Microbiota and Bone Health: The Gut-Musculoskeletal Axis

Excerpt

The largest number of cells (10^E14) in the human body are located within the intestinal tract lumen. This number is much higher than the number of cells in any human body parenchyma. The estimated number of different species varies between 1000 and 5000 comprising gram-positive and gram-negative bacteria, Archaea, Eukarya, as well as viruses. These organisms are collectively called the gut microbiota (GM). They mostly refer to the large intestine content, but all parts of the gastrointestinal tract are colonized with an increasing density from the duodenum to the distal colon. GM is now considered as an organ modulating the expression of genes involved in mucosal barrier function, immune system, food digestion, and energy metabolism [1]. The microbiome refers to the aggregate collection of genomes and genes present in gut microbiota. Dysbiosis is a state of microbial imbalance in the gut. It refers to a change in microbiota structure and/or function [2]. Gnotobiotic animals are animals raised under germ-free conditions or under germ-free conditions and then colonized with well-defined and controlled microbes. …