A new source of cells contributing to the developing gastrointestinal tract demonstrated in chick embryos

Background & Aims: Smooth muscle cells in the walls of the gastrointestinal tract are thought to derive solely from mesoderm surrounding the primitive gut. A population of neuroepithelial cells has recently been shown to migrate from the ventral part of the neural tube in the region joined by the vagus nerve. We sought to determine if these cells contributed to the development of the stomach and intestine. Methods: Cells of the ventral hindbrain of chick embryos were tagged by replication-deficient retroviral vectors containing the lacZ gene, providing a permanent label that is transmitted without dilution as the cells divide. Embryos were processed for detection of labeled cells. Specific markers were used to determine differentiation of progeny in the gastrointestinal tract. Results: Cells labeled in the ventral neural tube migrate in association with the vagus nerve. Labeled cells are found in the intestine and stomach after time for further migration and differentiation. Using a specific marker, they were clearly identified as smooth muscle cells. Conclusions: Some of the smooth muscle cells of the gastrointestinal tract are derived from precursor cells that originate in the ventral part of the hindbrain neural tube. Their developmental importance and functional significance remain to be determined.