to produce a ready-to-use solution. Freshly isolated AdSVF has exhibited promising osteogenic and vasculogenic capacity. AdSVF has already been proven to possess therapeutic potential for osteoarthritis management. It is also an attractive therapeutic option for enhancing wound healing. In addition, the combined use of AdSVF and platelet-rich plasma has an additive stimulatory effect in accelerating wound healing and can be considered an alternative to AdMSC treatment. It is also widely used for managing various orthopaedic conditions in clinical settings and has the potential for regenerating bone, cartilage, and tendons. Autologous AdSVF cells are used along with bone substitutes and other biological factors as an alternative to conventional bone grafting techniques owing to their promising osteogenic and vasculogenic capacity. It can also be used for treating osteonecrosis, meniscus tear, chondromalacia, and tendon injuries in veterinary practice. It has several advantages over in vitro expanded AdMSC, including precluding the need for culturing, reduced risk of cell contamination, and cost-effectiveness, making it ideal for clinical use.

Comparison of Stromal Vascular Fraction and Adipose-Derived Stem Cells for Protection of Renal Function in a Rodent Model of Ischemic Acute Kidney Injury

Aims

Few studies have compared the use of different cell types derived from adipose tissue or the optimal route for efficient and safe cell delivery in ischemic acute kidney injury (AKI). We compared the abilities of stromal vascular fraction (SVF) and adipose-derived stem cells (ADSC), injected via three different routes, to protect renal function in a rodent model of ischemic AKI.

Methods

Ninety male Sprague-Dawley rats were randomly divided into 9 groups: sham, nephrectomy control, AKI control, transaortic renal arterial SVF injection, renal parenchymal SVF injection, tail venous SVF injection, transaortic renal arterial ADSC injection, renal parenchymal ADSC injection, and tail venous ADSC injection groups. Their renal function was assessed 4 days before and 1, 2, 3, 4, 7, and 14 days after surgical procedures to induce ischemic AKI. The histomorphometric studies were performed 14 days after surgical procedures.

Results

Renal parenchymal injection of SVF notably reduced the level of serum blood urea nitrogen and creatinine elevation compared to the AKI control group. Renal parenchymal injection of SVF notably reduced the level of creatinine clearance decrease. In addition, collagen content was lower in the renal parenchymal SVF injection group, and fibrosis was reduced. Apoptosis was reduced in the renal parenchymal SVF injection group, and proliferation was increased. The expression levels of antioxidative markers such as glutathione reductase and peroxidase were higher in the renal parenchymal SVF injection group.

Conclusions

Our findings suggest that renal function is protected from ischemic AKI through renal parenchymal injection of SVF, which has enhanced antifibrotic, antiapoptotic, and antioxidative effects.

Adipose-derived mesenchymal stem cells with hypoxic preconditioning improve tenogenic differentiation

Background

Adipose-derived mesenchymal stem cells (ADSCs), as seed cells for tendon tissue engineering, are promising for tendon repair and regeneration. But for ADSCs, diverse oxygen tensions have different stimulatory effects. To explore this issue, we investigated the tenogenic differentiation capability of ADSCs under hypoxia condition (5% O₂) and the possible signaling pathways correspondingly. The effects of different oxygen tensions on proliferation, migration, and tenogenic differentiation potential of ADSCs were investigated.

Methods

P4 ADSCs were divided into a hypoxic group and a normoxic group. The hypoxic group was incubated under a reduced O₂ pressure (5% O₂, 5% CO₂, balanced N₂). The normoxic group was cultured in 21% O₂. Two groups were compared: HIF-1α inhibitor (2-MeOE2) in normoxic culturing conditions and hypoxic culturing conditions. Hypoxia-inducible factor-1α (HIF-1α) and VEGF were measured using RT-qPCR. Specific HIF-1α inhibitor 2-methoxyestradiol (2-MeOE2) was applied to investigate whether HIF-1α involved in ADSCs tenogenesis under hypoxia.

Results

Hypoxia significantly reduced proliferation and migration of ADSCs. Continuous treatment of ADSCs at 5% O₂ resulted in a remarkable decrease in HIF-1α expression in comparison with 20% O₂. Additionally, ADSCs of hypoxia preconditioning exhibited higher mRNA expression levels of the related key tenogenic makers and VEGF than normoxia via RT-qPCR measurement (p ˂ 0.05). Furthermore, the effects of hypoxia on tenogenic differentiation of ADSCs were inhibited by 2-MeOE2. Hypoxia can also stimulate VEGF production in ADSCs.

Conclusions

Our findings demonstrate that hypoxia preconditioning attenuates the proliferation and migration ability of ADSCs, but has positive impact on tenogenic differentiation through HIF-1α signaling pathway.

