Plasma biomarkers of depressive symptoms in older adults

The pathophysiology of negative affect states in older adults is complex, and a host of central nervous system and peripheral systemic mechanisms may play primary or contributing roles. We conducted an unbiased analysis of 146 plasma analytes in a multiplex biochemical biomarker study in relation to number of depressive symptoms endorsed by 566 participants in the Alzheimer's Disease Neuroimaging Initiative (ADNI) at their baseline and 1-year assessments. Analytes that were most highly associated with depressive symptoms included hepatocyte growth factor, insulin polypeptides, pregnancy-associated plasma protein-A and vascular endothelial growth factor. Separate regression models assessed contributions of past history of psychiatric illness, antidepressant or other psychotropic medicine, apolipoprotein E genotype, body mass index, serum glucose and cerebrospinal fluid (CSF) τ and amyloid levels, and none of these values significantly attenuated the main effects of the candidate analyte levels for depressive symptoms score. Ensemble machine learning with Random Forests found good accuracy (∼80%) in classifying groups with and without depressive symptoms. These data begin to identify biochemical biomarkers of depressive symptoms in older adults that may be useful in investigations of pathophysiological mechanisms of depression in aging and neurodegenerative dementias and as targets of novel treatment approaches

Manufacture of a weakly denatured collagen fiber scaffold with excellent biocompatibility and space maintenance ability.

Although collagen scaffolds have been used for regenerative medicine, they have insufficient mechanical strength. We made a weakly denatured collagen fiber scaffold from a collagen fiber suspension (physiological pH 7.4) through a process of freeze drying and denaturation with heat under low pressure (1 × 10(-1) Pa). Heat treatment formed cross-links between the collagen fibers, providing the scaffold with sufficient mechanical strength to maintain the space for tissue regeneration in vivo. The scaffold was embedded under the back skin of a rat, and biocompatibility and space maintenance ability were examined after 2 weeks. These were evaluated by using the ratio of foreign body giant cells and thickness of the residual scaffold. A weakly denatured collagen fiber scaffold with moderate biocompatibility and space maintenance ability was made by freezing at -10 °C, followed by denaturation at 140 °C for 6 h. In addition, the direction of the collagen fibers in the scaffold was adjusted by cooling the suspension only from the bottom of the container. This process increased the ratio of cells that infiltrated into the scaffold. A weakly denatured collagen fiber scaffold thus made can be used for tissue regeneration or delivery of cells or proteins to a target site