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PubMed1: Neurosci Lett 1999 Jan 8;259(2):75-8

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Cat peripheral nerve regeneration across 50 mm gap repaired with a novel nerve guide composed of freeze-dried alginate gel.

Suzuki Y, Tanihara M, Ohnishi K, Suzuki K, Endo K, Nishimura Y.

Department of Plastic and Reconstructive Surgery , Faculty of Medicine, Kyoto University , Japan.

We have developed a novel artificial nerve guide composed of biodegradable freeze-dried alginate gel covered by poly glycolic acid mesh, and evaluated its effect on peripheral nerve regeneration, using a 5O-mm gap cat sciatic nerve model. Functional reinnervation of motor and sensory nerves occurred 13 weeks after implantation, as demonstrated by recovery of compound muscle action potential (CMAP) and somatosensory evoked potential (SEP). For histologic evaluation, samples of tissue were harvested from the grafted material segment 7 months after operation.

Many newly developed nerve fasciculi were found, and the implanted nerve guidance material had completely disappeared with little inflammation. These results indicate that freeze-dried alginate gel allows the nerve to regenerate across longer gaps than described in previous literature.

PMID: 10025561 [pubMed -indexed for MEDLlNE]

PubMed 1: J Neurotrauma 2001 Mar;18(3):329-38 Related Articles, Links

Sciatic nerve regeneration through alginate with tubulation or nontubulation repair in cat.

Sufan W, Suzuki Y, Tanihara M, Ohnishi K, Suzuki K, Endo K, Nishimura Y. Department of Plastic and Reconstructive Surgery , Kyoto University Graduate School of Medicine, Japan.

A novel material for nerve regeneration, alginate, was employed in both tubulation and nontubulation repair of a long peripheral nerve defect injury .Twelve cats underwent severing of the right sciatic nerve to generate a 5O-mm gap, which was .treated by tubulation repair (n = 6) or nontubulation repair (n = 6). In the tubulation group, a nerve conduit consisting of polyglycolic acid mesh tube filled with alginate sponge was implanted into the gap and the tube was sutured to both nerve stumps. In the nontubuIation group, the nerve defect was repaired by a simple inte~lation of two pieceS of alginate sponge without any suture. The animals in both groups exhibited similar recovery of locomotor function. Three months ~stoperatively, successful axonal elongation and reinnervation in both the afferent and efferent systems were detected by electrophysiological examinations. Intracellular electrical activity was also

recorded, which is directly indicative of continuity of the regenerated nerve and restoration of the spinal reflex circuit. Eight months after operation, many regenerated myelinated axons with fascicular organization by perineurial cells were observed within the gap, peroneal and tibial branches were found in both groups, while no alginate residue was found within the regenerated nerves. In morphometric analysis of the axon density and diameter, there were no significant differences between the two groups.

These results suggest that alginate is a potent material for promoting peripheral nerve regeneration. It can also be concluded that the nontubulation method is a possible repair approach for peripheral nerve defect injury .

PMID: 11284552 [pubMed -indexed for MEDLINE]

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PubMed 1: Exp Brain Res 2002 Oct;I46(3):356-68

alginate Pg-27

Peripheral nerve regeneration through alginate gel: analysis of early outgrowth and late increase in diameter of regenerating axons.

Hashimoto T, Suzuki Y, Kitada M, Kataoka K, Wu S, Suzuki K, Endo K, Nishimura Y, Ide C. Department of Anat~my and Neurobiology and Cell Biology, Kyoto University Graduate Scfiool of Medicine, Yoshidakonoe-cho, Sakyo- ku, Kyoto 606-850 1, Japan.

Our previous study revealed that alginate gel cross-linked with covalent bonds promoted peripneral nerve regeneration in the cat and rat. The present study analyzed nerve regeneration thrOugh alginate gel in the early stages within 2 weeks and the late stages up to 21 months after implantation. Four days after surgery , regenerating axons grew without Schwann cell investment through the partially degraded alginate gel, being in direct contact with the alginate without a basal lamina covering. Numerous mast cells infiltrated into the alginate. One to 2 weeks after surgery , regenerating axons were surroun

~ed b common Schwann cells to form smal~ bundles, with some axons at the periphery ~ing .y in dir~t contact with alginate. At the distal stump,- numerous Schwann cells had mIgrat mto the algmate 8-14 days after surgery .They had no basal laminae. The diameter of regenerated myelinated fibers was small (apEroximately 1 micro m) at 8 weeks, but increased in diameter, having a distribution pattern simIlar to that of normal nerve 21 months after surgery .Much better nerve regeneration was found in alginate gel-, than collagen sponge-, and fibrm glue-implanted distal stump 12 months after surgery .

These results indicate that alginate gel has good biocompatibility for regenerating axon outgrowth and Schwann cell migration, and that regenerated fibers can have a diameter as thick as that of normal fibers in the long term.. Alginate gel is a promising material for use as an implant for peripheral nerve regeneration.

PMID: 12232692 [pubMed -in process]