Mesenchymal stem cell therapy using Pal-KTTKS-enriched carboxylated cellulose improves burn wound in rat model.

Despite the great progress in developing wound dressings, delayed wound closure still remains a global challenge. Thus, developing novel wound dressings and employing advanced strategies, including tissue engineering, are urgently desired. The carboxylated cellulose was developed through the in situ synthesis method and further reinforced by incorporating pal-KTTKS to stimulate collagen synthesis and improve wound healing. The developed composites supported cell adhesion and proliferation and showed good biocompatibility. To boost wound-healing performance, adipose-derived mesenchymal stem cells (MSC) were seeded on the pal-KTTKS-enriched composites to be implanted in a rat model of burn wound healing. Healthy male rats were randomly divided into four groups and wound-healing performance of Vaseline gauze (control), carboxylated cellulose (CBC), pal-KTTKS-enriched CBC (KTTKS-CBC), and MSCs seeded on the KTTKS-CBC composites (MSC-KTTKS-CBC) were evaluated on days 3, 7, and 14 post-implantation. In each group, the designed therapeutic dressings were renewed every 5 days to increase wound-healing performance. We found that KTTKS-CBC and MSC-KTTKS-CBC composites exhibited significantly better wound healing capability, as evidenced by significantly alleviated inflammation, increased collagen deposition, improved angiogenesis, and considerably accelerated wound closure. Nevertheless, the best wound-healing performance was observed in the MSC-KTTKS-CBC groups among all four groups. This research suggests that the MSC-KTTKS-CBC composite offers a great deal of promise as a wound dressing to enhance wound regeneration and expedite wound closure in the clinic.

Report of a phase 1 clinical trial for safety assessment of human placental mesenchymal stem cells therapy in patients with critical limb ischemia (CLI).

BACKGROUND: Critical limb ischemia (CLI) is associated with increased risk of tissue loss, leading to significant morbidity and mortality. Therapeutic angiogenesis using cell-based treatments, notably mesenchymal stem cells (MSCs), is essential for enhancing blood flow to ischemic areas in subjects suffering from CLI. The objective of this study was to evaluate the feasibility of using placenta-derived mesenchymal stem cells (P-MSCs) in patients with CLI. METHODS: This phase I dose-escalation study investigated P-MSCs in nine CLI patients who were enrolled into each of the two dosage groups (20 × 106 and 60 × 106 cells), delivered intramuscularly twice, two months apart. The incidence of treatment-related adverse events was the primary endpoint. The decrease in inflammatory cytokines, improvement in the ankle-brachial pressure index (ABI), maximum walking distance, vascular collateralization, alleviation of rest pain, healing of ulceration, and avoidance of major amputation in the target leg were the efficacy outcomes. RESULTS: All dosages of P-MSCs, including the highest tested dose of 60 × 106 cells, were well tolerated. During the 6-month follow-up period, there was a statistically significant decrease in IL-1 and IFN-γ serum levels following P-MSC treatment. The blood lymphocyte profile of participants with CLI did not significantly differ, suggesting that the injection of allogeneic cells did not cause T-cell proliferation in vivo. We found clinically substantial improvement in rest pain, ulcer healing, and maximum walking distance after P-MSC implantation. In patients with CLI, we performed minor amputations rather than major amputations. Angiography was unable to demonstrate new small vessels formation significantly. CONCLUSION: The observations from this phase I clinical study indicate that intramuscular administration of P-MSCs is considered safe and well tolerated and may dramatically improve physical performance and minimize inflammatory conditions in patients with CLI. TRIAL REGISTRATION: IRCT, IRCT20210221050446N1. Registered May 09, 2021.

Emerging roles of mesenchymal stem cell therapy in patients with critical limb ischemia.

Critical limb ischemia (CLI), the terminal stage of peripheral arterial disease (PAD), is characterized by an extremely high risk of amputation and vascular issues, resulting in severe morbidity and mortality. In patients with severe limb ischemia with no alternative therapy options, such as endovascular angioplasty or bypass surgery, therapeutic angiogenesis utilizing cell-based therapies is vital for increasing blood flow to ischemic regions. Mesenchymal stem cells (MSCs) are currently considered one of the most encouraging cells as a regenerative alternative for the surgical treatment of CLI, including restoring tissue function and repairing ischemic tissue via immunomodulation and angiogenesis. The regenerative treatments for limb ischemia based on MSC therapy are still considered experimental. Despite recent advances in preclinical and clinical research studies, it is not recommended for regular clinical use. In this study, we review the immunomodulatory features of MSC besides the current understanding of different sources of MSC in the angiogenic treatment of CLI subjects and their potential applications as therapeutic agents. Specifically, this paper concentrates on the most current clinical application issues, and several recommendations are provided to improve the efficacy of cell therapy for CLI patients.

