Cardiovascular and Autonomic Dysfunction in Murine Ligature-Induced Periodontitis

The present study examined the hemodynamics [arterial pressure (AP), AP variability (APV), heart rate (HR), and heart rate variability (HRV)], cardiac function (echocardiographycally), and myocardial inflammation in Balb/c mice submitted to Periodontitis, through the ligation of the left first molar, or Sham surgical procedure. The first protocol indicated that the AP was similar (136 ± 2 vs. 132 ± 3 mmHg in Sham), while the HR was higher in mice with Periodontitis (475 ± 20 vs. 412 ± 18 bpm in Sham), compared to their Sham counterparts. The APV was higher in mice with Periodontitis when evaluated in the time domain (4.5 ± 0.3 vs. 3.4 ± 0.2 mmHg in Sham), frequency domain (power of the LF band of systolic AP), or through symbolic analysis (patterns 0V + 1V), indicating a sympathetic overactivity. The HRV was similar in the mice with Periodontitis, as compared to their Sham counterparts. In the second protocol, the mice with Periodontitis showed decreased cardiac output (10 ± 0.8 vs. 15 ± 1.4 mL/min in Sham) and ejection fraction (37 ± 3 vs. 47 ± 2% in Sham) associated with increased myocardial cytokines (Interleukin-17, Interleukin-6, and Interleukin-4). This study shows that experimental Periodontitis caused cardiac dysfunction, increased heart cytokines, and sympathetic overactivity, in line with epidemiological studies indicating an increased risk of cardiovascular events in clinical Periodontitis.

Abstract P239: Toll-Like Receptors 9 (TLR9) Play a Key Role in Cardiac and Vascular Dysfunction Associated With 2-Kydney 1-Clip (2K1C) Hypertension in Mice

Introduction: Renovascular hypertension is the leading cause of secondary hypertension and is also involved in the physiopathogenesis of resistant hypertension. The activation of toll-like receptors 9 (TLR9) was demonstrated to contribute to the increase in arterial pressure (AP) in spontaneously hypertensive rats. We hypothesize that the TLR9 are also activated in two-kidney one- clip (2K1C) hypertensive mice, eliciting cardiac and vascular dysfunction; therefore, contributing to the increase in AP.

Methods and Results: C57BL (WT) and TLR9 knockout (TLR9_KO) mice were anesthetized with isoflurane and submitted to 2K1C hypertension by placing a silver clip (0.12 mm) around the left renal artery. After 4 weeks, the cardiac function of mice was evaluated by echocardiography in anesthetized subjects. Following, the direct AP measurement was carried out and the third-order mesenteric resistance arteries (MRA) were removed for vascular function evaluation. All data were compared to Sham-operated WT mice. The AP was remarkably elevated in 2K1C WT mice (133±2 vs 93 ± 4 mmHg), whereas this increase was partially prevented by the absence of the TLR9 (114±5 mmHg). 2K1C hypertension caused cardiac dysfunction in WT mice, displaying decreased ejection fraction (42.6±3.1 vs 52.7±1.5%), fractional shortening (10.1±0.7 vs 13.7±0.9%), stroke volume (25.9±2.2 vs 37.9±1.9 μL) and cardiac output (9.2±0.8 vs 14.6±0.8 mL/min); however, the 2K1K hypertension did not affect the cardiac function in TLR9_KO mice: ejection fraction (54.5±1.6%), fractional shortening (14.5±1.1%), stroke volume (43.4±4.6 μL) and cardiac output (15.2±1.6 mL/min). Vascular dysfunction, characterized by increased contractile response to phenylephrine (Emax: 167.2±2.2 vs 125.9±3.5%) and reduced relaxation to acetylcholine (Emax: 69.3±1.6 vs 87.6±1.4%) and sodium nitroprusside (pD2: 7.3±0.07 vs 7.9±0.05), was observed in 2K1C WT mice, but not in 2K1C TLR9_KO mice (Emax: 127.7±2.9%, 88.5±2.0% and pD2: 7.78±0.06, to phenylephrine, acetylcholine and sodium nitroprusside).

Conclusions: TLR9 is involved in both cardiac and vascular dysfunctions of 2K1C mice and also in the increase of AP of this experimental model.

Changes in the Complexity of Heart Rate Variability with Exercise Training Measured by Multiscale Entropy-Based Measurements

Quantifying complexity from heart rate variability (HRV) series is a challenging task, and multiscale entropy (MSE), along with its variants, has been demonstrated to be one of the most robust approaches to achieve this goal. Although physical training is known to be beneficial, there is little information about the long-term complexity changes induced by the physical conditioning. The present study aimed to quantify the changes in physiological complexity elicited by physical training through multiscale entropy-based complexity measurements. Rats were subject to a protocol of medium intensity training ( n = 13 ) or a sedentary protocol ( n = 12 ). One-hour HRV series were obtained from all conscious rats five days after the experimental protocol. We estimated MSE, multiscale dispersion entropy (MDE) and multiscale SDiff q from HRV series. Multiscale SDiff q is a recent approach that accounts for entropy differences between a given time series and its shuffled dynamics. From SDiff q , three attributes (q-attributes) were derived, namely SDiff q m a x , q m a x and q z e r o . MSE, MDE and multiscale q-attributes presented similar profiles, except for SDiff q m a x . q m a x showed significant differences between trained and sedentary groups on Time Scales 6 to 20. Results suggest that physical training increases the system complexity and that multiscale q-attributes provide valuable information about the physiological complexity.

Methylphenidate in a patient with depression and respiratory insufficiency

OBJECTIVE

We report a case of severe depression in an elderly and critically ill patient with multiple medical complications who was treated with a combination of methylphenidate and sertraline. The objective of this report is to outline the usefulness of methylphenidate as an antidepressant in a patient with respiratory insufficiency.

METHOD

Case description.

RESULTS

The patient had a positive clinical response with initial mental confusion due to methylphenidate. An initial dose of 2.5 mg/day allowed antidepressant response and improvement of respiratory function permitting the removal of mechanical ventilation.

CONCLUSION

Methylphenidate may be useful for patients with severe medical conditions including ventilatory insufficiency.