P5355Evaluation of maternal heart rate during the first week postpartum with wearable device

Background

Throughout pregnancy and puerperium significant cardiovascular changes occur. Maternal heart rate (HR) increases from the first to the third trimester of pregnancy, with a further increase during labor. Changes in the postpartum period are less well defined, in particular, the phenomenon of postpartum maternal bradycardia (PMB).

Purpose

To describe the distribution of HR in the first week postpartum, the incidence of PMB and to investigate the relationship between PMB and other maternal factors such as age, BMI and type of delivery.

Methods

Women who gave their informed consent during a clinical evaluation in the third trimester of pregnancy, and delivered at our tertiary centre between 01/01/2018 and 30/09/2018, were included. Within 12 hours from delivery, a wrist-worn tracker with a light-emitting diode (FitBit Alta HR) was applied and then removed one week postpartum. Data were extracted as 5 minutes recordings, each showing a mean HR. Only day-time recordings were considered. PMB was defined as ratio between bradycardia recordings (mean HR<60 bpm) and all recordings >0.6. SPSS was used for statistical analysis.

Results

252 women were included (mean age 35.3±5 years, BMI 23.3±5 kg/m2). 63% of women underwent caesarean section. Mean HR of the total population on day 1 after delivery was 80.7±11 bpm and then progressively decreased, with a mean HR on day 7 of 76.5±12 bpm (figure 1). 24 women developed PMB, with an incidence of 9.5%. The trend of HR in bradycardic women was opposite to that of non-bradycardic women, with an increase from day 1 (55±7 bpm) to day 7 (60.5±9 bpm) (figure 2). Device recordings during the first two days were in agreement with periodic bedside HR measurements. No bradycardic woman experienced syncope or pre-syncope or required treatment. PMB showed a positive correlation with caesarean section vs. vaginal delivery (p<0.01) and maternal age (p<0.05). No correlation was found with BMI and postpartum haemoglobin.

Trend of HR in the first week postpartum

Conclusion

In our population the incidence of PMB identified with wearable device was 9.5% and was associated with caesarean section and maternal age. Considering that HR returned within normal limits 7 days after delivery and no woman was symptomatic, our study suggests that PMB might be considered a benign entity.

P5356NT-proBNP is a valuable diagnostic tool of heart failure even during post partum period

Background

Post-partum period is characterized by complex haemodynamic changes that may lead to heart failure (HF) in a minority of patients. B-type natriuretic peptides inactive amino terminal fragment (NT-proBNP) is an established biomarker in the management of HF. Patients presenting with dyspnea are considered at high risk of HF if NT-proBNP is above 125 pg/ml. Higher levels of NT-proBNP in the post natal period were reported to be associated with increased risk of cardiovascular events, but there is no defined cut-off value established for prediction of HF in this setting.

Purpose

We conducted this study to identify an adequate cut-off value which would predict haemodynamic overload among post-partum women.

Methods

All women who gave informed consent during an obstetric clinical evaluation at our tertiary centre between 01/01/2018 and 30/09/2018 were included in the study. NT-proBNP was measured within 24 hours from delivery. The primary endpoint of the study was the development of signs and symptoms of heart failure (with the need of intravenous diuretics or a cardiological evaluation) within 15 days after delivery. We therefore analyzed the ability of different cut-off of NT-proBNP values in predicting the primary outcome. Confidence intervals (CI) for sensitivity and specificity were calculated with the Wilson score method.

Results

252 women were included in the study. Eleven of them developed in the study timeframe signs and symptoms of HF (4.3%); all of them were treated with diuretics. Nine patients were evaluated with echocardiography and 3 of them required cardiological counseling. The cut-off value of 600 pg/mL was found to have the best sensitivity (73%, CI 95% 0.43–0.9), specificity (98%, CI 95% 0.95–0.98), positive likelihood ratio (29, CI 95% 12–69) and negative likelihood ratio (0.28, IC 95% 0.10–0.70). The diagnostic odds ratio was 104 (CI 95% 22–494, p<0.001). Mean NT-proBNP was 169±121 pg/mL (cutoff <600 pg/mL) versus 852±245 pg/mL.

