Adipogenic potential of stem cells derived from rabbit subcutaneous and visceral adipose tissue in vitro

Identification of the Reference Genes for Relative qRT-PCR Assay in Two Experimental Models of Rabbit and Horse Subcutaneous ASCs

Obtaining accurate and reliable gene expression results in real-time RT-PCR (qRT-PCR) data analysis requires appropriate normalization by carefully selected reference genes, either a single or a combination of multiple housekeeping genes (HKGs). The optimal reference gene/s for normalization should demonstrate stable expression across varying conditions to diminish potential influences on the results. Despite the extensive database available, research data are lacking regarding the most appropriate HKGs for qRT-PCR data analysis in rabbit and horse adipose-derived stem cells (ASCs). Therefore, in our study, we comprehensively assessed and compared the suitability of some widely used HKGs, employing RefFinder and NormFinder, two extensively acknowledged algorithms for robust data interpretation. The rabbit and horse ASCs were obtained from subcutaneous stromal vascular fraction. ASCs were induced into tri-lineage differentiation, followed by the eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) treatment of the adipose-differentiated rabbit ASCs, while horse experimental groups were formed based on adipogenic, osteogenic, and chondrogenic differentiation. At the end of the experiment, the total mRNA was obtained and used for the gene expression evaluation of the observed factors. According to our findings, glyceraldehyde 3-phosphate dehydrogenase was identified as the most appropriate endogenous control gene for rabbit ASCs, while hypoxanthine phosphoribosyltransferase was deemed most suitable for horse ASCs. The obtained results underscore that these housekeeping genes exhibit robust stability across diverse experimental conditions, remaining unaltered by the treatments. In conclusion, the current research can serve as a valuable baseline reference for experiments evaluating gene expression in rabbit and horse ASCs. It highlights the critical consideration of housekeeping gene abundance and stability in qPCR experiments, emphasizing the need for an individualized approach tailored to the specific requirements of the study.

Horse serum potentiates cellular viability and improves indomethacin-induced adipogenesis in equine subcutaneous adipose-derived stem cells (ASCs)

Subcutaneous fat tissue is an accessible and abundant source of multipotent stem cells for cell therapy in regenerative medicine. Successful trilineage differentiation is required to define the stemness features of the obtained mesenchymal cells, and adipogenesis is a part of it. Since indomethacin is bound to serum albumin, replacing foetal bovine serum (FBS) with horse serum (HS) in adipogenic induction protocols would suppress its cytotoxic effect and reveal a better adipogenic potential in equine MSCs. The equine subcutaneous adipose-derived stem cells (ASCs) were separately induced in adipogenesis by three different concentrations of 3-isobutyl-1-methylxanthine, IBMX (0.5 mM; 0.25 mM and 0.1 mM) and indomethacin (0.1 mM; 0.05 mM and 0.02 mM) for 48 h. In contrast to the IBMX, indomethacin in all concentrations caused dramatic cellular detachment. Further, the same induction concentrations were used in FBS and HS conditions for adipogenic induction. The MTT assay revealed that the culture media supplemented with HS raised cellular vitality by about 35% compared to those cultured in FBS. Based on those results, an adipogenic cocktail containing indomethacin (0.05 mM) and IBMX (0.5 mM), supplemented with HS and FBS, respectively, was applied for 18 days. The adiponectin gene expression was significantly up-regulated in HS-supplemented media since established changes in PPAR-gamma were insignificant. The tri-lineage differentiation was successful, and a cross-sectional area of adipocytes was performed. The albumin concentration was higher in HS than in FBS. In conclusion, our study revealed that HS is an appropriate supplement in induced adipogenesis since it probably suppresses the indomethacin-related cytotoxic effect and increases adipogenic ability in equine subcutaneous ASCs.