Different applications of virus-like particles in biology and medicine: Vaccination and delivery systems.

Virus-like particles (VLPs) mimic the whole construct of virus particles devoid of viral genome as used in subunit vaccine design. VLPs can elicit efficient protective immunity as direct immunogens compared to soluble antigens co-administered with adjuvants in several booster injections. Up to now, several prokaryotic and eukaryotic systems such as insect, yeast, plant, and E. coli were used to express recombinant proteins, especially for VLP production. Recent studies are also generating VLPs in plants using different transient expression vectors for edible vaccines. VLPs and viral particles have been applied for different functions such as gene therapy, vaccination, nanotechnology, and diagnostics. Herein, we describe VLP production in different systems as well as its applications in biology and medicine.

VLP production in Leishmania tarentolae: A novel expression system for purification and assembly of HPV16 L1.

Viral like particles (VLPs) have been used as immunogen for improvement of preventive vaccines against several viral infections in preclinical and clinical trials. These constructs can stimulate both cellular and humoral immunity. Two prophylactic HPV L1 VLP vaccines known as Gardasil and Cervarix were commercialized worldwide. However, there are main problems for expression and purification of VLPs in eukaryotic expression systems such as baculovirus and yeast leading to high cost of these vaccines. A novel Leishmania protozoan system has been applied to produce different recombinant proteins due to unique properties including generation of similar proteins with mammalian, easy handling, and large-scale culture. In the current study, we developed a novel strategy to produce HPV L1 VLP using stably transfected Leishmania cells. The positive transfectants were analyzed by SDS-PAGE and Western blot analysis. The assembly of purified L1 protein was detected by TEM microscopy. Finally, C57BL/6 mice were immunized by crude VLPs and antibody responses were assessed. The results of electronic microscopy revealed average 55-60 nm for L1 VLP. Furthermore, high IgG1 and IgG2a antibody responses were generated by L1 VLPs in mice similar to L1 VLPs produced in baculovirus-infected insect cells. Regarding the results, the amount of recombinant protein generated by Leishmania was 2-3mg/500 ml media, suggesting further optimization of this system for using in large animals and human.

A Live Vector Expressing HPV16 L1 Generates an Adjuvant-Induced Antibody Response In-vivo.

BACKGROUND: The association between human papillomavirus (HPV) infections and cervical cancer has suggested the design of prophylactic and therapeutic vaccines against genital warts. The HPV capsid has made of two L1 and L2 coat proteins that have produced late in viral infections. Regarding to the recent studies, two commercial prophylactic vaccines have based on L1 viral like particles (VLPs) could strongly induce antibody responses, and protect human body from HPV infections. However, the use of these HPV vaccines has hindered due to their high cost and some limitations. Currently, among various vaccination strategies, live vector-based vaccines have attracted a great attention. OBJECTIVES: Herein, a non-pathogenic strain of the protozoan organism known as Leishmania tarentolae has utilized to induce potent humoral immunity in mice model. MATERIALS AND METHODS: At first, cloning of HPV16 L1 gene into Leishmania expression vector has performed and confirmed by PCR and digestion with restriction enzymes. The promastigotes of Leishmania tarentolae (L.tar) have transfected with linearized DNA construct by electroporation. Protein expression has analyzed by SDS-PAGE and western blotting. Then, the immunogenicity of leishmania expressing L1 protein (L.tar-L1) has assessed in mice model. RESULTS: Our data has indicated that subcutaneous immunization of mice with the recombinant L.tar-L1 has led to enhance the levels of IgG1 and lgG2a in comparison with control groups. Furthermore, there was no significant increase in antibody levels between two and three times of immunizations. CONCLUSIONS: The recombinant live vector was able to induce humoral immunity in mice without need of any adjuvant. However, further studies have required to increase its efficiency.