Our study aims to determine if urine dicarboxylic acids (DCA) concentrations might be associated with specific brain region volumes in older cognitively healthy (CH) adults. We recruited CH study participants (> 65 years) and acquired MRI data analyzed using NeuroQuant. Urine DCAs were quantified using GC-MS. For n=62 participants, DCA variables of interest—C4+C5 and C7+C8+C9 (% of the sum of C4 to C10), and their ratio—were assessed for association with each of six intracranial volume (icv)-normalized brain region volumes; C4+C5 with 61 additional regions. We modeled volume as a function of a discretized DCA variable (sample tertiles), age, and sex, for each pair. Pairs with a statistically significant estimated association were assessed by fitting natural cubic spline models with a range of spline degrees of freedom in a second stage of analysis. The Benjamini–Hochberg procedure was used to control the false discovery rate below q 1 = 0.2 in the first stage and q 2 = 0.05 in the second stage. There was a significant estimated inverse association of categorical C7+C8+C9 with the fusiform gyrus (FG) volume (Table 1). Similarly, there was a significant estimated positive association between categorical (C4+C5)/(C7+C8+C9) and FG volume (Table 1). The FG was estimated to decrease by 0.004 for every one-unit increase in C7+C8+C9, and this estimated association remained significant after adjusting P values for all tests (95% CI -0.007 to 0.002; adjusted P = .035, Table 2). The observed Cohen’s f2 for the DCA variable was 0.18. For the (C4+C5)/(C7+C8+C9)–FG couple, it was the 2-df natural cubic spline model that had the lowest Bayesian information criterion values among the spline models considered, with a significant estimated association of the DCA variable with the FG (spline adjusted P = 0.035). Figure 1 depicts the estimated spline. The observed Cohen’s f2 for the spline was 0.29. Our analysis suggests that DCA metabolism may be associated with FG volume differences between individuals. Since the FG participates in visual processing, memory, and multisensory integration, urinary DCA levels may be biomarkers to monitor AD pathophysiology associated with differences in these functions.

Introduction: Myocardial infarct size (IS) is the most robust endpoint for evaluating cardioprotective strategies in preclinical ischemia/reperfusion studies. The gold standard for IS quantification in preclinical studies (triphenyl tetrazolium chloride (TTC) staining) is traditionally performed manually and is prone to inter-operator variability. Here, we propose a deep learning segmentation pipeline to automate IS quantification in TTC-stained rat heart sections. Methods: We used n=165 Sprague-Dawley rats (150–300 g, 1–2 months, 69% female). Myocardial infarction (MI) was induced using a standard occlusion/reperfusion model by occluding the proximal left coronary artery for 30 minutes, followed by 3 hours of reperfusion. After euthanasia, the left ventricle (LV) was excised, transversely sliced, and incubated in 1% TTC at 37 °C for 15 minutes to distinguish necrotic myocardium (pale white) from viable tissues (brick red, Fig. 1). Manual IS was quantified by contouring infarcted and total LV areas in each slice using ImageJ (NIH, USA). To automate the IS measurement from TTC-stained heart slices, we implemented a deep learning segmentation pipeline based on the mask region-based convolutional neural network (Mask R-CNN) architecture. Ground truth masks for infarcted regions and LV area were created using VGG Image Annotator. Images from n=140 rats were used for training, as well as an additional 1,400 images generated by data augmentation. All training and preprocessing pipelines were conducted in Python. Dice similarity coefficient (Dice score) was used to evaluate the model performance. The best-performing Mask R-CNN model was blindly tested on 25 additional MI rats. Results: Infarct sizes calculated from Mask R-CNN-generated segmentations showed strong agreement with the ones from expert-annotated manual segmentations from TTC-stained LV slices (R = 0.97, p < 0.0001) when tested on heart slices from 25 additional MI rats, supporting the model’s accuracy and validity. Conclusions: Our results demonstrate that deep learning segmentation accurately and automatically quantifies infarct size from TTC-stained images without operator input. This automated approach is rapid, reproducible, and unbiased, significantly reducing inter-operator variability and manual workload in preclinical studies. By streamlining infarct size assessment in preclinical cardio-protection studies, it has the potential to improve consistency and translational value in cardiac research.

