Comorbidities of ischemic heart disease, including diabetes mellitus (DM), hypercholesterolemia (HC) and chronic kidney disease (CKD), are associated with coronary microvascular dysfunction (CMD). Increasing evidence suggests that CMD may contribute to myocardial 'Ischemia and No Obstructive Coronary Artery disease' (INOCA). In the present study, we tested the hypothesis that CMD results in perturbations in myocardial perfusion and oxygen delivery using a novel swine model with multiple comorbidities. DM (streptozotocin), HC (high-fat diet) and CKD (renal embolization) were induced in 10 female swine (DM + HC + CKD), while 12 healthy female swine on a normal diet served as controls (Normal). After 5 months, at a time when coronary atherosclerosis was still negligible, myocardial perfusion, metabolism, and function were studied at rest and during treadmill exercise. DM + HC + CKD animals showed hyperglycemia, hypercholesterolemia, and impaired kidney function. During exercise, DM + HC + CKD swine demonstrated perturbations in myocardial blood flow and oxygen delivery, necessitating a higher myocardial oxygen extraction-achieved despite reduced capillary density-resulting in lower coronary venous oxygen levels. Moreover, myocardial efficiency was lower, requiring higher oxygen consumption for a given level of myocardial work. These perturbations in myocardial oxygen balance were associated with lower myocardial lactate consumption, stroke volume, and LVdP/dt max , suggestive of myocardial ischemia and dysfunction. Further analyses showed a reduction in adenosine-recruitable coronary flow reserve, but this was exclusively the result of an increase in basal coronary blood flow, while maximal coronary flow per gram of myocardium was maintained; the latter was consistent with the unchanged arteriolar wall/lumen ratio, arteriolar density and peri-arteriolar collagen content. However, isolated small arteries displayed selective blunting of endothelium-dependent vasodilation in response to bradykinin in DM + HC + CKD swine, suggesting that changes in coronary microvascular function rather than in structure contributed to the perturbations in myocardial oxygen delivery. In conclusion, common comorbidities in swine result in CMD, in the absence of appreciable atherosclerosis, which is severe enough to produce perturbations in myocardial oxygen balance, particularly during exercise, resembling key features of INOCA.

Heart failure with a preserved ejection fraction (HFpEF) is associated with multiple comorbidities, such as old age, hypertension, type 2 diabetes and obesity and is more prevalent in females. Although the male obese ZSF1 rat has been proposed as a suitable model to study the development of diastolic dysfunction and early HFpEF, studies in female animals have not been performed yet. Therefore, we aimed to characterize the cardiac phenotype in female obese ZSF1 rats and their lean counterparts. Additionally, we aimed to investigate whether differences exist in disease progression in obese male and female ZSF1 rats. Therefore, male and female ZSF1 rats, lean as well as obese (N = 6-9/subgroup), were used. Every two weeks, from 12 to 26 weeks of age, systolic blood pressure and echocardiographic measurements were performed, and venous blood was sampled. Female obese ZSF1 rats, as compared to female lean ZSF1 rats, developed diastolic dysfunction with cardiac hypertrophy and fibrosis in the presence of severe dyslipidemia, increased plasma growth differentiation factor 15 and mild hypertension, and preservation of systolic function. Although obese female ZSF1 rats did not develop hyperglycemia, their diastolic dysfunction was as severe as in the obese males. Taken together, the results from the present study suggest that the female obese ZSF1 rat is a relevant animal model for HFpEF with multiple comorbidities, suitable for investigating novel therapeutic interventions.

