Pompe disease (PD) is an autosomal recessive disorder caused by absence of acid alpha-glucosidase (GAA). Enzyme replacement therapies do not address neural glycogen accumulation, and many patients still progress to respiratory failure. Adeno-associated virus (AAV) gene therapy offers the potential to effectively target skeletal and cardiac muscle, as well as the central nervous system (CNS). We recently reported that neonatal treatment with a single-dose AAV encoding GAA could prevent cardiorespiratory decline in a Gaa-/- rat PD model (PMID: 40518673). Herein, we compared several different AAV-based strategies for their ability to normalize respiratory waveform cluster patterns across the lifespan of PD rats. Three strategies were tested: 1) AAV9-Des, expressing GAA under a muscle-specific desmin promoter (rAAV9-des-H201L-coGAA at 1x1014 vector genomes (vg)/kg), at P1; 2) AAV9-Syn, using a neuron-specific synapsin promoter (rAAV9-Syn-H201L-coGAA at 1x1014 vg/kg) at P1; and 3) a dual-delivery approach, AAV9-Dual, where rAAV9-LSP-H201L-coGAA at 1x1014 vg/kg (LSP, liver-specific promoter) was given at P1 followed by AAV9-Des at 1 month (mo). Untreated Gaa-/- rats served as disease controls; Sprague Dawley rats served as wild-type (WT) controls. The waveforms generated by breathing during whole-body plethysmography (WBP) were captured at ages 6, 9, and 12mos. Using custom MATLAB scripts, waveforms were identified via a threshold-crossing method. Individual breaths were then sorted into breath duration-based arrays (0.0-0.2s, 0.2-0.5s, 0.5-1.2s, and 1.2-4s). Within each array, a dimensionality reduction (Principal Component Analysis) was applied, followed by hierarchical clustering to identify distinct waveform patterns. WT rats exhibited a heterogeneous inspiratory waveform cluster distribution that remained stable over 6-12mos age. Untreated Gaa-/- rats had less heterogeneity, with increased prevalence of low-amplitude inspiratory waveforms, indicating reduced breathing variability and increased reliance on low-volume breaths. At age 6mos, both the AAV9-Syn and AAV9-Dual treatments produced WT-like cluster distributions, including the dominant WT waveform cluster. AAV9-Des treatment showed partial heterogeneity of clusters but remained biased toward low-amplitude breaths. At 9mos, AAV9-Syn and AAV-Dual continued to show mixed clustering, but favoring waveforms with steeper inspiratory rise slopes, while AAV9-Des rats still displayed predominant low-amplitude types. By 12mos, all three treatments demonstrated broad WT-like waveform diversity. Notably, AAV9-Des rats transitioned to a WT-like cluster pattern, consistent with ventilatory data showing long-term correction and biochemical analysis showing strong GAA expression in the diaphragm and CNS. We conclude that AAV9-Syn and AAV9-Dual produce early normalization of respiratory patterns, whereas AAV9-Des provides a slower but ultimately near-complete restoration of breathing by 12mos. These data underscore the value of full motor-unit targeting therapies to support long-term respiratory recovery in PD. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.
Grams et al. (Fri,) studied this question.