Considerations for the clinical use of stem cells in genitourinary regenerative medicine

The genitourinary tract can be affected by several pathologies which require repair or replacement to recover biological functions. Current therapeutic strategies are challenged by a growing shortage of adequate tissues. Therefore, new options must be considered for the treatment of patients, with the use of stem cells (SCs) being attractive. Two different strategies can be derived from stem cell use: Cell therapy and tissue therapy, mainly through tissue engineering. The recent advances using these approaches are described in this review, with a focus on stromal/mesenchymal cells found in adipose tissue. Indeed, the accessibility, high yield at harvest as well as anti-fibrotic, immunomodulatory and proangiogenic properties make adipose-derived stromal/SCs promising alternatives to the therapies currently offered to patients. Finally, an innovative technique allowing tissue reconstruction without exogenous material, the self-assembly approach, will be presented. Despite advances, more studies are needed to translate such approaches from the bench to clinics in urology. For the 21^st century, cell and tissue therapies based on SCs are certainly the future of genitourinary regenerative medicine.

Comparison of the Cytokine Profile in Mesenchymal Stem Cells from Human Adipose, Umbilical Cord, and Placental Tissues

Human mesenchymal stem cells (MSCs) can be isolated from various tissues. However, the cytokine profile in different MSC types remains unclear. In this study, MSCs were extracted from adipose, umbilical cord, and placental tissues. The surface marker expression, multilineage differentiation potential, and cytokine secretion of these cells were compared. The isolated MSCs exhibited similar morphology and surface marker expression. However, they differed with regard to their differentiation potential. Adipose-MSCs (A-MSCs) exhibited a higher potential for adipogenesis and osteogenic differentiation compared with umbilical cord-MSCs (UC-MSCs) and placental-MSCs (P-MSCs). The expression levels of 80 cytokines were detected, and the data demonstrated that the three MSC types abundantly secreted insulin-like growth factor-binding protein (IGFBP)-4, IGFBP-3, tissue inhibitor of metalloproteinase (TIMP)-1, TIMP-2, IGFBP-6, monocyte chemoattractant protein-1, and granulocyte colony-stimulating factor. However, the expression levels of vascular endothelial growth factor, tumor necrosis factor alpha, interleukin (IL)-6 receptor, and IL-13 in A-MSCs were higher compared with those of UC-MSCs and P-MSCs. Moreover, the expression levels of intercellular adhesion molecule-1 and growth differentiation factor 15 were lower in A-MSCs. Kyoto Encyclopedia of Genes and Genomes analysis indicated that the "adipocytokine" and the "PI3K/Akt pathways" were enriched in A-MSCs. Taken together, the results demonstrated that MSCs from different sources exhibited differences in the secretion of specific factors. A-MSCs were associated with the expression of several proangiogenic factors and may be an improved source for angiogenesis and tissue regeneration.

Adipose-Derived Stem/Stromal Cells in Kidney Transplantation: Status Quo and Future Perspectives

Kidney transplantation (KT) is the gold standard treatment of end-stage renal disease. Despite progressive advances in organ preservation, surgical technique, intensive care, and immunosuppression, long-term allograft survival has not significantly improved. Among the many peri-operative complications that can jeopardize transplant outcomes, ischemia–reperfusion injury (IRI) deserves special consideration as it is associated with delayed graft function, acute rejection, and premature transplant loss. Over the years, several strategies have been proposed to mitigate the impact of IRI and favor tolerance, with rather disappointing results. There is mounting evidence that adipose stem/stromal cells (ASCs) possess specific characteristics that could help prevent, reduce, or reverse IRI. Immunomodulating and tolerogenic properties have also been suggested, thus leading to the development of ASC-based prophylactic and therapeutic strategies in pre-clinical and clinical models of renal IRI and allograft rejection. ASCs are copious, easy to harvest, and readily expandable in culture. Furthermore, ASCs can secrete extracellular vesicles (EV) which may act as powerful mediators of tissue repair and tolerance. In the present review, we discuss the current knowledge on the mechanisms of action and therapeutic opportunities offered by ASCs and ASC-derived EVs in the KT setting. Most relevant pre-clinical and clinical studies as well as actual limitations and future perspective are highlighted.

Therapeutic Effects of Stem Cells From Different Source on Renal Ischemia- Reperfusion Injury: A Systematic Review and Network Meta-analysis of Animal Studies

Objective: Although stem cell therapy for renal ischemia-reperfusion injury (RIRI) has made immense progress in animal studies, conflicting results have been reported by the investigators. Therefore, we aimed to systematically evaluate the effects of different stem cells on renal function of animals with ischemia-reperfusion injury and to compare the efficacies of stem cells from various sources. Methods: PubMed, Web of Science, Embase, Cochrane, CNKI, VIP, CBM, and WanFang Data were searched for records until April 2021. Two researchers independently conducted literature screening, data extraction, and literature quality evaluation. Results and conclusion: Seventy-two animal studies were included for data analysis. Different stem cells significantly reduced serum creatinine and blood urea nitrogen levels in the early and middle stages (1 and 7 days) compared to the negative control group, however there was no significant difference in the late stage among all groups (14 days); In the early stage (1 day), the renal histopathological score in the stem cell group was significantly lower than that in the negative control group, and there was no significant difference among these stem cells. In addition, there was no significant difference between stem cell and negative control in proliferation of resident cells, however, significantly less apoptosis of resident cells than negative control. In conclusion, the results showed that stem cells from diverse sources could improve the renal function of RIRI animals. ADMSCs and MDMSCs were the most-researched stem cells, and they possibly hold the highest therapeutic potential. However, the quality of evidence included in this study is low, and there are many risks of bias. The exact efficacy of the stem cells and the requirement for further clinical studies remain unclear.

