Maternal microbiome disturbance induces deficits in the offspring's behaviors: a systematic review and meta-analysis.

Recent evidence has suggested that changes in maternal gut microbiota in early life may generate neurobiological consequences associated with psychiatric-related abnormalities. However, the number of studies on humans investigating this problem is limited, and preclinical findings sometimes conflict. Therefore, we run a meta-analysis to examine whether maternal microbiota disturbance (MMD) during neurodevelopment might affect the offspring during adulthood. We found thirteen studies, from a set of 459 records selected by strategy registered on PROSPERO (#289224), to target preclinical studies that evaluated the behavioral outcomes of the rodents generated by dams submitted to perinatal enteric microbiota perturbation. The analysis revealed a significant effect size (SMD = -0.51, 95% CI = -0.79 to -0.22, p < .001, T2 = 0.54, I2 = 79.85%), indicating that MMD might provoke behavioral impairments in the adult offspring. The MMD also induces a significant effect size for the reduction of the sociability behavior (SMD = -0.63, 95% CI = -1.18 to -0.07, p = 0.011, T2 = 0.30, I2 = 76.11%) and obsessive-compulsive-like behavior (SMD = -0.68, 95% CI = -0.01 to -1.36, p = 0.009, T2 = 0.25, I2 = 62.82%) parameters. The effect size was not significant or inconclusive for memory and anxiety-like behavior, or inconclusive for schizophrenia-like and depressive-like behavior. Therefore, experimental perinatal MMD is vertically transmitted to the offspring, negatively impacting behavioral parameters related to psychiatric disorders.

Maternal Immune Activation with H1N1 or Toxoplasma gondii Antigens Induces Behavioral Impairments Associated with Mood Disorders in Rodents.

INTRODUCTION: Epidemiological studies revealed that maternal exposure to influenza A (H1N1) and Toxoplasma gondii (T. gondii) infection during pregnancy may increase the risk for mood disorders of the offspring. However, the impact of maternal infections in different stages of neural development and the nature of antigens remain to be elucidated. OBJECTIVE: This study investigated behavioral impairments induced by maternal immune activation (MIA) due to H1N1 or T. gondii infection during preborn neurodevelopment. METHODS: Maternal infection with influenza or toxoplasma was mimicked by administration of influenza vaccine antigens or suspension of soluble T. gondii antigen (STAg) in pregnant Balb/c mice at E6 or E16. Adult male offspring were evaluated for anxiety-like and depressive-like behavior in elevated plus maze (EPM) and forced swimming test (FST). RESULTS: In FST, immobility time at E6 and E16 increased when the mothers were treated with both antigen solutions. There was increased immobility in the pups whose mothers were treated with STAg at E16. MIA with influenza antigens reduced the exploration of the open arms of EPM for the pups whose progenitors received treatment at E6 and E16. The animals at E6 exhibited a greater number of stretch-attend postures compared with the saline group. STAg at E6 reduced the time of exploration in the open arms and increased the number of stretch-attend postures compared with the saline group. CONCLUSION: These results suggest that immunological responses to H1N1 or T. gondii during pregnancy may impact differently the susceptibility of adult offspring to mood disorder.

Resveratrol ameliorates the effect of maternal immune activation associated with schizophrenia in adulthood offspring.

Maternal exposure to infectious agents such as arboviruses, bacteria, or other protozoans has been associated with an elevated risk of schizophrenia (SZ). Evidence suggests that immunological processes occurring during infection may disturb the neural progenitor, impacting the central nervous system (CNS) functions. Moreover, growing evidence suggests that resveratrol (RSV) has neuroprotective activity through anti-oxidant and anti-inflammatory mechanisms. Therefore, we investigated if the treatment with RSV during pregnancy would prevent the abnormalities associated with a SZ-like phenotype induced by maternal immune activation (MIA). Pregnant dams stimulated with a subcutaneous (s.c.) injection of polyriboinosinic-polyribocytidylic acid (poly I:C; 50 mg/kg), a viral nucleic acid mimetic or vehicle, on gestational day (GD) 12.5, were treated with RSV (40 mg/kg, s.c.) or saline, from GD 9.5 to GD 14.5. On day 45 after birth, the offspring was evaluated using a three-compartment social interaction test, elevated plus maze, and hyperlocomotion test induced by amphetamine. After the behavioral tests, the relative expression of mRNA to synapsin 1 (Syn1), oligodendrocyte transcription factor 1 (Olig1), and SRY (sex-determining region Y)-box 2 (Sox2) was determined in the hippocampus and cortex. Treatment with RSV restored the social behavior and attenuated the hyperlocomotion of the offspring bred by dams submitted to MIA. RSV prevented the effects of MIA on Syn1 and Olig1 expression in the hippocampus and Syn1 in the cortex. The present study showed that maternal treatment with RSV attenuates some of the negative behavioral impacts caused by MIA, with modulation of synaptic and oligodendrogenesis processes.

