Lead is a toxic metal which widespread use has resulted in environmental contamination and significant health problems. It is a cumulative toxicant that affects multiple body systems, including the cardiovascular, hematopoietic, reproductive, and renal systems. Lead is also a well-known neurotoxin, inducing changes in neurogenesis, neurodegeneration and changes on glial cells. These changes in the molecular and cellular processes lead to cognitive and behaviour alterations, particularly during developmental phases, persisting throughout the lifetime. Most of the studies that have been performed in both humans and animals were focused in a continuous chronic exposure to lead. This lead exposure causes behavioural changes, cognitive impairment and hypertension associated with sympathoexcitation, baroreceptor reflex hyposensitivity and increased chemoreceptor reflex sensitivity. But the effects of an intermittent lead exposure are scarse and standardized animal models are non-existent. This pattern of exposure has been increasing in the last years due to migrations, implementation of school exchange programs and/or residential changes. Therefore, the overall purpose of this work was to evaluate lead effects on mammal’s physiology along different profiles of lead exposure, including a new animal model of intermittent low-level lead exposure. Animal models of lead exposure were developed by replacing the tap water of seven-day pregnant Wistar females with 0.2% (p/v) solution of lead acetate. After being weaned at 21 days, rat pups, both sexes, were divided into 3 groups of lead exposure: long-term (exposure from foetal period until 28 weeks of age), short-term (exposure from foetal period until 12 weeks) and intermittent (exposure from foetal period until 12 weeks, lead-free period until 20 weeks and a second exposure between 20 and 28 weeks of age). At 12, 20 and 28 weeks of age, behavioural tests were performed for anxiety (Elevated Plus Maze Test), locomotor activity (Open Field Test), spatial working memory (Y-Maze) and episodic long-term memory (Novel Object Recognition test) assessment. Blood pressure (BP), electrocardiogram (ECG), heart rate (HR) and respiratory frequency (RF) were recorded at the same timepoints in the acute experiment. Baroreflex gain (BRG), chemoreflex sensitivity (ChS), cardiovascular variability were also evaluated. Immunohistochemistry studies for neuronal nuclear antigen (NeuN), Synaptophysin (Syn), ionized calcium binding adapter molecule-1 (Iba-1) and Glial fibrillary acidic protein (GFAP) stainings were performed in brain slices, and confocal imaging acquired and stainings quantified at dentate gyrus (DG) of the hippocampus. Blood lead levels were assessed by atomic absorption spectroscopy and metabolic evaluation of all groups was done using metabolic cages. A control group of Wistar rats without lead exposure, of both sexes, with the same number of individuals, underwent the same protocol and were evaluated in the same time points. Student T-test and one-way ANOVA with Tukey’s multiple comparison between means were used (significance p<0.05) for statistical analysis. Our data showed a clear association between lead exposure, hypertension and cardiorespiratory reflexes impairment, without heart rate changes, independently of the type of lead exposure profile. We also demonstrated for the first time that lead intermittent exposure causes adverse health effects, i.e, hypertension, sympathetic overactivity, increased chemoreflex sensitivity and baroreflex impairment, similar to a chronic exposure, however less pronounced. In fact, at 28 weeks, PbI group, the intermittent animal model of lead exposure developed, had a less severe hypertension when compared to the long-term exposure group (PbP), which might suggest that the duration of Pb exposure is more relevant than the time of exposure. Moreover, the effect on diastolic blood pressure produced by lead exposure was more evident than that of systolic blood pressure. Lead exposure from foetal period until 12 weeks of age causes long lasting hypertension and chemoreceptor reflex dysfunction even after a 16 weeks period without exposure. However, the clearance of lead promoted an improvement in baroreceptor reflex function, with repercussions on blood pressure values, since these values decreased, but did not reached the normotensive values. Regarding the autonomic data, in our study, the overactivity of the sympathetic nervous system, evaluated by the LF band, is concomitant with baroreceptor reflex impairment and/or hypertension. This means that the sympathetic nervous system may be involved in the modulation of the baroreceptor reflexes responses or in the hypertension development due to lead exposure. Concerning the effect of lead at behavioural level, all groups exposed to lead, evaluated in the three different time points, had behavioural changes, namely anxiety, hyperactivity and/or long-term memory impairment and molecular changes in the hippocampus region, more specifically, reactive astrogliosis and microgliosis were detected, indicating the presence of neuroinflammation. However, these alterations seem to reverse after lead abstinence for a certain period (single exposure) and are enhanced when a second exposure occurs (intermittent exposure), along with a synaptic loss. In summary, this study shows, that exposure to lead during the developmental phase can alter the normal course of development, with lifelong health consequences. Since all exposed Pb groups had the same route of exposure (i.e. exposure to lead by water) and the same dose and, despite the different time of exposure, all were exposed to lead since foetal period until adulthood, the most susceptible period to adverse health effects. Therefore, we can conclude that the different effects of lead toxicant between groups mainly depends on the total duration of lead exposure. This comparative study brings new insights on the environmental factors that influence nervous and cardiovascular systems during development, which can help creating public policy strategies to prevent and control the adverse effects of Pb toxicity.

