Understanding Dysphagia: A Growing Challenge in Canada

Dysphagia, or difficulty swallowing, affects daily life profoundly, leading to risks like choking, malnutrition, and aspiration pneumonia. In Canada, self-reported swallowing difficulties impact about 10.6% of adults over 45, rising to 13.7% over time, with seniors aged 50+ facing 15-22% prevalence. Head and neck cancer (HNC) survivors experience even higher rates, up to 20-70% long-term, while aging exacerbates muscle degeneration in the pharynx and esophagus. These statistics underscore the urgent need for innovative regenerative solutions.

Limitations of Current Dysphagia Treatments

Today's approaches focus on symptom management: speech-language pathology exercises like the Mendelsohn maneuver or effortful swallows strengthen muscles; neuromuscular electrical stimulation (NMES) aids coordination; and dietary modifications—thicker liquids or soft foods—reduce risks. Surgery, such as esophageal myotomy, is reserved for severe cases. However, these do not repair damaged muscle tissue directly, leaving many patients with persistent issues.

McGill University’s Game-Changing Nanogel Innovation

Researchers at McGill University, in collaboration with Kyoto University, have pioneered an injectable hybrid system combining stem cells with nanogels to regenerate swallowing muscles. This breakthrough, detailed in Biomaterials, addresses stem cell therapy's key flaw: poor survival post-injection.

How the Nanogel Works: Engineering for Optimal Delivery

Nanogels are tiny, crosslinked polymer networks—here, derived from cholesterol-bearing pullulan (a polysaccharide) modified with acryloyl groups (CHPA nanogels). Using 'click' chemistry (rapid, bioorthogonal reactions), they form stable microfiber fragments (NG-MF). These act as porous spacers in 3D spheroids made with adipose-derived mesenchymal stem cells (ADSCs), harvested from fat tissue. The spheroids, refined to 100μm for injectability, enhance oxygen diffusion, preventing core cell death (necrosis).

Lab Breakthroughs: Boosted Cell Viability and Secretion

In vitro tests showed hybrid spheroids achieving 5.6-fold higher viability than cell-only ones. They secreted more regenerative factors: interleukin-6 (IL-6, inflammation modulator), IL-10 (anti-inflammatory), and hepatocyte growth factor (HGF, promotes repair). Viscoelastic properties mimicked native tissue, ensuring injectability without losing function.

Animal Model Success: Real Muscle Regeneration

In rats with swallowing muscle injury (sternohyoid model), hybrid injections yielded 20.8% better cell engraftment, reduced fibrosis (scarring), faster myogenin expression (muscle differentiation marker), and 9-10% improved electromyography (EMG) amplitude for contraction. Lead author Hideaki Okuyama noted: "Smart material design unlocks stem cells' full potential."

The Research Team: McGill-Kyoto Synergy

Spearheaded by McGill's Nicole Y.K. Li-Jessen (Canada Research Chair in Laryngeal Tissue Engineering), Luc Mongeau, and Jianyu Li, with Kyoto's Yo Kishimoto and Kazunari Akiyoshi. This interdisciplinary effort blends biomedical engineering, biomaterials, and otolaryngology. McGill's animal protocols (MCGL-8275) ensured ethical rigor.

Implications for Canadian Patients and Healthcare

With Canada's aging population (20% over 65 by 2030) and 15,000+ annual HNC cases, this could transform care. Reduced pneumonia hospitalizations (dysphagia-linked in 50% of cases) might save millions. Speech-language pathologists note S-LPs lead dysphagia management across settings. For HNC survivors, long-term prevalence drops from 27%+ could improve quality of life.

Comparing to Existing Therapies: A Regenerative Leap

• Exercises/NMES: Strengthen but don't regenerate; 50-70% partial success.
• Diet Mods: Palliative, risk malnutrition.
• Surgery: Invasive, for end-stage.
• New Gel: Targets root cause—muscle repair via stem cells + scaffold.

Hybrid approach outperforms cell-only by addressing migration/necrosis.

Path to Clinic: Trials and Broader Applications

Next: long-term studies, human trials. Potential for other muscles (heart, limbs), sarcopenia. McGill's VUA lab advances laryngeal/upper airway regen.Phys.org coverage highlights scalability.

McGill’s Leadership in Canadian Biomedical Research

McGill, a top Canadian research powerhouse, invests in tissue engineering. This aligns with CIHR funding priorities, positioning Canada in global regen med. Students/faculty opportunities abound in bioeng.

Photo by CDC on Unsplash

Future Outlook: Transforming Lives Through Innovation

This McGill breakthrough promises safer swallowing for thousands, reducing healthcare burdens. As Okuyama states, it overcomes transplantation barriers. Watch for trials—regen med's future is injectable.