Background: Emerging evidence suggests that empagliflozin (EMPA) may offer additional benefits beyond its primary use in diabetes. Ischemic stroke is known to cause distinctive alterations in EEG signals. However, the influences of EMPA on the stroke-induced EEG changes has not been investigated. Here, we study such influences via EEG time-frequency features using the Hilbert-Huang Transform (HHT) and examine how these features correlate with the cerebral infarction. Methods: n= 47 male SD rats were randomized into 3 groups: 1] Control (n = 16, regular diet); 2] Acute EMPA treatment (n = 16, EMPA 10 mg/kg, IV given at 10 mins prior to middle cerebral artery occlusion (MCAO) and 1 min prior to reperfusion); 3] Chronic EMPA treatment (n = 15, EMPA by food, 20 mg/kg for 7 days before MCAO). To induce ischemic stroke, standard MCAO was performed for 1 hour followed by 3 hours of reperfusion. Post-surgery, triphenyltetrazolium chloride (TTC) staining was used to measure volume of cerebral infarction. EEG signals were continuously recorded throughout the procedure. We applied the Hilbert-Huang Transform (HHT) to analyze the EEG signals. HHT includes 2 steps: 1] empirical mode decomposition (EMD) to decompose the EEG signal into a set of intrinsic mode functions (IMFs); 2] the Hilbert Transform is applied to each IMF to compute analytic signals. Such analytic signals are represented in the complex plane, where they often form circular or elliptical contours (Fig. 1). The area of these contours in the complex plane contains unique information about variations in the signal properties. We computed the HHT area metric for the first four IMFs by using EEG recordings at 3 hours post-reperfusion (duration: 2 minute). Results and Conclusions: Our results showed the control group demonstrates higher correlations between the HHT area metric and the cerebral infarction size, compared to acute or chronic EMPA treatments (Fig. 2), with an especially significant correlation for IMF1in controls (R= -0.76). No significant difference was found in the HHT area metric between control, acute, and chronic EMPA (Fig. 3). It revealed that while EMPA treatments do not alter the EEG time-frequency features compared to controls, control group exhibits a stronger correlation between EEG features and cerebral infarction size. This indicates that EMPA's neuroprotective effects might not be directly reflected in EEG changes, highlighting the need for further investigation of its mechanisms.

Introduction: Cerebral blood flow (CBF) signals contain physiological information about the dynamics of the heart, brain, and their interaction during ischemic stroke. Traditional frequency-based analyses may miss critical dynamic changes due to inter-subject variability. We hypothesize that a time-frequency approach can extract more detailed information from CBF’s physiological frequency bands to better detect stroke-induced cerebral hemodynamic changes. This study applies empirical mode decomposition (EMD) and the Hilbert transform to extract dynamic-specific features from CBF signals in a rat stroke model. Methods: Sixteen rats underwent transient right middle cerebral artery (MCA) occlusion, with CBF recorded continuously from the right cortex. 5-minute CBF recordings were analyzed at three timepoints: baseline, 1 hour post-MCA occlusion, and 3 hours post-reperfusion. EMD decomposed each signal into 13 intrinsic mode functions (IMFs), with instantaneous frequencies extracted via the Hilbert transform. IMFs were then recombined into five physiological bands: cardiac (~2–5 Hz), respiratory (~0.4-2 Hz), myogenic (~0.15-0.4 Hz), sympathetic (~0.04-0.15 Hz), and endothelial (~0.0095-0.04 Hz). The Hilbert transform was then applied to each band to compute a 95% area metric (CBF 95%-Area Index) from the analytic signal’s complex-plane trajectory. Statistical tests compared physiological states across timepoints. P-value < 0.05 was considered significant. Results: The myogenic band (~0.15-0.4 Hz), associated with vascular smooth muscle activity, showed a significant reduction in the 95% area metric from baseline to occlusion (p<0.0001), and from baseline to reperfusion (p<0.05). No significant change between occlusion and reperfusion, suggesting persistent suppression of myogenic vasomotion during early reperfusion. Other bands showed minor or nonsignificant changes. Conclusion: Persistent myogenic oscillatory suppression during early reperfusion suggests a form of cerebral vascular stunning, analogous to stunned myocardium, where contractile function remains impaired despite restored perfusion. This may represent post-ischemic vascular dysfunction in the brain. Alternatively, it may reflect a microvascular no-reflow phenomenon within the cerebral circulation. Frequency-resolved CBF analysis offers a noninvasive approach to detect reperfusion-related vascular dysfunction, with the potential to guide acute stroke therapies and improve cerebrovascular outcomes.

