A recent study in Biomedicine & Pharmacotherapy, done by researchers from the Emory University School of Medicine in Atlanta, has suggested probiotic supplementation with Bifidobacterium adolescentis may prevent pathologies and accelerate recovery following femoral fracture.
The experiment was done on eight-week old male mice, which were randomly assigned to receive either sterile PBS (phosphate buffered saline) or 1x108 CFU of B. adolescentis through oral gavage five times per week. Following this, the researchers caused femoral fractures in the mice before measuring callus bone using Micro-Computed tomography and gut permeability through plasma analysis. The mice continued to receive their respective supplementation throughout a 22 day recovery period.
The researchers sought to determine firstly; whether femoral fracture would cause an increase in gut permeability throughout the healing process, and secondly; what effect probiotic supplementation with B. adolescentis would have on this process.
Plasma analysis indicated significantly increased gut permeability three and seven days after fracture, while at day 10 and 18, permeability had returned to baseline levels. The authors concluded the femoral fracture caused a significant increase in gut permeability in the 10 days following fracture before a return to baseline levels.
The researchers found that the prophylactic dietary supplementation, which they describe as “analogous to consuming a probiotic supplement as part of a normal daily health routine,” resulted in accelerated remodelling of callus cartilage between days 10 and 14 of recovery, a result which was not observed in the control group.
There was also a significant increase in osteoclasts (cells responsible for the breaking down of bone tissue during the process of bone remodelling) in the supplemented mice at 18 days post fracture. Beyond this, supplementation with B. adolescentis had no effect on total body weight, spleen weight, or intestine appearance, indicating its daily consumption should have no negative effects.
Further findings showed that the supplemented mice maintained higher gut barrier integrity during the recovery period, reducing the transmission of pro-inflammatory bacterial products, and that these mice experienced a significantly dampened inflammatory response following the fracture. Lastly, supplementation with B. adolescentis had a preventative effect on bone loss within the intact skeleton following fracture, a pathology which occurs as a result of heightened inflammation.
More positively still, the researchers noted the majority of effects observed from B. adolescentis supplementation were noticeable only after the fracture. They describe this as consistent with previous studies which have shown the bacteria has no effect on a healthy host.
The researchers suggest that the inflammatory issues following a fracture are likely a result of increased gut permeability, and therefore that the supplementation’s reinforcing effect on the gut barrier had knock-on benefits to both the mice’s inflammatory response and their bone loss. Their results are also described as “therapeutically promising” for the progression of bone repair, which was indicated by faster cartilaginous callus remodelling, said to be a result of increased osteoclasts. The researchers say their study is the first to directly link supplementation to cartilage recovery, but that it adds to a “growing body of evidence that consumption can positively influence fracture healing”.