Impact of Season of Birth on Psychiatric Disorder Susceptibility and Drug Abuse Incidence in a Population from the Köppen Tropical Savanna Region of Brazil.

BACKGROUND: Despite much evidence that season of birth (SOB) my influence the vulnerability to psychiatric disorders, divergence has been reported, in particular between populations born in the northern and southern hemispheres. We analyzed the potential modified risk by SOB to psychiatric disorder or drug addiction comorbidity in a population born in the Triângulo Mineiro region, a southern hemisphere Köppen tropical savanna region in Brazil. METHOD: We accessed the records of 98,457 of patients and healthy controls of the National Datacenter of Medical Promptuary to evaluate the influence of SOB as a modifying factor on the occurrence of mental disorders and drug abuse conditions among individuals born from the year 2000 to 2016. RESULTS: The data revealed significant modification of the relative incidence of major depressive disorder (MDD) (F11, 72 = 2.898; p = 0.003; eta-squared, ES = 0.313; ⍺ = 0.97), anxiety-related disorder (ARD) (F11, 81 =2.389; p = 0.013; ES = 0.241; ⍺ = 0.932), and schizophrenia (SZ) (F11, 83 = 2.764; p = 0.005; ES = 0.303; α = 0.963), while there was no increase in the number of healthy controls born in any month of the year (F11, 71 = 1.469; p = 0.163). Post hoc analyses indicated a significant higher vulnerability to MDD or ARD if the patient was born in August, or October to December, respectively. A relative increase in the incidence of SZ was also observed in patients born from August to October, compared to patients born from November to January. CONCLUSIONS: SOB may influence the risk for psychiatric disorders in the TMR population. Regional particularities associated with the climatic regime may account for the apparent divergence between studies.

The Presence of the Neuronal Nitric Oxide Synthase Isoform in the Intervertebral Disk.

Intervertebral disk degeneration is a progressive and debilitating disease with multifactorial causes. Nitric oxide (NO) might contribute to the cell death pathway. We evaluated the presence of the constitutive form of the neuronal NOS (nNOS) in both health and degenerated intervertebral disk through qPCR and immunohistochemistry. We also analyzed the potential role of nNOS modulation in the tail needle puncture model of intervertebral disk degeneration. Male Wistar rats were submitted to percutaneous disk puncture with a 21-gauge needle of coccygeal vertebras. The selective nNOS pharmacological inhibitor N (ω)-propyl-L-arginine (NPLA) or a nNOS-target siRNA (siRNAnNOShum_4400) was injected immediately after the intervertebral disk puncture with a 30-gauge needle. Signs of disk degeneration were analyzed by in vivo magnetic resonance imaging and histological score. We found that intact intervertebral disks express low levels of nNOS mRNA. Disk injury caused a 4 fold increase in nNOS mRNA content at 5 h post disk lesion. However, NPLA or nNOS-target siRNA slight mitigate the intervertebral disk degenerative progress. Our data show evidence of the nNOS presence in the intervertebral disk and its upregulation during degeneration. Further studies would disclose the nNOS role and its potential therapeutical value in the intervertebral disk degeneration.

Increased nitric oxide-mediated neurotransmission in the medial prefrontal cortex is associated with the long lasting anxiogenic-like effect of predator exposure.

