Rheumatoid Arthritis (RA) is the most common and most severe of the inflammatory joint diseases affecting about 1% of the adult population while Osteoarthritis (OA) is the most common degenerative joint disorder affecting a large proportion of the elderly population aged above 60 years.
Despite the very effective biological therapeutics developed in the past decade for treatment of RA and other chronic inflammatory conditions definite cure of RA is still not possible and treatment of OA is mainly conservative and largely ineffective because regeneration of cartilage tissue cannot be achieved. Therefore, balneotherapy, and particularly sulphur spa therapy is still widely used for treatment of this disease. However, the clinical efficacy is uncertain because studies are rare, often underpowered and have sometimes led to controversial results. Moreover, the underlying molecular mechanisms have so far not been investigated in great detail and are therefore still poorly understood. Nevertheless, interest in the mode of action of H2S has increased in recent years when it became evident that H2S is a natural gaseous transmitter molecule comaprable to nitric oxide.