Loxosceles and Loxoscelism: Biology, Venom, Envenomation, and Treatment

Málaque, Ceila Maria Sant’Ana; Chaim, Olga Meiri; Entres, Marlene; Barbaro, Kátia Cristina

doi:10.1007/978-94-007-6389-0_4

Cited by 5 publications

(15 citation statements)

References 55 publications

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“…Brown spiders of the genus Loxosceles (Heineken and Lowe, 1832) are globally distributed in temperate and tropical regions [1][2][3] . Bites by Loxosceles spp., clinically referred to as loxoscelism, are the main cause of envenomation by spiders of medical importance in Brazil and may result in local dermonecrosis with gravitational spreading (cutaneous-necrotic loxoscelism).…”

Section: Introductionmentioning

confidence: 99%

“…On rare occasions, severe systemic complications, such as massive intravascular hemolysis and acute kidney injury (AKI) (cutaneous-hemolytic loxoscelism) may occur. Although at least 19 species of Loxosceles have been described in Brazil, most bites occur in southern and southeastern Brazil and are caused by L. intermedia, L. laeta, and L. gaucho [2][3][4] .…”

Section: Introductionmentioning

confidence: 99%

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Temporal evolution of dermonecrosis in loxoscelism assessed by photodocumentation

Borrasca-Fernandes

Prado

Capitani

et al. 2022

Rev. Soc. Bras. Med. Trop.

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Background: Although loxoscelism (bites by brown spiders of the genus Loxosceles) frequently results in dermonecrosis, no previous clinical reports have provided detailed temporal photodocumentation of the evolution of dermonecrotic lesions in a case series. Methods:This was a retrospective cohort study involving a case series of loxoscelism. Only cases of dermonecrosis with photodocumentation of lesion evolution (from admission until complete or almost complete healing) were included.Results: Eight patients (six men, two women; median age, 38 years) fulfilled the inclusion criteria. The bite sites included the thigh (n = 4), forearm (n = 2), abdomen (n = 1), and trunk (n = 1). Time interval between the bite and first contact with our service ranged from 15 to 216 h (median = 29 h). The main clinical manifestations included local erythematous and ischemic violaceous lesions overlying a base of indurated edema (livedoid plaque, 8), local pain (8), exanthema (6), serohemorrhagic vesicles/blisters (5), fever (5), and jaundice (1). Based on a previously established classification, the cases were classified as probable cutaneous-necrotic loxoscelism (CNL, n = 4), presumptive CNL (n = 3), and presumptive cutaneous-hemolytic loxoscelism (n = 1). Seven patients were treated with anti-arachnidic antivenom (AV; median time post-bite = 46 h). Complete lesion healing ranged from 34 to 98 days post-bite (median, 68 days; six patients). None of the patients required reconstructive plastic surgery. Conclusions:The sequential photographic documentation showed considerable variation in the process of wound healing, with complete epithelialization requiring up to 3 months after the bite.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Temporal evolution of dermonecrosis in loxoscelism assessed by photodocumentation

Borrasca-Fernandes

Prado

Capitani

et al. 2022

Rev. Soc. Bras. Med. Trop.

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“…In addition, it is difficult to evaluate the efficacy of the treatment because of the diverse forms of cutaneous lesions and often late diagnosis. While systemic corticosteroids are widely used in Brazil – either alone or associated with the antivenom – dapsone is frequently used in the USA, although there is no consensus on the efficacy of these treatments [ 21 ].…”

Section: Introductionmentioning

confidence: 99%

“…This was corroborated by an experimental study that showed that necrotic injuries in rabbits were about 90% smaller compared with the control when the antivenom was administered up to 6 h, while the reduction in the lesion dropped to 30% when the antivenom was administered up to 48 h after the bite [ 22 ]. Health protocols in Brazil, Peru and Argentina advise the use of intravenous antivenom in cases of cutaneous or cutaneous-hemolytic forms of loxoscelism – when hemolysis is present the antivenom is indicated even 48 h after the bite [ 21 ].…”

