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Enzymatic activity toward poly(L-lactic acid) implants.
J M Schakenraad1, M J Hardonk, J Feijen
1University of Groningen, Department of Histology and Cell Biology, The Netherlands.
Journal of Biomedical Materials Research
|May 1, 1990
Summary
Biodegradable poly(L-lactic acid) implants show good tissue compatibility. Enzyme activity patterns confirm a mild foreign body response and the polymer's biodegradable nature, indicated by lactic acid release.
Area of Science:
- Biomaterials Science
- Tissue Engineering
- Enzymology
Background:
- Assessing tissue response to biodegradable implants is crucial for medical applications.
- Poly(L-lactic acid) (PLLA) is a widely used biodegradable polymer in biomedical devices.
- Understanding cellular enzymatic activity provides insights into implant-tissue interactions.
Purpose of the Study:
- To investigate the enzymatic profiles of cellular responses to PLLA implants.
- To differentiate between normal wound healing and foreign body reactions.
- To confirm the biodegradability of PLLA through enzymatic markers.
Main Methods:
- Implantation of PLLA in a study model.
- Monitoring of seven key enzyme activities (alkaline phosphatase, acid phosphatase, esterase, beta-glucuronidase, ATP-ase, NADH-reductase, lactate dehydrogenase) over time.
- Cell type identification using enzyme patterns, morphology, and location.
Main Results:
- Early influx of granulocytes with specific enzyme activities (alkaline phosphatase, beta-glucuronidase).
- Macrophages exhibiting ATP-ase, acid phosphatase, and esterase from day 3.
- Increased lactate dehydrogenase (LDH) and NADH-reductase in macrophages and fibroblasts from day 7, exceeding levels seen with inert materials.
- Overall, a mild foreign body reaction with minor macrophage and giant cell activity observed over 3 weeks.
Conclusions:
- PLLA demonstrates good tissue compatibility.
- The observed enzyme patterns are primarily indicative of wound healing.
- Elevated LDH and NADH-reductase levels suggest lactic acid release, confirming PLLA biodegradability.