When Origin Matters: Properties of Mesenchymal Stromal Cells From Different Sources for Clinical Translation in Kidney Disease

Advanced therapy medicinal products (ATMPs) offer new prospects to improve the treatment of conditions with unmet medical needs. Kidney diseases are a current major health concern with an increasing global prevalence. Chronic renal failure appears after many years of impairment, which opens a temporary window to apply novel therapeutic approaches to delay or halt disease progression. The immunomodulatory, anti-inflammatory, and pro-regenerative properties of mesenchymal stromal cells (MSCs) have sparked interest for their use in cell-based regenerative therapies. Currently, several early-phase clinical trials have been completed and many are ongoing to explore MSC safety and efficacy in a wide range of nephropathies. However, one of the current roadblocks to the clinical translation of MSC therapies relates to the lack of standardization and harmonization of MSC manufacturing protocols, which currently hinders inter-study comparability. Studies have shown that cell culture processing variables can have significant effects on MSC phenotype and functionality, and these are highly variable across laboratories. In addition, heterogeneity within MSC populations is another obstacle. Furthermore, MSCs may be isolated from several sources which adds another variable to the comparative assessment of outcomes. There is now a growing body of literature highlighting unique and distinctive properties of MSCs according to the tissue origin, and that characteristics such as donor, age, sex and underlying medical conditions may alter the therapeutic effect of MSCs. These variables must be taken into consideration when developing a cell therapy product. Having an optimal scale-up strategy for MSC manufacturing is critical for ensuring product quality while minimizing costs and time of production, as well as avoiding potential risks. Ideally, optimal scale-up strategies must be carefully considered and identified during the early stages of development, as making changes later in the bioprocess workflow will require re-optimization and validation, which may have a significant long-term impact on the cost of the therapy. This article provides a summary of important cell culture processing variables to consider in the scale-up of MSC manufacturing as well as giving a comprehensive review of tissue of origin-specific biological characteristics of MSCs and their use in current clinical trials in a range of renal pathologies.

Pain relief and cartilage repair by Nanofat against osteoarthritis: preclinical and clinical evidence

Background

Osteoarthritis (OA) is the most common joint degenerative disorder, with little effective therapy to date. Nanofat is a cocktail of cells obtained from fat tissue, which possesses regenerative capacity and has a potential in treating OA. This study aimed to determine the anti-OA efficacy of Nanofat from basic and clinical aspects and explore its action mode.

Methods

Flow cytometry was performed to characterize Nanofat. A monoiodoacetate-induced OA rat model was employed for in vivo study. Cell viability and wound healing assays were conducted for in vitro study. Real-time PCR and Western blot assays were applied to explore the molecular action mode of Nanofat. Moreover, a retrospective analysis was conducted to determine the clinical efficacy and safety of Nanofat on knee OA patients.

Results

The in vivo results showed that Nanofat significantly attenuated pain symptoms and protected cartilage ECM (Col2) from damage, and its effects were not significantly differed with adipose tissue-derived stem cells (both P > 0.05). The in vitro results showed that Nanofat promoted the cell viability and migration of chondrocytes and significantly restored the IL-1β-induced abnormal gene expressions of Col2, Aggrecan, Sox9, Adamts5, Mmp3, Mmp9 Mmp13, IL-6 and Col10 and protein expressions of Col2, MMP9, MMP13, and Sox9 of chondrocytes. The regulatory actions of Nanofat on these anabolic, catabolic, and hypertrophic molecules of chondrocytes were similar between two treatment routes: co-culture and conditioned medium, suggesting a paracrine-based mode of action of Nanofat. Moreover, the clinical data showed that Nanofat relieved pain and repaired damaged cartilage of OA patients, with no adverse events.

Conclusion

In sum, this study demonstrated the anti-OA efficacy as well as a paracrine-based action mode of Nanofat, providing novel knowledge of Nanofat and suggesting it as a promising and practical cell therapy for clinical treatment of OA.

Administration of Donor-Derived Nonexpanded Adipose Stromal Vascular Fraction Attenuates Ischemia-Reperfusion Injury in Donation After Cardiac Death Rat Renal Transplantation

Donation after cardiac death (DCD) has become a potential source for transplantation organs. However, ischemia/reperfusion injury (IRI) induced by cardiac arrest has limited the use of DCD organs. Stromal vascular fraction (SVF) without the culturing step has been proposed as a safer and easier source for stem cell therapy, which has emerged as an attractive technology that could facilitate the recovery of renal function and structure from acute kidney injury induced by IRI after DCD renal transplantation. In this study, freshly isolated donor-derived SVF was identified and then delivered intra-arterially into the grafts in DCD rat renal transplantation. Administration of freshly isolated donor-derived SVF could significantly alleviate the IRI of renal grafts and enhance graft reparation by promoting graft cell proliferation and microvascularization in DCD renal transplantation. Moreover, results revealed that the oxidative stress in grafts was significantly alleviated with SVF treatment, and this might be attributed to the overexpression of antioxidative molecules including nuclear factor erythroid-related factor 2, superoxide dismutase-1, and heme oxygenase-1. In conclusion, our study demonstrated that the administration of freshly isolated donor-derived nonexpanded adipose SVF could attenuate IRI and protect the grafts after DCD rat renal transplantation.

