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IntroductionAvian head lice comprise a diverse group of distantly related genera of lice that exhibit a strongly convergent morphology. Due to their lack of free-living stages, their strong morphological adaptations to living on the host’s head, and the limited opportunities for transfer between hosts during mating or nesting, the lateral transmission of head lice between non-conspecific hosts may be presumed to be restricted. Despite this, many species of head lice are ostensibly host generalists. We here examine lice of the head louse genus Philopteroides Mey, 2004, from bulbuls (Passeriformes: Pycnonotidae).MethodsWe use two different methods, ParaFit and Jane, to get insights on the co-evolutionary history of Philopteroides species and their bulbul hosts. Jane was run with a variation of event costs.ResultsOur phylogenetic analysis indicate that several morphologically cryptic species can be found in this group, most of which appear to be host specific. However, co-phylogenetic analyses indicate that host-switching has been common in the history of these lice, and co-speciation events have been rarer than expected. Moreover, lowest-cost co-evolutionary reconstructions under a variety of event costs are indistinguishable from random. An expanded dataset with more Philopterus-complex lice was found to be evenly balanced between host-switching and co-speciation events.DiscussionThe transfer of avian head lice between host species is poorly understood, but evidently fairly common. Several potential routes are discussed, but direct evidence is missing. Potentially, the presence of multiple bulbul species at fruiting trees may be an important factor in this transfer. However, such transfer routes also do not explain why Philopteroides lice on bulbuls appear to be distinct from those of other hosts. Moreover, as many of the species recovered in our analysis are morphologically indistinguishable, cryptic speciation appears to be common in this group.

Stem cell-based therapy has drawn attention as an alternative option for promoting prosthetic osteointegration in osteoporosis by virtue of its unique characteristics. However, estrogen deficiency is the main mechanism of postmenopausal osteoporosis. Estrogen, as an effective antioxidant, deficienncy also results in the accumulation of reactive oxygen species (ROS) in the body, affecting the osteogenic differentiation of stem cells and the bone formation i osteoporosis. In this study, we prepared a ROS-scavenging hydrogel by crosslinking of epigallocatechin-3-gallate (EGCG), 3-acrylamido phenylboronic acid (APBA) and acrylamide. The engineered hydrogel can scavenge ROS efficiently, enabling it to be a cell carrier of bone marrow-derived mesenchymal stem cells (BMSCs) to protect delivered cells from ROS-mediated death and osteogenesis inhibition, favorably enhancing the tissue repair potential of stem cells. Further in vivo investigations seriously demonstrated that this ROS-scavenging hydrogel encapsulated with BMSCs can prominently promote osteointegration of 3D printed microporous titanium alloy prosthesis in osteoporosis, including scavenging accumulated ROS, inducing macrophages to polarize toward M2 phenotype, suppressing inflammatory cytokines expression, and improving osteogenesis related markers (e.g., ALP, Runx-2, COL-1, BSP, OCN, and OPN). This work provides a novel strategy for conquering the challenge of transplanted stem cells cannot fully function in the impaired microenvironment, and enhancing prosthetic osteointegration in osteoporosis.

Biphasic calcium phosphate (BCP) containing hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) is considered the gold standard for bone repair. However, the complex synthesis of BCP restricts the wide application of BCP. In the preliminary work, we proved that the HA/β-TCP BCP ceramic material extracted from fishery waste had a good prospect as a bone replacement graft material for filling bone defects. This study aimed to explore the osteogenesis effect of BCP material derived from butterfish bones in vivo and in vitro. After loading human bone marrow mesenchymal stem cells (hBMSCs) with materials, we used scanning electron microscopy to observe cell adhesion and survival. Western blot analysis was used to detect osteogenic expression in vitro. Micro-computed tomography and hematoxylin–eosin staining were used to detect bone regeneration and material degradation rate in the rat femoral defect model. The results showed that hBMSCs grew well and adhered closely to the material. In vitro, the expression levels of bone formation–related markers ALP and Runx-2 of butterfish bones calcined at 900°C were generally higher than those in the other groups. Notably, in vivo, the osteogenesis ability of butterfish bones calcined at 900°C was almost comparable to that of the most commonly used Bio-Oss in clinical practice and was significantly better than that in the other groups. In summary, the BCP ceramic material derived from butterfish bones had good biocompatibility, osteoconductivity, and osteoinductivity, and had a good application prospect in the field of bone graft substitutes.

A hydrogel system loaded with mesenchymal stem cell–derived exosome (MSC-Exos) is an attractive new tool for tissue regeneration. However, the effect of the stiffness of exosome-loaded hydrogels on tissue regeneration is unclear. Here, the role of exosome-loaded hydrogel stiffness, during the regeneration of injured nerves, was assessed in vivo. The results showed that the photocrosslinkable hyaluronic acid methacrylate hydrogel stiffness plays an important role in repairing nerve injury. Compared with the stiff hydrogels loaded with exosomes, soft hydrogels loaded with exosomes showed better repair of injured peripheral nerves. The soft hydrogel promoted nerve repair by quickly releasing exosomes to inhibit the infiltration of macrophages and the expression of the proinflammatory factors IL-1β and TNF-α in injured nerves. Our work revealed that exosome-loaded hydrogel stiffness plays an important role in tissue regeneration by regulating exosome release behavior and provided important clues for the clinical application of biological scaffold materials.

Loading human umbilical mesenchymal stem cell (hUMSC) derived exosomes onto hydrogel scaffolds is a strategy for rapid wound healing. The clinical application of exosomes is hindered by low production, and exosome mimetics could be substituted for exosomes. Here, the therapeutic effects of exosome-loaded hydrogels and exosome mimetic-loaded hydrogels on wounds are evaluated. Our results revealed that exosome mimetic-loaded hydrogels promote wound healing more efficiently than exosome-loaded hydrogels. Exosome mimetics can promote the proliferation and migration of dermal fibroblasts (hDF-a) cells in vitro. To investigate how exosome mimetics play a role, proteomics analysis was applied, and the obtained results suggested that exosome mimetics significantly enrich mitochondrial-derived oxidative phosphorylation-related proteins in comparison to exosomes. Overall, our work envisages the emerging potential of exosome mimetics, which take the advantage of exosomes and can be promising candidates for exosomes. It also suggests that hUMSC-derived exosome mimetic-loaded hydrogels have remarkable prospects for clinical application.