Introduction: The clinical diagnosis of Parkinson’s disease (PD) remains centred on cardinal motor features. However, non-motor manifestations, particularly autonomic nervous system dysfunction, are prevalent throughout the course of the disease, sometimes preceding motor symptoms by years and significantly impairing quality of life. Interoception refers to the process by which the nervous system senses, integrates, interprets, and regulates signals originating from within the body itself. Preliminary research has demonstrated that patients with Parkinson’s (PwP) exhibit reduced interoceptive accuracy and awareness, which can lead to missed opportunities for early interventions due to a failure to recognise and report these impairments. This study aimed to analyse the association between interoception and autonomic function in PwP.Methods:An observational case-control study was conducted, including PwP recruited from the outpatient clinic of the Neurology department of ULS Coimbra during the third trimester of 2025 and the first trimester of 2026, and age and sex matched healthy controls (HC). Clinical evaluation included demographic and disease-related variables, motor severity assessment using the MDS-UPDRS-III, and levodopa equivalent daily dose (LEDD). Participants completed validated scales evaluating interoception (MAIA, BPQ-AS), non-motor symptoms (NMSS, SCOPA-AUT), cognition (MoCA), mood (HAM, BDI), and quality of life (PDQ-39). Descriptive and comparative analyses were performed between groups and interoceptive dimensions.Results:The PD cohort was in the early disease stage, with a Hoehn & Yahr stage of 1.3 and a mean disease duration of 3.4 years. PwP showed a higher burden of non-motor symptoms (total, gastrointestinal and mix domains) and autonomic dysfunction (total, gastrointestinal, genitourinary and sexual domains) and poorer quality of life compared with HC. There were no significant differences in the MAIA scores between groups. However, the group of PwP showed a correlation between the Noticing and Emotional Awareness subdomains and a higher anxiety score and poorer quality of life. Noticing and Emotional Awareness were also inversely related to motor symptom severity. Additionally, the Attention Regulation subdomain showed a negative correlation with the LEDD. Conclusion:Interoception has an important role in the early non-motor phenotype of PD. PwP show a substantial non-motor, autonomic and cognitive burden, even in early disease stages, which significantly affects their quality of life. While subjective interoceptive awareness remained preserved, patients with hypervigilance towards inner signals present a higher level of psychological distress and reduced quality of life. Awareness declines along the motor disability, possibly paralleling the neurodegeneration of interoceptive hubs.

