Topical timolol in dermatology: infantile hemangiomas and beyond

Mechanism and application of β-adrenoceptor blockers in soft tissue wound healing

Soft tissue damage stimulates sympathetic nerves to release large amounts of catecholamine hormones which bind to β-adrenergic receptors (β-ARs) on the cell membrane surface. It activates the downstream effector molecules and impairs soft tissue wound healing. β-blockers specifically inhibit β-ARs activation in acute/chronic skin lesions and ulcerative hemangiomas. They also accelerate soft tissue wound healing by shortening the duration of inflammation, speeding keratinocyte migration and reepithelialization, promoting wound contraction and angiogenesis, and inhibiting bacterial virulence effects. In addition, β-blockers shorten wound healing periods in patients with severe thermal damage by reducing the hypermetabolic response. While β-blockers promote/inhibit corneal epithelial cell regeneration and restores limbal stem/progenitor cells function, it could well accelerate/delay corneal wound healing. Given these meaningful effects, a growing number of studies are focused on examining the efficacy and safety of β-blockers in soft tissue wound repair, including acute and chronic wounds, severe thermal damage, ulcerated infantile hemangioma, corneal wounds, and other soft tissue disorders. However, an intensive investigation on their acting mechanisms is imperatively needed. The purpose of this article is to summerize the roles of β-blockers in soft tissue wound healing and explore their clinical applications.

In Vivo Study of the Effects of Propranolol, Timolol, and Minoxidil on Burn Wound Healing in Wistar Rats

Propranolol, timolol, and minoxidil have all shown benefits in treatment of burn injury and other skin wounds. The study evaluated their effects on full-thickness thermal skin burns in a Wistar rat model. Performed on 50 female rats; two dorsal skin burns were created on each animal. On the next day, the rats were divided into 5 groups (n = 10); each has received a specific treatment daily for 14 days: group I-topical vehicle (control), group II-topical silver sulfadiazine (SSD), group III-oral propranolol (5.5 mg) associated with topical vehicle, group IV-topical timolol 1% cream, and group V-topical minoxidil 5% cream. Wound contraction rates, malondialdehyde (MDA), glutathione (GSH, GSSG), and catalase activity in skin and/or serum were evaluated, and histopathological analyses were performed. Propranolol did not show advantages in necrosis prevention and wound contraction and healing, and did not reduce oxidative stress. It impaired keratinocyte migration, and promoted ulceration, chronic inflammation, and fibrosis, yet reducing the necrotic zone. Timolol prevented necrosis and promoted contraction and healing, increased antioxidant capacity and promoted keratinocyte migration and neo capillarization in comparison to the other treatments. Minoxidil reduced necrosis and enhanced contraction, resulting in positive outcomes after 1 week of treatment regarding local antioxidant defense, keratinocyte migration, neo capillarization, chronic inflammation, and fibrosis rates. However, after 2 weeks, it resulted in contrasting outcomes. In conclusion, topical timolol promoted wound contraction and healing, reducing local oxidative stress and improving keratinocyte migration, bringing arguments for potential benefits in skin epithelization.

Topical timolol maleate 0.5% after fractional carbon dioxide laser versus fractional carbon dioxide laser alone in treatment of acne scars: split face comparative study

Acne is a common inflammatory condition that mostly involves the face, chest and back. A number of different modalities had been employed for treating scars of which laser remains to be a pivotal choice. We aimed to compare the efficacy of topical timolol maleate 0.5% after fractional CO2 (AFCO2) laser versus fractional CO2 Laser alone for treatment of atrophic acne scars. A split-face comparative clinical experiment on 30 cases of atrophic post-acne scars that were treated on one side with ablative fractional CO2 laser followed by timolol application while with only ablative fractional CO2 laser on the other side. Following treatment, both sides demonstrated significant improvement with the laser + timolol treated side showing better improvement; yet not significantly higher than the laser only treated side. In conclusion, both topical timolol maleate 0.5% after fractional CO2 laser and fractional CO2 laser may achieve comparable significant improvement. The good safety profile, easy accessibility, low cost, and non-invasive nature merits the use of timolol in acne scars pending verification by larger sample reproduced and controlled trials.

Current state of the red scrotum syndrome

Red scrotum syndrome is a chronic, difficult-to-recognize dermatosis affecting middle-aged and elderly people. It is manifested by erythema of the scrotum with clear boundaries, without neck. The etiology and pathogenesis of the disease have not been established. Hypotheses about the causes of dermatosis as a consequence of uncontrolled use of topical steroids, neurological inflammation, formation of microbial biofilm are based on anamnestic data and the results of trial treatments. Etiologically and pathogenetically justified therapy has not been proposed. Therapy with the use of doxycycline, gabapentin, pregabalin, indomethacin, tacrolimus was carried out in small groups of patients. The lack of clarity in the etiology and understanding of the mechanism of development of the disease explains the lack of a unified focus of the proposed therapies based on isolated clinical cases. In general, the problem of diagnosis and treatment rests on the absence of major clinical, epidemiological and laboratory studies that allowed to establish the pathophysiology and assess the true prevalence of red scrotum syndrome.