Introduction: Heart rate variability (HRV), which represents fluctuations in heart rate, provides critical insights into autonomic regulation and cardiovascular function. This study aims to evaluate how HRV metrics change before, during, and after an ischemic stroke in a rat model, with a focus on understanding the impact of stroke and subsequent reperfusion on autonomic control. Methods: We employed the standard intraluminal suture middle cerebral artery (MCA) occlusion model to induce ischemic stroke in anesthetized adult male and female Sprague Dawley rats (n=11, 2-3 months old, average body weight: 296 ± 47 g, 27% female). The procedure involved temporary occlusion of the common carotid artery (CCA) while advancing a suture into the internal carotid artery to occlude the MCA for 1 hour, followed by 3 hours of reperfusion (Fig. 1). Electrocardiogram (ECG) signals were continuously recorded throughout the procedure. Post-surgery, cerebral infarction was confirmed via the triphenyl tetrazolium chloride (TTC) staining technique. HRV metrics were analyzed from 1-minute ECG recordings taken at three time points: baseline, 1 hour post-MCA occlusion (pre-reperfusion), and 3 hours post-reperfusion. Results and Conclusions: Significant alterations in HRV metrics were observed between baseline and 3 hours after reperfusion (p<0.05; Fig. 2; see figure’s caption for the metric descriptions). Specifically, high-frequency relative power percentage (HF%) and the SD1/SD2 ratio decreased significantly, while low-frequency relative power percentage (LF%) and the LF/HF ratio increased significantly. Additionally, the LF/HF power ratio showed a notable increase from baseline to 1 hour post-MCA occlusion. Our findings reveal distinct HRV metric changes associated with the ischemic stroke. The observed alterations reflect a shift of autonomic regulation towards sympathetic dominance, which intensifies after reperfusion, supporting other preclinical and clinical findings. These results suggest the potential for developing non-invasive, HRV-based techniques for real-time detection and monitoring of ischemic stroke. Further research could enhance these techniques' applicability in clinical settings.

INTRODUCTION:The long-term effects of chronic electronic cigarette (e-cigarette) exposure on lung and heart inflammation during the healing phase of myocardial infarction (MI) remain unexplored. Additionally, the impact of e-cigarette exposure on blood parameters in this context is unclear. This study aims to assess e-cigarette with nicotine (e-cig Nic+) effects on lung histology, inflammatory gene expression in cardiac tissue, and blood parameters during MI recovery. METHODS:Sprague Dawley rats of both sexes underwent proximal left coronary artery occlusion to induce a large anterior wall MI. After one week, rats were randomized to either air or e-cig Nic+ exposure for 12 weeks. RESULTS:In the lungs, e-cig Nic+ exposure led to a significant accumulation of inflammatory cells within the alveolar spaces and increased inflammatory cell numbers in the lung parenchyma compared to the air group. Numerically elevated levels of malondialdehyde (MDA), an oxidative stress biomarker, were observed in the e-cig Nic+ group. In the heart, a PCR array analysis of inflammatory cytokines and receptors revealed that 70 out of 84 inflammatory-related genes were downregulated in the e-cig Nic+ group, with 11 reaching statistical significance. Additionally, the blood of rats exposed to e-cig Nic+ exhibited significantly lower white blood cell, lymphocyte, and platelet counts compared to the air group. CONCLUSIONS:Chronic exposure to e-cig Nic+ exacerbates lung inflammation, alters inflammatory gene expression in the heart, and suppresses immune cell counts in the blood during MI recovery. These findings suggest that e-cigarette with nicotine aerosol inhalation contributes to lung lesions and dampens immune and inflammatory responses in an already compromised MI setting.

Introduction: Coronary artery calcium (CAC) scans contain more information than currently reported. The AI-CVD initiative aims to extract actionable opportunististic infomration from a CAC scan to maximize its predictive value beyond the CAC score. We previously reported new AI-CVD algorithms applied to CAC scans for opportunistic measurement of bone mineral density (BMD), cardiac chamber volumes, left ventricular mass, liver steatosis, emphysema and other imaging biomarkers. In this report, we investigate the incremental value of these biomarkers on top of the CAC score for prediction of incident all cardiovascular disease (CVD) events. Methods: We applied AI-CVD to CAC scans from 5798 asymptomatic individuals (52% female, age 62±10 years) in the Multi-Ethnic Study of Atherosclerosis. Liver fat was estimated as the liver attenuation index (LAI) using the percentage of voxels below 40 HU. Phantomless BMD for three consecutive thoracic vertebrae (T2-T4) was calculated using the mean HU. Emphysema was estimated using the percentage of voxels within the entire lung in the field of view below -950 HU. We used Kaplan–Meier cumulative incidence curves to evaluate the incremental prognostic value of opportunistically derived biomarkers beyond the Agatston CAC score, using the highest quartile of risk per predictor. Results: A total of 1173 CVD accrued over 19 years follow-up (median [IQR]: 17.7 [12.9-18.5] years). The top quartile of CAC, LAI, and emphysema were defined as >90, >50.4% voxels below 40 HU, > 4.1% below -950 HU, respectively. The bottom quartile of BMD was defined as <130.1 mg/cc. Individuals in the highest risk quartile of all 4 measures (n=44) experienced 69.0% (95% CI: 57.3%-80.1%) incidence of all CVD events. While individuals with a high Agatston score alone experienced 47.9% (44.6%-51.4%) incidence of CVD events over 19 years. Both low BMD and high LAI revealed incremental CVD risk on top of high CAC scores, while high emphysema measurements did not. Conclusion: Applying AI to CAC scans can extract opportunistic incremental risk information for early detection of patients at risk of CVD events. The clinical utility of incorporating LAI, BMD, and emphysema and other opportunistic findings in CAC scans as part of the AI-CVD initiative to improve CVD risk prediction warrants further investigations.

