Neuroimmune cardiovascular interfaces control atherosclerosis.

Atherosclerotic plaques develop in the inner intimal layer of arteries and can cause heart attacks and strokes1. As plaques lack innervation, the effects of neuronal control on atherosclerosis remain unclear. However, the immune system responds to plaques by forming leukocyte infiltrates in the outer connective tissue coat of arteries (the adventitia)2-6. Here, because the peripheral nervous system uses the adventitia as its principal conduit to reach distant targets7-9, we postulated that the peripheral nervous system may directly interact with diseased arteries. Unexpectedly, widespread neuroimmune cardiovascular interfaces (NICIs) arose in mouse and human atherosclerosis-diseased adventitia segments showed expanded axon networks, including growth cones at axon endings near immune cells and media smooth muscle cells. Mouse NICIs established a structural artery-brain circuit (ABC): abdominal adventitia nociceptive afferents10-14 entered the central nervous system through spinal cord T6-T13 dorsal root ganglia and were traced to higher brain regions, including the parabrachial and central amygdala neurons; and sympathetic efferent neurons projected from medullary and hypothalamic neurons to the adventitia through spinal intermediolateral neurons and both coeliac and sympathetic chain ganglia. Moreover, ABC peripheral nervous system components were activated: splenic sympathetic and coeliac vagus nerve activities increased in parallel to disease progression, whereas coeliac ganglionectomy led to the disintegration of adventitial NICIs, reduced disease progression and enhanced plaque stability. Thus, the peripheral nervous system uses NICIs to assemble a structural ABC, and therapeutic intervention in the ABC attenuates atherosclerosis.

Targeting Interleukin-1ß Protects from Aortic Aneurysms Induced by Disrupted Transforming Growth Factor ß Signaling.

Aortic aneurysms are life-threatening conditions with effective treatments mainly limited to emergency surgery or trans-arterial endovascular stent grafts, thus calling for the identification of specific molecular targets. Genetic studies have highlighted controversial roles of transforming growth factor ß (TGF-ß) signaling in aneurysm development. Here, we report on aneurysms developing in adult mice after smooth muscle cell (SMC)-specific inactivation of Smad4, an intracellular transducer of TGF-ß. The results revealed that Smad4 inhibition activated interleukin-1ß (IL-1ß) in SMCs. This danger signal later recruited innate immunity in the adventitia through chemokine (C-C motif) ligand 2 (CCL2) and modified the mechanical properties of the aortic wall, thus favoring vessel dilation. SMC-specific Smad4 deletion in Il1r1- or Ccr2-null mice resulted in milder aortic pathology. A chronic treatment with anti-IL-1ß antibody effectively hampered aneurysm development. These findings identify a mechanistic target for controlling the progression of aneurysms with compromised TGF-ß signaling, such as those driven by SMAD4 mutations.

Comparative analysis of blood protein fractions in two mediterranean farmed fish: Dicentrarchus labrax and Sparus aurata.

Total protein levels in fish are widely used in health and welfare studies, providing a simple and accessible measure. However, the multifaceted role of blood proteins makes it sometimes challenging to link total protein content to specific health issues, while specific protein fractions may offer more precise insights into fish biology and health, particularly in farmed fish species where such data is often lacking. Data were gathered from two experiments involving Dicentrarchus labrax and Sparus aurata, key species in European marine aquaculture. The aim was (1) to assess how different globulin fractions contribute to total protein content in blood and (2) how these contributions vary across different sampling times in healthy animals. In D. labrax, the beta1 globulin fraction emerged as the major contributor (34.16%), followed by albumin and alpha2 globulins (18.24% and 16.41%, respectively). In contrast, pre-albumins and alpha1 fractions had the least contribution (5.49% and 7.71%). S. aurata exhibited albumin as the primary contributor (23.39%), followed by beta1 and alpha2 globulins (19.71% and 19.15%, respectively), with gamma and alpha1 fractions contributing the least (5.34% and 8.63%). Notably, the study revealed relatively stable contributions of globulin fractions to total proteins within both species, albeit with minor variations over time, potentially linked to environmental and individual factors. Furthermore, larger fish displayed higher total protein levels. This research underscores the need for further investigation into the diverse factors influencing globulin contributions to total proteins, ultimately enhancing health and welfare monitoring for farmed fish species.

Genetic analyses identify brain structures related to cognitive impairment associated with elevated blood pressure.

