A Maternal High Fat Diet Leads to Sex-Specific Programming of Mechanical Properties in Supraspinatus Tendons of Adult Rat Offspring

Novel In Vitro Platform for Studying the Cell Response to Healthy and Diseased Tendon Matrices

Current in vitro models poorly represent the healthy or diseased tendon microenvironment, limiting the translation of the findings to clinics. The present work aims to establish a physiologically relevant in vitro tendon platform that mimics biophysical aspects of a healthy and tendinopathic tendon matrix using a decellularized bovine tendon and to characterize tendon cells cultured using this platform. Bovine tendons were subjected to various decellularization techniques, with the efficacy of decellularization determined histologically. The biomechanical and architectural properties of the decellularized tendons were characterized using an atomic force microscope. Tendinopathy-mimicking matrices were prepared by treating the decellularized tendons with collagenase for 3 h or collagenase-chondroitinase (CC) for 1 h. The tendon tissue collected from healthy and tendinopathic patients was characterized using an atomic force microscope and compared to that of decellularized matrices. Healthy human tendon-derived cells (hTDCs) from the hamstring tendon were cultured on the decellularized matrices for 24 or 48 h, with cell morphology characterized using f-actin staining and gene expression characterized using real-time PCR. Tendon matrices prepared by freeze-thawing and 48 h nuclease treatment were fully decellularized, and the aligned structure and tendon stiffness (1.46 MPa) were maintained. Collagenase treatment prepared matrices with a disorganized architecture and reduced stiffness (0.75 MPa), mimicking chronic tendinopathy. Treatment with CC prepared matrices with a disorganized architecture without altering stiffness, mimicking early tendinopathy (1.52 MPa). hTDCs on a healthy tendon matrix were elongated, and the scleraxis (SCX) expression was maintained. On tendinopathic matrices, hTDCs had altered morphological characteristics and lower SCX expression. The expression of genes related to actin polymerization, matrix degradation and remodeling, and immune cell invasion were higher in hTDCs on tendinopathic matrices. Overall, the present study developed a physiological in vitro system to mimic healthy tendons and early and late tendinopathy, and it can be used to better understand tendon cell characteristics in healthy and diseased states.

Association between High-Fat Diet during Pregnancy and Heart Weight of the Offspring: A Multivariate and Mediation Analysis

Maternal nutrition and health status in the peri-pregnancy period are closely related to offspring health. Currently, population studies are unable to provide quantitative relationships and effective measures of peri-pregnancy high-fat diet and offspring myocardial remodeling due to the difficulty of obtaining human samples. This study aimed to establish the mouse models of maternal obesity and high-fat diet supplementation and deprivation during pregnancy. The effects of obesity, periconceptional high-fat diet window, fetal weight, sex, and placental weight on myocardial remodeling in the offspring were measured by single-factor and multiple-factor regression analyses. Moreover, the relationship between perinatal high-fat diet/fetal weight and offspring myocardial remodeling was explored using the mediation analysis model. The multivariate analysis showed that the heart weight to body weight (HW/BW) ratio of the offspring decreased by -1.6525 mg/g for every 1-g increase in fetal weight. The offspring HW/BW increased by 1.1967 mg/g if pregnant women were exposed to a high-fat diet throughout pregnancy. The mediation analysis model of a perinatal high-fat diet for the myocardial remodeling of offspring revealed that fetal weight had a suppression effect on the myocardial weight of offspring, accounting for 60.70%; also, it had a mediating effect on the HW/BW of offspring, accounting for 17.10%. Moreover, subgroup analysis showed an interaction between offspring sex and HW/BW in a maternal high-fat diet during pregnancy. Additionally, a quantitative real-time polymerase chain reaction experiment further proved that a perinatal high-fat diet could change the important indicators of myocardial remodeling in offspring. In conclusion, this study found that a high-fat diet in the periconceptional period influenced factors in offspring myocardial remodeling. Moreover, maternal high-fat diet deprivation attenuated the changes in offspring myocardial remodeling. In addition, the role of fetal weight in mediating maternal high-fat diet-mediated offspring myocardial remodeling was quantified. Our study showed that a sensible and healthy diet during the perinatal period, especially during pregnancy, played a positive role in the health of the offspring.