Minimal Effects of Intravenous Administration of Xenogeneic Adipose Derived Stem Cells on Organ Function in a Porcine 40%TBSA Burn Model

Adipose stem cells (ASCs) have shown therapeutic promise for various conditions, including burn injury. While ASCs have immunomodulatory properties, concerns exist over pro-coagulant activity after intravenous (IV) administration. In the present study, we examined IV human ASC delivery in terms of coagulation, organ function, and inflammation in a 40% total body surface area (TBSA) swine burn model. Anesthetized female Yorkshire swine were burned and randomized to receive 15ml/kg Lactated Ringer's containing: no ASCs; a low dose (5x10 5 ASCs/kg), or a high dose (5x10 6 ASCs/kg). For biochemical analysis, blood was collected at baseline (BL), 3, 6, 12, and 24 hours post-burn, while kidney and liver tissue was collected post-euthanasia. A significant, but transient, effect of ASCs was seen on prothrombin times and INR, wherein low doses revealed slight hypercoagulation. Burns increased partial thromboplastin time, fibrinogen, and d-dimer levels, which was unchanged with ASC administration. ASCs tended to exacerbate increases in bilirubin at 3 hours, but this didn't reach statistical significance. A significant effect of ASCs on creatinine and BUN was seen, wherein low doses elevated levels at 24 hours (creatinine, p=0.0012; BUN, p=0.0195). Hepatic and renal TUNEL staining were similar for all groups. A dose-dependent decrease in IL-8 was observed, while low doses significantly increased IL-1RA at 3 (p=0.050), IL-12 at 12 (p=0.021) and IL-6 at 24 hours post-burn (p=0.035). IV administration of xenogeneic ASCs slightly increased coagulation, but effects on burn-induced renal and hepatic dysfunction effects were minimal. Despite some significant immunomodulation, organ dysfunction effects were modest. Collectively, this study provides evidence to be skeptical about xenogeneic ASC administration in regards to burn.

Transplantation of chicken egg white extract-induced rabbit PBMCs as a treatment for renal ischemia-reperfusion injury in rabbits

Ischemia-reperfusion injury is an important contributor to acute kidney injury and a major factor affecting early functional recovery after kidney transplantation. We conducted this experiment to investigate the protective effect of induced multipotent stem cell transplantation on renal ischemia-reperfusion injury. Forty rabbits were divided into four groups of 10 rabbits each. Thirty rabbits were used to establish the renal ischemia-reperfusion injury model, and ten rabbits served as the model group and were not treated. Among the 30 rabbits with renal ischemia-reperfusion injury, 10 rabbits were treated with induced peripheral blood mononuclear cells (PBMCs), and 10 other rabbits were treated with noninduced PBMCs. After three weekly treatments, the serum creatinine levels, urea nitrogen levels and urine protein concentrations were quantified. The kidneys were stained with hematoxylin-eosin (HE), periodic acid-Schiff (PAS) and Masson’s trichrome and then sent for commercial metabolomic testing. The kidneys of the rabbits in the model group showed different degrees of pathological changes, and the recovery of renal function was observed in the group treated with induced cells. The results indicate that PBMCs differentiate into multipotent stem cells after induction and exert a therapeutic effect on renal ischemia-reperfusion injury.

Kidney extracellular matrix hydrogel enhances therapeutic potential of adipose-derived mesenchymal stem cells for renal ischemia reperfusion injury

Stem cell-based therapy has been suggested as a promising option for the treatment of renal ischemia-reperfusion injury (IRI). However, how to efficiently deliver stem cells remains a challenge. In the present study, we firstly proposed the utilization of kidney extracellular matrix hydrogel (ECMH) as an injectable scaffold for delivering adipose-derived mesenchymal stem cells (ad-MSCs) into ischemic kidneys. A modified strategy of decellularization and gelation was introduced to prepare the ECMH, by which the bioactive ingredients were retained as much as possible. Bioluminescence living imaging and immunofluorescence revealed that ECMH could significantly elevate the retention and survival rate of transplanted ad-MSCs in damaged kidneys and reduce their escape rate to other organs, which consequently resulted to the enhanced therapeutic effect of ad-MSCs on renal IRI. Further, in vitro evidence demonstrated that ECMH could remarkably reduce the oxidative stress and apoptosis, promote the proliferation, secretion, and epithelial differentiation of ad-MSCs, as well as facilitate cell migration while acting as a sustained-release scaffold. This study establishes an effective approach to enhance the therapeutic potential of ad-MSCs for renal IRI. Our findings suggest that ECMH derived from organs or tissues would be a promising injectable scaffold for stem cell-based therapy. STATEMENT OF SIGNIFICANCE: It remains a challenge to efficiently deliver stem cells to target tissues, which may limit the clinical application of stem cell-based therapy. In this study, we developed a modified strategy of decellularization and gelation to prepare the kidney extracellular matrix hydrogel (ECMH). In vivo and in vitro evidence indicated that the kidney ECMH could improve the retention and survival rate, as well as multiple biological functions of adipose-derived mesenchymal stem cells, thereby contributing to the histological and functional recovery of injured kidneys induced by ischemia-reperfusion. Our findings highlight the use of organs or tissues derived ECMH as a promising stem cell delivery scaffold for tissue repair.

