Valsartan Gel Helps Treat Chronic Diabetic Wounds

A topical gel made from the angiotensin type 1 receptor blockers (ARB) valsartan is effective in healing chronic skin wounds, according to a new study.

Researchers at Johns Hopkins University (JHU; Baltimore, MD, USA) and Vanderbilt University (Nashville, TN, USA) conducted a study to determine the effects of topical reformulations of the ARBs losartan and valsartan, and the angiotensin-converting enzyme (ACE) inhibitor captopril, on wound healing in diabetic and aged mice by applying the gels directly to wounds, thus increasing wound tissue level of the drugs. ARBs and ACE inhibitors block the renin-angiotensin system (RAS) and increase wound blood flow.

The results showed that valsartan was more effective in accelerating wound healing than losartan, without any significant difference in healing time between valsartan doses. Overall, a 1% valsartan gel had the greatest impact on total closure compared with the other agents, while 10% losartan led to the worst wound healing, which was attributed to toxicity. The final results showed that half of all mice that received 1% valsartan achieved complete wound healing, while only 10% of the mice given the placebo did.

The researchers then tested the valsartan gel on wounds in aged, diabetic pigs, since pig skin has more similar properties to human skin. The results showed that the pigs that received 1% valsartan healed much more quickly, and all 12 wounds were closed by day 50, compared with none of the placebo-treated wounds. The pigs treated with valsartan also had a thicker epidermal and dermal collagen layer, as well as a more organized collagen fiber arrangement. The study was published on October 16, 2017, in the Journal of Investigative Dermatology.

“Our strategy for specifically targeting the biology that underlies chronic wounds in diabetics and older adults differs greatly from other approaches to wound care thus far. The topical gel likely enables a cascade of positive biological effects that facilitates and accelerates chronic wound healing,” said senior author professor Jeremy Walston, MD, of JHU. “Now that we've proven efficacy in animals, we're moving on to the next stage of FDA-required testing in humans. Hopefully, this medication will be available for public use in a few years, if further research bears out our results.”

Diabetes patients often suffer from nerve and circulation problems in the feet, which reduce their perception of pain. The nerve pathways that ensure that weight is automatically transferred from one foot to the other during prolonged standing are disrupted, and as a result, diabetics do not notice that their toes, heels, or the balls of their feet are too heavily loaded. The foot receives no relief, and pressure sores, ulcers, and infections may go unnoticed.

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