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Background: Matrilin-2 is a key extracellular matrix protein involved in peripheral nerve regeneration. We sought to develop a biomimetic scaffold to enhance peripheral nerve regeneration by incorporating matrilin-2 within a chitosan-derived porous scaffold. We hypothesized that the use of such a novel biomaterial delivers microenvironmental cues to facilitate Schwann cell (SC) migration and enhance axonal outgrowth during peripheral nerve regeneration.Materials and Methods: The effect of matrilin-2 on SC migration was evaluated with agarose drop migration assay on matrilin-2 coated dishes. SC adhesion was determined with SCs cultured atop tissue culture dishes coated with matrilin-2. Various formulations of chitosan vs matrilin-2 in scaffold constructs were examined with scanning electron microscopy. The effect of the matrilin-2/chitosan scaffold on SC migration in the collagen conduits was determined by capillary migration assays. Neuronal adhesion and axonal outgrowth were evaluated with three-dimensional (3D) organotypic assay of dorsal root ganglions (DRG). DRG axonal outgrowth within the scaffolds was determined by immunofluorescence staining of neurofilaments.Results: Matrilin-2 induced SC migration and enhanced its adhesion. A formulation of 2% chitosan with matrilin-2 demonstrated an optimal 3D porous architecture for SC interaction. Matrilin-2/chitosan scaffold enabled SCs to migrate against gravity within conduits. Chemical modification of chitosan with lysine (K-chitosan) further improved DRG adhesion and axonal outgrowth than the matrilin-2/chitosan scaffold without lysine modification.Conclusion: We developed a matrilin-2/K-chitosan scaffold to mimic extracellular matrix cues and provide a porous matrix to enhance peripheral nerve regeneration. Taking advantage of matrilin-2’s capability to stimulate SC migration and adhesion, we formulated a porous matrilin-2/chitosan scaffold to support axongal outgrowth. Chemical modification of chitosan with lysine further improved matrilin-2 bioactivity in the 3D scaffold. The 3D porous matrilin-2/K-chitosan scaffolds have high potential for enhancing nerve repair by stimulating SC migration, neuronal adhesion, and axonal outgrowth.

Peripheral nerves are crucial to the motor and sensory function provided by our upper and lower extremities to our brain and spinal cord. Following trauma or illness, these nerves may be injured, leading to a loss of function that can be significantly debilitating. Fortunately, given the type of injury and under the right conditions, peripheral nerves can regenerate through well-coordinated biochemical processes. However, as individuals age, the ability for nerves to regenerate becomes less efficient, reducing nerve's potential for the nerve to return to its prior level of function. In this article, we review the research that has been conducted to illustrate the reasons for such a decline in regenerative capacity. In doing so, we explore the concept of inflammaging alongside aging-related impairments of the macrophage and Schwann cell during nerve regeneration.

The growth, mortality rates and the fisheries yield of Parailia pellucida (Schilbeidae) caught from Cross River at Obubra were studied. The seasonalized von Bertalanffy growth equation fitted to the length frequency data gave the following parameters: Loo= 18.0cm TL,K=0.47yr-1 , C=0.4, WP=0.86 and t0= -0.389yr with Rn=0.56. The instantaneous total mortality coefficient estimated from the seasonalized length converted catch curve, was Z = 1.57yr-1 The instantaneous natural mortality coefficient was M = 1.28yr-1 while the instantaneous fishing mortality coefficient was F = 0.03yr-1 the estimated current exploitation rate was E = 0.19. The probability of capture of each size class showed that the length at first capture was Lc = 7. 82cm TL. The Beverton and Holt's relative yield per recruit and relative biomass per recruited predicted a maximum exploitation rate Emax =0.52. The stock is not over exploited since E