In Vitro and In Vivo Studies of Alar-Nasal Cartilage Using Autologous Micro-Grafts: The Use of the Rigenera® Protocol in the Treatment of an Osteochondral Lesion of the Nose

Abstract

Cartilage defects represent a serious problem due to the poor regenerative properties of this tissue. Regarding the nose, nasal valve collapse is associated with nasal blockage and persistent airway obstruction associated with a significant drop in the quality of life for patients. In addition to surgical techniques, several cell-based tissue-engineering strategies are studied to improve cartilage support in the nasal wall, that is, to ameliorate wall insufficiency. Nevertheless, there are no congruent data available on the benefit for patients during the follow-up time. In this manuscript, we propose an innovative approach in the treatment of cartilage defects in the nose (nasal valve collapse) based on autologous micro-grafts obtained by mechanical disaggregation of a small portion of cartilage tissue (Rigenera^® protocol). In particular, we first analyzed in vitro murine and human cartilage micro-grafts; secondly, we analyzed the clinical results of a patient with pinched nose deformity treated with autologous micro-grafts of chondrocytes obtained by Rigenera^® protocol. The use of autologous micro-graft produced promising results in surgery treatment of cartilage injuries and could be safely and easily administrated to patients with cartilage tissue defects.

Keywords: Rigenera® protocol; autologous micro-grafts; chondrocytes; nasal valve collapse; tissue engineering approaches.

Figure 1

(A,B): Hoechst 33342 staining on micro-grafts suspension obtained from murine auricular cartilage. (*) represents single nuclei cells, while (**) represents clusters of micro-grafts containing small groups of living cells. Magnification at 20×. (C): Gene expression analysis of the indicated specific markers as determined by qRT-PCR. qRT-PCR analyses were performed on murine MSCs cultivated in proliferative medium for 7 days and on micro-grafts obtained from murine auricular cartilage. The graph shows the fold induction of gene expression expressed in arbitrary units. Statistical significance values are indicated as *: p < 0.05, **: p < 0.01.

Figure 2

(A,B): Hoechst 33342 staining on micro-grafts suspension obtained from human auricular cartilage. (*) represents single nuclei cells, while (**) represents clusters of micro-grafts containing small groups of living cells. Magnification at 20×. (C): Gene expression analysis of the indicated specific markers as determined by qRT-PCR. qRT-PCR analyses were performed on human MSCs cultivated in proliferative medium for 7 days and on micro-grafts obtained from auricular cartilage. The graph shows the fold induction of gene expression expressed in arbitrary units. Statistical significance values are indicated as *: p < 0.05, **: p < 0.01.

Figure 3

(A) Pre-operative situation of patient affected by bilateral external and internal nasal valve collapse with nasal obstruction produced by excessive resection during previous surgery. (B) Post-operative situation after 12 months of the same patient treated with condrocyte micro-grafts obtained by Rigeneracons^® (CE certified Class I) mixed with platelet-rich plasma (PRP) in solid form. The authors used septum cartilage cut in the strips, processed by Rigenera^® Centrifuge. These composite grafts provided functional support to the alar cartilages. Trans-columellar open-tip access was necessary to allow for better visualization of the valve collaspe, alar cartilage, and for the fixation of the cartila.

Figure 4

(A) CT scans show the pre-operative situation with bilateral soft tissue defect of nasal tip and cartilage collapse. In addition, nasal septum deviation was detected. (B) CT scans of the same area after 12 months show the regenerated site in the post-operative image with soft tissue volume improvement and the correction of the nasal septum deviation.