Outlook of Adipose-Derived Stem Cells: Challenges to Their Clinical Application in Horses

Adipose tissue is recognized as the major endocrine organ, potentially acting as a source of mesenchymal stem cells for various applications in regenerative medicine. Athletic horses are often exposed to traumatic injuries, resulting in severe financial losses. The development of adipose-derived stem cells' regenerative potential depends on many factors. The extraction of stem cells from subcutaneous adipose tissue is non-invasive, non-traumatic, cheaper, and safer than other sources. Since there is a lack of unique standards for identification, the isolated cells and applied differentiation protocols are often not species-specific; therefore, the cells cannot reveal their multipotent properties, so their stemness features remain questionable. The current review discusses some aspects of the specificity of equine adipose stem cells concerning their features, immunophenotyping, secretome profile, differentiation abilities, culturing conditions, and consequent possibilities for clinical application in concrete disorders. The presented new approaches elucidate the possibility of the transition from cell-based to cell-free therapy with regenerative purposes in horses as an alternative treatment to cellular therapy. In conclusion, their clinical benefits should not be underestimated due to the higher yield and the physiological properties of adipose-derived stem cells that facilitate the healing and tissue regeneration process and the ability to amplify the effects of traditional treatments. More profound studies are necessary to apply these innovative approaches when treating traumatic disorders in racing horses.

Visceral mesenchymal stem cells from type 2 diabetes donors activate triglycerides synthesis in healthy adipocytes via metabolites exchange and cytokines secretion

BACKGROUND

In recent years, there has been an increase in the prevalence of obesity and type 2 diabetes mellitus (T2DM). Development of visceral instead of subcutaneous adipose tissue is pathogenic and increases the risk of metabolic abnormalities. We hypothesize that visceral adipocytes and stromal cells are able to deteriorate other fat depots metabolism via secretory mechanisms.

METHODS

We study the regulatory role of visceral adipose-derived stem cells (vADSC) from donors with obesity and T2DM or normal glucose tolerance (NGT) on healthy subcutaneous ADSC (sADSC) in the Transwell system. Lipid droplets formation during adipogenesis was assessed by confocal microscopy. Cell metabolism was evaluated by 14C-glucose incorporation analysis and western blotting. vADSC secretome was assessed by Milliplex assay.

RESULTS

We showed that both NGT and T2DM vADSC had mesenchymal phenotype, but expression of CD29 was enhanced, whereas expressions of CD90, CD140b and IGF1R were suppressed in both NGT and T2DM vADSC. Co-differentiation with T2DM vADSC increased lipid droplet size and stimulated accumulation of fatty acids in adipocytes from healthy sADSC. In mature adipocytes T2DM vADSC stimulated triglyceride formation, whereas NGT vADSC activated oxidative metabolism. Secretome of NGT vADSC was pro-inflammatory and pro-angiogenic in comparison with T2DM vADSC.

CONCLUSIONS

The present study has demonstrated the critical role of secretory interactions between visceral and subcutaneous fat depots both in the level of progenitor and mature cells. Mechanisms of these interactions are related to direct exchange of metabolites and cytokines secretion.

Dynamics of the development of subcutaneous fat depots in rabbits – a gross anatomical and microscopic study

In this study, gross anatomical and microscopic features of interscapular (IsFD) and inguinal (InFD) fat depots of 24 New Zealand White rabbits were evaluated. Rabbits were equally distributed into 4 groups: 1st - newborns, 2nd - 1 month old, 3rd - 2 months old and 4th - 3 months old. The cranial subcutaneous fat pad in newborns covered dorsal and ventral cervical and interscapular regions. As age advanced, cervical lobes underwent a rapid reduction but the development of interscapular lobes continued. IsFD in rabbits from 1st and 2nd group was composed of both white and brown adipocytes, while in 3rd and 4th groups it consisted of white adipocytes only. InFD in rabbits from all tested groups occupied respective inguinal region and no age-dependent changes in shape and topography were observed. In all groups InFD was composed of white adipocytes only. The highest growth rate of interscapular and inguinal adipocytes was established in one-month-old rabbits. Differences in anatomy and histology of interscapular and inguinal fat depots in rabbits could be successfully used for comparison in other experiments in the field of adipobiology and autologous transplantation, where fat depots undergo significant morphological changes.

Adipose-Derived Stem Cells: Current Applications and Future Directions in the Regeneration of Multiple Tissues

Adipose-derived stem cells (ADSCs) can maintain self-renewal and enhanced multidifferentiation potential through the release of a variety of paracrine factors and extracellular vesicles, allowing them to repair damaged organs and tissues. Consequently, considerable attention has increasingly been paid to their application in tissue engineering and organ regeneration. Here, we provide a comprehensive overview of the current status of ADSC preparation, including harvesting, isolation, and identification. The advances in preclinical and clinical evidence-based ADSC therapy for bone, cartilage, myocardium, liver, and nervous system regeneration as well as skin wound healing are also summarized. Notably, the perspectives, potential challenges, and future directions for ADSC-related researches are discussed. We hope that this review can provide comprehensive and standardized guidelines for the safe and effective application of ADSCs to achieve predictable and desired therapeutic effects.