Background Migraine is a disabling and chronic neurovascular headache disorder. Trigeminal vascular activation and release of calcitonin gene-related peptide (CGRP) play a pivotal role in the pathogenesis of migraine. This knowledge has led to the development of CGRP(-receptor) therapies. Yet, a substantial proportion of patients do not respond to these treatments. Therefore, alternative targets for future therapies are warranted. The current narrative review provides a comprehensive overview of the pathophysiological role of these possible non-CGRP targets in migraine. Findings We covered targets of the metabotropic receptors (pituitary adenylate cyclase-activating polypeptide (PACAP), vasoactive intestinal peptide (VIP), amylin, and adrenomedullin), intracellular targets (nitric oxide (NO), phosphodiesterase-3 (PDE3) and -5 (PDE5)), and ion channels (potassium, calcium, transient receptor potential (TRP), and acid-sensing ion channels (ASIC)). The majority of non-CGRP targets were able to induce migraine-like attacks, except for (i) calcium channels, as it is not yet possible to directly target channels to elucidate their precise involvement in migraine; (ii) TRP channels, activation of which can induce non-migraine headache; and (iii) ASICs, as their potential in inducing migraine attacks has not been investigated thus far. Drugs that target its receptors exist for PACAP, NO, and the potassium, TRP, and ASIC channels. No selective drugs exist for the other targets, however, some existing (migraine) treatments appear to indirectly antagonize responses to amylin, adrenomedullin, and calcium channels. Drugs against PACAP, NO, potassium channels, TRP channels, and only a PAC1 antibody have been tested for migraine treatment, albeit with ambiguous results. Conclusion While current research on these non-CGRP drug targets has not yet led to the development of efficacious therapies, human provocation studies using these targets have provided valuable insight into underlying mechanisms of migraine headaches and auras. Further studies are needed on these alternative therapies in non-responders of CGRP(-receptor) targeted therapies with the ultimate aim to pave the way towards a headache-free future for all migraine patients.

Pulmonary hypertension is common in heart failure with preserved ejection fraction (HFpEF). Here, we tested the hypothesis that comorbidities [diabetes mellitus (DM, streptozotocin), hypercholesterolemia (HC, high-fat diet) and chronic kidney disease (CKD, renal microembolization)] directly impair pulmonary vasomotor control in a DM + HC + CKD swine model. 6 months after induction of DM + HC + CKD, pulmonary arterial pressure was similar in chronically instrumented female DM + HC + CKD (n = 19) and Healthy swine (n = 18). However, cardiac output was lower both at rest and during exercise, implying an elevated pulmonary vascular resistance (PVR) in DM + HC + CKD swine (153 ± 10 vs. 122 ± 9 mmHg∙L−1∙min∙kg). Phosphodiesterase 5 inhibition and endothelin receptor antagonism decreased PVR in DM + HC + CKD (− 12 ± 12 and − 22 ± 7 mmHg∙L−1∙min∙kg) but not in Healthy swine (− 1 ± 12 and 2 ± 14 mmHg∙L−1∙min∙kg), indicating increased vasoconstrictor influences of phosphodiesterase 5 and endothelin. Inhibition of nitric oxide synthase produced pulmonary vasoconstriction that was similar in Healthy and DM + HC + CKD swine, but unmasked a pulmonary vasodilator effect of endothelin receptor antagonism in Healthy (− 56 ± 26 mmHg∙L−1∙min∙kg), whereas it failed to significantly decrease PVR in DM + HC + CKD, indicating loss of nitric oxide mediated inhibition of endothelin in DM + HC + CKD. Scavenging of reactive oxygen species (ROS) had no effect on PVR in either Healthy or DM + HC + CKD swine. Cardiovascular magnetic resonance imaging, under anesthesia, showed no right ventricular changes. Finally, despite an increased contribution of endogenous nitric oxide to vasomotor tone regulation in the systemic vasculature, systemic vascular resistance at rest was higher in DM + HC + CKD compared to Healthy swine (824 ± 41 vs. 698 ± 35 mmHg∙L−1∙min∙kg). ROS scavenging induced systemic vasodilation in DM + HC + CKD, but not Healthy swine. In conclusion, common comorbidities directly alter pulmonary vascular control, by enhanced PDE5 and endothelin-mediated vasoconstrictor influences, well before overt left ventricular backward failure or pulmonary hypertension develop.