Different cut-off evaluated NT-proBNP value (pg/mL) Specificity Sensibility Diagnostic Odds ratio 125 42 81 3.4 (95% CI 0.7–16, p=0.1) 300 85 72 14 (95% CI 4–62, p<0.01) 600 98 73 104 (95% CI 22–494, p<0.01) 700 98 66 65 (95% CI 12–341, p<0.01)

Conclusion

Our study suggests that NT-proBNP higher than 600 pg/mL is a high risk marker for developing HF in the post partum period. This value is slightly higher compared to the one adopted among the general population for diagnosis of HF and may reflect the peculiar haemodynamic changes of this setting.

A role for D-aspartate oxidase in schizophrenia and in schizophrenia-related symptoms induced by phencyclidine in mice

Increasing evidence points to a role for dysfunctional glutamate N-methyl-D-aspartate receptor (NMDAR) neurotransmission in schizophrenia. D-aspartate is an atypical amino acid that activates NMDARs through binding to the glutamate site on GluN2 subunits. D-aspartate is present in high amounts in the embryonic brain of mammals and rapidly decreases after birth, due to the activity of the enzyme D-aspartate oxidase (DDO). The agonistic activity exerted by D-aspartate on NMDARs and its neurodevelopmental occurrence make this D-amino acid a potential mediator for some of the NMDAR-related alterations observed in schizophrenia. Consistently, substantial reductions of D-aspartate and NMDA were recently observed in the postmortem prefrontal cortex of schizophrenic patients. Here we show that DDO mRNA expression is increased in prefrontal samples of schizophrenic patients, thus suggesting a plausible molecular event responsible for the D-aspartate imbalance previously described. To investigate whether altered D-aspartate levels can modulate schizophrenia-relevant circuits and behaviors, we also measured the psychotomimetic effects produced by the NMDAR antagonist, phencyclidine, in Ddo knockout mice (Ddo(-)(/-)), an animal model characterized by tonically increased D-aspartate levels since perinatal life. We show that Ddo(-/-) mice display a significant reduction in motor hyperactivity and prepulse inhibition deficit induced by phencyclidine, compared with controls. Furthermore, we reveal that increased levels of D-aspartate in Ddo(-/-) animals can significantly inhibit functional circuits activated by phencyclidine, and affect the development of cortico-hippocampal connectivity networks potentially involved in schizophrenia. Collectively, the present results suggest that altered D-aspartate levels can influence neurodevelopmental brain processes relevant to schizophrenia.

Dysfunctional dopaminergic neurotransmission in asocial BTBR mice

Autism spectrum disorders (ASD) are neurodevelopmental conditions characterized by pronounced social and communication deficits and stereotyped behaviours. Recent psychosocial and neuroimaging studies have highlighted reward-processing deficits and reduced dopamine (DA) mesolimbic circuit reactivity in ASD patients. However, the neurobiological and molecular determinants of these deficits remain undetermined. Mouse models recapitulating ASD-like phenotypes could help generate hypotheses about the origin and neurophysiological underpinnings of clinically relevant traits. Here we used functional magnetic resonance imaging (fMRI), behavioural and molecular readouts to probe dopamine neurotransmission responsivity in BTBR T(+) Itpr3(tf)/J mice (BTBR), an inbred mouse line widely used to model ASD-like symptoms owing to its robust social and communication deficits, and high level of repetitive stereotyped behaviours. C57BL/6J (B6) mice were used as normosocial reference comparators. DA reuptake inhibition with GBR 12909 produced significant striatal DA release in both strains, but failed to elicit fMRI activation in widespread forebrain areas of BTBR mice, including mesolimbic reward and striatal terminals. In addition, BTBR mice exhibited no appreciable motor responses to GBR 12909. DA D1 receptor-dependent behavioural and signalling responses were found to be unaltered in BTBR mice, whereas dramatic reductions in pre- and postsynaptic DA D2 and adenosine A2A receptor function was observed in these animals. Overall these results document profoundly compromised DA D2-mediated neurotransmission in BTBR mice, a finding that is likely to have a role in the distinctive social and behavioural deficits exhibited by these mice. Our results call for a deeper investigation of the role of dopaminergic dysfunction in mouse lines exhibiting ASD-like phenotypes, and possibly in ASD patient populations.

