Biomarcadores na dermatite atópica / Biomarkers in atopic dermatitis

O objetivo deste estudo é descrever os achados de artigos recentemente publicados a respeito dos avanços diagnósticos, prognósticos e terapêuticos sobre o uso de biomarcadores na dermatite atópica. Foi realizada revisão bibliográfica de 19 artigos publicados no Journal of Allergy and Clinical Immunology e no The New England Journal of Medicine. Atualmente, mais de 1 bilhão de pessoas têm algum tipo de doença alérgica, entre as quais a dermatite atópica é altamente prevalente. Por mais que possa ser diagnosticada de forma clínica através dos critérios de Hanifin e Rajka, estes são avaliador-dependentes, havendo grande variação dos resultados. Da mesma forma, a dosagem de IgE não é específica. Assim, tais métodos não são precisos para o diagnóstico, aumentando a importância da descoberta de novos marcadores mais fidedignos. Os biomarcadores são características biológicas quantificáveis que fornecem medidas objetivas do estado de saúde ou doença. Eles têm potencial para estratificação de risco, detecção precoce, identificação do tratamento, monitorização de resposta e prevenção da progressão para marcha atópica. Os avanços tecnológicos permitem aos clínicos determinar um grande número de biomarcadores através de fluidos corporais, o que resultará em uma melhor caracterização e estratificação dos pacientes com dermatite atópica, bem como acarretará medidas objetivas da resposta terapêutica e melhores comparações entre tratamentos correntes e novas terapias.

The objective of this study is to describe the findings of recently published articles on the diagnostic, prognostic and therapeutic advances in the use of biomarkers in atopic dermatitis. Nineteen articles published in the Journal of Allergy and Clinical Immunology and in The New England Journal of Medicine were reviewed. Currently, more than 1 billion people have some type of allergic disease; among such diseases, atopic dermatitis is highly prevalent. Even though atopic dermatitis can be diagnosed clinically using the Hanifin and Rajka criteria, diagnosis is examiner-dependent, leading to major variations in results. Likewise, IgE dosage is non-specific. Thus, these methods are not accurate for diagnosis, highlighting the importance of finding new, more reliable markers. Biomarkers are quantifiable biological characteristics that provide objective measures of health status or disease. They have a potential for risk stratification, early detection, treatment identification, response monitoring and prevention of progression to the atopic march. Technological advances allow clinicians to determine a large number of biomarkers through body fluids, which will result in a better characterization and stratification of patients with atopic dermatitis and lead to objective measures of treatment response and better comparisons between current and new therapies.

Seasonal allergies and suicidality: results from the National Comorbidity Survey Replication.

OBJECTIVE: Studies have shown an association between allergies and suicidality, and a seasonality of suicide has also been described. We hypothesize an association between history of seasonal allergies and suicide ideation and attempt. METHOD: Data came from the National Comorbidity Survey Replication, a nationally representative sample (n = 5692) of adults living in the US. Logistic regression models were used to calculate adjusted odds ratios (OR) controlling for the following: age, sex, race, smoking, asthma and depression. RESULTS: After weighting and adjustment, a positive and statistically significant association was found between history of seasonal allergies and history of suicidal ideation [adjusted OR = 1.27 (1.01-1.58)]. We found no association between history of seasonal allergies and history of suicide attempts [adjusted OR = 1.17 (0.89-1.52)]. CONCLUSION: Findings from a population-based sample support the hypothesized relationship between allergies and suicidal ideation.

Summer birth and deficit schizophrenia in the epidemiological catchment area study.

Winter birth is a widely replicated risk factor for schizophrenia. However, previous studies have suggested that patients with the deficit syndrome of schizophrenia have an excess of summer births. We tested the summer birth effect in a population-based study. Data came from the Epidemiological Catchment Area study, which had a representative sample of the U.S. population. Psychotic patients with features of the deficit syndrome had a significant association with summer birth, compared with the general population. There was also a significant association between summer birth and the deficit syndrome within the psychotic population, after accounting for the variance due to disorganization, hallucinations and delusions, and demographic characteristics. These findings add to the evidence suggesting the etiopathophysiology of the deficit group differs from that found in other patients with schizophrenia.

