Implanted Phrenic Stimulation Impairs Local Diaphragm Myofiber Reinnervation in Amyotrophic Lateral Sclerosis

Diaphragm pacing compared with mechanical ventilation in patients with chronic respiratory failure caused by diaphragmatic dysfunction: a systematic review and meta-analysis

BACKGROUND

The effectiveness of diaphragmatic electrical stimulation (DES) compared to mechanical ventilation (MV) in improving clinical outcomes such as quality-of-life (QOL) and hospital stay remains inconsistent.

METHODS

We conducted a systematic review and meta-analysis by searching PubMed, Scopus, Google Scholar, LILACS, and IEEE Xplore. We included comparative studies (randomized controlled trials and observational studies) of DES administered via the phrenic nerve or intramuscular electrodes, compared with MV in adults with diaphragmatic paralysis or paresis. Two authors independently extracted data and assessed bias, with discrepancies resolved by a senior author. Results were pooled using the inverse variance method.

RESULTS

Out of 1,290 articles, nine were included in the systematic review, totaling 852 subjects. In spinal cord injury (SCI), one study reported lower mortality with DES, while three found no difference compared to MV. In these patients, DES was associated with shorter hospital stay, similar QOL, and heterogeneous results on respiratory infections. In amyotrophic lateral sclerosis (ALS), DES was associated with higher mortality and similar QOL compared to MV. Most SCI studies had a serious risk of bias.

CONCLUSION

DES shows potential in reducing hospital stay and respiratory infections in SCI but is associated with higher mortality in ALS.

An optogenetic cell therapy to restore control of target muscles in an aggressive mouse model of amyotrophic lateral sclerosis

Breakdown of neuromuscular junctions (NMJs) is an early pathological hallmark of amyotrophic lateral sclerosis (ALS) that blocks neuromuscular transmission, leading to muscle weakness, paralysis and, ultimately, premature death. Currently, no therapies exist that can prevent progressive motor neuron degeneration, muscle denervation, or paralysis in ALS. Here, we report important advances in the development of an optogenetic, neural replacement strategy that can effectively restore innervation of severely affected skeletal muscles in the aggressive SOD1G93A mouse model of ALS, thus providing an interface to selectively control the function of targeted muscles using optical stimulation. We also identify a specific approach to confer complete survival of allogeneic replacement motor neurons. Furthermore, we demonstrate that an optical stimulation training paradigm can prevent atrophy of reinnervated muscle fibers and results in a tenfold increase in optically evoked contractile force. Together, these advances pave the way for an assistive therapy that could benefit all ALS patients.