Posttraumatic stress disorder (PTSD) is an anxiety disorder caused by the experience of a severe traumatic event. In rats this disorder has been modeled by exposure to a predator threat. PTSD has been associated to structural and functional changes in the medial prefrontal cortex (mPFC). Direct injections into this brain region of glutamate antagonists or inhibitors of the nitric oxide synthase (NOS) enzyme cause anxiolytic-like effects in rodents. In the present work we investigated if the behavioral changes induced by predator exposure are associated with changes in the mPFC nitrergic system. Since the hippocampus, amygdala and dorsal periaqueductal grey have also been associated to anxiety disorders, including PTSD, we also verified if this procedure would modify the nitrergic system in these regions. Male Wistar rats were exposed to a dummy or live cat for ten minutes and tested in the elevated plus maze test (EPM) seven days later. Immediately after the test their brains were removed for neuronal NOS (nNOS) immunohistochemistry detection and measurements of nitrite/nitrate (NOx) levels. Exposure to the live cat increased freezing responses. One week later the animals that froze when confronted with the cat presented a decreased percentage of entries in the open arms of the EPM and an increased number of nNOS positive neurons in the mPFC and basolateral nucleus of amygdala, but not in the hippocampus, central and medial nuclei of amygdaloid complex or dorsal-lateral periaqueductal grey. Moreover, cat exposed animals showed increased NOx levels in the mPFC but not in the hippocampus one week later. The number of nNOS neurons and NOx levels in the mPFC showed a significant correlation with freezing time during cat exposure. Our results suggest that plastic modifications of the nitrergic system in the mPFC could be related to long lasting behavioral changes induced by severe traumatic events such as predator exposure.

Involvement of serotonin-mediated neurotransmission in the dorsal periaqueductal gray matter on cannabidiol chronic effects in panic-like responses in rats.

RATIONALE: Cannabidiol (CBD) is a non-psychotomimetic constituent of Cannabis sativa plant that promotes antianxiety and anti-panic effects in animal models after acute systemic or intra-dorsal periaqueductal gray (DPAG) administration. However, the effects of CBD repeated administration, and the possible mechanisms involved, in animal models of anxiety- and panic-related responses remain poorly understood. OBJECTIVE: The present study evaluates the role of the serotonergic neurotransmission within the DPAG in the modulation of escape responses of rats chronically treated with CBD. METHODS: Male Wistar rats received acute or repeated (5 mg/Kg/daily/21 days) administration of CBD and were submitted to the elevated T-maze (ETM). We also investigated if CBD effects on the ETM depend on facilitation of 5-HT1A-mediated neurotransmission in the DPAG. To this latter aim, we verified if these effects would be prevented by intra-DPAG injection of the 5-HT1A receptor antagonist WAY100635 (0.37 nmol/0.2 µL). Also, we verified, by in vivo microdialysis, if CBD chronic treatment increases serotonin (5-HT) release and, by quantitative polymerase chain reaction, if there are changes in 5HT-1A or 5HT-2C mRNA expression in DPAG. RESULTS: The results showed that repeated but not acute peripheral administration of CBD decreases escape responses in the ETM, suggesting a panicolytic effect. This treatment did not change 5HT-1A or 5-HT-2C receptor mRNA expression nor modify serotonin extracellular concentrations in the DPAG. CBD effects were prevented by DPAG injection of the 5-HT1A receptor antagonist. CONCLUSIONS: Together, these findings suggest that repeated treatment with CBD induces anti-panic effects by acting on 5-HT1A receptors in DPAG.

Predator threat stress promotes long lasting anxiety-like behaviors and modulates synaptophysin and CB1 receptors expression in brain areas associated with PTSD symptoms.

Several studies have suggested that changes in hippocampal, prefrontal cortex and amygdaloid complex function are associated with the main symptoms of Posttraumatic Stress Disorder (PTSD). Predator exposure can mimic some aspects of PSTD such as hyperarousal and chronic anxiety. However, little is known about the neural substrate involved in this model. Synaptophysin (SYP) expression has been used to evaluate synaptic plastic changes while cannabinoids have emerged as a therapeutic target for the treatment of stress- and anxiety-related disorders. The present work evaluated whether the long lasting behavioral effects evoked by predator exposure are associated to long-term changes in the expression of the Cannabinoid receptor 1 (CB1) and the synaptic protein SYP in brain areas related to the genesis of PTSD symptoms (frontal cortex, hippocampus and amygdaloid complex). Male Wistar rats were exposed to a live or a dummy cat and seven days later submitted to the elevated plus maze test. To explore possible neurobiological mechanisms involved in these effects, CB1 receptor and SYP mRNA expression were measured in the hippocampus, frontal cortex and amygdaloid complex. Single predator exposure promoted long-lasting anxiogenic effects. Seven days after predator threat CB1 mRNA expression was down regulated in the frontal cortex and amygdaloid complex while SYP gene was up regulated in the amygdaloid complex. Our results suggested that predator exposure causes long-lasting anxiogenic effects associated with hyperactivation of amygdaloid complex and modulation of CB1 receptor in brain areas related to PTSD symptoms.

