Oral therapy with proteolytic enzymes decreases excessive TGF-β levels in human blood

Therapy with oral proteolytic enzymes (OET) with combination drug products containing papain, bromelain, trypsin, and chymotrypsin has been shown to be beneficial in clinical settings such as radiotherapy-induced fibrosis, bleomycin pneumotoxicity and immunosuppression in cancer, all of which are nowadays known to be accompanied by excessive transforming growth factor-beta (TGF-beta) production. It has been demonstrated that proteolytic enzymes reduce TGF-beta levels in serum by converting the protease inhibitor alpha2 macroglobulin (alpha 2M) from the "slow" form into the "fast" form, whereby the "fast" form binds and inactivates TGF-beta irreversibly. In this study we have investigated the effect of OET on the concentration of TGF-beta in serum of patients with rheumatoid arthritis (RA) (n = 38), osteomyelofibrosis (OMF) (n = 7) and herpes zoster (HZ) (n = 7). Seventy-eight healthy volunteers served as controls. TGF-beta levels in serum were assessed by enzyme-linked immunosorbent assay (ELISA). We have demonstrated that in healthy volunteers and in patients there exists a correlation between active and latent TGF-beta in serum (r = 0.8021; P < 0.0001). Treatment with OET had no significant effect on TGF-beta1 concentration in healthy volunteers or patients with a normal level of TGF-beta. In patients with elevated TGF-beta1 concentration (> 50 ng/ml serum), OET reduced TGF-beta1 in RA (P < 0.005), in OMF (P < 0.05) and in HZ (P < 0.05). Conclusion: These results support the concept that OET is beneficial in diseases characterized in part by TGF-<beta>1 overproduction.