Preliminary Evaluation of Wound Healing Potential of Leonurus japonicus Houtt. Extracts

Leonurus japonicus Houtt. is a medicinal plant popular in Brazil as "rubim", used in local folk medicine for several applications as an anti-inflammatory, antioxidant, analgesic, and antimicrobial phytomedicine. The traditional use for wound healing is related; however, few studies have evaluated the wound healing activity. Thus, this study aimed to analyse the popular indication of the hydroalcoholic and aqueous extracts of L. japonicus aerial parts in a rat wound healing model. The initial chemical characterization was performed using flavonoid quantification and complemented with mass spectroscopy/chemometrics analysis. The wound's lesion contraction and tissue regeneration (histological study stained with hematoxylin-eosin and picrosirius) were determined. Hydroalcoholic and aqueous extracts presented high flavonoid content, and mass spectrometry analysis of the extracts demonstrated the presence of compounds with a mass between 100-650, reinforcing the presence of polyphenolic constituents. The extracts of L. japonicus improve various wound healing phases, like inflammatory modulation, wound contraction, and collagen synthesis, resulting in faster healing in rats. These effects could be related to the extracts' polyphenolic compounds.

Low-dose naltrexone's utility for non-cancer centralized pain conditions: a scoping review

BACKGROUND

At low doses, naltrexone (LDN) has been shown to modulate inflammation through the interruption of microglial cell activation within the central nervous system. One of the most likely contributors to centralized pain is changes in microglial cell processing. Therefore, it has been postulated that LDN can be used to manage patients with pain resulting from central sensitization due to this relationship. This scoping review aims to synthesize the relevant study data for LDN as a novel treatment strategy for various centralized pain conditions.

METHODS

A comprehensive literature search was conducted in PubMed, Embase, and Google Scholar, guided by the Scale for Assessment of Narrative Review Articles (SANRA) criteria.

RESULTS

Forty-seven studies related to centralized pain conditions were identified. Many of the studies were case reports/series and narrative reviews, but a few randomized control trials have been conducted. Overall, the body of evidence revealed improvement in patient-reported pain severity and in outcomes related to hyperalgesia, physical function, quality of life, and sleep. Variability in dosing paradigms and the time to patient response was present in the reviewed studies.

CONCLUSIONS

Evidence synthesized for this scoping review supports the ongoing use of LDN for the treatment of refractory pain in various centralized chronic pain conditions. Upon review of the currently available published studies, it is apparent that further high-quality, well-powered randomized control trials need to be conducted to establish efficacy, standardization for dosing, and response times. In summary, LDN continues to offer promising results in the management of pain and other distressing symptoms in patients with chronic centralized pain conditions.

The Emerging Biological Functions of Exosomes from Dental Tissue-Derived Mesenchymal Stem Cells

Exosomes are one kind of small-cell extracellular membranous vesicles that can regulate intercellular communication and give rise to mediating the biological behaviors of cells, involving in tissue formation, repair, the modulation of inflammation, and nerve regeneration. The abundant kinds of cells can secret exosomes, among them, mesenchymal stem cells (MSCs) are very perfect cells for mass production of exosomes. Dental tissue-derived mesenchymal stem cells (DT-MSCs), including dental pulp stem cells, stem cells from exfoliated deciduous teeth, stem cells from apical papilla, stem cells from human periodontal ligament (PDLSCs), gingiva-derived mesenchymal stem cells, dental follicle stem cells, tooth germ stem cells, and alveolar bone-derived mesenchymal stem cells, are now known as a potent tool in the area of cell regeneration and therapy, more importantly, DT-MSCs can also release numerous types of exosomes, participating in the biological functions of cells. Hence, we briefly depict the characteristics of exosomes, give a detailed description of the biological functions and clinical application in some respects of exosomes from DT-MSCs through systematically reviewing the latest evidence, and provide a rationale for their use as tools for potential application in tissue engineering.

A Single Dose of Local Injection of Adipose Stem Cells Promotes Ectopic Cartilage Regeneration In Vivo by Modulating Inflammatory Response and Enhancing Cartilage Extracellular Matrix Synthesis in a Porcine Model

BACKGROUND

Uncontrollable inflammatory response following ectopic engineered cartilage implantation is devastating to the aesthetic and functional outcomes of the recipients. Adipose stem cells (ASCs) have a good immunomodulatory capacity via a paracrine mechanism. However, works of literature are scarce regarding ASC modulation in ectopic engineered cartilage regeneration in vivo. This study aims to explore how ASCs modulate the inflammatory response after engineered cartilage implantation and affect the implants in a nonchondrogenic milieu in large immunocompetent animals.

METHODS

Porcine engineered elastic cartilages were cultured in vitro for 3 weeks with chondrocyte cell sheeting technology and then assigned into two groups: ASCs and Control (saline injection). All samples (n= 6 per group) were autologously implanted into different subcutaneous pockets, and a single dose of ASCs was injected at three points around the implant. All samples were harvested after 2 weeks in vivo for analysis.

RESULTS

In the examination of inflammation, we observed reduced inflammatory cell infiltration and improved M2 macrophage polarization in the implanted engineered cartilage with ASC injection compared to the control. There were also enhanced anti-inflammatory cytokines and reduced proinflammatory cytokines inside and adjacent to the implants, while in serum, there were no significant differences. In the examination of the cartilage quality, there were significant increases in cartilage extracellular matrix and chondrogenic factors, and the elastic cartilage phenotype was maintained compared to control.

CONCLUSION

This study finds that a single dose of ASCs can promote ectopic cartilage regeneration by modulating inflammation and enhancing cartilage matrix synthesis in a porcine model.

The Impact of Activity-Based Interventions on Neuropathic Pain in Experimental Spinal Cord Injury

Physical activity-based rehabilitative interventions represent the main treatment concept for people suffering from spinal cord injury (SCI). The role such interventions play in the relief of neuropathic pain (NP) states is emerging, along with underlying mechanisms resulting in SCI-induced NP (SCI-NP). Animal models have been used to investigate the benefits of activity-based interventions (ABI), such as treadmill training, wheel running, walking, swimming, and bipedal standing. These activity-based paradigms have been shown to modulate inflammatory-related alterations as well as induce functional and structural changes in the spinal cord gray matter circuitry correlated with pain behaviors. Thus far, the research available provides an incomplete picture of the cellular and molecular pathways involved in this beneficial effect. Continued research is essential for understanding how such interventions benefit SCI patients suffering from NP and allow the development of individualized rehabilitative therapies. This article reviews preclinical studies on this specific topic, goes over mechanisms involved in SCI-NP in relation to ABI, and then discusses the effectiveness of different activity-based paradigms as they relate to different forms, intensity, initiation times, and duration of ABI. This article also summarizes the mechanisms of respective interventions to ameliorate NP after SCI and provides suggestions for future research directions.