Systemic arterial hypertension is considered the main risk factor for the development of cardiovascular diseases and its etiology seems to be linked to sympathetic hyperactivity. Studies have shown that intestinal dysbiosis can play a fundamental role in the development of arterial hypertension since the composition of the intestinal microbiota affects the cardiovascular, immune, neural and metabolic systems. Thus, the use of probiotics has emerged as a therapeutic strategy with the potential to treat hypertension. In this sense, the present study aims to evaluate the effects of supplementation with a probiotic mixture on cardiovascular parameters, anthropometric, biochemical, food consumption variables and the composition of fecal microbiota in hypertensive women. This is a randomized, triple-blind, placebo-controlled clinical trial, conducted with 40 hypertensive women aged between 20 and 50 years. Patients were randomized into two groups: probiotic group- (n = 20) treated with 1g / of a probiotic mixture containing Lactobacillus paracasei Lpc-37 R SD 5275 R, Lactobacillus rhamnosus HN001 R SD 5675 R, Lactobacillus acidophilus NCFM R SD 5221 R , Bifidobacterium lactis HN019 R SD 5674 and placebo group (n = 20) treated with 1 g / day of polydextrose for 8 weeks, respectively. Biochemical tests, blood pressure assessment, heart rate variability, anthropometric assessment, food consumption and fecal microbiota count were performed before and after the intervention for 8 weeks. Weight, BMI and waist circumference were similar between the two groups (p> 0.05). Probiotic supplementation significantly reduced fasting glycemia (-10.3 mg / dL range, p <0.05) and cholesterol levels (-23.4 mg / dL range, p <0.05) and increased HDL-cholesterol (range 6.5 mg / dL, p <0.05) compared to baseline condition. Probiotic supplementation resulted in higher Lactobacillus fecal counts (p <0.05) and reduced the number of patients with bacterial overgrowth of the small intestine by 67%. Probiotic supplementation reduced systolic BP by 5 mmHg and diastolic BP by 2 mmHg in hypertensive women, and reduced LF oscillation and the LF / HF ratio (p <0.05) in the frequency domain of heart rate variability. Probiotic supplementation for 8 weeks had beneficial effects on fasting blood glucose levels, lipid profile, intestinal microbiota and autonomic modulation in hypertensive women.

The cardiac effects of experimentally induced myocarditis, when the parasite is obtained from mouse blood, are well known. However, the consequences of the infection when the parasites are obtained from bug faeces are less well defined. In the present investigation, we have used the "Y" strain of Trypanosoma cruzi, which was maintained in Rhodnius prolixus by repeated passages in mice. The faeces of 30 infected bugs were collected, the number of parasites counted and 4,000 parasites inoculated by the conjunctival route in 60 rats. Twenty-nine other rats received faeces from noninfected bugs (sham-inoculated controls) and 40 were used as normal controls. The heart rate of the three groups of animals was recorded under general anesthesia with ether. The heart rate, at day 0 pre-inoculation, was similar in the three groups of animals (Controls: 379 ± 27 beats/min Mean ± SD; Sham-inoculated: 366 ± 31; Infected: 351 ± 29) (p> 0.05). In the infected animals, the mean heart rate began to increase significantly by day 12 following infection (375 ± 31), reaching the highest values between days 18 (390 ± 33) and 21 (403 ± 33) and returned to baseline by day 30 (359 ± 28) (p< 0.05). The heart rate changes were statistically different from those observed in the sham-inoculated controls and in the control animals. Therefore, these heart rate changes were provoked by the Trypanosoma cruzi-induced infection. Thus, it appears that irrespective of the source of the parasite and route of inoculation Trypanosoma cruziacute infection provokes a transient sinus tachycardia.

ABSTRACT BACKGROUND: Although autonomic dysfunction has been shown to be associated with liver cirrhosis, the prevalence and prognostic implications are unclear. Abnormal heart rate variability (HRV), a measure of autonomic function, has not been well investigated in cirrhosis. OBJECTIVE: To evaluate the prevalence of high-risk HRV parameters in a cohort of cirrhotic patients and their association with cardiac dysfunction and mortality. DESIGN AND SETTING: Prospective observational study conducted in the Federal University of São Paulo. METHOD: A cohort of 120 patients, comprising 17 healthy controls and 103 cirrhotic outpatients, was evaluated and followed for 10 months. HRV analysis was based on 24-hour Holter monitoring and defined using time-domain and frequency-domain parameters. RESULTS: The HRV parameters were statistically lower in cirrhotic patients than in healthy subjects. High-risk HRV parameters were prevalent, such that 64% had at least one high-risk parameter. Time-domain parameters correlated with Child scores (P < 0.0001). In regression models, HRV parameters were independent predictors of diastolic dysfunction and mortality. During 10 months of follow-up, there were 11 deaths, all of patients with at least one high-risk HRV parameter. Kaplan-Meier analysis estimated low survival rates among patients with standard deviation of normal-to-normal RR intervals (SDNN) < 100. CONCLUSION: Reduced HRV is prevalent in liver cirrhosis and is related to cardiac dysfunction, severity of liver disease and mortality. Abnormal high-risk HRV parameters are prevalent among cirrhotic patients and are also predictors of mortality. Our findings highlight the need for a more careful cardiac evaluation of cirrhotic patients.

