Diaphragmatic reconstruction with autologous tendon engineered from mesenchymal amniocytes

Presented at the 55th Annual Meeting of the Section on Surgery of the American Academy of Pediatrics, New Orleans, Louisiana, October 31-November 2, 2003.
https://doi.org/10.1016/j.jpedsurg.2004.02.014Get rights and content

Abstract

Purpose

This study examined the effects of amniocyte-based engineered tendons on partial diaphragmatic replacement.

Methods

Ovine mesenchymal amniocytes were labeled with green fluorescent protein (GFP), expanded, and seeded into a collagen hydrogel. Composite grafts (20 to 25 cm2) based on acellular dermis (group I), or acellular small intestinal submucosa (group II) received either a cell-seeded or an acellular hydrogel within their layers. Newborn lambs (n = 20) underwent partial diaphragmatic replacement with either an acellular or a cellular autologous construct from either group. At 3 to 12 months’ postoperatively, implants were subjected to multiple analyses.

Results

Diaphragmatic hernia recurrence was significantly higher in animals with acellular grafts (5 of 5) then in animals with cellular ones (1 of 4) in group I (P < .05) but not in group II (3 of 6 and 4 of 5, respectively). Cellular grafts had higher modular (5.27 ± 1.98 v. 1.27 ± 0.38 MPa) and ultimate (1.94 ± 0.70 v. 0.29 ± 0.05 MPa) tensile strength than acellular implants in group I (P < .05), but not in group II. Quantitative analyses showed no differences in extracellular matrix components between cellular and acellular implants in either group. All cellular implants showed GFP-positive cells.

Conclusions

Diaphragmatic repair with an autologous tendon engineered from mesenchymal amniocytes leads to improved mechanical and functional outcomes when compared with an equivalent acellular bioprosthetic repair, depending on scaffold composition. The amniotic fluid may be a preferred cell source for engineered diaphragmatic reconstruction.

Section snippets

Materials and methods

The current study was approved by the Harvard Medical School Standing Committee on Animals, under protocol # 03354.

Results

Fetal and neonatal survival rates were 100%. On gross inspection (Fig 1), diaphragmatic hernia recurrence was significantly higher in animals with acellular grafts (5 of 5) then in animals with cellular implants (1 of 4) in group I (P < .05), but not in group II (3 of 6 and 4 of 5, respectively). There was no evidence of chest wall deformity in either experimental group. Cellular grafts showed higher modulus (5.27 ± 1.98 v 1.27 ± 0.38 MPa; P < .05) and ultimate (1.94 ± 0.70 v 0.29 ± 0.05 MPa; P

Discussion

Three reasons led us to explore the concept of engineering a tendon, instead of a muscle patch, for diaphragmatic repair: (1) except for the rare cases of complete diaphragmatic agenesis, the native diaphragmatic muscle seems to develop and function normally in the majority of children with CDH (2) a sizeable portion of the normal diaphragm is comprised of a tendon, and (3) meaningful muscular function driven by substantial nerve ingrowth from the host is yet to be shown in engineered skeletal

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