Browsing by Author "Pérez-Mateluna, Guillermo"

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    Association between obesity and atopic dermatitis in children: A case-control study in a high obesity prevalence population
    (2022) Iturriaga, Carolina; Bustos, María Francisca; Le Roy, Catalina; Rodríguez, Rocío; Cifuentes, Lorena; Silva-Valenzuela, Sergio; Vera-Kellet, Cristián; Cristi, Francisca; Pérez-Mateluna, Guillermo; Cabalín, Carolina; Hoyos-Bachiloglu, Rodrigo; Camargo Jr., Carlos A.; Borzutzky Schachter, Arturo
    Background/Objective: Atopic dermatitis (AD) is a chronic inflammatory skin disease. Research suggests an association between obesity and AD, although evidence is lacking from Latin American populations. This study evaluated the association of obesity with AD in children from Chile, a country with high obesity prevalence. Methods: A case-control study was performed in children with active AD (cases) and healthy controls (HCs) from Santiago, Chile. Body mass index was evaluated by z-score (z-BMI), with overweight defined as z-BMI ≥+1 and <+2, and obesity as z-BMI ≥+2. Abdominal obesity was defined by a waist circumference-to-height ratio (WHR) ≥0.5. AD severity was evaluated by Scoring AD (SCORAD) index. Results: A total of 174 children with AD and 101 controls were included. AD patients had similar overweight (27% vs. 28%) and obesity (21% vs. 26%) rates as HCs (p = .65). Abdominal obesity rates were also comparable (64% vs. 62%, p = .81). In sex-specific analyses, girls with AD had higher abdominal obesity rates than HCs (71% vs. 53%, p < .05) while boys with AD had lower abdominal obesity rates than HCs (53% vs. 75%, p = .03). Among children with AD, higher z-BMI or WHR did not correlate with higher SCORAD, eosinophil counts or total IgE. Conclusion: In our study, Chilean children with AD had high but similar rates of obesity as HCs, but showed sex-specific associations of abdominal obesity and AD. Further research is needed to evaluate these associations and the roles that weight excess and weight loss could play in the pathogenesis and treatment of AD.
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    High prevalence of lupin allergy among patients with peanut allergy: identification of γ-conglutin as majo allergen
    (American College of Allergy, Asthma and Immunology, 2022) Aguilera-Insunza, Raquel; Iturriaga, Carolina; Mariñanco, Angélica; Venegas, Luis; Aravena, Gabriela; Pérez-Mateluna, Guillermo; Baptista-Dias, Nathalia; Borzutzky Schachter, Arturo; Wandersleben, Traudy
    Background: Lupin is a protein-rich legume with a growing presence in the food market worldwide. With increased consumption, lupin allergy (LA) reports are also rising. Uncertainties exist on the cross-reactivity between peanut and lupin, the allergenic potential of different lupin species, and sensitization patterns among different populations. Objective: To evaluate the molecular basis of LA and to determine lupin allergens from 3 different species that may be involved in peanut allergy (PA) cross-reactivity. Methods: A total of 43 subjects with PA, those with LA, or controls without food allergy were evaluated with skin prick tests (SPTs) and specific IgEs (sIgEs). Lupin-sensitized subjects were offered a lupin oral food challenge (OFC). Immunoblots and enzyme-linked immunosorbent assays were performed on sera from lupin-sensitized subjects. Results: In this study, 44% of the PA subjects were confirmed to have LA by OFC. Anaphylaxis was the most frequent manifestation after lupin consumption, with a minimal eliciting dosage of 1 g lupin flour. There was no difference in lupin sIgE or SPT wheal size between lupin-sensitized and confirmed LA subjects or in the severity of symptoms among confirmed LA subjects. Sera from lupin-sensitized subjects uniformly reacted to all 3 different lupin species. Immunoblotting and enzyme-linked immunosorbent assays revealed immunoglobulin E binding to a- and g-conglutin in all analyzed sera, whereas a- and b-conglutin recognition was variable. Conclusion: Our findings reveal a high prevalence of LA among PA subjects, emphasizing lupin must be labeled as an allergen in foods. Owing to high variability in lupin-sIgE and lupin-SPT results, LA diagnosis may require OFC. In our population, g-conglutin is the major allergen of lupin
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    Oral vitamin D modulates the epidermal expression of the vitamin D receptor and cathelicidin in children with atopic dermatitis
    (2022) Cabalín, Carolina; Pérez-Mateluna, Guillermo; Iturriaga, Carolina; Camargo Jr., Carlos A.; Borzutzky Schachter, Arturo
    Although vitamin D (VD) is known to have multiple effects on the skin and immunity, its effects on atopic dermatitis (AD) severity remain unclear. We investigated whether oral cholecalciferol (VD3) supplementation changes stratum corneum expression of the vitamin D receptor (vdr), and the epidermal alarmins Cathelicidin Antimicrobial Peptide (camp/LL-37) and Thymic Stromal Lymphopoietin (tslp) in children with AD. We conducted an open-label supplementation study with weekly oral VD3 for six weeks in children with AD. Serum 25-hydroxyvitamin D (25OHD), lesional Staphylococcus aureus colonization, and AD severity evaluated by SCORAD index were evaluated before and after supplementation. Tape stripping (TS) was performed on non-lesional and lesional skin to measure mRNA expression of vdr, camp, and tslp through RT-qPCR and LL-37 peptide by ELISA. Twenty-two children with moderate–severe AD received weekly oral VD3 for six weeks. Total serum 25OHD increased from 45.1 ± 23 to 93.5 ± 24.3 nmoL/L (p < 0.0001), while SCORAD decreased from 41.4 ± 13.5 to 31.5 ± 15.8 (p < 0.0001). After treatment, epidermal gene expression of camp increased significantly in non-lesional (p = 0.014) and lesional (p = 0.0007) tape stripping samples, while vdr only increased in lesional skin samples (p < 0.0001). LL-37 peptide increased significantly only in lesional skin samples (p = 0.008). Gene expression of tslp did not change after oral VD3 treatment. In children with AD, oral VD3 supplementation was associated with improved VD status and AD severity, as well as increased VDR and Cathelicidin expression in lesional skin, which provide mechanistic clues on its effects.