Expression of Endothelin-1, Endothelin Receptor-A, and Endothelin Receptor-B in facial melasma compared to adjacent skin.

Background/objectives: Although melasma is highly prevalent, its pathogenesis is not yet fully understood. In the skin, endothelin-1 (ET-1) is primarily produced by keratinocytes in response to UVB exposure, which is mediated by an increase in IL-1α or reactive oxygen species. ET-1 plays a role in melanogenesis by binding to specific receptor B (ERB) or receptor A (ERA).

Update on Melasma-Part II: Treatment.

Melasma is a prevalent chronic relapsing pigmentary disorder that affects photoexposed areas, especially in women of childbearing age. Although there is currently no curative treatment available for melasma, this manuscript critically reviews the knowledge regarding photoprotection, topical and oral therapies, and procedures such as peelings, laser, and microneedling that represent the main strategies for control and prevention of this disease. As the pathogenesis of melasma is not entirely understood, there are prospects for the development of new therapeutic strategies that might act on the pathways that promote sustained pigmentation rather than merely decreasing melanin synthesis and removing melanin from the epidermis.

Update on Melasma-Part I: Pathogenesis.

Melasma is a multifactorial dyschromia that results from exposure to external factors (such as solar radiation) and hormonal factors (such as sex hormones and pregnancy), as well as skin inflammation (such as contact dermatitis and esthetic procedures), in genetically predisposed individuals. Beyond hyperfunctional melanocytes, skin with melasma exhibits a series of structural and functional alterations in the epidermis, basement membrane, and upper dermis that interact to elicit and sustain a focal hypermelanogenic phenotype. Evolution in the knowledge of the genetic basis of melasma and the cutaneous response to solar radiation, as well as the roles of endocrine factors, antioxidant system, endothelium proliferation, fibroblast senescence, mast cell degranulation, autophagy deficits of the melanocyte, and the paracrine regulation of melanogenesis, will lead to the development of new treatments and preventive strategies.

From the PnTx2-6 Toxin to the PnPP-19 Engineered Peptide: Therapeutic Potential in Erectile Dysfunction, Nociception, and Glaucoma.

The venom of the "armed" spider comprises several potent toxins. One of the most toxic components from this venom is the neurotoxin PnTx2-6 (LD = ∼ 0.7 μg/mouse, 48 residues, five disulfide bridges, MW = 5,289.

Intravitreal ketamine promotes neuroprotection in rat eyes after experimental ischemia.

Retinal ischemia, one of the most common cause of visual loss, is associated with blood flow inadequacy and subsequent tissue injury. In this setting, some treatments that can counteract glutamate increase, arouse interest in ischemic pathogenesis. Ketamine, a potent N-methyl-d-aspartate (NMDA) receptor antagonist, provides a neuroprotective pathway via decreasing the excitotoxicity triggered by excess glutamatergic.

Intravitreal injection of peptides PnPa11 and PnPa13, derivatives of spider venom, prevents retinal damage.

Background: PnPa11 and PnPa13 are synthetic peptides derived from spider venom, which display antinociceptive and neuroprotective properties. In this work, we evaluated the safety of intravitreal use and the neuroprotective effect of these peptides.

Methods: The cytotoxicity and the antiangiogenic activity of these peptides were evaluated by the sulforhodamine-B method and chicken chorioallantoic membrane (CAM) assay, respectively.

PnPP-19 Peptide as a Novel Drug Candidate for Topical Glaucoma Therapy Through Nitric Oxide Release.

Purpose: Evaluation of PnPP-19 safety and efficacy in reducing the intraocular pressure (IOP) of animals with healthy (normotensive) and ocular hypertensive eyes. PnPP-19 is a synthetic peptide designed from spider toxin PnTx2-6.

Methods: Toxicity tests used chicken chorioallantoic membranes.

Assessment of the safety of intravitreal injection of metoprolol tartrate in rabbits.

Purpose: To verify the safety of different doses of intravitreal metoprolol tartrate (MT) after intravitreal injection in rabbit eyes.

Methods: Animals were randomly assigned into 2 groups: group I received 50 µg of MT and group II 100 µg of MT. A volume of 0.

The proteolytic fraction from Vasconcellea cundinamarcensis accelerates wound healing after corneal chemical burn in rabbits.

Introduction: Chemical ocular burns are among the most frequently eye-related injuries, which require immediate and intensive evaluation and care since they may lead to potential complications such as superinfection, corneal perforation, and blindness.Vasconcellea cundinamarcensis, a species from Caricaceae family, contains highly active proteolytic enzymes in its latex that show healing activity in animal models bearing lesions of different etiologies.

Methods: We evaluate the ocular toxicity of the proteolytic fraction from V.

Crotoxin from Crotalus durissus terrificus snake venom induces the release of glutamate from cerebrocortical synaptosomes via N and P/Q calcium channels.

Crotoxin (Crtx), the main toxin in the venom of Crotalus durissus terrificus snake, is a heterodimer with a basic subunit, CB, and an acidic subunit, CA. CB is a phospholipase A2 that depends on CA to specifically bind to the cell membrane. This toxin acts in the central nervous system (CNS) causing chronic seizure effects and other cytotoxic effects.