In the present study, we tested the hypothesis that multiple risk factors, including diabetes mellitus (DM), dyslipidaemia and chronic kidney disease (CKD) result in a loss of nitric oxide (NO) signalling, thereby contributing to coronary microvascular dysfunction. Risk factors were induced in 12 female swine by intravenous streptozotocin injections (DM), a high fat diet (HFD) and renal artery embolization (CKD). Female healthy swine (n = 13) on normal diet served as controls (Normal). After 5 months, swine were chronically instrumented and studied at rest and during exercise. DM + HFD + CKD swine demonstrated significant hyperglycaemia, dyslipidaemia and impaired kidney function compared to Normal swine. These risk factors were accompanied by coronary microvascular endothelial dysfunction both in vivo and in isolated small arteries, due to a reduced NO bioavailability, associated with perturbations in myocardial oxygen balance at rest and during exercise. NO synthase inhibition caused coronary microvascular constriction in exercising Normal swine, but had no effect in DM + HFD + CKD animals, while inhibition of phosphodiesterase 5 produced similar vasodilator responses in both groups, indicating that loss of NO bioavailability was principally responsible for the observed coronary microvascular dysfunction. This was associated with an increase in myocardial 8-isoprostane levels and a decrease in antioxidant capacity, while antioxidants restored the vasodilation to bradykinin in isolated coronary small arteries, suggesting that oxidative stress was principally responsible for the reduced NO bioavailability. In conclusion, five months of combined exposure to DM + HFD + CKD produces coronary endothelial dysfunction due to impaired NO bioavailability, resulting in impaired myocardial perfusion at rest and during exercise.

Introduction Comorbidities of ischemic heart disease, including diabetes mellitus (DM), hypercholesterolemia and chronic kidney disease (CKD), are associated with coronary microvascular dysfunction (CMD) and may contribute to myocardial “Ischemia and No Obstructive Coronary Artery disease” (INOCA). Purpose We studied myocardial perfusion and oxygen delivery using a novel swine model with multiple comorbidities. Methods DM (streptozotocin), HFD (high fat diet) and CKD (renal embolization), were induced in 12 female swine (DM+HFD+CKD), while 12 healthy female swine on a normal diet served as controls (CON). After 6 months, in the absence of coronary atherosclerosis, myocardial perfusion and function were studied at rest and during treadmill exercise. Results DM+HFD+CKD animals showed hyperglycemia, hypercholesterolemia and impaired kidney function. During exercise, DM+HFD+CKD demonstrated impaired myocardial blood flow and oxygen delivery, necessitating higher myocardial oxygen extraction (despite reduced capillary density), resulting in lower coronary venous oxygen levels, (Fig. 1). These perturbations were associated with lower myocardial efficiency, requiring higher oxygen consumption for a given level of myocardial work (Fig. 1), lower myocardial lactate consumption, stroke volume and LVdP/dtmax, suggestive of myocardial ischemia and dysfunction. Furthermore DM+HFD+CKD showed a reduction in adenosine-recruitable coronary flow reserve (2.69±0.26 vs 3.64±0.2 in CON, p<0.05), which was exclusively the result of an increase in basal coronary blood flow, while maximal coronary flow per gram of myocardium was maintained. The latter was consistent with the unchanged arteriolar wall/lumen ratio, arteriolar density and peri-arteriolar collagen content. eNOS blockade indicated loss of NO bioavailability in DM+HFD+CKD swine in vivo (Fig. 1), which was supported by blunted endothelium-dependent vasodilation to bradykinin in isolated small arteries. These findings suggest that changes in coronary microvascular function rather than structure contributed to the perturbations in myocardial oxygen delivery. Conclusion Common comorbidities result in CMD and impaired NO bioavailability rather than structural alterations in the microvasculature in swine, in the absence of appreciable atherosclerosis. These alterations are severe enough to produce perturbations in myocardial oxygen balance and coronary metabolism and function, particularly during exercise, resembling key features of INOCA. Figure 1 Funding Acknowledgement Type of funding source: Public grant(s) – EU funding. Main funding source(s): This study was supported by grants from the European Commission FP7-Health-2010 grant MEDIA-261409, the Netherlands CardioVascular Research Initiative: an initiative with support of the Dutch Heart Foundation [CVON2014-11 (RECONNECT)].

