Concentration of PDGF-AB, BB and TGF-β1 as valuable human serum parameters in adipose-derived stem cell proliferation

Optimization of culture conditions for HBV-specific T cell expansion in vitro from chronically infected patients

BACKGROUND

Hepatitis B virus (HBV) clearance depends on an effective adaptive immune response, especially HBV-specific T cell-mediated cellular immunity; however, it is difficult to produce enough HBV-specific T cells effectively.

RESULTS

In this work, we investigated the proportions of stimulated cells, serum, and culture media as the three primary factors to determine the most effective procedure and applied it to HLA-A2 (+) people. In parallel, we also examined the correlation between clinical parameters and HBV-specific immunity. Concerning amplification efficiency, 4 × 105 cells stimulation was superior to 2 × 106 cells stimulation, AIM-V medium outperformed 1640 medium, and fetal bovine serum (FBS) exceeded human AB serum under comparable conditions. As expected, this procedure is also suitable for developing HBV-specific CD8 + T cells in HLA-A2(+) individuals. Expanded HBV-specific T cell responses decreased with treatment time and were negatively correlated with HBV DNA and HBsAg. Furthermore, the number of HBV-specific IFN-γ + SFCs was strongly correlated with the ALT level and negatively correlated with the absolute lymphocyte count and the ALB concentration.

CONCLUSIONS

We confirm that stimulating 4 × 105 PBMCs in AIM-V medium supplemented with 10% FBS is the best approach and that HBeAg, HBsAg, and ALB are independent predictors of HBV-specific T-cell responses.

A review on the safety of growth factors commonly used in cultivated meat production

Growth factors are commonly added to cell culture media in cellular agriculture to mimic the endogenous process of proliferation and differentiation of cells. Many of these growth factors are endogenous to humans and known to be present in the edible tissues and milk of food animals. However, there is little or no information on the use of growth factors intentionally added in food production before the advent of cultivated meat. Ten commonly used growth factors have been reviewed to include information on their mode of action, bioavailability, occurrence in food and food animals, endogenous levels in humans, as well as exposure and toxicological information drawn from relevant animal studies and human clinical trials with a focus on oral exposure. In addition, a comparison of homology of growth factors was done to compare the sequence homology of growth factors from humans and domestic animal species commonly consumed as food, such as bovine, porcine, and poultry. This information has been gathered as the starting point to determine the safety of use of growth factors in cultivated meat meant for human consumption. The change in levels of growth factors measured in human milk and bovine milk after pasteurization and high-temperature treatment is discussed to give an indication of how commercial food processing can affect the levels of growth factors in food. The concept of substantial equivalence is also discussed together with a conservative exposure estimation. More work on how to integrate in silico assessments into the routine safety assessment of growth factors is needed.

Biomolecules-releasing click chemistry-based bioadhesives for repairing acetabular labrum tears

Currently, there are no effective clinical or experimental treatments to fully restore the function of the torn acetabular labrum. To fill the gap, here, we report the finding of progenitor cells in labral tissue, which can be recruited and stimulated to repair torn acetabular labral tissue. This study aimed to develop a biomolecule releasing bioadhesive which can speed up labral tissue healing by eliciting autologous labral progenitor cellular responses. A click chemistry-based bioadhesive, capable of releasing biomolecules, was synthesized to exert ~3× adhesion strength compared with fibrin glue. Via the release of platelet-derived growth factor (PDGF), the adhesive was shown to actively recruit and stimulate the proliferation of labral progenitor cells to the tear sites and within the adhesive. Finally, the ability of this biomolecules-releasing adhesive designed to promote labral tissue regeneration was evaluated using discarded human acetabular labrum tissue compared with surgical suture ex vivo. Histological analysis shows that PDGF-releasing bioadhesive yielded significantly more labrum cell responses and extracellular matrix protein (proteoglycan and collagen) production at the tear tissue site than surgical suture controls. The results confirm that the new PDGF-releasing bioadhesive can activate the responses of autologous labral progenitor cells to significantly improve labral tissue regeneration. Clinical significance: These PDGF-releasing bioadhesives may serve as a new and effective tool for repairing and regenerating acetabular labrum tears.