Introduction: Heart rate fragmentation (HRF) is an inter-beat interval dynamics approach that enhances the analysis of short-term heart rate variability. HRF has been shown to reflect disruptions in the neuroautonomic-electrophysiologic control of the sino-atrial node. Migraine, the fifth leading cause of disability worldwide, is increasingly recognized as a neurovascular disorder with significant autonomic dysfunction. However, HRF signatures in the context of migraine remain unexplored. Here, we investigate HRF dynamics in a validated rodent model of chronic migraine to identify electrophysiological correlates of altered heart-brain connectivity. Methods: We used a total number of n=20 Sprague-Dawley rats (50% female; 150-250g; 6-8 weeks), which were randomized into two groups: (1) Chronic migraine Group (n=10, 50% female): rats received repeated intraperitoneal (IP) administration of Nitroglycerin (NTG, 10 mg/kg), a well-established migraine trigger, every other day over a nine-day period (Fig1); (2) Control Group (n=10, 50% female): rats received an equivalent volume of saline at the same regime. At the last injection day, rats were anesthetized prior to NTG or saline injection for invasive electrocardiogram (ECG) recording via subcutaneous needle electrodes. HRF metrics were computed using a 2-minute ECG recording at 2 hours after NTG/saline administration. These included quantification of soft and hard inflection points (Soft: transitions between steady and accelerating/decelerating heart rate; Hard: abrupt switches between acceleration and deceleration). Results: Significant differences were observed between the control and chronic migraine groups (Fig.2) for three HRF metrics. PIPH% (percentage of hard inflection points in heart rate acceleration sign throughout the ECG recording) was significantly increased in the migraine group. W1s% and W2s% (percentages of only one and only two soft inflection points, respectively, in sequences of five consecutive heart rate intervals) were both significantly decreased in the migraine group. Conclusions: Our findings suggest alterations in heart-brain connectivity in rats with chronic migraine, as evidenced by distinct changes in the HRF. The results also indicate that HRF metrics may serve as novel, noninvasive biomarkers for detecting and monitoring migraine-related autonomic dysfunction. Future studies may explore the clinical utility of HRF-based techniques in management and monitoring of migraine patients.

Introduction: New innovations in AI allow opportunistic detection of non-coronary features on coronary artery calcium (CAC) scans, enabling screening for a range of conditions, and improved cardiovascular disease (CVD) prediction. Myosteatosis, excessive fat infiltration into skeletal muscle, is increasingly recognized as a marker of systemic metabolic dysfunction and can be quantified in CT using the mean attenuation of skeletal muscle. We evaluated AI-measured myosteatosis in thoracic skeletal muscle for predicting future atrial fibrillation (AF), heart failure (HF), and total CVD. Methods: We used baseline CAC scans and 15-year follow-up data from 5,489 asymptomatic participants (47.8% male) in the Multi-Ethnic Study of Atherosclerosis (MESA). Myosteatosis was operationally defined as the lowest quartile of thoracic skeletal muscle mean attenuation (males<33 Hounsfield Units (HU) and females<27 HU). Hazard ratios [HR] for bottom vs top quartile of mean muscle CT density were evaluated using proportional hazards regression models adjusted for CVD risk factors, inflammatory markers, and social determinants of health. Results: Myosteatosis was associated with worse outcomes in both sexes: HRs in males were 4.59 (95% CI, 3.52–5.99) for AF, 8.46 (4.61–15.52) for HF, and 3.56 (2.89–4.37) for total CVD, with corresponding HRs in females of 4.68 (3.48–6.29), 8.01 (3.62–17.72), and 4.37 (3.42–5.57), respectively. After full adjustment, associations remained significant for HF (1.93 [1.31–2.82]), AF (1.78 [1.26–2.50]), and total CVD (1.44 [1.09–1.91]) in males, and for AF (1.69 [1.17–2.45]) and total CVD (1.75 [1.29–2.39]) in females. Individuals in the top quartile of CAC (>89.5 HU) who also had myosteatosis had greater 15-year incidence of AF (45.4%) and HF (21.8%) than those in either group alone (CAC, AF: 29%, HF: 9.5%; myosteatosis, AF: 20.9%, HF: 5.3%). Conclusion: Thoracic skeletal myosteatosis in CAC scans is an independent predictor of AF, HF, and total CVD over 15 years. Improving clinical outcomes through the detection of myosteatosis, and other opportunistic findings in CAC scans as part of the AI-CVD initiative, merits further investigation.

