Biology subjects

Pellegrino, P. R.

Publications and source records attributed to Pellegrino, P. R..

5 recordsLinked to original sources

bioRxiv2026

Limitations of renal arterial hemodynamic measures as candidate biomarkers of renal sympathetic innervation

Introduction: The key role of maladaptive renal sympathetic activation in hypertension has led to the development of catheter-based renal denervation therapies. Unfortunately, the lack of practical physiological biomarkers impairs patient selection and prevents intraprocedural feedback for renal denervation. Methods: We tested whether renal arterial hemodynamic measures and the beat-to-beat variability of these measures reflect renal sympathetic innervation in two tightly controlled preclinical models of renal denervation. Bilateral renal hemodynamic data were obtained from ten conscious unilaterally denervated rabbits and ten anesthetized unilaterally denervated pigs that subsequently underwent stepwise catheter-based radiofrequency denervation of the contralateral kidney. Renal arterial mechanics were assessed by quantification of wave speed and input impedance modulus and phase shift. Variability was quantified as the within-recording standard deviation of each metric when measured on a beat-to-beat basis. Results: Wave speed trended down after surgical denervation in rabbits (P = 0.054) but not swine (P = 0.57); wave speed variability was unchanged in both models. Renal arterial input impedance modulus was not significantly affected by surgical denervation. Surgical renal denervation increased input impedance phase shift in rabbits (P = 0.0048) but not in swine (P = 0.85). The beat-to-beat variability of modulus did not differ significantly between innervated and surgically denervated kidneys in either species. Surgical renal denervation decreased phase shift variability in swine (P = 0.0048) but not rabbits. The difference in phase shift variability between kidneys in swine was eliminated after a single round of branch-vessel ablation (P = 0.42). Discussion: Renal arterial wave speed, input impedance, and their beat-to-beat variability did not consistently or dose-dependently reflect renal sympathetic innervation in these models. These findings argue against their use as direct physiological surrogates for renal sympathetic outflow.

physiology↗

bioRxiv2026

Cardiac Mitochondrial Dysfunction Following Bleomycin-Induced Acute Lung Injury in Rats

BackgroundAcute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are frequently associated with cardiac complications, including myocardial injury and right ventricular dysfunction. However, the mechanisms linking pulmonary injury to cardiac dysfunction remain incompletely understood. In this study, we investigated ventricular mitochondrial respiratory function during the acute phase of bleomycin-induced ALI. MethodsALI was induced in male and female rats by intratracheal bleomycin (2.5 mg/kg); saline served as a control. Circulating cardiac troponin I (cTnI) was measured as an indicator of myocardial injury. Mitochondrial respiration was assessed in permeabilized ventricular fibers using high-resolution respirometry (HRR). The mitochondrial respiration rate of the H9C2 cardiomyoblast cell line was performed using Seahorse Xfe96 Cell Mitochondrial Stress Test. Cells were treated with pro-inflammatory cytokine cocktails (PRO; IL1{beta} plus TNF plus IL6), anti-inflammatory cytokine cocktails (ANTI; IL4 plus IL10), a mixture of PRO and ANTI (BOTH), and (-)-norepinephrine (NE) in either hypoxic (1% oxygen) or normoxic conditions. ResultsBleomycin-induced ALI increased circulating cTnI levels in male rats, indicating early cardiac stress following lung injury. Mitochondrial respiration in the LV appeared to show modest alterations, with preserved oxidative phosphorylation (OXPHOS) and electron transport (ET) capacity. In contrast, the RV of male animals demonstrated marked reductions in absolute respiratory flux and substrate-supported OXPHOS capacity, indicating impaired mitochondrial oxidative capacity. Female animals exhibited greater preservation of mitochondrial respiratory function, particularly in the RV, with higher OXPHOS capacity and greater Complex I gain than males. H9C2 cells treated with PRO showed a significant increase in uncoupled respiration following 6- and 24-hour incubation periods, under normoxic conditions. Maximal respiration and spare respiratory capacity were increased following 24-hours under hypoxia. No significant changes were observed following treatment with NE alone and in combination with PRO under normoxia or hypoxia for 24 hours. ConclusionsALI induces ventricle-specific and sex-dependent alterations in cardiac mitochondrial bioenergetics, with pronounced impairment in males and relative mitochondrial resilience in females. In H9C2 cardiomyoblasts, short-term exposure (6-24 hours) to pro-inflammatory cytokines enhances uncoupled mitochondrial respiration under normoxic conditions, while short-term hypoxic exposure independently increases maximal respiration and spare respiratory capacity.

