Dispase/collagenase cocktail allows for coisolation of satellite cells and fibroadipogenic progenitors from human skeletal muscle.

Satellite cells (SCs) and fibroadipogenic progenitors (FAPs) are progenitor populations found in muscle that form new myofibers postinjury. Muscle development, regeneration, and tissue-engineering experiments require robust progenitor populations, yet their isolation and expansion are difficult given their scarcity in muscle, limited muscle biopsy sizes in humans, and lack of methodological detail in the literature. Here, we investigated whether a dispase and collagenase type 1 and 2 cocktail could allow dual isolation of SCs and FAPs, enabling significantly increased yield from human skeletal muscle. Postdissociation, we found that single cells could be sorted into CD56 + CD31-CD45- (SC) and CD56-CD31-CD45- (FAP) cell populations, expanded in culture, and characterized for lineage-specific marker expression and differentiation capacity; we obtained ∼10% SCs and ∼40% FAPs, with yields twofold better than what is reported in current literature. SCs were PAX7+ and retained CD56 expression and myogenic fusion potential after multiple passages, expanding up to 1012 cells. Conversely, FAPs expressed CD140a and differentiated into either fibroblasts or adipocytes upon induction. This study demonstrates robust isolation of both SCs and FAPs from the same muscle sample with SC recovery more than two times higher than previously reported, which could enable translational studies for muscle injuries.NEW & NOTEWORTHY We demonstrated that a dispase/collagenase cocktail allows for simultaneous isolation of SCs and FAPs with 2× higher SC yield compared with other studies. We provide a thorough characterization of SC and FAP in vitro expansion that other studies have not reported. Following our dissociation, SCs and FAPs were able to expand by up to 1012 cells before reaching senescence and maintained differentiation capacity in vitro demonstrating their efficacy for clinical translation for muscle injury.

Facial dog bites in children: A public health problem highlighted by COVID-19 lockdown.

BACKGROUND: Stay-at-home injunction during COVID-19 pandemic led to new dynamics in households and increased the risk of domestic accidents involving pets. The aim of the study was to demonstrate an increase of facial dog bites in children during first lockdown period in France, compared to the same period in 2018 and 2019. Secondary objective was to investigate the demographics and circumstances in which dog bites occurred. METHODS: A retrospective multicentric study was conducted nationwide. Patients under 18 years old managed in fifteen oral and maxillofacial surgery departments for a dog bite were included. RESULTS: Eighty-seven patients were included. A significant increase of the number of children managed for facial dog bite was noticed in 2020 (p=0.0005). The male-to-female ratio was significantly reversed in 2020 with more bites in girls than boys (p=0.02). In 2020, children were mostly bitten to cheeks (28.6 %), lips-and-chin region (26.2 %), and eyelids (23.8 %). Severe bites increased in 2020, in comparison with 2018 and 2019. Dog bites occurring while petting or playing significantly increased in 2020 (31 %) (p=0.03). CONCLUSION: The process leading to bites is highly dependent on the balance of dog-owner relationship. This was strongly disrupted during COVID-19 pandemic, resulting in the increase of dog bites in households. Regarding dog bites, face is the most vulnerable area in children. Its injury has lots of esthetic and functional consequences and maxillofacial surgeons have a key role to play in their prevention. Reminders of some of these management and prevention strategies are presented in this article.