The Combination of Stromal Vascular Fraction Cells and Platelet-Rich Plasma Reduces Malondialdehyde and Nitric Oxide Levels in Deep Dermal Burn Injury

Introduction

Thermal burns release reactive oxygen species, which cause profound systemic and local changes. Stromal vascular fraction cells (SVFs) combined with platelet-rich plasma accelerate burn wound healing. This study investigated the effect of a combination of locally injected SVFs and PRP on malondialdehyde (MDA) and nitric oxide (NO) serum and tissue levels in a deep dermal burn model in Wistar rats.

Methods

Thirty-six adult Wistar rats weighing between 150 and 250 grams were used in this study to establish a deep dermal degree burn wound model. They were randomly divided into 4 groups: locally injected the combination SVFs and PRP, the Vaseline group, the placebo group, and healthy Wistar rats (the normal control group). MDA and NO levels in blood serum and burn wound tissue were measured at 8, 24, and 48 hours. Data were analyzed with one-way ANOVA followed by multiple comparisons tests and regression tests.

Results

Local injection of SVFs and PRP in combination affected blood MDA, tissue MDA, blood NO and tissue NO levels, with reductions of 0.257µmol/L, 0.427 µmol/L, 21.78nmol/mg, and 23.777nmol/mg, respectively. Injection of SVFs and PRP in combination reduced tissue MDA levels by 1.282 times, NO blood levels by 2.305, and NO tissue levels by 2.377 times compared to Vaseline application.

Conclusion

The combination of SVFs and PRP undeniably reduced the MDA and NO levels in blood and tissue compared to those in the Vaseline and placebo groups. The injection of these two preparations in combination inhibited the local and systemic stress oxidative response, as illustrated by the decreased MDA and NO levels in blood serum and tissue.

Liposomes loaded with transforming growth factor β1 promote odontogenic differentiation of dental pulp stem cells

OBJECTIVES

This study investigated whether novel liposome formulations loaded with transforming growth factor β1 (TGF-β1) could promote the odontogenic differentiation of human dental pulp stem cells (hDPSCs) for dentine-pulp regeneration.

METHODS

0-100 ng/mL of liposomal TGF-β1 was prepared using the thin-film hydration method. Release of TGF-β1 from the liposomes was quantified by an enzyme-linked immunosorbent assay (ELISA). The hDPSCs were treated with different concentrations of liposomal TGF-β1 and cell viability was tested using an MTT assay. "Osteodentine" differentiation capacity was assessed by RT-qPCR, ELISA and Alizarin red S staining.

RESULTS

The ELISA results showed that liposomal TGF-β1 achieved a controlled and prolonged release over time. The MTT results demonstrated that the liposomes (100 μg/mL) were not cytotoxic to the cells. Liposomal TGF-β1 up-regulated the expression of "osteodentine" markers, RUNX-2, DMP-1 and DSPP, in hDPSCs after 7 days of treatment and resulted in the accumulation of mineralised nodules.

CONCLUSION

This study indicated that liposomes are an effective carrier for delivering TGF-β1 over time. Liposomal TGF-β1 promoted dentinogenesis and increased mineralisation in hDPSCs. This highlights the potential of liposomal TGF-β1 for future use in dentine-pulp regeneration.

CLINICAL SIGNIFICANCE

Liposomal TGF-β1 may be used as a synergist for promoting dentine-pulp regeneration of immature permanent teeth or as a pulp capping agent for inducing reparative dentine formation.

Growth factors-based beneficial effects of platelet lysate on umbilical cord-derived stem cells and their synergistic use in osteoarthritis treatment

Poor viability of mesenchymal stem cells (MSCs) at the transplanted site often hinders the efficacy of MSCs-based therapy. Platelet lysate (PL) contains rich amounts of growth factors, which benefits cell growth. This study aimed to explore how human PL benefits umbilical cord-derived MSCs (huc-MSCs), and whether they have synergistic potential in osteoarthritis (OA) treatment. As quality control, flow cytometry and specific staining were performed to identify huc-MSCs, and ELISA was used to quantify growth factors in PL. CCK-8 and flow cytometry assays were performed to evaluate the effects of PL on the cell viability and cell cycle progression of huc-MSCs. Wound healing and transwell assays were conducted to assess the migration of huc-MSCs. RNA sequencing, real time PCR, and Western blot assays were conducted to explore the growth factors-based mechanism of PL. The in vitro results showed that PL significantly promoted the proliferation, cell cycle, and migration of huc-MSCs by upregulating relevant genes/proteins and activating beclin1-dependent autophagy via the AMPK/mTOR signaling pathway. The main growth factors (PDGF-AA, IGF-1, TGF-β, EGF, and FGF) contributed to the effects of PL in varying degrees. The in vivo data showed that combined PL and huc-MSCs exerted significant synergistic effect against OA. The overall study determined the beneficial effects and mechanism of PL on huc-MSCs and indicated PL as an adjuvant for huc-MSCs in treating OA. This is the first report on the growth factors-based mechanism of PL on huc-MSCs and their synergistic application. It provides novel knowledge of PLʹs roles and offers a promising strategy for stem cell-based OA therapy by combining PL and huc-MSCs.