molecular biology↗

bioRxiv2025

Neural Inflammation in Thoracic Dorsal Root Ganglia Mediates Cardiopulmonary Spinal Afferent Sensitization in Chronic Heart Failure

The cardiac sympathetic afferent reflex (CSAR) and pulmonary spinal afferent reflex (PSAR) amplify sympathetic outflow, and their sensitization contributes to chronic heart failure (CHF). Using a myocardial infarction (MI) rat model, molecular profiling, imaging, and functional assays revealed that thoracic dorsal root ganglia (DRGs) undergo marked macrophage and glial activation and suppression of voltage-gated potassium (Kv) channels after MI. In vitro studies confirmed that pro-inflammatory cytokines and activated macrophages directly reduce Kv channel expression and activity in DRG neurons. Cardiac afferents mediated cytokine transport from the heart to DRGs, driving macrophage infiltration in a cytokine receptor-dependent manner. Anti-inflammatory strategies including systemic minocycline, liposomal clodronate-induced macrophage depletion, or local epidural dexamethasone prodrug delivery reduced neuroinflammation, restored Kv channel levels, attenuated the exaggerated CSAR and PSAR, and improved cardiac remodeling. These findings highlight a cytokine uptake-driven inflammatory pathway in cardiopulmonary spinal afferent sensitization and support targeted DRG anti-inflammatory therapy as a potential cardioprotective approach. AbstractThe cardiac sympathetic afferent reflex (CSAR) and pulmonary spinal afferent reflex (PSAR) amplify sympathetic activity and may contribute to chronic heart failure (CHF). We hypothesized that neural inflammation in thoracic dorsal root ganglia (DRGs) drives cardiopulmonary afferent sensitization through suppression of voltage-gated potassium (Kv) channels after myocardial infarction (MI). MI was induced in rats by coronary ligation. Molecular profiling, immunofluorescence, tissue clearing, and functional assays were used to assess neuroinflammation and reflex responses. Post-MI, thoracic DRGs showed macrophage infiltration, glial activation, cytokine upregulation, and reduced Kv channel expression. Bulk RNA-seq identified enrichment of macrophage activation-related genes, and in vitro studies confirmed that pro-inflammatory cytokines and activated macrophages suppressed Kv channels and increased DRG neuron excitability. Epicardial injection of biotinylated TNF- demonstrated cardiac afferent-mediated cytokine transport to DRGs, inducing macrophage infiltration via a cytokine receptor-dependent mechanism. Anti-inflammatory interventions including oral minocycline, systemic macrophage depletion, and local epidural delivery of thermo-responsive hydrogel-forming dexamethasone prodrug (ProGel-Dex) significantly reduced DRG neuroinflammation, restored Kv channel levels, and attenuated exaggerated CSAR and PSAR responses. ProGel-Dex also improved cardiac chamber dilation in the post-MI rats. These findings identify a cytokine uptake-glial activation- macrophage activation pathway as a driver of cardiopulmonary afferent sensitization after MI. Targeting DRG inflammation, particularly with sustained local dexamethasone delivery using ProGel-Dex, offers a precision medicine to dampen pathological sympathetic activation and improve cardiac outcomes in CHF. HighlightsO_LIBoth cardiac (CSAR) and pulmonary (PSAR) spinal afferent reflexes are sensitized after myocardial infarction, contributing to sympathetic overactivation. C_LIO_LIThoracic dorsal root ganglia (T1-T4) exhibit macrophage activation, glial responses, pro- inflammatory cytokine upregulation, and suppression of Kv channels following MI. C_LIO_LICardiac afferents mediate receptor-dependent uptake and transport of cytokines (e.g., TNF-) from the heart to DRGs, driving macrophage infiltration and inflammation. C_LIO_LIActivated macrophages and pro-inflammatory cytokines reduce Kv channel expression and Kv current density (Ito) in DRG neurons, enhancing excitability. C_LIO_LIAnti-inflammatory strategies including minocycline, liposomal clodronate-induced macrophage depletion, and local epidural dexamethasone prodrug attenuate neuroinflammation, restore Kv channel expression, and suppress exaggerated CSAR/PSAR. C_LIO_LITargeting DRG inflammation, particularly via sustained epidural dexamethasone delivery, represents a promising cardioprotective precise medicine. C_LI