ABSTRACT BACKGROUND: Coronary artery disease is an important cause of morbidity and mortality. The impact of ventricular arrhythmias with impaired cardiac vagal activity is one of the most recently studied prognostic factors. However, there are no studies evaluating the phenomenon of heart rate turbulence (HRT) during physical exertion. OBJECTIVE: To study the behavior of HRT during exercise testing, among individuals after myocardial infarction. DESIGN AND SETTING: Feasibility study conducted in a university hospital among individuals 4-6 weeks after myocardial infarction. METHODS: All subjects underwent 24-hour Holter monitoring and ergometric stress testing. We considered that abnormal HRT was present if the turbulence onset was ≥ 0% or turbulence slope was ≤ 2.5 mm/relative risk interval. RESULTS: All 32 subjects were asymptomatic. Their median age was 58 years (interquartile range 12.8) and 70% were male. Abnormal HRT was associated with ventricular dysfunction in this population. We found no differences regarding the behavior of HRT, in relation to age, gender, smoking, systemic arterial hypertension, diabetes mellitus or dyslipidemia. Ergometric stress testing detected premature ventricular beats (PVB) in approximately 44% of the examinations, and these occurred both during the active phase of effort and in the recovery period. The low occurrence of several isolated PVB in beta-blocked subjects made it difficult to perform statistical analysis to correlate HRT between ergometric and Holter testing. CONCLUSION: The data obtained in this study do not support performing HRT through ergometric stress testing among patients who remain on beta-blockers post-myocardial infarction, for the purpose of assessing cardiac vagal activity.

A hipertensão arterial pulmonar (HAP) é uma doença progressiva e fatal, que promove um remodelamento vascular pulmonar obstrutivo, culminando no aumento da resistência vascular pulmonar (PVR) e da pressão arterial pulmonar média (mPAP). Como consequência, há sobrecarga de pressão para o VD que hipertrofia (HVD) e, em estágios avançados, desenvolve insuficiência cardíaca direita (ICD). A monocrotalina (MCT) corresponde ao principal modelo experimental de estudo da patologia e de novos alvos terapêuticos para a HAP. No entanto, poucos estudos focaram na análise da progressão da HAP induzida por MCT e seus efeitos em diferentes tecidos. Por isso, o objetivo desta tese foi avaliar a progressão da HAP induzida por MCT através da análise de parâmetros morfométricos, ecocardiográficos, hemodinâmicos, bioquímicos, moleculares e histológicos, a fim de caracterizar a evolução da doença em diferentes tecidos. Este estudo foi aprovado pelo Comitê de Ética em Pesquisa da UFRGS (número 32151). Ratos machos foram divididos em dois grupos: MCT e controle. O grupo MCT recebeu uma única injeção (60 mg / kg, i.p.) de MCT, enquanto o controle recebeu solução salina na mesma dose. Na sequência, os grupos MCT e controle foram divididos em 3 grupos: 1, 2, e 3 semanas (primeiro protocolo experimental) ou em 4 grupos: 1, 2, 3 e 4 semanas (segundo protocolo experimental). Para o primeiro protocolo experimental, as seguintes análises foram realizadas: ecocardiográfica (índice de performance miocárdica (MPI) e relação entre tempo de aceleração e tempo de ejeção pela artéria pulmonar (AT/ET), hemodinâmica (pressão arterial pulmonar média-mPAP) e morfométrica (hipertrofia do ventrículo direito-HVD). O pulmão foi usado para análises histológicas (determinação da espessura da parede pulmonar, extensão do dano tecidual, quantificação celular e deposição de colágeno), bioquímicas (atividade da NADPH oxidase –Nox, catalase –CAT, superóxido dismutase –SOD, glutationa peroxidase –GPx, tiorredoxina redutase – TrxR, glutationa redutase –GR e óxido nítrico sintase –NOS, concentração de sulfidrila, espécies reativas de oxigênio total –ROS e TBARS), moleculares (expressão da eNOS, relação entre os receptores da endotelina-1 [ETAR e ETBR], expressão de Trx-1 e seu regulador VDUP-1- vitamina D (3) proteína regulada positivamente 1; fator nuclear 2 relacionado ao fator eritroide; proliferação celular [razão entre Akt total e fosforilada], vias de morte celular [caspase-3, razão entre JNK total e fosforilada e razão entre p38 total e fosforilada] e inflamação [razão entre NF-κβ 65 total e fosforilado, HSP70]) e imunohistoquímica (marcação com nitrotirosina). O segundo protocolo experimental consistiu na submissão dos animais ao exame ecocardiográfico (excursão