Analysis of the harmonized growth pattern of fetal organs by multidimensional scaling and hierarchical clustering

The development of an organ may be affected by various growth and differentiation factors released from other organs. These factors are believed to have important effects on the development of multiple organs. To detect and analyze harmonized development among multiple organs, similarities in growth patterns among fetal organs were examined using multivariate analysis. Ninety human fetuses obtained from the Kyoto Collection of Human Embryos were dissected. Harmonized development of organs was evaluated by multidimensional scaling and cluster analysis using measurements (length, width, height, and weight) of the fetal organs. Similar growth patterns were observed between the brain, including cerebrum, diencephalon, and midbrain (cerebrum-to-midbrain [Cer-Mid]), and pituitary (crown-rump length [CRL] 95-155 mm). Further, similar growth patterns were observed between the liver and Cer-Mid and cerebellum (Cb; CRL 156-202 mm), and between Cer-Mid and Cb (CRL 203-253 mm). Similarities in growth patterns were also observed between right and left lungs (CRL 99-235 mm) and between the aorta and heart (CRL 139-187 mm), but not between the lung and pulmonary trunk. These findings revealed synchronized development among fetal organs and suggested a functional and structural relationship among different organs in the prenatal period. These relationships include the existence of common factors in organ development, such as cross-talk mediated by humoral factors, and the presence of an anatomical and functional relationship in the fetal circulatory system.