neuroscience↗

bioRxiv2025

Sympathetic vasomotion as an early marker of hemorrhage

Each year, over 1.8 million people die from hemorrhagic shock, and, since the median time from onset to death is only two hours, early recognition is the cornerstone of management. The sympathetic nervous system is the fastest physiological hemodynamic compensatory mechanism, and we have developed a novel measure of sympathetic vascular control called sympathetic vasomotion which could serve as an early marker of hemorrhage. We performed unilateral renal denervation on six rabbits and instrumented these rabbits with bilateral renal flow probes and arterial pressure telemeters to allow for measurement of sympathetic vasomotion in paired vascular beds that differed only by sympathetic innervation. After a two-week recovery period, conscious rabbits then underwent controlled blood withdrawal via an auricular arterial catheter to simulate hemorrhage. Vasomotion differences between innervated and denervated kidneys in admittance gain, phase shift, and coherence increased significantly prior to increases in heart rate or decreases in blood pressure. These data suggest that sympathetic vasomotion could be a useful physiologically based biomarker for the early detection of hemorrhage. Further studies are needed to evaluate the utility of monitoring the sympathetic nervous system in clinical settings. NEW & NOTEWORTHYSympathetic vasomotion, a novel marker of sympathetic outflow, increases prior to other hemodynamic changes. Sympathetic vasomotion could serve as an early detection tool for hemorrhage that facilitates prompt and precise resuscitation.

physiology↗

bioRxiv2025

Sympathetic Vasomotion Reflects Catheter-based Radiofrequency Renal Denervation

The field of renal denervation remains challenged by the inability to confirm successful ablation of the targeted renal sympathetic nerves. The availability of technology to measure regional blood flow in real time makes sympathetic control of the renal vasculature a logical endpoint to assess effective renal denervation, but autoregulatory mechanisms mask effects on mean renal blood flow. We hypothesized that renal sympathetic vasomotion, a novel marker of rhythmic sympathetic control, reflects successive rounds of catheter-based radiofrequency renal denervation. To test this, ten pigs underwent unilateral surgical renal denervation, recovered for at least seven days, and then underwent four successive rounds of catheter-based radiofrequency denervation of the contralateral kidney. Bilateral renal blood flow velocity and abdominal aortic pressure were measured before and after ablations to assess renal vasomotion. Prior to catheter-based denervation, the renal vasomotion profiles of the innervated and surgically denervated kidneys differed significantly (P < 0.005). Ablation of the largest renal branch artery reduced renal sympathetic vasomotion by 52%. Ablation of the remaining renal branch arteries reduced sympathetic vasomotion 95% from baseline and eliminated the statistical differences between surgically and catheter denervated kidneys. Two additional rounds of catheter denervation of the main renal artery did not consistently decrease renal sympathetic vasomotion magnitude any further. These results indicate that renal sympathetic vasomotion could provide intraprocedural feedback for interventionalists performing catheter-based renal denervation and thereby improve the efficacy, safety, and consistency of this antihypertensive intervention.

physiology↗