Cannabidiol blocks long-lasting behavioral consequences of predator threat stress: possible involvement of 5HT1A receptors.

Posttraumatic stress disorder (PTSD) is an incapacitating syndrome that follows a traumatic experience. Predator exposure promotes long-lasting anxiogenic effect in rodents, an effect related to symptoms found in PTSD patients. Cannabidiol (CBD) is a non-psychotomimetic component of Cannabis sativa with anxiolytic effects. The present study investigated the anti-anxiety actions of CBD administration in a model of PTSD. Male Wistar rats exposed to a predator (cat) received, 1 h later, singled or repeated i.p. administration of vehicle or CBD. Seven days after the stress animals were submitted to the elevated plus maze. To investigate the involvement of 5HT1A receptors in CBD effects animals were pre-treated with WAY100635, a 5HT1A receptor antagonist. To explore possible neurobiological mechanisms involved in these effects, 5HT1A receptor mRNA and BDNF protein expression were measured in the hippocampus, frontal cortex, amygdaloid complex and dorsal periaqueductal gray. Repeated administration of CBD prevented long-lasting anxiogenic effects promoted by a single predator exposure. Pretreatment with WAY100635 attenuated CBD effects. Seven days after predator exposure 5HT1A mRNA expression was up regulated in the frontal cortex and hippocampus. CBD and paroxetine failed to prevent this effect. No change in BDNF expression was found. In conclusion, predator exposure promotes long-lasting up-regulation of 5HT1A receptor gene expression in the hippocampus and frontal cortex. Repeated CBD administration prevents the long-lasting anxiogenic effects observed after predator exposure probably by facilitating 5HT1A receptors neurotransmission. Our results suggest that CBD has beneficial potential for PTSD treatment and that 5HT1A receptors could be a therapeutic target in this disorder.

Leptina e o controle neuroendócrino do peso corporal / Leptin and the neuroendocrine control body weight

A obesidade nos últimos anos vem sendo tratada como um problema de saúde pública, despertando grande interesse nos profissionais da saúde. Compreender o papel da leptina no controle neuroendócrino da ingestão de nutrientes, do gasto energético, depósito de gorduras e do peso corporal é objetivo de um número crescente de pesquisadores, visto que este é um hormônio com papel relevante na interação entre os adipócitos e os neurônios.Nesta revisão atualizamos aspectos como a estrutura da leptina, local e fatores que influenciam na sua síntese, tecidos que expressam receptores e mecanismos de ação. Enfatizamos a ação da leptina no hipotálamo, sítio em que ocorre o controle da ingestão alimentar, com foco em novas perspectivas de intervenção farmacológica no sentido de favorecer maior equilíbrio entre o metabolismo e a ingestão alimentar.

Chronic lithium treatment prevent anxiety-like behavior related to dietary restriction / Tratamento crônico com lítio previne comportamento relacionado à ansiedade induzida pela restrição dietária

Caloric intake reduction has been considered as the major experimental manipulation able to increase longevity in experimental models. Therefore, its effects upon cognition and mood like behavior are poorly explored. On the other hand, Li+ is a re-emergent therapeutic drug used to treat mood disorders, mainly bipolar disorder, with antipanic and antidepressant actions. On the hypothesis that lithium treatment could attenuate the negatives effects of stress on Central Nervous Systems (CNS), we evaluated the role of chronic lithium treatment on anxiety-like behaviors in animals submitted to stress by chronic moderated feed restriction (FR). Male wistar rats were divided into four groups (n = 7-8/group) according to dietary and drug manipulation: ad libitum (AL) with unlimited access to standard rat diet, lithium treatment (AL + Li) which received approximately 50 mg/Kg animal/day of LiCl solved in water and ad libitum diet, FR that were fed with equivalent to 70 percent of total rat diet consumed by AL group, and FR + Li which received diet corresponding to FR and Li administration. After 12 weeks of drug and FR manipulation, anxiety like behavior was evaluated in elevated plus mazes (EPM). Chronic lithium treatment prevent the anxiogenic like effect of FR (open time, F3,30 = 3.588; P = 0.0265; percentage of open entries, F3,30 = 6.004; P= 0.00029; and open time at the first min, 2.35; F3,30 = 4.937; P = 0.0073, Duncan test P < 0.05) compared to AL diet. Ours results adding to evidences that moderate feed restriction my increase anxiety-like behavior; also suggest that chronic lithium treatment may be attenuated this effects.