Introduction/Background: Myosteatosis, defined as pathological fat infiltration into skeletal muscle, is an emerging marker of metabolic dysfunction and cardiovascular risk, particularly when measured in abdominal CT. However, its association with lung health and risk of chronic obstructive pulmonary disease (COPD) is not well established. The AI-CVD initiative aims to extract all useful opportunistic screening information from coronary artery calcium scans and combines them with traditional risk factors to create a stronger predictor of cardiovascular diseases. We hypothesized that myosteatosis measured from cardiac CT scans using AI-CVD is associated with increased risk of incident COPD in a population free of clinical cardiovascular disease at baseline. Methods/Approach: A retrospective cohort analysis was conducted using baseline data from Exam 1 of the Multi-Ethnic Study of Atherosclerosis including men and women aged 45 to 84 free of cardiovascular disease at baseline. Myosteatosis was quantified using AI-CVD to segment muscle and compute thoracic skeletal muscle density as a proxy for fat infiltration. Chronic obstructive pulmonary disease (COPD) was defined using clinical diagnosis with ICD codes. Proportional hazards models were used to assess the association between myosteatosis and incident COPD disease over 15 years. Models were adjusted for confounders including age, sex, pack years of smoking, emphysema, body mass index, inflammation, diabetes, and socioeconomic status. Results/Data: A total of 283 cases of incident COPD were identified. Individuals in the lowest quartile of muscle attenuation had significantly higher cumulative incidence compared to other quartiles. In minimally adjusted models, the hazard ratio comparing the lowest to highest quartile was 1.87. In fully adjusted models, the association remained significant with a hazard ratio of 1.32. Conclusion(s): AI-based quantification of myosteatosis on routine cardiac CT scans independently predicts future risk of COPD. Adverse muscle composition in the pectoralis, intercostal, and paraspinal muscles may precede lung function decline. Opportunistic assessment of myosteatosis could enable early identification of individuals at elevated risk and support preventive interventions at elevated risk for COPD and guide preventive strategies before clinical disease onset.

Stroop task is used to evaluate inhibition, a core executive function. Alpha Event-Related Desynchronization (ERD) from analysis of electroencephalogram (EEG) during Stroop task reflects brain interference processing. We previously reported different relationships between heart rate variability (HRV) and alpha ERD during Stroop task. However, HRV proxied autonomic function can be confounded by increasing erratic rhythm with age, quantified by heart rate fragmentation (HRF). The knowledge of HRF is limited in a Cognitively Healthy (CH) cohort. To fill this gap, we studied these measurements in CH participants who underwent a Stroop task. We studied HRF in an established EEG dataset during Stroop task from CH participants when their CSF amyloid/tau ratio were normal (≥2.71, CH-NATs) or pathological (<2.71, CH-PATs). Heart rate fragmentation (HRF) was analyzed from 5-minute electrocardiogram (ECG) during resting or task. HRF was classified into three categories: hard inflection point, soft inflection point, and non-inflection. Hard inflection point represents an acceleration-to-deceleration (AD) in heart rate and vice versa (DA). Soft inflection point describes heart rate transitions from acceleration or deceleration-to-zero acceleration (AZ or DZ) and vice versa (ZA or ZD). Non inflection means heart rates are accelerating (NA), decelerating (ND), or no change (NZ). We previously reported that alpha ERD during incongruent trials were negatively correlated with heart rate (HR) in CH-NATs but not in CH-PATs (Figure 1). In CH-NATs, there was a decrease in a subcategory of non-inflection during task compared to resting (Figure 2A). We observed a significant increase in hard inflection points and a decrease in non-inflections during Stroop task compared to resting in CH-PATs (Figure 2B). These pilot results suggest: 1) from resting to task, CH-PATs presented increase of HRF hard inflection points, which was not observed in CH-NATs; 2) our previous analysis show that HR was negatively correlated with alpha ERD in CH-NATs (higher HR related to more brain activation - more negative alpha ERD), which was not observed in CH-PATs. Although a larger sample size is needed, these results support a potential heart-brain dysregulation using non-invasive EEG and ECG in cognitively healthy individuals at higher risk of cognitive decline.

