This patent covers the use of zFGF-5 (currently known as FGF-18) for expansion in vitro and in vivo of chondrocytes and neural stem cells. According to the Zymogenetics website, FGF-18 is out-licensed to Serono for use in cartilage repair and stroke. The product is in preclinical phases of testing.
While the specification provides numerous uses for FGF-18, the claims are restricted to one independent claim covering a method of augmenting cartilage deposition through administration of FGF-18 and various homologous thereof. The independent claim describes the use for treating injury of: fibrocartilage, hyaline, or elastic cartilage.
Fibrocartilage is comprised of mixture of fibrous and cartilaginous tissue. The fibrous tissue endows structural strength, whereas the cartilaginous tissue endows elasticity. There are 4 types of fibrocartilage: interarticular, connecting, circumferential, and stratiform. Fibrocartilage is found in symphyseal joints, intervertebral and articular discs.
Hyaline cartilage is found in joints (articular cartilage) and inside bones. When bones are injured, hyaline cartilage is often replaced by fibrocartilage, which can not bear weight as efficiently.
Elastic cartilage is found in areas such as the epiglottis, the pinna of the ear, and the walls of the auditory canal.
The dependent claims cover the use of FGF-18 for treating conditions such as osteoarthritis, rheumatoid arthritis, and traumatic injury.
The examples section of the patent provides several interesting uses for FGF-18, including:
1. Treatment of cardiomyopathy. What appears to be a prophetic example, describes the induction of cardiomyopathy by either chronic catecholamine injection, or ligation of the coronary artery, and treatment of this condition through administration of FGF-18. However, in Example 14, this experiment is actually performed, and reduction of cardiomyopathy is seen.
2. Increasing bone density. Adenovirally delivered FGF-18 appeared to increase bone density in CD-1 mice.
3. In vitro neural stem cell proliferation.
4. Stimulation of bone marrow cell proliferation.
5. Stimulation of osteogenesis.