The Optimal Effective Dose of Adipose-Derived Stem Cell Exosomes in Wound Healing.

INTRODUCTION: Although the effect of adipose-derived mesenchymal stem cell exosomes (ADSC-exos) on wound healing with different doses are shown in various studies, efficient and sufficient doses of ADSC-exos are still unknown. The study aimed to determine the optimal dose of ADSC-exos in wound healing. METHODS: The 45 Sprague-Dawley rats were randomly divided into five groups, with seven animals in each. After dorsal circular defects were created, each wound was injected as follows: group 1: saline, group 2: 10 µg/mL of ADSC-exos, group 3: 100 µg/mL of ADSC-exos, group 4: 200 µg/mL of ADSC-exos, and group 5: 400 µg/mL of ADSC-exos. The effects of ADSC-exos on epithelization, angiogenesis, and collagen formation were analyzed macroscopically, histopathologically, and immunohistochemically on day 14. RESULTS: A total of 200 µg/mL and 400 µg/mL ADSC-exos groups had higher epithelial tongue length, epithelial tongue area, and angiogenesis scores than the other groups. Although there was no statistical difference in fibrosis scores among groups, collagen fibers were becoming well-organized as the ADSC-exos doses increased. While the wound area was clinically smaller in the 200 µg/mL ADSC-exos group, there was no statistically significant difference among groups on day 14. CONCLUSIONS: A total of 200 µg/mL of ADSC-exos was found to be the adequate and effective dose for re-epithelialization and angiogenesis in cutaneous wound healing. Moreover, the collagen density increased with a more regular pattern in the 200 µg/mL group, which can be important in scar regulation.

Dental Pulp-Derived Mesenchymal Stem Cells Increase Axon Numbers in Mental Nerve Repair.

Aim: The mental nerve, the extended part of the inferior alveolar nerve, is often injured during dentoalveolar, orthognathic, or tumor surgery. Numerous therapeutic interventions, including surgery and pharmacotherapy, have been used to enhance the recovery of nerve injuries. Dental pulp stem cells (DPSCs) represent an easily accessible source of adult stem cells that can be isolated from the pulp of extracted teeth. This study evaluated the effect of DPSCs on the regeneration of the mental nerve injury model of rabbits. Methods: In this presented study, DPSCs were cultured and cell characterizations were performed by using flow cytometry and immunostainings. Bilateral mental nerve injury models of rabbits were created. In the control group (n = 10), saline was applied, and in the study group (n = 10), 2 × 106 DPSCs were applied to the repaired nerve areas. After 3 weeks, animals were killed and histological examination was obtained by using Masson's trichrome staining. An unpaired Student's t test was used when comparing the groups. Differences were considered to be statistically significant at P values of less than 0.05. Results: The DPSCs demonstrated a homogeneous population of mesenchymal stromal cells which expressed cluster of differentiation CD44, CD73, CD90, and CD105 and lack of CD34, CD45, and HLA-DR. Our finding clearly demonstrated that a lower number of cross-sectioned axons were founded in the control group (60.18 ± 2.52) compared to the study group (72.96 ± 2.43) (p = 0.00). Conclusions: DPSCs promote mental nerve axonal regeneration. These results suggest that DPSCs provide an important accessible source of adult stem cells for mental nerve regeneration.

A pilot study for treatment of severe COVID-19 pneumonia by aerosolized formulation of convalescent human immune plasma exosomes (ChipEXO™).

