An enzymatic debriding preparation was formulated with purified
enzyme derived from a crude pineapple stem extract. The primary component of this preparation was the sulfhydryl
protease ananain which represented >/=85% of the proteolytic activity. The remaining proteolytic activity in the preparation was contributed by a co-purifying homologous
cysteine protease comosain. Taken together these two
proteases provided a
protein purity of greater than 95% as judged by
sodium dodecyl sulfate polyacrylamide gel electrophoresis. This
ananain-based
enzyme preparation exhibited both gelatinolytic and fibrinolytic activity in vitro.
Ananain-based
enzyme preparation was formulated in a hydrophilic cream vehicle at concentrations ranging from 115 to 260 U/gm vehicle.
Ananain-based
enzyme preparation formulated in this fashion is referred to as Vianain debriding agent. Vianain was applied to partial-thickness cutaneous
burn wounds produced in the skin of domestic pigs. A maximum of two 4-hour applications of Vianain provided complete
debridement of eschar from the partial-thickness
burn wounds as judged by light and electron microscopic analyses of biopsy specimens harvested before and after
debridement.
Wounds debrided with Vianain exhibited more rapid reepithelialization as compared with
wounds that were not debrided.
Wounds on pigs that were hyperimmunized to
ananain-based
enzyme preparation before burning and
debridement with Vianain exhibited a similar enhancement in reepithelialization as compared with
wounds treated with vehicle alone. The capacity of Vianain to debride necrotic tissue was also evaluated in a guinea pig ischemic
ulcer model. Full-thickness ischemic lesions were created on the back of guinea pigs. Vianain was applied to the hardened necrotic tissue for 6 hours per day for up to a maximum of 5 days. Complete
debridement of these
wounds was accomplished within 4 to 5 days. Treatment of ischemic cutaneous ulcerations in this animal model with two commercially available
enzyme-debriding agents provided little or no
debridement of the necrotic tissue. In vitro, Vianain treatment of surgically debrided human tissue samples, obtained from patients with
burn injury or cutaneous
ulcers, showed that the
protease preparation was effective in rapidly digesting these necrotic tissues.