Subclinical suspiciousness as a risk factor for depressive episodes.

OBJECTIVE: Previous studies suggest suspiciousness is associated with an increased risk of major depressive episodes in psychotic patients. We tested the hypothesis that this relationship would extend to nonpsychotic groups. METHOD: Data came from the Epidemiological Catchment Area (ECA) study, a longitudinal population-based study conducted at five sites in the United States. Baseline clinical and demographic features were used to predict the onset of episodes of depression at 1-year follow-up in subjects without psychotic symptoms. RESULTS: Subclinical suspiciousness was associated with an increased risk of new episodes of depression after accounting for demographic variables. However, three of six subclinical delusion-like experiences were also associated with an increased risk of depressive episodes. None of the subclinical hallucination-like experiences predicted subsequent risk. CONCLUSION: Subclinical suspiciousness appears to increase the risk of depression in the general population. Some other delusion-like experiences may do the same.

Schizophrenia and season of birth in a tropical region: relationship to rainfall.

Winter birth has been shown to increase the risk of schizophrenia in adult life. It has been hypothesized that this effect is due to seasonal variation in infectious diseases, including influenza, as exposure to influenza during mid gestation also increases the risk of schizophrenia. However, in many areas there is little variation in temperature during the year, although rainfall may vary greatly. We tested the hypothesis that, in a tropical region with wet and dry seasons, schizophrenia births would be related to rainfall. The data came from the city of Mossoro in north-eastern Brazil. In this area there is no meaningful variation in temperature, but there is a rainy season with little precipitation during the rest of the year. In this region, the prevalence of influenza parallels that of rainfall. There was a significant relationship between rainfall and the number of schizophrenia births three months later. In contrast, there was no significant relationship between rainfall and general population births three months later. The relationship of birth to rainfall, rather than winter birth, may be associated with risk of schizophrenia in tropical regions; exposure to influenza during gestation may be the basis for such a relationship.

Suspiciousness as a specific risk factor for major depressive episodes in schizophrenia.

OBJECTIVE: Serious depression is a common and important complication of schizophrenia. In a prospective, population-based study, we tested the hypothesis that suspiciousness increases the risk for the later development of depression in schizophrenia. METHOD: Data came from the Epidemiological Catchment Area (ECA) study. Baseline clinical and demographic features were used to predict the onset of new episodes of depression at 1 year follow-up. As ECA diagnoses were based on lay interviews, which may have low sensitivity compared with clinical diagnoses, two overlapping groups of putative schizophrenia patients were defined. RESULTS: Suspiciousness was associated with an increased risk of new episodes of depression in both patient groups, after accounting for demographic variables. There was no association between an increased risk of depression and either disorganization or hallucinations and delusions. CONCLUSIONS: Suspiciousness appears to be a specific risk factor for depression in psychotic groups. Interventions that decrease suspiciousness, or mitigate its isolating effects, might decrease the risk of serious depression and suicide.

Psychiatric assessment in transplantation.

The implementation of the presumptive donor law in Brazil is expected to increase the availability of organs for transplantation. As medical management of end-stage organ dysfunction continues to improve, increasing numbers of potential transplant recipients will be available to meet this supply. There is mounting evidence that supports the involvement of skilled psychiatric practitioners in the selection of transplant candidates. Data supporting the influence of psychosocial factors on compliance and therefore medical outcomes continues to grow. The literature review allows delineating the components and rationale for comprehensive psychosocial evaluations as a component of preoperative transplantation evaluation.