The crosstalk between platelets and body fat: A reverse translational study

BACKGROUND & AIMS

Our previous study found that platelet counts were positively associated with body fat percentage in human. In the present study, we conducted a reverse translational study to explore the role of platelets in modulating pre-adipocyte proliferation in mice.

METHODS

Mouse pre-adipocyte cell line (3T3-L1) and human pre-adipocytes harvested from female subcutaneous fat were used. Pre-adipocytes were co-cultured with platelets or platelet releasate, which were isolated from mice or humans. The cell viability and proliferative ability of the pre-adipocytes were examined by MTT and flow cytometry assays. Western blotting analysis was used to determine the phosphorylation levels of proteins in the mTOR pathway.

RESULTS

The number of platelets in the adipose tissues from obese mice was significantly higher than that from lean mice. Platelets and collagen-activated platelet releasate stimulated the proliferation of human pre-adipocytes and 3T3-L1 cells in vitro. Besides, platelets from obese mice were more potent in stimulating pre-adipocyte proliferation than those from lean control mice. Mechanistically, platelets enhanced pre-adipocyte proliferation through the acceleration of cell cycle progression from G0/G1 to S phase cell cycle progression. At the molecular level, platelets promoted pre-adipocyte proliferation through mTOR pathway-mediated upregulation of cyclin D1 expression.

CONCLUSION

In conclusion, platelets and platelet releasate play an important role in the proliferation of pre-adipocytes. Our study may provide new clues and the molecular mechanism of the causal pathways between platelets and body fat to explain the finding we observed in population study.

Mussel-inspired dopamine oligomer intercalated tough and resilient gelatin methacryloyl (GelMA) hydrogels for cartilage regeneration

Gelatin methacryloyl (GelMA) hydrogels are widely used for tissue regeneration.

Adipose Stem Cells Incorporated in Fibrin Clot Modulate Expression of Growth Factors

PURPOSE

To evaluate the platelet capture rate of whole blood fibrin clots and the expression, secretion, and retention of the growth factors vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), and basic fibroblast growth factor (bFGF) from fibrin clots and to determine how these levels may be modulated by allogeneic adipose-derived stem cells (ASCs).

METHODS

Whole blood from 10 human volunteers was transferred to a clotting device and the platelet capture rate determined. Two experimental conditions and 1 control were evaluated over 2 weeks in vitro. Clots made from human whole blood without ASCs, clot(-)ASC, were compared with clots with ASCs incorporated, clot(+)ASC, and a control group of synthetic polyethylene glycol gels with ASCs incorporated, control(+)ASCs. All conditions were examined for secretion and retention of VEGF, PDGF, and bFGF via enzyme-linked immunosorbent assay and immunohistochemistry. The analysis of platelet retention for clots made with this device was performed.

RESULTS

Enzyme-linked immunosorbent assay analysis showed significantly higher (P < .001) secretion of VEGF in clot(+)ASC compared with clot(-)ASC or control(+)ASC. In contrast, clot(-)ASC produced soluble PDGF, and the addition of ASCs results in decreased soluble PDGF with concomitant increases in PDGF immunoreactivity of ASCs. Soluble bFGF levels were low in clot(-)ASC, and were found to increase at early time points in clot(+)ASC. Furthermore, bFGF immunoreactivity could be detected in clot(+)ASC, whereas no bFGF immunoreactivity is present in clot(-)ASC or control(+)ASC. Control(+)ASC displayed a spike in bFGF secretion at day 0, which may be due to a stress response elicited by the encapsulation process. Approximately 98% of available platelets in whole blood were concentrated in the clot on formation.