n-3 polyunsaturated fatty acids provoke a specific transcriptional profile in rabbit adipose-derived stem cells in vitro

Adipose-derived stem cells (ADSCs) possess multipotent properties, and their proper functionality is essential for further development of metabolic disorders. In the current study, we explored the impact of two n-3 LC-PUFAs (long-chain polyunsaturated fatty acids, DHA-docosahexaenoic; C22:6, and EPA-eicosapentaenoic; C20:5) on a specific profile of lipolytic-related gene expressions in the in vitro-differentiated subcutaneous and visceral ADSCs from rabbits. The subcutaneous and visceral ADSCs were obtained from 28-day-old New Zealand rabbits. The primary cells were cultured up to passage 4 and were induced for adipogenic differentiation. Thereafter, the differentiated cells were treated with 100 µg EPA or DHA for 48 hr. The total mRNA was isolated and target genes expression evaluated by real-time RCR. The results demonstrated that treatment of rabbit ADSCs with n-3 PUFAs significantly enhanced mRNA expression of Perilipin A, while the upregulation of leptin and Rab18 genes was seen mainly in ADSCs from visceral adipose tissue. Moreover, the EPA significantly enhanced PEDF (Pigment Derived Epithelium Factor) mRNA expression only in visceral cells. Collectively, the results suggest activation of an additional lipolysis pathway most evident in visceral cells. The data obtained in our study indicate that in vitro EPA up-regulates the mRNA expression of the studied lipolysis-associated genes stronger than DHA mainly in visceral rabbit ADSCs.

Effects of Adipose-derived Mesenchymal Stem Cell Exosomes on Corneal Stromal Fibroblast Viability and Extracellular Matrix Synthesis

Background

Corneal stromal cells (CSCs) are components of the corneal endothelial microenvironment that can be induced to form a functional tissue-engineered corneal endothelium. Adipose-derived mesenchymal stem cells (ADSCs) have been reported as an important component of regenerative medicine and cell therapy for corneal stromal damage. We have demonstrated that the treatment with ADSCs leads to phenotypic changes in CSCs in vitro. However, the underlying mechanisms of such ADSC-induced changes in CSCs remain unclear.

Methods

ADSCs and CSCs were isolated from New Zealand white rabbits and cultured in vitro. An Exosome Isolation Kit, Western blotting, and nanoparticle tracking analysis (NTA) were used to isolate and confirm the exosomes from ADSC culture medium. Meanwhile, the optimal exosome concentration and treatment time were selected. Cell Counting Kit-8 and annexin V-fluorescein isothiocyanate/propidium iodide assays were used to assess the effect of ADSC- derived exosomes on the proliferation and apoptosis of CSCs. To evaluate the effects of ADSC- derived exosomes on CSC invasion activity, Western blotting was used to detect the expression of matrix metalloproteinases (MMPs) and collagens.

Results:

ADSCs and CSCs were successfully isolated from New Zealand rabbits. The optimal concentration and treatment time of exosomes for the following study were 100 μg/ml and 96 h, respectively. NTA revealed that the ADSC-derived exosomes appeared as nanoparticles (40-200 nm), and Western blotting confirmed positive expression of CD9, CD81, flotillin-1, and HSP70 versus ADSC cytoplasmic proteins (all P < 0.01). ADSC-derived exosomes (50 μg/ml and 100 μg/ml) significantly promoted proliferation and inhibited apoptosis (mainly early apoptosis) of CSCs versus non-exosome-treated CSCs (all P < 0.05). Interestingly, MMPs were downregulated and extracellular matrix (ECM)-related proteins including collagens and fibronectin were upregulated in the exosome-treated CSCs versus non-exosome-treated CSCs (MMP1: t = 80.103, P < 0.01; MMP2: t = 114.778, P < 0.01; MMP3: t = 56.208, P < 0.01; and MMP9: t = 60.617, P < 0.01; collagen I: t = -82.742, P < 0.01; collagen II: t = -72.818, P < 0.01; collagen III: t = -104.452, P < 0.01; collagen IV: t = -133.426, P < 0.01, and collagen V: t = -294.019, P < 0.01; and fibronectin: t = -92.491, P < 0.01, respectively).