sistólica do plano anular tricúspide (TAPSE), velocidade máxima de enchimento rápido e lento do ventrículo direito (relação E / A), mudança da área fracional do ventrículo esquerdo (FAC) e fração de ejeção ventricular (FE) e análise hemodinâmica (pressões sistólica e diastólica de VD e VE e suas derivadas de contratilidade e relaxamento), seguida de eutanásia. A modulação autonômica foi avaliada pela análise espectral considerando dois componentes espectrais: baixa frequência (LF) e alta frequência (HF). VD e VE foram usados, ainda, para análises morfométricas (HVD), bioquímicas (concentração de peróxido de hidrogênio (H2O2) e TBARS, atividade da SOD, CAT, GPx e conteúdo de sulfidrila) e histológicas (determinar o infiltrado inflamatório). Os dados foram submetidos ao teste de normalidade Shapiro-Wilk. Os resultados com distribuição normal foram analisados pela ANOVA de duas vias, complementada pelo teste de Student-Newman-Keuls, enquanto os resultados sem distribuição normal foram analisados pelo teste de comparação múltipla de Kruskal-Wallis (P <0,05). No pulmão, a HAP promoveu aumento nas atividades da Nox e SOD, aumento de ROS, expressão de eNOS e dano nitrosativo na primeira semana. Além disso, houve aumento da atividade de TrxR, da expressão de Trx-1 e VDUP-1, e redução da atividade da GR. Após duas semanas da administração de MCT, mostrou-se aumento da NOS e redução da atividade da CAT. Foi observada, também, redução da expressão da Trx-1, Nrf2 e HSP70, bem como aumento da expressão de VDUP-1 e das vias de proliferação, inflamação e apoptose. Na terceira semana, a HAP aumentou a atividade de SOD e NOS, diminuiu a expressão de eNOS e o conteúdo de sulfidrilas, aumentou a razão ETAR/ETBR, a concentração de ROS e do dano oxidativo (TBARS) e nitrosativo (nitrotirosina). Somado a isso, foi observado aumento da atividade de TrxR, redução da expressão de Trx-1, Nrf2 e HSP70, aumento da expressão de VDUP-1, ativação de proliferação celular e inflamação. Nenhuma diferença significativa foi encontrada nas vias apoptóticas. Todas essas alterações foram acompanhadas por remodelamento dos vasos pulmonares e extensa lesão no parênquima pulmonar. Além disso, deposição de colágeno foi encontrada em estágios avançados. Como consequência desse remodelamento pulmonar, houve aumento da mPAP e desenvolvimento de HVD após 2 e 3 semanas em comparação aos seus grupos controles.O desenvolvimento de HAP induziu redução da razão AT/ET e aumento do MPI na terceira semana. No tecido cardíaco, a indução com MCT promoveu aumento na pressão sistólica do VD, na concentração de H2O2, atividade de CAT e TBARS, e diminuição do conteúdo de sulfidrilas no VD, associado à inflamação leve, enquanto no VE foi encontrado apenas aumento no conteúdo de sulfidrilas. Após duas semanas, houve, aumento da pressão sistólica do VD, conteúdo de sulfidrilas no VD, inflamação leve a moderada, HVD, enquanto no VE foi constatada inflamação leve e diminuição do conteúdo de sulfidrilas. Após três semanas, a HAP, no VD, levou à inflamação moderada a acentuada, diminuição da atividade da SOD e aumento da atividade da GPx e do dano oxidativo a lipídios. No VE, foi encontrado aumento de dano oxidativo e inflamação leve. Esta fase também foi caracterizada pelo aumento do tônus simpático e diminuição do tônus parassimpático. Dessa forma, no tecido pulmonar, a primeira semana foi marcada pela presença de estresse nitrosativo, que levou a uma adaptação após 2 semanas. O estresse oxidativo pulmonar foi evidente na terceira semana, provavelmente por um desequilíbrio entre os receptores da endotelina-1, resultando em remodelamento da matriz extracelular, disfunção endotelial e HVD. Assim, acredita-se que essas alterações no VD sejam decorrentes de alterações pulmonares anteriores. Aqui demonstramos essas alterações pulmonares através de um desequilíbrio na expressão das defesas antioxidantes, destacando uma redução na expressão de Trx-1 e um aumento no seu inibidor intrínseco, VDUP-1. Também demonstramos um envolvimento temporal das vias de sinalização relacionadas à proliferação e inflamação. No tecido cardíaco, é plausível supor que as mudanças observadas no estresse oxidativo e na inflamação estejam intimamente relacionadas às alterações iniciais induzidas pela HAP no VD, enquanto o desequilíbrio autonômico parece contribuir para a exacerbação dessa conversa cruzada nas fases avançadas da doença. Em contrapartida, devido à falta de efeito direto, o VE sofreu poucas alterações em resposta à administração da MCT.