Remote Ischemic Preconditioning Ameliorates Renal Fibrosis After Ischemia-Reperfusion Injury via Transforming Growth Factor beta1 (TGF-β1) Signalling Pathway in Rats

Background

The present study was conducted to explore the influence of remote ischemic preconditioning (RIPC) on the adjustment of renal fibrosis after ischemia-reperfusion injury (IRI).

Material/Methods

Male Sprague-Dawley rats were randomly assigned to 3 groups following right-side nephrectomy: the Sham group (without renal artery clamping), the IRI group (45 min left renal artery clamping), and the RIPC group (rats were treated daily with 3 cycles of 5 min of limb ischemia and 5 min of reperfusion on 3 consecutive days before left renal artery occlusion). After 3 months of reperfusion, the renal function and the extent of tubular injury and renal fibrosis were assessed. The expressions of transforming growth factor beta1 (TGF-β1), p-Smad2, Smad2, p-Smad3, and Smad3 were also evaluated.

Results

There was no significant difference in renal function and tubular damage among the 3 groups after 45 min of kidney ischemia followed by 3 months of reperfusion. However, an obvious increase of extracellular matrix components and α-SMA could be observed in the kidney tissues of the IRI group, and the changes were significantly ameliorated in rats treated with enhanced RIPC. Compared with the IRI group, the expression of TGF-β1 and the level of p-Smad2 and p-Smad3 were decreased after the intervention of enhanced RIPC.

Conclusions

Enhanced RIPC ameliorated renal fibrosis after IRI in rats, which appears to be associated with inhibition of the TGF-β1/p-Smad2/3 signalling pathway.

Adipose-derived cellular and cell-derived regenerative therapies in dermatology and aesthetic rejuvenation

Cellular and cell-derived components of adipose-derived tissue for the purposes of dermatologic and aesthetic rejuvenation applications have become increasingly studied and integrated into clinical practice. These components include micro-fragmented fat (nanofat), the stromal vascular fraction (SVF), adipose-derived mesenchymal stem cells (ASC), and extracellular vesicles (EVs), which have all shown capability to repair, regenerate, and rejuvenate surrounding tissue. Various aesthetic applications including hair growth, scar reduction, skin ischemia-reperfusion recovery, and facial rejuvenation are reviewed. In particular, results from preclinical and clinical studies are discussed, with a focus on clarification of nomenclature.

Human intracerebroventricular (ICV) injection of autologous, non-engineered, adipose-derived stromal vascular fraction (ADSVF) for neurodegenerative disorders: results of a 3-year phase 1 study of 113 injections in 31 patients

We have chosen to test the safety of human intracerebroventricular (ICV) brain injections of autologous non-genetically-modified adipose-derived stromal vascular fraction (ADSVF). In this IRB-approved trial, 24 patients received ICV ADSVF via an implanted reservoir between 5/22/14 and 5/22/17. Seven others were injected via their ventriculo-peritoneal shunts. Ten patients had Alzheimer's disease (AD), 6 had amyotrophic lateral sclerosis (ALS), 6 had progressive multiple sclerosis (MS-P), 6 had Parkinson's "Plus" (PD+), 1 had spinal cord injury, 1 had traumatic brain injury, and 1 had stroke. Median age was 74 (range 41-83). Injections were planned every 2-3 months. Thirty-one patients had 113 injections. Patients received SVF injection volumes of 3.5-20 cc (median:4 cc) containing 4.05 × 10⁵ to 6.2 × 10⁷ cells/cc, which contained an average of 8% hematopoietic and 7.5% adipose stem cells. Follow-up ranged from 0 to 36 months (median: 9.2 months). MRIs post injection(s) were unchanged, except for one AD patient whose hippocampal volume increased from < 5th percentile to 48th percentile (NeuroQuant^® volumetric MRI). Of the 10 AD patients, 8 were stable or improved in tests of cognition. Two showed improvement in P-tau and ß-amyloid levels. Of the 6 MS-P patients all are stable or improved. Four of 6 ALS patients died of disease progression. Twelve of 111 injections (11%) led to 1-4 days of transient meningismus, and mild temperature elevation, which resolved with acetaminophen and/or dexamethasone. Two (1.8% of injections) required hospitalization for these symptoms. One patient (0.9% of injections) had his reservoir removed and later replaced for presumed infection. In this Phase 1 safety trial, ADSVF was safely injected into the human brain ventricular system in patients with no other treatment options. Secondary endpoints of clinical improvement or stability were particularly promising in the AD and MS-P groups. These results will be submitted for a Phase 2 FDA-approved trial.