This is a single-center prospective, open-label, single arm interventional study to test the safety and efficacy of recently described ChipEXO™ for severe COVID-19 pneumonia. The ChipEXO™ is a natural product derived from convalescent human immune plasma of patients recovered from moderate COVID-19 infection. In September 2021, 13 patients with pending respiratory failure were treated with ChipEXO™ adapted for aerosolized formulation delivered via jet nebulizer. Patients received 1-5x1010 nano vesicle/5 mL in distilled water twice daily for five days as an add-on to ongoing conventional COVID-19 treatment. The primary endpoint was patient safety and survival over a 28-day follow-up. The secondary endpoint was longitudinal assessment of clinical parameters following ChipEXO™ to evaluate treatment response and gain insights into the pharmacodynamics. ChipEXO™ was tolerated well without any allergic reaction or acute toxicity. The survival rate was 84.6% and 11 out of 13 recovered without any sequel to lungs or other organs. ChipEXO™ treatment was effective immediately as shown in arterial blood gas analyses before and two hours after exosome inhalation. During the 5 days of treatment, there was a sustainable and gradual improvement on oxygenation parameters: i.e. respiratory rate (RR) [20.8% (P < 0.05)], oxygen saturation (SpO2) [6,7% (P < 0.05)] and partial pressure of oxygen to the fraction of inspired oxygen (PaO2/FiO2) [127.9% (P < 0.05)] that correlated with steep decrease in the disease activity scores and inflammatory markers, i.e. the sequential organ failure assessment (SOFA) score (75%, p < 0.05), C-reactive protein (46% p < 0.05), ferritin (58% p = 0.53), D-dimer (28% p=0.46). In conclusion, aerosolized ChipEXO™ showed promising safety and efficacy for life-threatening COVID-19 pneumonia. Further studies on larger patient populations are required to confirm our findings and understand the pathophysiology of improvement toward a new therapeutic agent for the treatment of severe COVID-19 pneumonia.

Repair of Rat Calvarial Bone Defect by Using Exosomes of Umbilical Cord-Derived Mesenchymal Stromal Cells Embedded in Chitosan/Hydroxyapatite Scaffolds.

PURPOSE: To seek out the bone regeneration effect of human umbilical cord-mesenchymal stem cell (hUC-MSC)-derived exosomes of loaded chitosan/hydroxyapatite (CS/HA) scaffold in a rat calvarium bone regeneration model. MATERIALS AND METHODS: The hUC-MSC exosomes were purified and characterized. The scaffolds were prepared by a freeze-drying method. Animals were divided into five groups, and the CS/HA/exosome (CS/HA/Exo) scaffolds were transplanted to 5 × 2-mm critical-sized calvarial bone defects for repair in rats. All animals were sacrificed at the postoperative sixth week. Immunohistochemical and histologic analyses were performed. RESULTS: Scanning electron microscopy (SEM) images showed that the exosomes were round-shaped vesicles with bounded membrane, and the diameter of the exosomes was 83.728 ± 27.269 nm. Histologic analysis showed that mean new bone volumes were statistically significantly higher in the CS/HA/Exo group (1.83 ± 0.54, PCS/Exo-CS/HA/Exo = .000), and other new bone volumes in the other groups were statistically significant compared with the control (CS/Exo 1.50 ± 0.14 mm3; CS 1.20 ± 0.43 mm3; control 1.06 ± 0.10 mm3; and CS/HA 1.43 ± 0.66 mm3). CONCLUSION: The CS/HA/Exo combination is a novel treatment for bone defect repair to induce bone formation. The CS scaffold can significantly promote bone regeneration compared with the control. Moreover, the combination with HA and exosomes is promising for applications in bone tissue regeneration.

Efficacy of stem cell-based therapies for colistin-induced nephrotoxicity.

