Stem Cells and Cloning-Advances and Applications最新文献

Background: The ubiquitous diffusion of radiofrequency (RF) radiation across human living environments has attracted the attention of scientists. Though the adverse health effects of RF exposure remain debatable, it has been reported that the interaction of such radiation with biological macromolecular structures can be deleterious for stem cells, inducing impairment of their main functions involving self-renewal and differentiation.

Purpose: The purpose of this study was to determine whether exposure to RF of 169 megahertz (MHz) that is part of very high radiofrequency (VHF) range 30-300 MHz, could cause damage to stem cells by inducing senescence and loss of regenerative and DNA repair capacity.

Methods: The study was conducted on mesenchymal stromal cells (MSCs) containing a subpopulation of stem cells. The MSCs were exposed to RFs of 169 MHz administered via an open meter 2G "Smart Meter" for different durations of time.

Result: We did not observe modifications in MSC biology as a result of the RF exposure conducted in our experiments.

Conclusion: We concluded that MSCs are insensitive to RF radiation exposure at 169 MHz for various time intervals, including longer durations.

Background: Based on several attributes involved in bone formation, bone marrow-resident mesenchymal stem cells (MSCs) have been employed in the treatment of patients suffering from femoral head osteonecrosis. Due to the low content of MSCs in the bone marrow, ex vivo expansion procedures are utilized to increase the cell number. Customarily, before administration of the resulting expanded cell product MSCs to the patient, its cellular identity is usually evaluated according to a set of "minimal phenotypic" markers, which are not modified by ex vivo processing. However, MSC functional ("reparative") markers, which are severely impaired along the ex vivo expansion routine, are usually not assessed.

Patients and methods: In this proof-of-concept study, a cohort of five avascular osteonecrosis patients received an instillation of ex vivo-expanded autologous MSCs, manufactured under controlled conditions, with an aim to protect their functional ("reparative") capacity.

Results and conclusion: Outcomes of this study confirmed the safety and effectiveness of the MSC-based therapy used. After a follow-up period (19-54 months), in all patients, the hip function was significantly improved and pain intensity markedly reduced. As a corollary, no patient required hip arthroplasty.

Background: Neuromuscular junctions (NMJs) consist of the presynaptic cholinergic motoneuron terminals and the corresponding postsynaptic motor endplates on skeletal muscle fibers. At the NMJ the action potential of the neuron leads, via release of acetylcholine, to muscle membrane depolarization that in turn is translated into muscle contraction and physical movement. Despite the fact that substantial NMJ research has been performed, the potential of in vivo NMJ investigations is inadequate and difficult to employ. A simple and reproducible in vitro NMJ model may provide a robust means to study the impact of neurotrophic factors, growth factors, and hormones on NMJ formation, structure, and function.

Methods: This report characterizes a novel in vitro NMJ model utilizing immortalized human skeletal muscle stem cells seeded on 35 mm glass-bottom dishes, cocultured and innervated with spinal cord explants from rat embryos at ED 13.5. The cocultures were fixed and stained on day 14 for analysis and assessment of NMJ formation and development.

Results: This unique serum- and trophic factor-free system permits the growth of cholinergic motoneurons, the formation of mature NMJs, and the development of highly differentiated contractile myotubes, which exhibit appropriate configuration of transversal triads, representative of in vivo conditions.

Conclusion: This coculture system provides a tool to study vital features of NMJ formation, regulation, maintenance, and repair, as well as a model platform to explore neuromuscular diseases and disorders affecting NMJs.

Much research has been performed over the last decade on stem cell therapy as treatment for patients with inflammatory bowel disease. Hematopoietic and mesenchymal stem cells, both allogeneic (from someone else) and autologous (from own patient), have been studied with safe and efficacious results in the majority of patients treated for luminal, perianal, and/or fistulizing disease. Here in this review, we highlight all human trials that have been conducted utilizing stem cell therapy treatment in patients with inflammatory bowel disease.

Background: Although considerable research on neuromuscular junctions (NMJs) has been conducted, the prospect of in vivo NMJ studies is limited and these studies are challenging to implement. Therefore, there is a clear unmet need to develop a feasible, robust, and physiologically relevant in vitro NMJ model.

Objective: We aimed to establish a novel functional human NMJs platform, which is serum and neural complex media/neural growth factor-free, using human immortalized myoblasts and human embryonic stem cells (hESCs)-derived neural progenitor cells (NPCs) that can be used to understand the mechanisms of NMJ development and degeneration.

Methods: Immortalized human myoblasts were co-cultured with hESCs derived committed NPCs. Over the course of the 7 days myoblasts differentiated into myotubes and NPCs differentiated into motor neurons.

Results: Neuronal axon sprouting branched to form multiple NMJ innervation sites along the myotubes and the myotubes showed extensive, spontaneous contractile activity. Choline acetyltransferase and βIII-tubulin immunostaining confirmed that the NPCs had matured into cholinergic motor neurons. Postsynaptic site of NMJs was further characterized by staining dihydropyridine receptors, ryanodine receptors, and acetylcholine receptors by α-bungarotoxin.