Emerging Trends in the Syntheses of Heterocycles Using Graphene-based Carbocatalysts: An Update

Graphene-based carbocatalysts owing to numerous amazing properties such as large specific surface area, high intrinsic mobility, excellent thermal and electrical conductivities, chemical stability, ease of functionalization, simple method of preparation, effortless recovery and recyclability have gained a superior position amongst the conventional homogeneous and heterogeneous catalysts. In this review, an endeavor has been made to highlight the syntheses of diverse heterocyclic compounds catalyzed by graphene-based catalysts. Further, the study also reveals that all the catalysts could be reused several times without significant loss in their catalytic activity. Additionally, most of the reactions catalyzed by graphene-based carbocatalysts were carried out at ambient temperature and under solvent-free conditions. Thus, the graphene-based catalysts do not merely act as efficient catalysts but also serve as sustainable, green catalysts. This review is divided into various sub-sections, each of which comprehensively describes the preparation of a particular heterocyclic scaffold catalyzed by graphene-derived carbocatalyst in addition to synthesis of graphene oxide and reduced graphene oxide, functionalization, and structural features governing their catalytic properties. Synthesis of heterocycles catalyzed by graphene-based carbocatalysts.

Emerging therapeutic strategies for transplantation-induced acute kidney injury: protecting the organelles and the vascular bed

INTRODUCTION

Renal ischemia-reperfusion injury (IRI) is a significant clinical challenge faced by clinicians in a broad variety of clinical settings such as perioperative and intensive care. Renal IRI induced acute kidney injury (AKI) is a global public health concern associated with high morbidity, mortality, and health-care costs. Areas covered: This paper focuses on the pathophysiology of transplantation-related AKI and recent findings on cellular stress responses at the intersection of 1. The Unfolded protein response; 2. Mitochondrial dysfunction; 3. The benefits of mineralocorticoid receptor antagonists. Lastly, perspectives are offered to the readers. Expert opinion: Renal IRI is caused by a sudden and temporary impairment of blood flow to the organ. Defining the underlying cellular cascades involved in IRI will assist us in the identification of novel interventional targets to attenuate IRI with the potential to improve transplantation outcomes. Targeting mitochondrial function and cellular bioenergetics upstream of cellular damage may offer several advantages compared to targeting downstream inflammatory and fibrosis processes. An improved understanding of the cellular pathophysiological mechanisms leading to kidney injury will hopefully offer improved targeted therapies to prevent and treat the injury in the future.

A short-term plastic adherence incubation of the stromal vascular fraction leads to a predictable GMP-compliant cell-product

Introduction:Mesenchymal stromal/stem cells (MSCs) derived from fat tissue are an encouraging tool for regenerative medicine. They share properties similar to the bone marrow-derived MSCs, but the amount of MSCs per gram of fat tissue is 500x higher. The fat tissue can easily be digested by collagenase, releasing a heterogeneous cell fraction called stromal vascular fraction (SVF) which contains a variable amount of stromal/stem cells. In Europe, cell products like the SVF derived from fat tissue are considered advanced therapy medicinal product (ATMPs). As a consequence, the manufacturing process has to be approved via GMP-compliant process validation. The problem of the process validation for SVF is the heterogeneity of this fraction.

Methods: Here, we modified existing purification strategies by adding an additional plastic adherence incubation of maximal 20 hours after SVF isolation. The resulting cell fraction was characterized and compared to SVF as well as cultivated adipose-derived stromal/stem cells (ASCs) with respect to viability and cell yield, the expression of surface markers, differentiation potential and cytokine expression.

Results: Short-term incubation significantly reduced the heterogeneity of the resulting cell fraction compared to SVF. The cells were able to differentiate into adipocytes, chondrocytes, and osteoblasts. More importantly, they expressed trophic proteins which have been previously associated with the beneficial effects of MSCs. Furthermore, GMP compliance of the production process described herein was acknowledged by the national regulatory agencies (DE_BB_01_GMP_2017_1018).

Conclusion: Addition of a short purification-step after the SVF isolation is a cheap and fast strategy to isolate a homogeneous uncultivated GMP-compliant cell fraction of ASCs.

Protective Effects of Uncultured Adipose-Derived Stromal Vascular Fraction on Testicular Injury Induced by Torsion-Detorsion in Rats

Torsion‐detorsion (T/D)‐induced testicular injury may lead to male subfertility and even infertility. Stem cell therapy provides an alternative to attenuate testicular injury and promote spermatogenesis. Adipose‐derived stromal vascular fraction (SVF) can be acquired conveniently without in vitro expansion, which may avoid the potential risks of microbial contamination, xenogenic nutritional sources, etc., during cell culture. In this study, we investigate the protective effects of autologous uncultured SVF on testicular injury and spermatogenesis in a rat model of T/D. Animals were randomly divided into sham, T/D+ phosphate‐buffered saline, and T/D + SVF groups (18 rats in each group). SVF was isolated, labeled with lipophilic fluorochrome chloromethylbenzamido dialkylcarbocyanine, and transplanted into T/D testis by local injection. At 3, 7, 14, and 28 days F surgery, testicular tissue and serum samples were harvested for histopathological, immunohistochemical, Western blot, and enzyme‐linked immunosorbent assays. Histopathological findings demonstrated severe injury in the testis with decreased Johnsen's score led by T/D, while uncultured SVF reduced testicular injury and elevated the decreased score. Injected SVF cells were mainly integrated into interstitial region and seminiferous tubules, enhanced the secretion of basic fibroblast growth factor and stem cell factor in the testis, contributed to the declining level of malondialdehyde and restoration of hormonal homeostasis, and then reduced the injury of Leydig cells and germ cells, as well as promoting spermatogenesis. Our findings demonstrated that autologous uncultured SVF could protect the testis from testicular ischemia‐reperfusion injury and promote spermatogenesis, which provide significant clinical implications for the prevention of infertility induced by testicular T/D. stem cells translational medicine2019;8:383–391