Restrição calórica é a principal manipulação experimental capaz de aumentar a longevidade, contudo seus efeitos sobre cognição e comportamento são pouco explorados. Por outro lado, Li + é uma droga re-emergente para o tratamento de distúrbios afetivos como distúrbio bipolar com efeitos antipânicos e antidepressivos. Considerando a hipótese de que o tratamento com lítio poderia atenuar os efeitos negativos do estresse sobre o Sistema Nervos Central, foi avaliado o papel do tratamento crônico com lítio no comportamento do tipo ansiedade em animais submetidos ao estresse por restrição dietária (RD). Ratos machos wistar foram divididos em quatro grupos (n = 7-8/grupo): (AL) com acesso ad libitum à dieta padrão de ratos; (AL + Li) tratados com aproximadamente 50 mg/Kg animal/dia de LiCl dissolvido em água; (RD) alimentados com o equivalente a 70 por cento do total da dieta consumida pelos animais do grupo AL; (RD + Li) os quais receberem dieta correspondente ao grupo DR e tratamento com Li. Após 12 semanas nestas condições, o comportamento relacionado à ansiedade foi avaliada em labirinto em cruz elevada. O tratamento crônico com lítio preveniu o comportamento do tipo ansiogênico atribuído a DR (temo de exploração no braço aberto, F3,30 = 3.588; P = 0.0265; porcentagem de entradas no braço aberto, F3,30 = 6.004; P = 0.00029; e tempo utilizado no braço aberto no primeiro minuto; F3,30 = 4.937; P= 0.0073, Duncan test P < 0.05) comparado ao grupo AL. Estes resultados somam evidências para os efeitos do tipo ansiogênicos da restrição dietária moderada, além de sugerir que o tratamento crônico com lítio pode reverter estes efeitos.

Modulation of stress consequences by hippocampal monoaminergic, glutamatergic and nitrergic neurotransmitter systems.

Several findings relate the hippocampal formation to the behavioural consequences of stress. It contains a high concentration of corticoid receptors and undergoes plastic modifications, including decreased neurogenesis and cellular remodelling, following stress exposure. Various major neurotransmitter systems in the hippocampus are involved in these effects. Serotonin (5-HT) seems to exert a protective role in the hippocampus and attenuates the behavioural consequences of stress by activating 5-HT1A receptors in this structure. These effects may mediate the therapeutic actions of several antidepressants. The role of noradrenaline is less clear and possibly depends on the specific hippocampal region (dorsal vs. ventral). The deleterious modifications induced in the hippocampus by stress might involve a decrease in neurotrophic factors such as brain derived neurotrophic factor (BDNF) following glutamate N-methyl-D-aspartate (NMDA) receptor activation. In addition to glutamate, nitric oxide (NO) could also be related to these effects. Systemic and intra-hippocampal administration of nitric oxide synthase (NOS) inhibitors attenuates stress-induced behavioural consequences. The challenge for the future will be to integrate results related to these different neurotransmitter systems in a unifying theory about the role of the hippocampus in mood regulation, depressive disorder and antidepressant effects.

Efeito da adição de castanha-do-pará à dieta de arroz e feijão sobre o ganho de peso em camundongos / The effect of the addition of brazil nut to diet based in rice and bean on the increase in the bodyweight of rise