Earlier studies from the authors' laboratory showed that malnourishment induces alterations in the cardiovascular homeostasis increasing the basal mean arterial pressure and heart rate. In this study, the authors evaluated whether the sympathetic and parasympathetic efferent activities contribute to changes in the cardiovascular homeostasis through altered modulation of the arterial baroreflex of malnourished rats. After weaning, male Fischer rats were given 15% (Normal Protein—NP) or 6% (Low Protein—LP) protein diet for 35 d. The baroreflex gain and latency were evaluated before and after selective autonomic blockades in control and malnourished rats. It was observed that malnourishment affected the baroreflex gain in response to activation and deactivation of the arterial baroreflex. Moreover, malnourished rats showed increased baroreflex latency as compared to that of control rats. Regarding the autonomic efferent activity directed to the heart, the data showed increased sympathetic and decreased parasympathetic efferent activities in malnourished rats, and such alterations could be related to the observed changes in the arterial baroreflex gain as well as in the basal mean arterial pressure and heart rate.

Background: Sympathetic dysfunction can be evaluated by heart rate reserve (HRR) with exercise test. Objectives: To determine the value of HRR in predicting outcome of patients with hypertrophic cardiomyopathy (HCM). Methods: We enrolled 917 HCM patients (age = 49 +/- 15 years, 516 men) assessed with exercise stress echocardiography (ESE) in 11 centres. ESE modality was semi-supine bicycle in 51 patients (6%), upright bicycle in 476 (52%), and treadmill in 390 (42%). During ESE, we assessed left ventricular outflow tract obstruction (LVOTO), stress-induced new regional wall motion abnormalities (RWMA), and HRR (peak/rest heart rate, HR). By selection, all patients completed the follow-up. Mortality was the predetermined outcome measure Results: During ESE, RWMA occurred in 22 patients (2.4%) and LVOTO (>= 50 mmHg) in 281 (30.4%). HRR was 1.90 +/- 0.40 (lowest quartile <= 1.61, highest quartile > 2.13). Higher resting heart rate (odds ratio 1.027, 95% CI: 1.018-1.036, p < 0.001), older age (odds ratio 1.021, 95% CI: 1.009-1.033, p < 0.001), lower exercise tolerance (mets, odds ratio 0.761, 95% CI: 0.708-0.817, p < 0.001) and resting LVOTO (odds ratio 1.504, 95% CI: 1.043-2.170, p = 0.029) predicted a reduced HRR. During a median follow-up of 89 months (interquartile range: 36-145 months), 90 all-cause deaths occurred. At multivariable analysis, lowest quartile HRR (Hazard ratio 2.354, 95% CI 1.116-4.968 p = 0.025) and RWMA (Hazard ratio 3.279, 95% CI 1.441-7.461 p = 0.004) independently predicted death, in addition to age (Hazard ratio 1.064, 95% CI 1.043-1.085 p < 0.001) and maximal wall thickness (Hazard ratio 1.081, 95% CI 1.037-1.128, p < 0.001). Conclusions: A blunted HRR during ESE predicts survival independently of RWMA in HCM patients.