Barriers and Advances in Kidney Preservation

Despite the fact that a significant fraction of kidney graft dysfunctions observed after transplantation is due to ischemia-reperfusion injuries, there is still no clear consensus regarding optimal kidney preservation strategy. This stems directly from the fact that as of yet, the mechanisms underlying ischemia-reperfusion injury are poorly defined, and the role of each preservation parameter is not clearly outlined. In the meantime, as donor demography changes, organ quality is decreasing which directly increases the rate of poor outcome. This situation has an impact on clinical guidelines and impedes their possible harmonization in the transplant community, which has to move towards changing organ preservation paradigms: new concepts must emerge and the definition of a new range of adapted preservation method is of paramount importance. This review presents existing barriers in transplantation (e.g., temperature adjustment and adequate protocol, interest for oxygen addition during preservation, and clear procedure for organ perfusion during machine preservation), discusses the development of novel strategies to overcome them, and exposes the importance of identifying reliable biomarkers to monitor graft quality and predict short and long-term outcomes. Finally, perspectives in therapeutic strategies will also be presented, such as those based on stem cells and their derivatives and innovative models on which they would need to be properly tested.

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

Differential and Interactive Effects of Substrate Topography and Chemistry on Human Mesenchymal Stem Cell Gene Expression

Variations in substrate chemistry and the micro-structure were shown to have a significant effect on the biology of human mesenchymal stromal cells (hMSCs). This occurs when differences in the surface properties indirectly modulate pathways within numerous signaling networks that control cell fate. To understand how the surface features affect hMSC gene expression, we performed RNA-sequencing analysis of bone marrow-derived hMSCs cultured on tissue culture-treated polystyrene (TCP) and poly(l-lactide) (PLLA) based substrates of differing topography (Fl: flat and Fs: fibrous) and chemistry (Pr: pristine and Am: aminated). Whilst 80% of gene expression remained similar for cells cultured on test substrates, the analysis of differentially expressed genes (DEGs) revealed that surface topography significantly altered gene expression more than surface chemistry. The Fl and Fs topologies introduced opposite directional alternations in gene expression when compared to TCP control. In addition, the effect of chemical treatment interacted with that of topography in a synergistic manner with the Pr samples promoting more DEGs than Am samples in all gene ontology function groups. These findings not only highlight the significance of the culture surface on regulating the overall gene expression profile but also provide novel insights into cell-material interactions that could help further design the next-generation biomaterials to facilitate hMSC applications. At the same time, further studies are required to investigate whether or not the observations noted correlate with subsequent protein expression and functionality of cells.

Stem/Stromal Cells for Treatment of Kidney Injuries With Focus on Preclinical Models

Within the last years, the use of stem cells (embryonic, induced pluripotent stem cells, or hematopoietic stem cells), Progenitor cells (e.g., endothelial progenitor cells), and most intensely mesenchymal stromal cells (MSC) has emerged as a promising cell-based therapy for several diseases including nephropathy. For patients with end-stage renal disease (ESRD), dialysis or finally organ transplantation are the only therapeutic modalities available. Since ESRD is associated with a high healthcare expenditure, MSC therapy represents an innovative approach. In a variety of preclinical and clinical studies, MSC have shown to exert renoprotective properties, mediated mainly by paracrine effects, immunomodulation, regulation of inflammation, secretion of several trophic factors, and possibly differentiation to renal precursors. However, studies are highly diverse; thus, knowledge is still limited regarding the exact mode of action, source of MSC in comparison to other stem cell types, administration route and dose, tracking of cells and documentation of therapeutic efficacy by new imaging techniques and tissue visualization. The aim of this review is to provide a summary of published studies of stem cell therapy in acute and chronic kidney injury, diabetic nephropathy, polycystic kidney disease, and kidney transplantation. Preclinical studies with allogeneic or xenogeneic cell therapy were first addressed, followed by a summary of clinical trials carried out with autologous or allogeneic hMSC. Studies were analyzed with respect to source of cell type, mechanism of action etc.

Adipose-derived cellular therapies in solid organ and vascularized-composite allotransplantation

PURPOSE OF REVIEW

Controlling acute allograft rejection following vascularized composite allotransplantation requires strict adherence to courses of systemic immunosuppression. Discovering new methods to modulate the alloreactive immune response is essential for widespread application of vascularized composite allotransplantation. Here, we discuss how adipose-derived cellular therapies represent novel treatment options for immune modulation and tolerance induction in vascularized composite allotransplantation.