As crescentes necessidades nutricionais da população exigem o desenvolvimento de mecanismos para o aumento do valor nutricional na dieta. Uma alternativa é a complementação com diferentes fontes protéicas, sendo a combinação de arroz, feijão e castanha-do-pará uma possibilidade. O presente estudo analisou o efeito da adição da castanha-do-pará sobre o ganho de peso de animais e também observou o ritmo de absorção intestinal do óleo extraído da castanha-do-pará. Os experimentos foram conduzidos em conformidade com o guia de manipulação de animal de laboratório da Sociedade Brasileira de Biologia Experimental e normas do Comitê Internacional de Manipulação e Cuidados de Animais Experimentais. Utilizou-se 36 camundongos da linhagem albino suíço e 10 ratos da linhagem Wistar. O protocolo alimentício seguiu a dieta ideal proposta por Souza e Oliveira (1969). Camundongos alimentados com uma mistura de 3 partes de arroz e 1 de feijão acrescido 3,33 por cento, 6,67 por cento e 16,65 por cento de castanha-do-pará apresentaram, ao final de duas semanas, significativamente maior ganho de peso médio, 20,43 por cento, em relação aos camundongos alimentados com 0 por cento, 33,3 por cento e 50 por cento de castanha-do-pará. A dieta acrescida em 16,65 por cento de castanha-do-Pará aumentou de 40,74 por cento o ganho de peso comparado ao controle. O teste de absorção intestinal não mostrou diferença significativa na taxa de absorção. O maior ganho de peso entre animais que receberam dieta enriquecida com castanha-do-Pará relaciona-se, entre outros fatores, com a maior biodisponibilidade do aminoácido metionina. Contudo, o acréscimo de maiores quantidades de castanha-do-Pará não revelou aumento no peso dos animais.

The increase of nutritional needs of the population requests the development of mechanisms to the increase the nutritional value in the diet. One alternative is to complement it with different protein resources, being the combination of rice, beans and Brazil nut a possibility. This study analyzed the effect of the addition of Brazil nuts in the raise of mice bodyweight as well as observed the rhythm of intestinal absorption of Brazil nut oil. The experiment was conducted in conformity with Animal Labor Manipulation Guide of the Brazilian Experimental Biology Society and rules of The International Committee of the Manipulation and Care of Experimental Animals.Thirty six (36) mice of Swiss albino lineage were used and 10 rats of lineage Wistar. The alimentary protocol follows the proposal of Souza and Oliveira (1969) for an ideal diet. The mice fed with the mixture of o 3 parts of rice and 1 of beans plus 3,33 per cent, 6,67 per cent and 16,65 per cent of Brazil nut showed, at the end of two weeks, significantly raise in medium weight gain, 20,43 per cent - in relation to the mice fed with 0 per cent, 33,3 per cent and 50 per cent of Brazil nut. The diet plus with 16.65 per cent of Brazil nut increase the weight gain in 40,74 per cent in comparison with the control. The test of intestinal absorption didn’t show significant difference in the absorption rate. The bigger increase in bodyweight among the animals which received enriched diet with Brazil nut related to, among others factors, with the raised biodisponibility of methionine amminoacid. However, the addition of large quantities of Brazil nut didn’t reveal raise in animal weight gain.

Interaction of TaqI polymorphism at exon 9 of the vitamin D receptor gene with the negative lepromin response may favor the occurrence of leprosy.

Controversies over the vitamin D receptor (VDR) acting as a susceptibility factor in Mycobacterium sp. infections may be the result of incorrect population stratification. The risk of leprosy occurrence conditioned by VDR polymorphism was investigated by stratifying the population of a highly endemic Brazilian region into negative and positive Mitsuda responses. Leprosy patients (102) and a group of healthy nonconsanguineous household contacts (68) were genotyped for the VDR TaqI polymorphism (T/t). TT and Tt genotypes were not considered to be risk factors as their odds ratios (OR) were not different from those presented by the negative Mitsuda response individuals. The combination of the tt genotype and the negative Mitsuda test provided an occurrence rate 13 times higher in leprosy patients than in controls with positive Mitsuda responses. This suggests that there is a higher risk of leprosy development when individuals carry this unfavorable combination, and demonstrates a possible synergistic role of these two variables in leprosy susceptibility via effects on cellular immunity.

Detection of Mycobacterium leprae in nasal mucosa biopsies by the polymerase chain reaction.