Free D-aspartate regulates neuronal dendritic morphology, synaptic plasticity, gray matter volume and brain activity in mammals

D-aspartate (D-Asp) is an atypical amino acid, which is especially abundant in the developing mammalian brain, and can bind to and activate N-methyl-D-Aspartate receptors (NMDARs). In line with its pharmacological features, we find that mice chronically treated with D-Asp show enhanced NMDAR-mediated miniature excitatory postsynaptic currents and basal cerebral blood volume in fronto-hippocampal areas. In addition, we show that both chronic administration of D-Asp and deletion of the gene coding for the catabolic enzyme D-aspartate oxidase (DDO) trigger plastic modifications of neuronal cytoarchitecture in the prefrontal cortex and CA1 subfield of the hippocampus and promote a cytochalasin D-sensitive form of synaptic plasticity in adult mouse brains. To translate these findings in humans and consistent with the experiments using Ddo gene targeting in animals, we performed a hierarchical stepwise translational genetic approach. Specifically, we investigated the association of variation in the gene coding for DDO with complex human prefrontal phenotypes. We demonstrate that genetic variation predicting reduced expression of DDO in postmortem human prefrontal cortex is mapped on greater prefrontal gray matter and activity during working memory as measured with MRI. In conclusion our results identify novel NMDAR-dependent effects of D-Asp on plasticity and physiology in rodents, which also map to prefrontal phenotypes in humans.

Bimodal effect of D-aspartate on brain aging processes: insights from animal models

Nowadays it is widely recognized that D-amino acids are present in bacteria as well as in eukaryotes, including mammals. In particular, free D-serine and D-aspartate are found in the brain of mammals. Notably, D-aspartate occurs at substantial levels in the embryo brain to then consistently decrease at post-natal phases. Temporal regulation of D-aspartate content depends on the post-natal onset of D-aspartate oxidase expression, the only known enzyme able to catabolize this D-amino acid. Pharmacological evidence indicates that D-aspartate binds and activates NMDA receptors (NMDARs). To decipher the physiological function of D-aspartate in mammals, in the last years, genetic and pharmacological mouse models with abnormally higher levels of this D-amino acid have been generated. Overall, these animal models have pointed out a significant neuromodulatory role for D-aspartate in the regulation of NMDAR-dependent functions. Indeed, increased content of D-aspartate are able to increase hippocampal NMDAR-dependent long-term potentiation (LTP) and spatial memory of adult mice. However, if exposure to elevated levels of D-Asp lasts for the entire lifetime of mice, enhancement of synaptic plasticity turns into a dramatic worsening, thus triggering an acceleration of the NMDAR-dependent aging processes in the hippocampus. Nonetheless, administration of D-Asp to old mice can restore the physiological age-related decay of hippocampal NMDA-related LTP. Besides its effect on hippocampus-dependent processes in mouse models, different points of evidence are indicating, today, a potential role for D-Asp in neurologic and psychiatric disorders associated with aberrant signalling of NMDARs.

Management of childhood obesity in pediatric practice

Evaluation of obese children and adolescents in the pediatric office or clinic should include baseline assessment of weight for height and body fatness; rule out endocrine and genetic causes of obesity; and evaluate other health-risk factors, such as those for cardiovascular disease, cancer, diabetes, and hypertension. Treatment of obesity is most successful if realistic goals are set; a balanced low-fat/high-fiber diet is stressed; a safe rate of weight loss of 1 to 2 pounds per week is achieved through a moderate reduction of caloric intake (approximately 20-25% decrease); increased physical activity is stressed as much as diet; parental support is strong; and behavior therapy is provided during the course of treatment to help both child and parent achieve the diet, exercise, and behavior goals.