Section: Introductionmentioning

confidence: 99%

Highlights in the knowledge of brown spider toxins

Chaves-Moreira

Senff‐Ribeiro

Wille

et al. 2017

J Venom Anim Toxins Incl Trop Dis

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Brown spiders are venomous arthropods that use their venom for predation and defense. In humans, bites of these animals provoke injuries including dermonecrosis with gravitational spread of lesions, hematological abnormalities and impaired renal function. The signs and symptoms observed following a brown spider bite are called loxoscelism. Brown spider venom is a complex mixture of toxins enriched in low molecular mass proteins (4–40 kDa). Characterization of the venom confirmed the presence of three highly expressed protein classes: phospholipases D, metalloproteases (astacins) and insecticidal peptides (knottins). Recently, toxins with low levels of expression have also been found in Loxosceles venom, such as serine proteases, protease inhibitors (serpins), hyaluronidases, allergen-like toxins and histamine-releasing factors. The toxin belonging to the phospholipase-D family (also known as the dermonecrotic toxin) is the most studied class of brown spider toxins. This class of toxins single-handedly can induce inflammatory response, dermonecrosis, hemolysis, thrombocytopenia and renal failure. The functional role of the hyaluronidase toxin as a spreading factor in loxoscelism has also been demonstrated. However, the biological characterization of other toxins remains unclear and the mechanism by which Loxosceles toxins exert their noxious effects is yet to be fully elucidated. The aim of this review is to provide an insight into brown spider venom toxins and toxicology, including a description of historical data already available in the literature. In this review article, the identification processes of novel Loxosceles toxins by molecular biology and proteomic approaches, their biological characterization and structural description based on x-ray crystallography and putative biotechnological uses are described along with the future perspectives in this field.

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“…Envenomation can result in disfiguring dermonecrotic lesions (cutaneous loxoscelism) and in hemolytic anemia, renal failure, and coagulopathy, which can be fatal (systemic loxoscelism) [Hogan et al, ; Chaves‐Moreira et al, ; Gremski et al, ]. To date, there is no specific treatment for loxoscelism [Isbister and Fan, ; Malaque et al, ].…”

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confidence: 99%

Potential Implications for Designing Drugs Against the Brown Spider Venom Phospholipase‐D

Chaves-Moreira

Moraes

Caruso

et al. 2016

J of Cellular Biochemistry

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Loxoscelism refers to the clinical symptoms that develop after brown spider bites. Brown spider venoms contain several phospholipase-D isoforms, which are the main toxins responsible for both the cutaneous and systemic effects of loxoscelism. Understanding of the phospholipase-D catalytic mechanism is crucial for the development of specific treatment that could reverse the toxic effects caused by the spider bite. Based on enzymatic, biological, structural, and thermodynamic tests, we show some features suitable for designing drugs against loxoscelism. Firstly, through molecular docking and molecular dynamics predictions, we found three different molecules (Suramin, Vu0155056, and Vu0359595) that were able to bind the enzyme's catalytic site and interact with catalytically important residues (His12 or His47) and with the Mg co-factor. The binding promoted a decrease in the recombinant brown spider venom phospholipase-D (LiRecDT1) enzymatic activity. Furthermore, the presence of the inhibitors reduced the hemolytic, dermonecrotic, and inflammatory activities of the venom toxin in biological assays. Altogether, these results indicate the mode of action of three different LiRecDT1 inhibitors, which were able to prevent the venom toxic effects. This strengthen the idea of the importance of designing a specific drug to treat the serious clinical symptoms caused by the brown spider bite, a public health problem in several parts of the world, and until now without specific treatment. J. Cell. Biochem. 118: 726-738, 2017. © 2016 Wiley Periodicals, Inc.

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Loxosceles and Loxoscelism: Biology, Venom, Envenomation, and Treatment

Cited by 5 publications

References 55 publications

Temporal evolution of dermonecrosis in loxoscelism assessed by photodocumentation

Temporal evolution of dermonecrosis in loxoscelism assessed by photodocumentation

Highlights in the knowledge of brown spider toxins

Potential Implications for Designing Drugs Against the Brown Spider Venom Phospholipase‐D

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