Micronized Cellular Adipose Matrix Promotes the Therapeutic Effect of an Artificial Nerve Conduit in Peripheral Nerve Gap Injury

Abstract

Background: Stromal vascular fraction (SVF) isolated from adipose tissue has been shown to be beneficial for treating peripheral nerve injuries. Micronized cellular adipose matrix (MCAM) is an SVF-rich micronized fat tissue obtained by a series of simple mechanical processes. This study assessed the therapeutic effect of MCAM for peripheral nerve injury. Methods: Microscopic evaluation of the cell phenotype and functions was performed to determine the adipose-derived stem cell content of the MCAM. An artificial nerve conduit (ANC) filled with MCAM was implanted into a sciatic nerve defect in immunodeficient mice. Comparisons of this treatment with an autograft, an ANC filled with SVF cells, and an ANC alone were made based on electrophysiologic characteristics, Sciatic Functional Index, and histologic analyses of regenerated nerve fiber and myelination using electron microscopy, and the preventive effect on innervated muscle atrophy. Results: MCAM contained many cells with a phenotype and differentiation potency similar to those of ADSCs. The implantation experiment indicated that MCAM enhanced the efficiency of functional and structural recovery and prevented atrophy of the innervated muscle. These effects were significantly improved compared with the control group (ANC only) and comparable to those in the SVF group, whereas the improvement did not reach the same level of the autograft group. Conclusion: Injection of MCAM into an ANC accelerated nerve regeneration compared with use of an ANC alone, which indicates that MCAM is a promising transplant material for treatment of peripheral nerve injury and an alternative to use of SVF cells. Clinical Relevance Statement: Micronized cellular adipose matrix, which can be harvested and isolated from adipose tissue with a simple device, has been shown for the first time to be highly useful as an implantable material for new peripheral nerve regeneration.