Sodium-glucose co-transporter 2 (SGLT2) inhibitors have demonstrated potential neuroprotective and cardioprotective effects in preliminary studies. This study evaluates the efficacy of empagliflozin (EMPA) in reducing ischemia/reperfusion damage in both the brain and heart using rat models. Ischemic stroke and myocardial infarction (MI) were induced in male Sprague-Dawley rats, which were randomized into three groups: (1) Control (no EMPA), (2) Acute treatment (EMPA, 10 mg/kg IV, administered 10 min before ischemia and 1 min before reperfusion), and (3) Chronic treatment (EMPA, 20 mg/kg in food for 7 days before ischemia). Stroke was induced by middle cerebral artery occlusion (MCAO) for one hour, followed by 3 h of reperfusion, and MI was induced by left coronary artery occlusion for 30 min, followed by 3 h of reperfusion. Brain and heart tissues were analyzed for anatomic size of myocardial infarction and stroke. In the brain, cerebral infarction was significantly smaller in both EMPA treatment groups compared to controls (acute: 3.7 ± 1.2%, chronic: 6.9 ± 2.1% vs. control: 14.5 ± 2.5%, p < 0.05). Edema was also reduced in the EMPA groups (acute: 5.5 ± 0.9%, chronic: 5.9 ± 0.8% vs. control: 9.6 ± 1.2%, p < 0.05). In the heart, MI size was significantly reduced in both EMPA groups (acute: 46.9 ± 2.0%, chronic: 48.8 ± 5.8% vs. control: 70.0 ± 2.6%, p < 0.05), and no-reflow size was smaller in the EMPA groups (acute: 36.3 ± 3.3%, chronic: 33.9 ± 4.3% vs. control: 53.4 ± 3.3%, p < 0.05). EMPA treatment, both acute and chronic, significantly reduces cerebral infarct volume and edema, as well as myocardial infarct size and no-reflow in rat models of ischemic stroke and myocardial ischemia/reperfusion, indicating substantial neuroprotective and cardioprotective effects.

BACKGROUND:Early reperfusion after ST-segment-elevation myocardial infarction is essential for limiting infarct size. However, reperfusion injury can lead to progressive microvascular obstruction (MVO), reducing myocardial blood flow (MBF), aggravating ischemia and myocardial necrosis. We hypothesized that SuperSaturated Oxygen (SSO2) Therapy may reduce infarct size by alleviating MVO, so we evaluated the effects of SSO2 on the time course of MBF and MVO in a preclinical ischemia/reperfusion model. METHODS:Twelve swine surviving 90 minutes of balloon-induced anterior ST-segment-elevation myocardial infarction and 15-minute auto-reperfusion, were assigned to 120 minutes of SSO2 (n=6) or further 120 minutes of auto-reperfusion (control, n=6). Microspheres were injected into the left ventricle at multiple time points to assess MBF, calculated as the total blood flow within areas at risk normalized to the total flow within remote zones. An angiography-derived index of microcirculatory resistance was analyzed. MVO and infarct zones were identified using thioflavin-S and 2,3,5-triphenyl tetrazolium chloride staining and quantified with ImageJ software. RESULTS:SSO2 Therapy significantly reduced MVO compared with controls (4.64% versus 13.00% of left ventricular area; P<0.001) and improved myocardial salvage index (MSI, 64.76% versus 43.11%; P=0.03). MBF was significantly higher in the SSO2 group compared with controls at the end of therapy (1.1 versus 0.59; P=0.03). In the controls, following initial hyperemia, flow decreased significantly at 165, 195, and 225 minutes (P=0.01). Conversely, the SSO2 group showed no significant decrease in MBF in the same interval (P=0.38). Median angiography-derived index of microcirculatory resistance values showed a nonsignificant trend of reduced final microvascular resistance in the SSO2 group only. CONCLUSIONS:In a translational ST-segment-elevation myocardial infarction model, SSO2 prevented a reduction in MBF during the 120-minute reperfusion period, with significantly increased MBF at the end of the experiment. MBF improvement was translated to a 64% relative reduction in the extent of MVO, and a 50% relative increase in the myocardial salvage index.

Introduction: Myocardial ischemia results from an imbalance between oxygen supply and demand, typically affecting the subendocardium. The diastolic pressure time index (DPTI) and systolic pressure time index (SPTI) are well-established surrogates for myocardial oxygen supply and demand, respectively. Their ratio (DPTI: SPTI), the subendocardial viability ratio (SEVR), serves as an indicator of subendocardial perfusion adequacy. Methods: A total of 41 young, healthy adult male and female Sprague Dawley rats (n=20 female; weight 187–273 g) were randomized and exposed to: 1) purified air (n=20) and 2) electronic cigarette vapor without nicotine (EC NIC(-), n=21). Rats were exposed by nose-only inhalation for 4-5 hours/day, 4 days/week, for a total of 8 weeks (puff frequency=1 puff/min, puff duration=2 seconds, at a flow rate of 1.67 L/min). For EC(-), a third-generation mod-type vaporizer (VaporFi VEX 150 TC mod, with Volt Tank) was used with a tobacco-flavored e-liquid containing a 50/50 volume ratio of propylene glycol and vegetable glycerin (PG/VG). After 8 weeks of exposure, the rats were anesthetized and catheterized to measure invasive aortic and left ventricular pressure waveforms. These waveforms were used to quantify SPTI, DPTI, and SEVR (Fig. 1). Results: Exposure to EC NIC(-) resulted in a significant change in myocardial oxygen supply in male rats (p<0.05) but not in females (Fig. 2). As there was no significant change in oxygen demand in either sex, male rats showed a significant reduction in the supply: demand ratio (SEVR) compared to air-exposed controls (Fig. 3). Conclusion: Our results suggest that chronic exposure to nicotine-free EC vapor alters myocardial oxygen dynamics in a sex-specific manner. Male rats exhibited impaired subendocardial perfusion following EC NIC(-) exposure, suggesting heightened vulnerability to ischemic imbalance. We propose these effects may be driven by sex-specific cardiac responses to components in the PG/VG base and flavoring agents, which can induce mild oxidative stress and vascular dysfunction, disrupting myocardial oxygen balance differently in males and females.

