We have read your article entitled “The Beneficial Effects of Doxycycline, An Inhibitor of Matrix Metalloproteinases, on Sulfur Mustard-Induced Ocular Pathologies Depend on the Injury Stage” with great interest.Citation1 We would like to make a contribution to the article in terms of clinical practice.
In acute phase (0–7 days) of a chemical ocular injury; re-epithelization and excessive inflammatory response are the main characteristics. Epithelium is essential for patient comfort, preventing infections as well as keeping the enzymes of tear film from eroding the stroma. Epithelium also has modulator functions upon keratocytes’ collagen synthesis. Stromal remodeling usually begins in the early reparative phase (8–20 days) but not in the acute phase.Citation2 Therefore; minimizing the topical medications (including doxycycline (DC) which is more likely to be ineffective in this period) in order not to slow down re-epithelization is critical in this phase.
DC and minocyclines are the subgroup of tetracyclines and known for their reliable oral absorbsion.Citation3 Smith et al.Citation4 revealed that though oral DC does not reach tear film, it indirectly inhibits matrix metalloproteinases or the synthesis of these enzymes and interleukin-1 from corneal epithelial cells. Also SalminenCitation5 reported good penetrability of parenteral DC into the ocular compartments including cornea due to it’s lipophilic nature. These data suggest that oral administration of DC can provide sufficient desired activity.
Sulfur mustard is a chemical warfare agent. like alcaline chemicals, it penetrates tissues easily and leads to liquefaction necrosis in all parts of the body as well as ocular tissues. So, in case of a chemical assault in the battefield or upon a settlement causing hundreds of casualties; it woluld be more rational to choose oral administration. In addition; oral usage facilitates the recovery of the other organs and systems as well.
As a conclusion; it seems more reasonable to use DC orally especially in the acute phase of the injury.
Declaration of interest
None of the authors has conflict of interest with the submission.
The authors of this study did not receive any financial support for this submission.
The authors have no proprietary interests for the materials mentioned in the study.
References
- Horwitz V, Dachir S, Cohen M, Gutman H, Cohen L, Fishbine E, et al. The beneficial effects of doxycycline, an inhibitor of matrix metalloproteinases, on sulfur mustard-induced ocular pathologies depend on the injury stage. Curr Eye Res 2014;39:803–812
- McCulley JP. Chemical injuries. In: Smolin GTR, editor. The cornea: scientific foundation and clinical practice. Boston: Little BaC. 1983:422--435
- Agwuh KN, MacGowan A. Pharmacokinetics and pharmacodynamics of the tetracyclines including glycylcyclines. J Antimicrob Chemother 2006;58:256–265
- Smith VA, Khan-Lim D, Anderson L, Cook SD, Dick AD. Does orally administered doxycycline reach the tear film? Br J Ophthalmol 2008;92:856–859
- Salminen L. Penetration of ocular compartments by tetracyclines. II. An experimental study with doxycycline. Albrecht Von Graefes Arch Klin Exp Ophthalmol 1977;204:201–207