Conclusion:

The findings indicate that ADSCs might play an important role in CSC viability regulation and ECM remodeling, partially through the secretion of exosomes.

Identification and Multilineage Potential Research of a Novel Type of Adipose-Derived Mesenchymal Stem Cells from Goose Inguinal Groove

Adipose tissue-derived mesenchymal stem cells (ADSCs) play a crucial role in the field of regenerative medicine and tissue repair for its own unique features. However, up to date, the isolation and characterizations of multidifferentiation potentials of goose ADSCs are still uncertain. In this study, we successfully isolated ADSCs from goose inguinal groove in vitro for the first time and also attempted to unravel its fundamental differentiation potentials and genetic characteristics. The results showed that isolated ADSCs exhibited a typical fibroblast-like morphology and high proliferative potential, could be passaged for at least 40 passages and maintained high hereditary stability with more than 92.2% of cells were diploid (2n = 78) by G-banding analysis. Moreover, the ADSCs could express pluripotent marker gene (OCT4) and mesenchymal stem cells-related surface antigens, which are similar to previously reported human ADSCs. Additionally, the goose ADSCs could be induced to transdifferentiate into cells of three layers in vitro, such as osteoblasts, chondrocytes, and adipocytes derived from mesoderm, neurocytes from ectoderm, and hepatocytes of the endoderm. Most of all, we confirmed that the induced β-like cells and hepatocytes had metabolic functions similar to normal cells in vivo. Taken together, these results demonstrated the multidifferentiation potentials of ADSCs in vitro, which conferred an appealing candidate for cell regenerative therapy.

In vitro culture and biological properties of broiler adipose-derived stem cells

In the past 10 years, adipose-derived stem cells (ADSCs) have been applied due to their pluripotency. Experimental tissues have been frequently obtained from mammals, including rabbits, mice and humans, but rarely from broilers, Gallus gallus domesticus. In the present study, ADSCs were obtained from 20-day-old broiler embryos. Primary ADSCs were sub-cultured to passage 37 in vitro. The surface markers of ADSCs, namely CD29, CD31, CD44, CD71 and CD73, were detected by reverse transcription polymerase chain reaction and immunofluorescence assays. The result indicated that CD29, CD44, CD71 and CD73 were expressed on the surface of cells at various passages, but not CD31. The growth curve of cells at the different passages had a typical sigmoidal shape. Furthermore, ADSCs were successfully induced to differentiate into osteoblasts, adipocytes and hepatocyte-like cells. The results denote that the ADSCs isolated from broilers have similar biological properties to those of ADSCs obtained from other animals. The present study provided a theoretical and experimental foundation for the use of poultry as a source of stem cells, and laid a foundation for adipose tissue engineering and strategies in regenerative medicine.

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.

A comparative assessment of adipose-derived stem cells from subcutaneous and visceral fat as a potential cell source for knee osteoarthritis treatment

The intra‐articular injection of adipose‐derived stem cells (ASCs) is a novel potential therapy for patients with osteoarthritis (OA). However, the efficacy of ASCs from different regions of the body remains unknown. This study investigated whether ASCs from subcutaneous or visceral adipose tissue provide the same improvement of OA. Mouse and human subcutaneous and visceral adipose tissue were excised for ASC isolation. Morphology, proliferation, surface markers and adipocyte differentiation of subcutaneous ASCs (S‐ASCs) and visceral ASCs (V‐ASCs) were analysed. A surgically induced rat model of OA was established, and 4 weeks after the operation, S‐ASCs, V‐ASCs or phosphate‐buffered saline (PBS, control) were injected into the articular cavity. Histology, immunohistochemistry and gene expression analyses were performed 6 weeks after ASC injection. The ability of ASCs to differentiate into chondrocytes was assessed by in vitro chondrogenesis, and the immunosuppressive activity of ASCs was evaluated by co‐culturing with macrophages. The proliferation of V‐ASCs was significantly greater than that of S‐ASCs, but S‐ASCs had the greater adipogenic capacity than V‐ASCs. In addition, the infracted cartilage treated with S‐ASCs showed significantly greater improvement than cartilage treated with PBS or V‐ASCs. Moreover, S‐ASCs showed better chondrogenic potential and immunosuppression in vitro. Subcutaneous adipose tissue is an effective cell source for cell therapy of OA as it promotes stem cell differentiation into chondrocytes and inhibits immunological reactions.