Background: We previously reported that empagliflozin (EMPA), a sodium-glucose co-transporter 2 inhibitor, significantly reduced infarct size and cerebral edema in a rat model of ischemic stroke when administered either chronically via oral route for 7 days prior to middle cerebral artery occlusion (MCAO) or given IV acutely 10 minutes before MCAO (doi: 10.1038/s41598-025-93483-7). This is clinically relevant for patients already receiving this drug for diabetes, heart failure, or other indications. However, the vast majority of individuals presenting with acute stroke are unlikely to be on EMPA at the time of stroke onset. The neuroprotective potential of EMPA when administered after stroke onset remains unclear. Therefore, we investigated the effect of post-stroke EMPA administration on infarct size following MCAO. Methods: Male Sprague-Dawley rats were randomly assigned to (1) control group, receiving intravenous saline 10 minutes after MCAO (n =13); and (2) acute EMPA group, treated with EMPA (20 mg/kg, IV, n = 12) at the same post-occlusion time point. Transient focal cerebral ischemia was induced by intraluminal filament occlusion of the MCA for 60 minutes, followed by a 3-hour reperfusion period. Brain tissues were then collected and sectioned for 2,3,5-triphenyltetrazolium chloride (TTC) staining to quantify cerebral infarct and edema volumes. Results: Rats treated with EMPA post-MCAO exhibited significantly reduced infarct volumes (4.89 ± 1.02% of total brain volume) compared to controls (9.99 ± 1.59%, p = 0.0137). However, there was no significant difference in cerebral edema between groups: 6.93 ± 0.91% in the EMPA group versus 7.84 ± 0.81% in controls (p = 0.463). Conclusion: This study shows that a single intravenous dose of EMPA administered 10 minutes after MCAO effectively reduces cerebral infarction but does not impact edema formation in a rat model of stroke.

Introduction: Myocardial infarction (MI) alters the heart’s electrophysiology, often seen as ST-segment deviation, T-wave inversion, or QRS distortion in electrocardiogram (ECG). While these features support diagnosis, they may miss early or subtle waveform changes in single-channel ECGs during ischemic injury. Capturing such changes could enhance MI detection, particularly in non-classical presentations. Here, we propose a new analytical approach that reveals advanced ECG morphology changes, to capture MI-related signatures not easily detectable by standard interpretation. Methods: Acute MI was induced in SD rats (n=13; Male; ~300g) via 30 minutes of proximal left coronary artery occlusion, followed by 3 hours of reperfusion. Necrosis was confirmed post-surgery via triphenyl tetrazolium chloride (TTC) staining. ECG signals were continuously recorded via subcutaneous needle electrodes. The ECG time-frequency eyeball method involves: (1) empirical mode decomposition to extract intrinsic mode functions (IMFs) from ECG signal; (2) the Hilbert Transform to derive analytic signal of each IMF; (3) rotational mapping of the analytic signals onto the complex plane, where they exhibited a distinct eyeball-shaped pattern for IMF1 (ECG eyeball, Fig1). To quantify ECG dynamic changes, we performed symmetry analysis on the ECG eyeballs using the Structural Similarity Index Measurement (SSIM). Specifically, each eyeball was mirrored across incrementally rotated axes, and SSIM was calculated between the original and mirrored images at each angle. The normalized area under the SSIM curve over all rotation angles (SSIM-AUC) was used as a global symmetry metric (Fig1). SSIM-AUC was computed at three time points: baseline, pre-reperfusion (MI with occluded coronary), and 3 hours post-reperfusion (early recovery after MI). 2-minute ECG recordings were used at each time point for computing the eyeballs. Results: SSIM-AUC significantly decreased after MI (P<0.05), from baseline to both pre-reperfusion and post-reperfusion (Fig2). A modest post-reperfusion increase vs. pre-reperfusion was observed but not significant. Conclusion: We introduced a time-frequency-based analytics approach (ECG Eyeball) that maps multi-minute ECG data into a single interpretable pattern. Symmetry analysis of the ECG eyeball effectively captured MI-induced electrical changes. This method offers new directions for leveraging single-channel ECG data in noninvasive and interpretable tools for MI detection.