RECENT FINDINGS

Adipose-derived mesenchymal stromal cells are cultured from autologous or allogeneic adipose tissue and possess immunomodulatory qualities capable of prolonging allograft survival in animal models of vascularized composite allotransplantation. Similar immunosuppressive and immunomodulatory effects have been observed with noncultured adipose stromal-vascular-fraction-derived therapies, albeit publication of in-vivo stromal vascular fraction cell modulation in transplantation models is lacking. However, both stromal vascular fraction and adipose derived mesenchymal stem cell therapies have the potential to effectively modulate acute allograft rejection via recruitment and induction of regulatory immune cells.

SUMMARY

To date, most reports focus on adipose derived mesenchymal stem cells for immune modulation in transplantation despite their phenotypic plasticity and reliance upon culture expansion. Along with the capacity for immune modulation, the supplemental wound healing and vasculogenic properties of stromal vascular fraction, which are not shared by adipose derived mesenchymal stem cells, hint at the profound therapeutic impact stromal vascular fraction-derived treatments could have on controlling acute allograft rejection and tolerance induction in vascularized composite allotransplantation. Ongoing projects in the next few years will help design the best applications of these well tolerated and effective treatments that should reduce the risk/benefit ratio and allow more patients access to vascularized composite allotransplantation therapy.

Adipose-derived mesenchymal stem cells therapy for acute kidney injury induced by ischemia-reperfusion in a rat model

Acute kidney injury (AKI) represents a group of complicated syndromes with a high mortality rate. The administration of adipose-derived mesenchymal stem cells (ADMSCs) has been tested as a possible treatment method for AKI. The long-term evaluation of AKI induced by ischemia/reperfusion (IR) and the probable renal protection of ADMSCs are limited. In this study we have established a rat AKI model induced by IR and investigated the possible protective effects of ADMSCs. Adult Sprague-Dawley (SD) rats were divided into three groups (n = 6/each group). The MOCK group was as the normal control. Rats in the IR-AKI and IR-AKI+ADMSCs groups were subjected to IR injury by clamping both renal pedicles for 40 minutes. Rats in the MOCK and IR-AKI groups were injected with PBS via the tail vein as negative treatment controls. Rats in the IR-AKI+ADMSCs group received ADMSCs therapy (2 × 10⁶ cells were injected into the rats via the tail vein). We found that ADMSC transplantation restored the pathologic morphology induced by IR-AKI to normal compared with the MOCK group, suggesting the reparative function of ADMSCs in kidney tissues. Compared with IR-induced AKI alone, ADMSC treatment significantly decreased the number of apoptotic cells, the level of total urinary protein and serum creatinine, the expression of pro-inflammatory cytokines (IL-6, TNF-α, IL-1β, IFN-γ, TNF-α, IFN-γ, and TGF-β), and the inflammation-associated proteins (HGF and SDF1), but increased the expression of the anti-inflammatory cytokine, IL-10, and the anti-apoptotic regulator, Bcl-2. Our data have indicated that ADMSC transplantation may protect against IR-induced AKI by anti-apoptotic and anti-inflammatory effects.

Cell viability and extracellular matrix synthesis in a co-culture system of corneal stromal cells and adipose-derived mesenchymal stem cells

AIM

To investigate the impact of adipose-derived mesenchymal stem cells (ADSCs) on cell viability and extracellular matrix (ECM) synthesis of corneal stromal cells (CSCs).

METHODS

ADSCs and CSCs were obtained from the corneas of New Zealand white rabbits and indirectly co-cultured in vitro. The proliferative capacity of CSCs in the different groups was assessed by CCK-8 assays. Annexin V-fluorescein isothiocyanate (FITC)/proliferation indices (PI) assays were used to detect the apoptosis of CSCs. The expression levels of matrix metalloproteinase (MMP), such as MMP1, MMP2, MMP9, and collagens were also evaluated by Western blot.

RESULTS

ADSCs significantly promoted proliferation and invasion of CSCs in the indirect co-culture assays. The co-cultural group displayed much higher ability of proliferation, especially under the co-culture conditions of ADSCs for 3d, compared with that CSCs cultured alone. The PI of CSCs in the co-culture system were increased approximately 3-8-fold compared with the control group. A significant change was observed in the proportions of cells at apoptosis (early and late) between the negative control group (6.34% and 2.06%) and the ADCSs-treated group (4.69% and 1.59%). The expression levels of MMPs were down regulated in the co-culture models. Compared with the control group, the decrease intensities of MMP-1, MMP-2 and MMP-9 in CSCs/ADSCs group were observed, 3.90-fold, 1.09-fold and 3.03-fold, respectively. However, the increase intensities of collagen type (I, II, III, IV, and V) in CSCs were observed in CSCs/ADSCs group, 3.47-fold, 4.30-fold, 2.35-fold, 2.55-fold and 2.43-fold, respectively, compared to that in the control group. The expressions of aldehyde dehydrogenase and fibronectin in CSCs were upregulated in the co-culture models.

CONCLUSION

ADSCs play a promotive role in CSCs' growth and invasion, which may be partially associated with MMPs decrease and collagens increase, resulting in a positive participation in the plasticity and ECM synthesis of CSCs. This provided a new insight into the extensive role of ADSCs in CSCs and a potential molecular target for corneal therapy.