IntroductionMultiple comorbidities, including diabetes mellitus (DM), hypercholesterolemia and chronic kidney disease (CKD) are associated with diastolic dysfunction. These risk factors also cause coronary microvascular dysfunction leading to impaired myocardial perfusion and ischemia with non‐obstructive coronary artery disease (INOCA). Recently a link has been proposed between INOCA and HFpEF. We investigated the detrimental effects of DM, CKD and high fat diet (HFD) on myocardial function and perfusion.HypothesisProlonged exposure to multiple comorbidities in swine leads to diastolic dysfunction, associated with impaired myocardial perfusion and anaerobic metabolism.MethodsDM (streptozotocin 3×50mg/kg i.v.) and CKD (renal embolization) were induced in 7 female swine fed a high fat diet (DM+HFD+CKD), while 10 female healthy swine on normal diet served as controls (CON). After 6 months, myocardial perfusion and oxygen balance were studied at rest and during treadmill exercise. At sacrifice PV‐loop measurements and histology were performed.ResultsDM+HFD+CKD animals showed hyperglycemia (glucose: 19.2±1.5 vs 7.5±0.6 mmol/L), renal dysfunction (glomerular filtration rate: 132±14 vs 197±10 ml/min) and hypercholesterolemia (total cholesterol: 8.28±0.86 vs 1.65±0.06 mmol/l, all P<0.05). DM+HFD+CKD had an increased EDPVR (0.14±0.02 vs 0.09±0.01 mmHg/mL) with preserved ejection fraction, a lower cardiac index compared to CON at similar levels of exercise (fig A). Left ventricular myocardial capillary density was decreased (1229±59 vs 1502±86 #/mm2) and collagen content was increased (9.6±1.9 vs 5.0±0.6 %). Their myocardium required more oxygen for similar levels of cardiac work, suggesting cardiac inefficiency (fig B). Furthermore, they showed a lower myocardial oxygen delivery (fig C), forcing the myocardium to increase its oxygen extraction (fig D) leading to lower coronary venous oxygen saturation (fig E) both at rest and during exercise. This was accompanied by a decrease in myocardial lactate consumption at the same lactate supply as in CON (fig F), suggestive of anaerobic metabolism. Importantly, DM+HFD+CKD showed no coronary atherosclerosis.ConclusionMultiple co‐morbidities in swine result in severe perturbations in myocardial oxygen balance and anaerobic metabolism in the absence of significant atherosclerosis, indicating severe coronary microvascular dysfunction co‐occurring with diastolic dysfunction.Support or Funding InformationThis study was supported by grants from the European Commission FP7‐Health‐2010 grant MEDIA‐261409, the Netherlands CardioVascular Research Initiative: an initiative with support of the Dutch Heart Foundation [CVON2012‐08 (PHAEDRA), CVON2014‐11 (RECONNECT)]. Cardiac index (CI) of DM+HFD+CKD was lower than in CON swine (A). Myocardium of DM+HFD+CKD swine shows increased oxygen consumption (MVO2) for the same level of cardiac work (B), has a lower myocardial oxygen delivery (MDO2, C) and a higher oxygen extraction (MEO2, D), which results in lower coronary venous oxygen saturation (cv SaO2, E). Lower myocardial lactate consumption (MVlactate) at a given level of myocardial lactate delivery (MDlactate, F). *p<0.05 DM+HFD+CKD versus CONimageCardiac index (CI) of DM+HFD+CKD was lower than in CON swine (A). Myocardium of DM+HFD+CKD swine shows increased oxygen consumption (MVO2) for the same level of cardiac work (B), has a lower myocardial oxygen delivery (MDO2, C) and a higher oxygen extraction (MEO2, D), which results in lower coronary venous oxygen saturation (cv SaO2, E). Lower myocardial lactate consumption (MVlactate) at a given level of myocardial lactate delivery (MDlactate, F). *p<0.05 DM+HFD+CKD versus CONThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

No abstract