Introduction: Left ventricular pressure (LVP) waveforms offer critical insight into cardiac function after myocardial infarction. LVP is typically assessed via invasive catheterization, limiting routine use and longitudinal monitoring. We propose a novel analytical approach to reconstruct the entire LVP waveform using only carotid pressure waveforms (now measurable noninvasively with a phone camera) and standard echocardiography. We validated the method under normal and acute physiological conditions in an experimental model of myocardial ischemia and myocardial infarction (MI). Methods: Thirty-nine Sprague Dawley rats (28% female) were anesthetized and underwent coronary artery occlusion/reperfusion (30 min occlusion, 3 h reperfusion). Simultaneous LV and carotid pressures (via Millar Mikro-Tip catheters) and echocardiograms were recorded. LVP waveforms were reconstructed using a novel five-step analytical method at baseline, 15 min post-occlusion (ischemia), and 3 h post-reperfusion (acute MI, confirmed by TTC staining) for total of 71 cases. The reconstruction approach incorporated models of ventricular relaxation, diastolic filling, and systolic ejection governed by arterial-ventricular coupling, with constraints on temporal and morphological continuity of the waveform. Reconstructed waveforms were compared to invasive LVP recordings. Evaluation focused on accuracy in key clinical ischemia/MI metrics, including LV end-diastolic pressure (LVEDP) and subendocardial viability ratio (SEVR). SEVR is calculated as the ratio of myocardial oxygen supply to demand, serving as a surrogate for myocardial perfusion and correlates with cardiovascular risk. Results: Reconstructed LVP waveforms from carotid pressure closely matched invasive measurements during control, ischemia, and infarction (Figure 1). Reconstructed LVEDP strongly correlated with catheter measurements (Figure 2; r = 0.91), capturing its elevation during ischemia and partial recovery post-reperfusion. SEVR derived from reconstructions also closely matched invasive values (Figure 3; r = 0.96). Conclusions: Our findings show that the algorithm accurately reconstructs LVP waveforms and predicts clinically relevant metrics across physiological states. It captured elevated LVEDP and reduced SEVR during ischemia, with partial recovery after reperfusion. These results support its potential for noninvasive, longitudinal monitoring of left ventricular pressure in managing heart failure and myocardial infarction.

INTRODUCTION:The use of coronary artery bypass grafting (CABG) for primary revascularization during the acute care of ST-elevation myocardial infarction (STEMI) patients has declined significantly in the past decade; but there is little data to determine whether there has been a change in the use of CABG for STEMI patients treated by emergency medical services (EMS). In this study we described the incidence of urgent or emergent CABG for STEMI patients treated in a large, regionalized cardiac care system. METHODS:We obtained data obtained for patients transported by EMS between January 2011-December 2022 who were diagnosed with acute STEMI on prehospital or emergency department (ED) electrocardiogram and taken for primary diagnostic catheterization. All STEMI patients were transported by EMS to one of 34 STEMI receiving centers (SRC) in a regionalized cardiac care system, all of which are required to maintain onsite cardiac surgery as a condition of their SRC designation. Patients were considered to have undergone urgent or emergent CABG if it was performed within 72 hours of the primary diagnostic cardiac catheterization. We excluded patients if no diagnostic catheterization was performed or if CABG was performed >72 hours after diagnostic catheterization. The primary outcome was the incidence of urgent or emergent CABG. Patients were further stratified by time between diagnostic catheterization and CABG (<24 hours, 24-48 hours, 48-72 hours). RESULTS:A total of 28,349 patients were transported by EMS and diagnosed with an acute STEMI during the study period. Only 384 (1.35%) patients underwent CABG within 72 hours of diagnostic catheterization: 268 (0.95%) underwent CABG in <24 hours; 71 (0.25%) in 24-48 hours, and 45 (0.16%) in 48-72 hours. The median age of patients undergoing CABG was 64 years (interquartile range 58-72). Twenty-eight (7.3%) experienced prehospital cardiac arrest, and eight (2.1%) required vasopressors. Prior to undergoing CABG, 137 patients (36%) underwent primary percutaneous coronary intervention. The proportion of patients undergoing CABG within 72 hours remained relatively stable between 2011-2022 at 1.19% and 1.96%, respectively. CONCLUSION:Urgent or emergent CABG remained infrequently performed for acute STEMI patients after primary diagnostic catheterization. There was little change in the percentage of STEMI patients who received CABG within 72 hours of diagnostic catheterization over the past decade. These findings suggest that regional or local policies requiring on-site cardiac surgery at SRCs may be reconsidered.