The increase in infections with multidrug resistant bacteria has forced to return to the use of colistin, antibiotic with known nephrotoxicity. Mesenchymal stem cells (MSCs) are being extensively investigated for their potential in regenerative medicine. This study aimed to investigate the possible protective mechanisms of the MSCs against kidney injury induced by colistin. Forty adult female albino rats were randomly classified into 4 equal groups; the control group, the MSC-treated group (a single dose of 1 ×106 /ml MSCs through the tail vein), the colistin-treated group (36 mg/kg/day colistin was given for 7 days), and the both colistin and MSC group (36 mg/kg/day colistin and 1 ×106 /ml MSCs). Main outcome measures were histopathological alterations, kidney malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT) and immunohistological autophagy evaluation. MSC repressed the progression of colistin-induced kidney injury as evidenced by the improvement of histopathological alterations and the substantial increase MDA, and decrease SOD and CAT in serum levels. Moreover, MSC resulted in a profound reduction in oxidative stress as manifested by decreased MDA and increased SOD in serum. Notably, MSC suppressed colistin-induced autophagy; it reduced renal levels of Beclin-1, P62 and LC3A/B. Furthermore, MSC decreased renal levels of eNOS. Lastly, MSC efficiently decreased expression of the TUNEL positive cell number. MSC confers protection against colistin-induced kidney injury by alleviating oxidative stress, nitric oxide synthase besides modulating reducing autophagy and apoptosis.

Preclinical Studies on Convalescent Human Immune Plasma-Derived Exosome: Omics and Antiviral Properties to SARS-CoV-2.

The scale of the COVID-19 pandemic forced urgent measures for the development of new therapeutics. One of these strategies is the use of convalescent plasma (CP) as a conventional source for passive immunity. Recently, there has been interest in CP-derived exosomes. In this report, we present a structural, biochemical, and biological characterization of our proprietary product, convalescent human immune plasma-derived exosome (ChipEXO), following the guidelines set forth by the Turkish Ministry of Health and the Turkish Red Crescent, the Good Manufacturing Practice, the International Society for Extracellular Vesicles, and the Gene Ontology Consortium. The data support the safety and efficacy of this product against SARS-CoV-2 infections in preclinical models.

TGF-B1-over-expressed adipose stem cells-derived secretome exhibits CD44 suppressor and anti-cancer properties via antagonistic effects against SMAD4 in breast cancer cells.

OBJECTIVES: This study aimed to investigate the effect of TGF-B1-transfected adipose-derived mesenchymal stem cell (AD-MSC) conditional medium (TGF-B1-CM) on CD44 expression and biological activities in MCF-7 and MDA-MB-231 cells. METHODS: In the study, the experimental groups were created as a standard medium, AD-MSC-CM, TGF-B1-CM, and TGF-B1 recombinant protein. The medium and proteins specified in these groups were applied to MCF-7 and MDA-MB-231 cells separately at 24, 48 and 72 hours. Western blot and immunofluorescent staining were performed with antibodies suitable for CD44 and canonical smad signaling pathway analyses between groups. Cellular proliferation in MCF-7 and MDA-MB-231 cells was measured by MTT. Biological activity analyses such as apoptosis, cell cycle, proliferation, DNA damage, and membrane depolarization between groups were tested on the Muse Cell Analyzer using appropriate kits. Cellular migration between groups was determined by showing cells that migrated to the scar area with in vitro scar formation. Statistics were performed with GraphPad Prism 8.02 software. RESULTS: It was determined that TGF-B1-CM activates the smad signaling pathway in MCF-7 and MDA-MB-231 cells. TGF-B1-CM increased pSMAD2/3 expression and decreased SMAD4 expression in breast cancer cells. A decrease in CD44 expression was found at points of increase in pSMAD2/3 expression. Decreased expression of SMAD4 in breast cancer cells with TGF-B1-CM was associated with decreased expression of CD44. In MCF-7 and MDA-MB-231 cells, TGF-B1-CM was found to increase apoptosis, decrease proliferation, disrupt membrane depolarization, and arrest cells at G0/G1 stage. TGF-B1-CM suppressed MCF-7 and MDA-MB-231 migrations. CONCLUSION: SMAD4-targeted therapeutic strategies may be considered to suppress CD44 expression in breast cancer cells. Both the anti-tumorigenic factors released by AD-MSCs and the secretomes obtained as a result of supporting these factors with the overexpression of TGF-B1, severely suppressed breast cancer cells. With this study, it was planned to obtain a targeted biological product that suppresses breast cancer cells in vitro.