Several discoveries about leprosy indicate that Mycobacterium leprae transmission mainly occurs by inhalation, and the nose is major port of entry and exit. The present study evaluated the clinical application of PCR for detection of M. leprae DNA in nasal mucosa biopsies in untreated leprosy patients (52) and their contacts (99) from the State Reference Center in Sanitary Dermatology and Leprosy, Uberlandia, MG, Brazil. PCR detection of a 372-base pair DNA fragment from M. leprae was accomplished in 36 (69.2%) patients, from which 34 (91.9%) of them were multibacillaries. Furthermore, PCR was positive in 3 (16.7%) of 18 slit-skin smear negative, 4 (25.0%) of 16 skin lesion BI negative, 8 (33.3%) of 24 nasal mucosa BI negative patients, and 10 of 99 contacts (10.1%). The presence of bacilli in 10.1% of the contacts may potentially reflect an occult leprosy, and these patients must be accompanied, followed by a chemoprophylaxy treatment. Considering all PCR results against clinical and BI classification of patients and controls, we have found a sensitivity of 69.2%, a specificity of 89.9%, and an accuracy of 82.8%. It has been demonstrated here through PCR of nasal biopsies that the bacillus invades the mucosa, passing through the nasal inferior turbinate to reach peripheral blood. Therefore, the molecular investigation of invasive nasal biopsies by PCR tests has proven to be useful in defining patients of higher risk of transmission and risk-group contacts, which is an important step to reach the World Health Organization objective towards the elimination of leprosy as a public health problem.

Detection of Mycobacterium leprae in nasal mucosa biopsies by the polymerase chain reaction

Several discoveries about leprosy indicate that Mycobacterium leprae transmission mainly occurs by inhalation, and the nose is major port of entry and exit. The present study evaluated the clinical application of PCR for detection of M. leprae DNA in nasal mucosa biopsies in untreated leprosy patients (52) and their contacts (99) from the State Reference Center in Sanitary Dermatology and Leprosy, Uberlandia, MG, Brazil. PCR detection of a 372-base pair DNA fragment from M. leprae was accomplished in 36 (69.2%) patients, from which 34 (91.9%) of them were multibacillaries. Furthermore, PCR was positive in 3 (16.7%) of 18 slit-skin smear negative, 4 (25.0%) of 16 skin lesion BI negative, 8 (33.3%) of 24 nasal mucosa BI negative patients, and 10 of 99 contacts (10.1%). The presence of bacilli in 10.1% of the contacts may potentially reflect an occult leprosy, and these patients must be accompanied, followed by a chemoprophylaxy treatment. Considering all PCR results against clinical and BI classification of patients and controls, we have found a sensitivity of 69.2%, a specificity of 89.9%, and an accuracy of 82.8%. It has been demonstrated here through PCR of nasal biopsies that the bacillus invades the mucosa, passing through the nasal inferior turbinate to reach peripheral blood. Therefore, the molecular investigation of invasive nasal biopsies by PCR tests has proven to be useful in defining patients of higher risk of transmission and risk-group contacts, which is an important step to reach the World Health Organization objective towards the elimination of leprosy as a public health problem.

Susceptibility to leprosy may be conditioned by an interaction between the NRAMP1 promoter polymorphisms and the lepromin response.

Controversial results have been achieved by attempting to associate the NRAMP1 gene with Mycobacterium leprae susceptibility as well as with the Mitsuda reaction, which represents a specific immune response to M. leprae. This study evaluated this association as well as the interaction of the polymorphism (GT)(n) in the promoter region of the NRAMP1 gene with a specific immune response to M. leprae measured by the intradermal Mitsuda test in leprosy patients and in non-consanguineous household contacts. The study aimed to evaluate the association of this gene polymorphism with resistance or susceptibility to the disease, and/or with clinical forms of the disease, in a population in an endemic area served by the State Reference Center in Sanitary Dermatology and Leprosy, Federal University of Uberlandia, MG, Brazil. Leprosy patients (90) were diagnosed according to Ridley and Jopling criteria and they grouped into multibacillary (MB) and paucibacillary (PB) patients. The control group consisted of 61 non-consanguineous contacts. NRAMP1 promoter genotypes were obtained through amplification by the polymerase chain reaction (PCR) followed by the detection through the low ionic-strength single strand conformational polymorphism (LIS-SSCP) electrophoretic technique. There were no significant differences in the allelic and genotypic frequencies for alleles 2, 3, and 4 in relation to the Mitsuda test among patients and household contacts, nor between those with MB and PB forms. However, individuals with a negative lepromin response associated with genotypes 22 and 23 presented a 7- and 8-fold greater chance of developing leprosy, respectively. Therefore, the NRAMP1 gene promoter polymorphism exhibited an interaction with the lepromin response, suggesting that allele 2 of the NRAMP1 promoter is an independent genetic factor that predisposes cells to enable pathogen survival, probably due to its low efficiency in iron transport. However, establishment of the infection and disease development may be conditioned by other immunological and genetic factors.