CONCLUSIONS

Fibrin clots made by this method retain high concentrations of platelets, and when incorporated with ASCs show modulated secretion and immunoreactivity of VEGF, PDGF, and bFGF.

CLINICAL RELEVANCE

Whole blood fibrin clots capture platelets and release growth factors, and the addition of ASCs increases VEGF release for up to 2 weeks after clot formation. This suggests that whole blood fibrin clots may be a viable scaffold and delivery vehicle for future stem cell treatments.

Chemotaxis-driven disease-site targeting of therapeutic adult stem cells in dystrophic epidermolysis bullosa

Background

Dystrophic epidermolysis bullosa (DEB), a rare genodermatosis, is characterized by the formation of intra-epidermal blistering and the development of chronic nonhealing skin wounds. Recently, attempts have been made to develop cell-based therapies for this currently intractable disorder. The molecular mechanisms that govern directional migration of the adult stem cells, allowing their efficient and controlled homing to the skin affected with DEB, are poorly understood. The key mechanism that regulates recruitment of leukocytes and progenitor stem cells to distal anatomical tissues affected with disease is chemotaxis, which depends on the signaling molecules, chemokines, and acts primarily as part of the host defense and repair mechanism.

Methods

Comprehensive proteomic screening of chemokines in the blister fluids of DEB-affected mice was conducted to define the inflammatory and immune activities, thus providing potential to examine local biological mechanisms and define the protein signature within lesional skin as a potential marker of disease activity. Also, the therapeutic relevance of identified chemotactic pathways was investigated in vivo, providing a basis for future clinical investigations.

Results

Assessment of blister fluid-derived chemokines showed a persistent presence of several chemotactic molecules, including CXCL1 + 2 and CXCL5. The majority of blister-originated chemotactic signals were associated with preferential recruitment of CD45⁺CXCR2⁺ and CD11b⁺CXCR2⁺ leukocytes. Systemic transplantation of an enriched CXCR2 population of mouse adipose-derived stem cells (mADSC) into DEB-affected mice demonstrated effective recruitment of cells to the blistering skin under the influence of blister-derived ligands and deposition of therapeutic type VII collagen.

Conclusions

Collectively, these studies demonstrate that recruitment of mADSC into DEB skin is tightly controlled by disease-site chemotactic activities and suggest a potential mechanism for effective application of therapeutic stem cells for DEB.

Differentiation of Murine Bone Marrow-Derived Smooth Muscle Progenitor Cells Is Regulated by PDGF-BB and Collagen

Smooth muscle cells (SMCs) are key regulators of vascular disease and circulating smooth muscle progenitor cells may play important roles in vascular repair or remodelling. We developed enhanced protocols to derive smooth muscle progenitors from murine bone marrow and tested whether factors that are increased in atherosclerotic plaques, namely platelet-derived growth factor-BB (PDGF-BB) and monomeric collagen, can influence the smooth muscle specific differentiation, proliferation, and survival of mouse bone marrow-derived progenitor cells. During a 21 day period of culture, bone marrow cells underwent a marked increase in expression of the SMC markers α-SMA (1.93 ± 0.15 vs. 0.0008 ± 0.0003 (ng/ng GAPDH) at 0 d), SM22-α (1.50 ± 0.27 vs. 0.005 ± 0.001 (ng/ng GAPDH) at 0 d) and SM-MHC (0.017 ± 0.004 vs. 0.001 ± 0.001 (ng/ng GAPDH) at 0 d). Bromodeoxyuridine (BrdU) incorporation experiments showed that in early culture, the smooth muscle progenitor subpopulation could be identified by high proliferative rates prior to the expression of smooth muscle specific markers. Culture of fresh bone marrow or smooth muscle progenitor cells with PDGF-BB suppressed the expression of α-SMA and SM22-α, in a rapidly reversible manner requiring PDGF receptor kinase activity. Progenitors cultured on polymerized collagen gels demonstrated expression of SMC markers, rates of proliferation and apoptosis similar to that of cells on tissue culture plastic; in contrast, cells grown on monomeric collagen gels displayed lower SMC marker expression, lower growth rates (319 ± 36 vs. 635 ± 97 cells/mm2), and increased apoptosis (5.3 ± 1.6% vs. 1.0 ± 0.5% (Annexin 5 staining)). Our data shows that the differentiation and survival of smooth muscle progenitors are critically affected by PDGF-BB and as well as the substrate collagen structure.

