Evaluation methods as quality control in the generation of decellularized peripheral nerve allografts

Abstract

Nowadays, the high incidence of peripheral nerve injuries and the low success ratio of surgical treatments are driving research to the generation of novel alternatives to repair critical nerve defects. In this sense, tissue engineering has emerged as a possible alternative with special attention to decellularization techniques. Tissue decellularization offers the possibility to obtain a cell-free, natural extracellular matrix (ECM), characterized by an adequate 3D organization and proper molecular composition to repair different tissues or organs, including peripheral nerves. One major problem, however, is that there are no standard quality control methods to evaluate decellularized tissues. Therefore, in this review, a brief description of current strategies for peripheral nerve repair is given, followed by an overview of different decellularization methods used for peripheral nerves. Furthermore, we extensively discuss the available and currently used methods to demonstrate the success of tissue decellularization in terms of the cell removal, preservation of essential ECM molecules and maintenance or modification of biomechanical properties. Finally, orientative guidelines for the evaluation of decellularized peripheral nerve allografts are proposed.

Comparison of systematically combined detergent and nuclease‐based decellularization methods for acellular nerve graft: An ex vivo characterization and in vivo evaluation

“…The basic problem with allogenic nerve development is that a standard evaluation protocol for the decellularized nerve has not been established (Philips, Cornelissen, & Carriel, ). A comprehensive approach including various evaluation tools was recently emphasized for verification of the decellularized tissue or organs (Zilic, Wilshaw, & Haycock, ).…”

“…Crapo et al () suggested a criteria for evaluation of cell removal composed of histological analysis with H&E or DAPI staining and DNA quantification. Philips, Cornelissen, and Carriel () suggested that structural integrity should be demonstrated with a correlation between histological analysis of ECM components and structure, quantification of ECM components, and determination of biomechanical properties. Various decellularization methods have now been reported, but most of them used one or two less accurate tools for evaluation of their decellularized nerve.…”

“…However, these materials also have limitations, which are mainly related to their nonnerve origin (Crapo et al, ; Karabekmez, Duymaz, & Moran, ; Kehoe, Zhang, & Boyd, ). Above all, the outcomes of these methods have been proven to be significantly inferior to those of autogenous nerve grafting in several animal and clinical studies (Grinsell & Keating, ; Hundepool et al, ; Kim et al, ; Philips, Cornelissen, & Carriel, ; Whitlock et al, ).…”

“…Bone and tendons have been commonly used for allografting in musculoskeletal systems (Lomas, Chandrasekar, & Board, ; Shelton & Fagan, ) but not for nerves. There are several reasons for this, but the most pertinent is the uncertainty regarding whether decellularization of allogenous nerve grafts could effectively recover the functional deficits and provide the necessary immunogenic safety when treating injured nerves (Philips, Cornelissen, & Carriel, ). In other words, little consensus currently exists as to which decellularization technique best preserves the natural regenerative capacity of peripheral nerve tissue through the control of immunogenicity.…”

“…Several nerve decellularization techniques have now been utilized and could be categorized into physical, chemical, or biological methods (Philips, Cornelissen, & Carriel, ). These were used as a single treatment or in combination.…”