Abstract
Fortetropin® in a Rodent Model of FSHD: A Preclinical Assessment of Muscle Mass, Performance, and Muscle Remodeling Potential
Abstract
Facioscapulohumeral muscular dystrophy (FSHD) is a progressive neuromuscular disorder characterized by muscle wasting and impaired functional capacity. This study evaluated the effects of Fortetropin®, on muscle mass and performance in a rodent model of FSHD. Fortetropin-treated animals demonstrated significant increases in total muscle mass and improved treadmill performance compared to vehicle-treated diseased controls. While no changes in total force production were seen, these results suggest early anabolic activity, supporting the rationale for extended-duration studies.
Introduction
FSHD represents one of the most common forms of muscular dystrophy, with no currently approved therapies to halt or reverse disease progression. Muscle wasting and loss of functional endurance are central to its pathology. Fortetropin®, a bioactive compound derived from fertilized egg yolk, has been shown in prior studies to modulate myostatin levels and promote muscle growth. The present study assesses Fortetropin’s effect in a validated rodent model of FSHD.
Methods
Study Design
Mice were randomized into three groups (n=10 per group) and monitored for 4 weeks:
- Control: Healthy animals with no disease
- Vehicle: FSHD transgenic animals, treated with vehicle
- Fortetropin: FSHD transgenic animals receiving oral Fortetropin supplementation
Animals were assessed for gastrocnemius muscle mass, muscle force, and functional treadmill performance.
Results
Muscle Mass (gastrocnemius)
- Control: 0.148 ± 0.0114 g
- Vehicle: 0.098 ± 0.009 g
- Fortetropin: 0.109 ± 0.012 g
- Statistical comparison: Fortetropin vs. Vehicle, p = 0.0387 → Fortetropin produced a +12% increase in total muscle mass compared to untreated FSHD animals, indicating a statistically significant anabolic effect
Maximal Plantarflexion Muscle Force
- Control: 180 ± 20 mN
- Vehicle: 121 ± 20 mN
- Fortetropin: 118 ± 11 mN → Fortetropin did not demonstrate differences between disease groups.
Treadmill Running Distance and Time
- Control: 694 ± 114 meters
- Vehicle: 560 ± 118 meters
- Fortetropin: 734 ± 100meters
- Statistical comparison: p = 0.0022
- Control: 47.3 ± 6.5 minutes
- Vehicle: 40.0 ± 6.7 minutes
- Fortetropin: 48.7 ± 5.7 minutes
- Statistical comparison: p = 0.0064 → Fortetropin significantly increased forced running distance and time, indicating improved endurance and stamina.
Discussion
Early Efficacy Signals
Fortetropin induced measurable gains in total muscle mass and functional endurance within a relatively short study period. The absence of significant differences in muscle function suggests that tissue remodeling may lag behind mass and performance improvements in early-stage intervention.
Scientific Rationale for Longer Studies
- Myofiber hypertrophy, satellite cell activation, and extracellular remodeling typically require extended treatment durations to manifest in functional force improvements.
- Improvements in treadmill performance indicate neuromuscular efficiency and resilience, which often precede structural changes.
- Agents like Fortetropin, which influence myostatin inhibition and protein synthesis, have shown time-dependent effects in other muscle-wasting models.
Why Functional Gains Matter
Functional outcomes such as treadmill distance and endurance time are critical proxies for patient mobility and quality of life. That Fortetropin-treated animals exceeded healthy controls in distance suggests a physiologically meaningful improvement, not merely statistical noise.
Conclusion
Fortetropin demonstrated statistically significant improvements in total muscle mass, and treadmill running performance in an FSHD rodent model. Despite lack of muscle force improvements these outcomes strongly suggest early-stage muscle preservation and metabolic efficiency. These results support further investigation of Fortetropin in longer-duration preclinical studies and potentially in clinical development as a muscle-preserving therapeutic agent for neuromuscular diseases like FSHD.