Conclusion: We established a functional human motor unit platform for in vitro investigations. Thus, this co-culture system can be used as a novel platform for 1) drug discovery in the treatment of neuromuscular disorders, 2) deciphering vital features of NMJ formation, regulation, maintenance, and repair, and 3) exploring neuromuscular diseases, age-associated degeneration of the NMJ, muscle aging, and diabetic neuropathy and myopathy.

Bone marrow mesenchymal stromal cell (MSC) is a potential alternative in regenerative medicine and has great potential in many pathologic conditions including kidney disease. Although most of the studies demonstrate MSC efficiency, the regenerative potential may not be efficient in all diseases and patients. Stem cell feasibility is modified by donor characteristics as gender, age, diet, and health status, producing both positive and negative results. The conditioning of MSC can potentiate its effects and modify its culture medium (CM). In current practices, the cell-free treatment is gaining notable attention, while MSC-conditioned CM is being applied and studied in many experimental diseases, including, but not limited to, certain kidney diseases. This may be the next step for clinical trials. Studies in stem cell CM have focused mainly on extracellular vesicles, nucleic acids (mRNA and microRNA), lipids, and proteins presented in this CM. They mediate regenerative effects of MSC in a harmonic manner. In this review, we will analyze the regenerative potential of MSC and its CM as well as discuss some effective techniques for modifying its fractions and improving its therapeutic potential. CM fractions may be modified by hypoxic conditions, inflammation, lipid exposition, and protein growth factors. Other possible mechanisms of action of stem cells are also suggested. In the future, the MSC paracrine effect may be modified to more closely meet each patient's needs.

Background: Mesenchymal stem cells based paracrine bioactive factors that deploy their task as an essential mechanism, but their efficiency for skin regeneration still requires clarification.

Methods: The mesenchymal stem cell-based paracrine factors were administered by subcutaneous injection of 0.5 mL peptides (general protein 8 mg/mL). These were performed after radiation on different days like the first, third, sixth, eighth, and 10th. To determine the consequences, we performed photography, planimetry, and preclinical test each week after 15 days of radiation. MSC-based peptides were injected into a rat that had radiation burns, and its observation encouraged cell-free therapeutic remedies to regenerate skin. Both control and experimental groups were exposed to 110 Gy of X-rays, which resulted in the formation of localized radiation burns on the skin (S=6 cm²) 15 days later. Thirty days after radiation, the wound stabilized (surface of the wound was S=2.2±0.2 cm²) and fluctuated throughout the course of the pathological process.

Results: The wounded area on the skin from the 15th to the 29th day after radiation was practically the same in both groups. The wounded area gradually reduced by 6.1±0.4 cm² (experimental group) and 5.9±0.6 cm² (control group) 15 days after radiation up to 2.2±0.3 cm² (in both control and experimental groups) on the 29th day after radiation. However, starting from the 36th day, there was a constant reduction in the burn area in the experimental group up to 0.2±0.1 cm² till the 71st day after radiation.

Conclusion: In the control group, the area of the lesion ranged from 1.4±0.6 cm² on the 50th day to 1.9±0.8 cm² on the 71st day. During the 57th to the 71st day, the difference between the affected area in the experimental and control groups was 1:8. The experimental group has a significantly higher level of skin regeneration and significant decrease in the level of leukocyte infiltration, thereby reducing necrosis.

Introduction: Owing to their similarity with humans, rabbits are useful for multiple applications in biotechnology and translational research from basic to preclinical studies. In this sense, mesenchymal stem cells (MSCs) are known for their therapeutic potential and promising future in regenerative medicine. As many studies have been using rabbit adipose-derived MSCs (ASCs) as a model of human ASCs (hASCs), it is fundamental to compare their characteristics and understand how distinct features could affect the translation to human medicine.

Objective: The aim of this study was to comparatively characterize rabbit ASCs (rASCs) and hASCs to further uses in biotechnology and translational studies.

Materials and methods: rASCs and hASCs were isolated and characterized by their immunophenotype, differentiation potential, proliferative profile, and nuclear stability in vitro.

Results and discussion: Both ASCs presented differentiation potential to osteocytes, chondrocytes, and adipocytes and shared similar immunophenotype expression to CD105+, CD34-, and CD45-, but rabbit cells expressed significantly lower CD73 and CD90 than human cells. In addition, rASCs presented greater clonogenic potential and proliferation rate than hASCs but no difference in nuclear alterations.

Conclusion: The distinct features of rASCs and hASCs can positively or negatively affect their use for different applications in biotechnology (such as cell reprogramming) and translational studies (such as cell transplantation, tissue engineering, and pharmacokinetics). Nevertheless, the particularities between rabbit and human MSCs should not prevent rabbit use in preclinical models, but care should be taken to interpret results and properly translate animal findings to medicine.