Transplantation of olfactory ensheathing cells into spinal cord lesions restores breathing and climbing

Abstract

One of the most devastating effects of damage to the upper spinal cord is the loss of the ability to breathe; patients suffering these injuries can be kept alive only with assisted ventilation. No known method for repairing these injuries exists. We report here the return of supraspinal control of breathing and major improvements in climbing after the application of a novel endogenous matrix transfer method. This method permits efficient transfer and retention of cultured adult rat olfactory ensheathing cells when transplanted into large lesions that destroy all tracts on one side at the upper cervical level of the adult rat spinal cord. This demonstrates that transplantation can produce simultaneous repair of two independent spinal functions.

Fig. 1.

Horizontal sections through the mid-dorsoventral level of the spinal cord (top is rostral, left edge is the lateral edge of the spinal cord). A, Thionin; arrows indicate midline. B, Confocal image of the boxed area in Afrom an adjacent section stained with neurofilament immunohistochemistry (green) and counterstained with propidium iodide (red). Section thickness is 20 μm; survival time, 2 months. Scale bars: A, 250 μm;B, 100 μm.

Fig. 2.

Transplanted OECs labeled with an adenoviral GFP construct form a large and dense meshwork in the lesioned area at 3 d (A) and 10 d (B) after operation, by which time the cells have adopted an elongated shape, aligned rostrocaudally. This shows that the cells are efficiently retained and remain clustered in the transplant site. Confocal image, green fluorescence, OECs; counterstain propidium iodide, red. Section thickness, 100 μm. Scale bar, 100 μm.

Fig. 3.

The extent of the hemisections is plotted ingray on the left, with the medial boundary of the lesions marked. Each line represents a different animal. A, Lesions that spare the ventral white columns (**) also spare respiratory rhythm in the ipsilateral phrenic nerve.B, Lesions that abolish the rhythm. C, Transplanted lesioned rats in which the hemisections are equal to or larger than those in B, but the rhythm is present because of the presence of the transplants. Scale bar, 1 mm.D, Electrophysiological recording of the rhythmic compound action potential from the phrenic nerve in unoperated animals (“intact controls” shows two representative cases). The rhythm is abolished in animals with complete hemisections that include the ipsilateral ventral funiculus (B); “lesions alone” shows a representative 5 of this group of 14. The rhythm is present in 19 animals (C shows 5 representative cases) that have equally complete or even larger lesions but that also received transplanted OECs (“lesions with transplants”).Left column shows recordings made during spontaneous breathing. Right column shows recordings after curarization and 20–50 sec of asphyxia.

Fig. 4.

The extent of the hemisections, represented as in Figure 3. A, Lesions that give a lower climbing fault score (79 ± 15) and spare the region (***) of the dorsal columns and corticospinal tract. B, Lesions that are complete hemisections and give the highest fault scores (226 ± 18).C, Transplanted lesions with complete hemisections in which the fault score (55 ± 7) is reduced by the presence of the transplants. Scale bar, 1 mm. D, E, Faults in the use of the ipsilateral forepaw for climbing. The total fault score for two measured test climbs (average of 6 weekly tests) for the 14 individual animals in the lesion-alone group (D, gray bars) and the 23 individual animals in the lesion plus transplant group (E, black bars) is shown; inset compares group means ± SEM for lesion-alone (LES, gray), lesion plus transplant (TRA, black), and normal, unoperated (N).