Comparison of Bone Quality in Middle Ages and Late Modern Period Human Skeletons from Latvia

The analysis of bone microstructure and histological examination currently provides valuable insights into various facets of bone biology, ancient human existence, and bone-related diseases. This study aims to scrutinize the microstructure of historic Latvian bones, with three bone element groups selected (humerus, radius, and ulna) from a skeletal collection spanning from the Middle Ages to the Late Modern Period, procured through an archaeological excavation at St. George's Church in Riga. To evaluate the changes in bone samples over time, two methods are utilized: (i) micro-computed tomography, used for measuring and calculating bone volume/trabecular volume (BV/TV), cortical bone and trabecular thickness, and trabecular pore diameter; (ii) immunohistochemistry (IHC) is employed to detect the presence of Runx2, OPG, OC, MMP2, TIMP2, BFGF, IL-1, IL-10, OPN, defensin-2, BMP 2/4, TGF & beta; factor in bone cells-specifically osteocytes. Archaeological human bone remains from the Middle Ages period in Latvia display a decline in the average bone volume to trabecular volume ratio when compared with the Late Modern Period, indicating a potential reduction in bone quality in the skeletons, potentially associated with a lower living standard during the earlier era. Comparing factors between the periods reveals a higher value of TIMP2 (p = 0.047) in samples from the Late Modern Period group, while IL-1 is higher (p = 0.036) in the Middle Ages group, which may suggest the presence of disease and diminished bone quality in the skeletons from the Middle Ages.