Focused ultrasound stimulation of the inflammatory reflex at the spleen ameliorates pulmonary arterial hypertension in rodents

Background

Inflammation is a major contributor in pulmonary arterial hypertension (PAH) pathogenesis. Non-invasive, focused ultrasound stimulation (FUS) of the spleen activates the neuroimmune inflammatory reflex (IR) and suppresses systemic inflammation [1].

Purpose

We aimed to explore whether daily FUS of the spleen improves haemodynamics and biomarkers by modulating the IR, in a rat model of PAH.

Methods

Sprague-Dawley rats (n=12) were injected s.c. with Sugen5416 (VEGF receptor inhibitor) and then, were placed in a hypoxic chamber (FiO2=10%) for 21 days, followed by 14 days of re-exposure to normoxia (FiO2=10%). At day 21, rats were randomized to either FUS (n=6) or sham-stimulation of the spleen (n=6). Each FUS- or sham-stimulation session consisted of 12 minutes. After 14 days of treatment, in a terminal experiment, right ventricular systolic pressure (RVSP) and arterial pressure were measured invasively, as well as biomarkers, in each animal (Figure 1A).

Results

FUS significantly reduced RVSP compared with the sham-stimulation (Mean±SEM, 50.83±3.57 mmHg vs 72.50±5.81; p=0.009), resulting in a 30% relative reduction (Figure 1B). Mean systemic arterial pressure was similar in the 2 groups (Mean±SEM, 79.83±3.73 mmHg vs. 87.00±2.95; p=0.137) (Figure 1C), as was the change in heart rate between day 1 and day 14 of treatment period (−19.53±5.36% vs. −16.79±3.1, p=0.61) (Figure 1D). Consistently, plasma brain natriuretic peptide (BNP) levels are reduced in the FUS group (119.45±19.93 ng/μl vs. 319.39±91.85; p=0.019), indicative of reduced myocardial wall stress in the FUS group (Figure 1E).

Conclusion

Non-invasive FUS of the spleen reduced RVSP by ∼30% and BNP without significantly affecting systemic pressure or heart rate, in rats with severe PAH. Non-invasive FUS, by modulating the IR, may exert an anti-inflammatory effect in PAH. FUS of the spleen is noninvasive, safe, widely available and easy to perform, and should be further explored as a possible therapeutic option in PAH.

Funding Acknowledgement

Type of funding sources: Private hospital(s). Main funding source(s): Northwell Health

Stellate ganglion blockade for treatment of ventricular arrhythmia storm: a meta-analysis

Background

Autonomic neuromodulation and particularly stellate ganglion blockade (SGB) has been tested in ventricular arrhythmia (VA) storm, but there is so far no robust evidence to inform clinical practice and its use remains limited.

Purpose

We aimed to summarize the efficacy and safety of SGB in patients with VA storm.

Methods

We searched PubMed, the Cochrane Library and Scopus from inception to 15th March 2022, for studies performing either pharmacological or electrical SGB in the context of drug-refractory VA storm. Case series with less than 10 patients were excluded. We performed a single-arm random effects meta-analysis of studies to calculate the pooled proportion estimate of freedom from VA recurrence after SBG and the overall mean change of VA burden from baseline.

Results

Of 409 articles identified and screened, we considered eligible six studies comprising a total of 106 patients. The mean age was 61.6±13.9 years, 79.2% were male, the mean left ventricular ejection fraction was 28.8±12.7%, and 47.1% had underlying ischemic cardiomyopathy. In five trials the patients received pharmacological SGB with bupivacaine, ropivacaine, or/and lidocaine (left-sided or bilateral), while in one study transcutaneous magnetic stimulation of the left stellate ganglion was used. The pooled proportion of patients free of VA recurrences was 65% (95% CI 51–78%, I2=46%) at the first 24 hours post-SGB (Figure 1A), and 54% (95% CI 43–64%, I2=0%) at 72 hours (Figure 1B). The number of VA episodes was significantly reduced from a mean baseline of 7.01±8.34 episodes/24h before SGB to 0.93±1.64 episodes/24h after SGB. The mean absolute reduction of VA episodes was 5.44 (95% CI 2.83–8.05, I2=88%) (Figure 1C) while the mean absolute reduction of external or internal defibrillation events was 3.36 (95% CI 0.62–6.09, I2=84%) (Figure 1D). No serious procedure-related complications were reported. The overall in-hospital mortality was 28.4%.

Conclusions

SGB appears an effective and safe treatment in patients with VA storm with approximately 1 in 2 patients exhibiting complete suppression of VA for 72 hours and an approximately 80% mean relative reduction in VA burden.

Funding Acknowledgement

Type of funding sources: None.

Parathyroid hormone levels, calcium-channel blockers, and the dyslipidemia of nondiabetic hemodialysis patients

BACKGROUND

Experimental studies have shown that increased levels of parathyroid hormone (PTH) in uremia may cause elevation of intracellular calcium, predisposing to insulin resistance and lipid metabolism abnormalities. Administration of calcium-channel blockers (CCBs) in these models protects against the development of lipid profile abnormalities. This study evaluates the combined effect of intact PTH (iPTH) levels and administration of CCB on the lipid profiles of nondiabetic hemodialysis patients.

METHODS

One hundred and eight non-diabetic hemodialysis patients were studied for 6 months. The population was divided into four groups, according to iPTH levels and administration of CCB: (A) iPTH<70 pg/mL, administration of CCB (n=16), (B) iPTH>300 pg/mL without administration of CCB (n=43), (C) iPTH<70 pg/mL without CCB administration (n=19), and (D) iPTH>300 pg/mL with CCB administration (n=30). Serum concentrations of total cholesterol, high-density lipoprotein (HDL), triglycerides, and albumin were measured on a monthly basis.

RESULTS

All results are shown as mean SE. Total cholesterol values (in mg/ dL) were for group (A) 186 +/- 4, for group (B) 205 +/- 3, for group (C) 200 +/- 3, and for group (D) 203 +/- 4 [p NS between (C) and (D), p<.05 for all other comparisons]. Triglycerides values (in mg/dL) were for group (A) 171 +/- 9, for group (B) 199 +/- 6, for group (C) 190 +/- 6, and for group (D) 191 +/- 9 (p NS for all comparisons). HDL values (in mg/dL) were for group (A) 43.8 +/- 1, for group (B) 35.8 +/- 1, for group (C) 38.3 +/- 0.7, and for group (D) 37.2 +/- 0.7 mg/dL [p NS between (C) and (D), p<.001 for all other comparisons]. Low-density lipoprotein values (in mg/dL) were for group (A) 107.6 +/- 4.4, for group (B) 149.3 +/- 2.5, for group (C) 131.2 +/- 2.9, and for group (D) 126.8 +/- 4.1 [p NS between (C) and (D), p<.001 for all other comparisons]. Atherogenic index values, calculated as [triglycerides/HDL] ratio, were for group (A) 4.6 +/- 0.04 , for group (B) 6.2 +/- 0.04, for group (C) 4.9 +/- 0.03, and for group (D) 5.9 +/- 0.03 [p NS between (C) and (D), p<.004 for all other comparisons].

CONCLUSION

In nondiabetic hemodialysis patients, lipid profile abnormalities often accompany high levels of iPTH. The decrease in iPTH and/or the administration of CCB are accompanied by significant improvements in the main lipid profiles, including the atherogenic index.