Gastroduodenal resistance and neural mechanisms involved in saline flow decrease elicited by acute blood volume expansion in anesthetized rats

We have previously demonstrated that blood volume (BV) expansion decreases saline flow through the gastroduodenal (GD) segment in anesthetized rats (Xavier-Neto J, dos Santos AA & Rola FH (1990) Gut, 31: 1006-1010). The present study attempts to identify the site(s) of resistance and neural mechanisms involved in this phenomenon. Male Wistar rats (N = 97,200-300 g) were surgically manipulated to create four gut circuits: GD, gastric, pyloric and duodenal. These circuits were perfused under barostatically controlled pressure (4 cmH2O). Steadysate changes in flow were taken to reflect modifications in circuit resistances during three periods of time: normovolemic control (20 min), expansion (10-15 min), and expanded (30 min). Perfusion flow rates did not change in normovolemic control animals over a period of 60 min. BV expansion (Ringer bicarbonate, 1 ml/min up to 5 percent body weight) significantly (p<0.05) reduced perfusion flow in the GD (10.3 + 0.5 to 7.6 + 0.6 ml/min), pyloric (9.0 + 0.6 to 5.6 + 1.2 ml/min) and duodenal (10.8 + 0.4 to 9.0 + 0.6 ml/min) circuits, but not in the gastric circuit (11.9 + 0.4 to 10.4 + 0.6 ml/min). Prazosin (1 mg/kg) and yohimbine (3 mg/kg) prevented the expansion effect on the duodenal but not on the pyloric circuit. Bilateral cervical vagotomy prevented the expansion effect on the pylorus during the expansion but not during the expanded period and had no effect on the duodenum. Atropine (0.5 mg/kg), hexamethonium (10 mg/kg) and propranolol (2 mg/kg) were ineffective on both circuits. These results indicate that 1) BV expansion increases the GD resistance to liquid flow, 2) pylorus and duodenum are important sites of resistance, and 3) yohimbine and prazosin prevented the increase in duodenal resistance and vagotomy prevented it partially in the pylorus.

Gastroduodenal resistance and neural mechanisms involved in saline flow decrease elicited by acute blood volume expansion in anesthetized rats.

We have previously demonstrated that blood volume (BV) expansion decreases saline flow through the gastroduodenal (GD) segment in anesthetized rats (Xavier-Neto J, dos Santos AA & Rola FH (1990) Gut, 31: 1006-1010). The present study attempts to identify the site(s) of resistance and neural mechanisms involved in this phenomenon. Male Wistar rats (N = 97, 200-300 g) were surgically manipulated to create four gut circuits: GD, gastric, pyloric and duodenal. These circuits were perfused under barostatically controlled pressure (4 cmH2O). Steady-state changes in flow were taken to reflect modifications in circuit resistances during three periods of time: normovolemic control (20 min), expansion (10-15 min), and expanded (30 min). Perfusion flow rates did not change in normovolemic control animals over a period of 60 min. BV expansion (Ringer bicarbonate, 1 ml/min up to 5% body weight) significantly (P < 0.05) reduced perfusion flow in the GD (10.3 +/- 0.5 to 7.6 +/- 0.6 ml/min), pyloric (9.0 +/- 0.6 to 5.6 +/- 1.2 ml/min) and duodenal (10.8 +/- 0.4 to 9.0 +/- 0.6 ml/min) circuits, but not in the gastric circuit (11.9 +/- 0.4 to 10.4 +/- 0.6 ml/min). Prazosin (1 mg/kg) and yohimbine (3 mg/kg) prevented the expansion effect on the duodenal but not on the pyloric circuit. Bilateral cervical vagotomy prevented the expansion effect on the pylorus during the expansion but not during the expanded period and had no effect on the duodenum. Atropine (0.5 mg/kg), hexamethonium (10 mg/kg) and propranolol (2 mg/kg) were ineffective on both circuits. These results indicate that 1) BV expansion increases the GD resistance to liquid flow, 2) pylorus and duodenum are important sites of resistance, and, 3) yohimbine and prazosin prevented the increase in duodenal resistance and vagotomy prevented it partially in the pylorus.