Development of Synthetic and Natural Materials for Tissue Engineering Applications Using Adipose Stem Cells

Adipose stem cells have prominent implications in tissue regeneration due to their abundance and relative ease of harvest from adipose tissue and their abilities to differentiate into mature cells of various tissue lineages and secrete various growth cytokines. Development of tissue engineering techniques in combination with various carrier scaffolds and adipose stem cells offers great potential in overcoming the existing limitations constraining classical approaches used in plastic and reconstructive surgery. However, as most tissue engineering techniques are new and highly experimental, there are still many practical challenges that must be overcome before laboratory research can lead to large-scale clinical applications. Tissue engineering is currently a growing field of medical research; in this review, we will discuss the progress in research on biomaterials and scaffolds for tissue engineering applications using adipose stem cells.

Accelerated wound closure in vitro by fibroblasts from a subgroup of cleft lip/palate patients: role of transforming growth factor-α

In a fraction of patients surgically treated for cleft lip/palate, excessive scarring disturbs maxillary growth and dento-alveolar development. Since certain genes are involved in craniofacial morphogenesis as well as tissue repair, a primary defect causing cleft lip/palate could lead to altered wound healing. We performed in vitro wound healing assays with primary lip fibroblasts from 16 cleft lip/palate patients. Nine foreskin fibroblast strains were included for comparison. Cells were grown to confluency and scratch wounds were applied; wound closure was monitored morphometrically over time. Wound closure rate showed highly significant differences between fibroblast strains. Statistically, fibroblast strains from the 25 individuals could be divided into three migratory groups, namely “fast”, “intermediate”, and “slow”. Most cleft lip/palate fibroblasts were distributed between the “fast” (5 strains) and the “intermediate” group (10 strains). These phenotypes were stable over different cell passages from the same individual. Expression of genes involved in cleft lip/palate and wound repair was determined by quantitative PCR. Transforming growth factor-α mRNA was significantly up-regulated in the “fast” group. 5 ng/ml transforming growth factor-α added to the culture medium increased the wound closure rate of cleft lip/palate strains from the “intermediate” migratory group to the level of the “fast”, but had no effect on the latter group. Conversely, antibody to transforming growth factor-α or a specific inhibitor of its receptor most effectively reduced the wound closure rate of “fast” cleft lip/palate strains. Thus, fibroblasts from a distinct subgroup of cleft lip/palate patients exhibit an increased migration rate into wounds in vitro, which is linked to higher transforming growth factor-α expression and attenuated by interfering with its signaling.

Decreased serum platelet derived growth factor BB levels in acute and increased in chronic pancreatitis

AIM: To examine circulating growth factor concentrations in patients with acute pancreatitis (AP) and chronic pancreatitis (CP), and walled-off pancreatic necrosis (WOPN).

METHODS: Forty patients with mild AP, 40 patients with alcoholic CP, 33 patients with WOPN and 40 healthy subjects were examined. Serum concentrations of platelet derived growth factor BB (PDGF-BB), transforming growth factor β-1 (TGFβ-1), chemerin and high-mobility group box chromosomal protein 1 (HMBG1) were assayed by enzyme linked immunosorbent assay.

RESULTS: Patients with mild AP and those with WOPN had significantly lower serum levels of PDGF-BB compared to healthy subjects (4.0 ± 0.61 ng/mL vs 6.2 ± 0.76 ng/mL, P = 0.027, and 1.60 ± 0.31 ng/mL vs 6.2 ± 0.76 ng/mL, P < 0.001, respectively), while CP was associated with higher serum levels of PDGF-BB (12 ± 1.3 ng/mL vs 6.2 ± 0.76 ng/mL, P < 0.001). Circulating TGFβ-1 and chemerin levels were elevated in CP patients (57 ± 3.6 ng/mL vs 39 ± 3.6 ng/mL, P < 0.001 and 73 ± 7.2 ng/mL vs 48 ± 2.3 ng/mL, P < 0.001, respectively), but not in patients with AP and WOPN. No significant changes in serum HMBG1 levels were found either in patients with AP, WOPN or CP.

CONCLUSION: The serum levels of some growth factors and cytokines differ significantly in AP, WOPN and CP. These data suggest that selected growth factors and cytokines may be considered as potential diagnostic biomarkers in patients with pancreatic diseases.