Townsend, J. M. | bioRxiv Science

bioRxiv2025

Controlled Release of Bone Morphogenetic Protein-2 Improves Motor Function After Traumatic Brain Injury in a Rat Model

Severe traumatic brain injury (TBI) is a life-threatening condition characterized by internal brain swelling and commonly treated using a two-stage surgical approach. The interval between surgeries, generally spaced weeks to months, is associated with secondary neurologic complications from leaving the brain unprotected. Hydrogels may reshape severe TBI treatment by enabling a single-stage surgical intervention, capable of being implanted at the initial surgery, remaining flexible to accommodate brain swelling, and calibrated to regenerate bone after brain swelling has subsided. The current study evaluated the use of a pentenoate-modified hyaluronic acid (PHA) polymer with thiolated devitalized tendon (TDVT) for calvarial bone regeneration in a rat TBI model. Additionally, PHA-TDVT hydrogels encapsulating microspheres containing bone morphogenetic protein-2 (BMP-2) were investigated to enhance bone regeneration. All hydrogel precursor formulations exhibited sufficient yield stress for surgical placement. The addition of TDVT to the crosslinked hydrogels increased the average compressive modulus. In vitro cell studies revealed that the PHA-TDVT hydrogel with the highest concentration of BMP-2 microspheres (i.e., PHA-TDVT+{micro}100) significantly improved calcium deposition and osteogenic gene expression. Minimal in vivo bone regeneration was observed for all hydrogel groups; however, BMP-2 microsphere addition fortuitously reduced motor skill impairment and brain atrophy. The PHA-TDVT+{micro}100 group had 2.8 times greater reach index and 2.3 times lower brain atrophy values compared to the negative control (p<0.05). Overall, hydrogels with controlled release of BMP-2 may provide neuroprotective benefits in TBI treatment. Future studies should explore BMP-2 delivery strategies to enhance both bone and brain recovery in rat TBI studies. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=82 SRC="FIGDIR/small/649206v1_ufig1.gif" ALT="Figure 1"> View larger version (25K): org.highwire.dtl.DTLVardef@136d4d4org.highwire.dtl.DTLVardef@cee564org.highwire.dtl.DTLVardef@13612e8org.highwire.dtl.DTLVardef@1134b4c_HPS_FORMAT_FIGEXP M_FIG C_FIG Statement of SignificanceSevere traumatic brain injury (TBI) is a life-threatening condition characterized by internal brain swelling and is commonly treated using a two-stage surgical approach. Complications associated with the two-stage treatment paradigm include secondary neurologic impairment, termed syndrome of the trephined (SOT). SOT is often reversible once the second surgery is performed, whereas a single-stage TBI treatment paradigm may avoid the occurrence of SOT altogether. Utilizing hydrogels comprised of pentenoate-modified hyaluronic acid and thiolated devitalized tendon encapsulating microspheres containing bone morphogenetic protein-2 (BMP-2), the current study demonstrated improvements in motor skill function and reductions in brain atrophy in a rat TBI model. The introduction of hydrogels with controlled release of BMP-2 as a neuroprotective strategy for TBI application offers a promising approach for single-stage TBI treatment.

bioengineering↗

bioRxiv2019

Net effects of field and landscape scale habitat on insect and bird damage to sunflowers

Agriculture-dominated landscapes harbor significantly diminished biodiversity, but are also areas in which significant gains in biodiversity can be achieved. Planting or retaining woody vegetation along field margins can provide farmers with valuable ecosystem services while simultaneously benefitting biodiversity. However, when crops are damaged by the biodiversity harbored in such vegetation, farmers are reluctant to incorporate field margin habitat onto their land and may even actively remove such habitats, at cost to both farmers and non-target wildlife. We investigated how damage by both insect pests (sunflower moth, Homoeosoma electellum) and avian pests to sunflower (Helianthus annuus) seed crops varied as a function of bird abundance and diversity, as well as by landscape-scale habitat. Surveys for insect damage, avian abundance, and bird damage were carried out over two years in 30 different fields on farms in Californias Sacramento Valley. The mean percentage of moth-damaged sunflowers sampled was nearly four times higher in fields that had bare or weedy margins (23.5%) compared to fields with woody vegetation (5.9%) and decreased in both field types as landscape-scale habitat complexity declined. Birds damaged significantly fewer sunflower seeds (2.7%) than insects, and bird damage was not affected by field margin habitat type, landscape-scale habitat variables, or avian abundance, but was significantly higher along field edges compared to [≥] 50m from the field edge. Avian species richness nearly doubled in fields with woody margin habitat compared to fields with bare/weedy margins in both the breeding season and in fall. These results indicate that the benefits of planting or retaining woody vegetation along sunflower field margins could outweigh the ecosystem disservices related to bird damage, while simultaneously increasing the biodiversity value of intensively farmed agricultural landscapes.

ecology↗