BACKGROUND AND AIMS: Observational studies have linked elevated blood pressure (BP) to impaired cognitive function. However, the functional and structural changes in the brain that mediate the relationship between BP elevation and cognitive impairment remain unknown. Using observational and genetic data from large consortia, this study aimed to identify brain structures potentially associated with BP values and cognitive function. METHODS AND RESULTS: Data on BP were integrated with 3935 brain magnetic resonance imaging-derived phenotypes (IDPs) and cognitive function defined by fluid intelligence score. Observational analyses were performed in the UK Biobank and a prospective validation cohort. Mendelian randomisation (MR) analyses used genetic data derived from the UK Biobank, International Consortium for Blood Pressure, and COGENT consortium. Mendelian randomisation analysis identified a potentially adverse causal effect of higher systolic BP on cognitive function [-0.044 standard deviation (SD); 95% confidence interval (CI) -0.066, -0.021] with the MR estimate strengthening (-0.087 SD; 95% CI -0.132, -0.042), when further adjusted for diastolic BP. Mendelian randomisation analysis found 242, 168, and 68 IDPs showing significant (false discovery rate P < 0.05) association with systolic BP, diastolic BP, and pulse pressure, respectively. Most of these IDPs were inversely associated with cognitive function in observational analysis in the UK Biobank and showed concordant effects in the validation cohort. Mendelian randomisation analysis identified relationships between cognitive function and the nine of the systolic BP-associated IDPs, including the anterior thalamic radiation, anterior corona radiata, or external capsule. CONCLUSION: Complementary MR and observational analyses identify brain structures associated with BP, which may be responsible for the adverse effects of hypertension on cognitive performance.

PI3K Isoforms in Vascular Biology, A Focus on the Vascular System-Immune Response Connection.

Cardiovascular diseases are the most common cause of death around the world. Hypertension and atherosclerosis, along with their sequalae and consequent target organ damage, constitute the main vascular risk factors contributing to the onset of cardiovascular disease. Disturbances in the homeostatic relationship established among the various components of the vascular milieu-namely endothelial and smooth muscle cells, adventitia, immune cells, and fibers of the autonomic nervous system-trigger the development of these arterial pathologies. In terms of molecular targets involved in vascular dysfunction and appealing for therapeutic purposes, the multitude of functions that phosphoinositide-3-kinases (PI3K) perform has become an attractive area of investigation in the field of arterial diseases. Composed of eight members arranged in III different classes based on their structure and substrate specificity, PI3Ks are characterized by their shared capability to produce phosphoinositides but, at the same time, they provide specificity and non-redundancy, owing to differences in expression levels of each member in different cell components of the vascular environment, different activation mechanisms and specific subcellular locations. This chapter aims at providing an overview of the functions of the different PI3K isoforms identified thus far in the vasculature, focusing on the emerging relationship established by components of the vascular and immune systems, at the steady-state and during pathology.

The angiogenic factor PlGF mediates a neuroimmune interaction in the spleen to allow the onset of hypertension.

Hypertension is a health problem affecting over 1 billion people worldwide. How the immune system gets activated under hypertensive stimuli to contribute to blood pressure elevation is a fascinating enigma. Here we showed a splenic role for placental growth factor (PlGF), which accounts for the onset of hypertension, through immune system modulation. PlGF repressed the expression of the protein Timp3 (tissue inhibitor of metalloproteinases 3), through the transcriptional Sirt1-p53 axis. Timp3 repression allowed costimulation of T cells and their deployment toward classical organs involved in hypertension. We showed that the spleen is an essential organ for the development of hypertension through a noradrenergic drive mediated by the celiac ganglion efferent. Overall, we demonstrate that PlGF mediates the neuroimmune interaction in the spleen, organizing a unique and nonredundant response that allows the onset of hypertension.

Identification of a brainstem locus that inhibits tumor necrosis factor.

In the brain, compact clusters of neuron cell bodies, termed nuclei, are essential for maintaining parameters of host physiology within a narrow range optimal for health. Neurons residing in the brainstem dorsal motor nucleus (DMN) project in the vagus nerve to communicate with the lungs, liver, gastrointestinal tract, and other organs. Vagus nerve-mediated reflexes also control immune system responses to infection and injury by inhibiting the production of tumor necrosis factor (TNF) and other cytokines in the spleen, although the function of DMN neurons in regulating TNF release is not known. Here, optogenetics and functional mapping reveal cholinergic neurons in the DMN, which project to the celiac-superior mesenteric ganglia, significantly increase splenic nerve activity and inhibit TNF production. Efferent vagus nerve fibers terminating in the celiac-superior mesenteric ganglia form varicose-like structures surrounding individual nerve cell bodies innervating the spleen. Selective optogenetic activation of DMN cholinergic neurons or electrical activation of the cervical vagus nerve evokes action potentials in the splenic nerve. Pharmacological blockade and surgical transection of the vagus nerve inhibit vagus nerve-evoked splenic nerve responses. These results indicate that cholinergic neurons residing in the brainstem DMN control TNF production, revealing a role for brainstem coordination of immunity.

Development of molecular and histological methods to evaluate stress oxidative biomarkers in sea bass (Dicentrarchus labrax).

In aquaculture, fish species may experience stressful episodes caused by poor farming conditions. The exponential increase of global aquaculture has raised the number of research studies aimed at demonstrating the sensitivity of aquatic animals in confined environments. The development of a real-time PCR and immunohistochemistry methods were investigated to evaluate the presence, localization, and quantity of biomarkers of oxidative stress in European sea bass (Dicentrarchus labrax). In particular, stress tests such as manipulation and temperature changes were conducted through molecular methods to identify the expression level of heat shock protein 70 (HSP70) in stressed animals compared with a control group. The immunohistochemical technique was also applied to locate and study the trends-levels of nitrotyrosine (NT), heat shock protein 70 (HSP70), malondialdehyde (MDA), and 4-hydroxy-2-nonenal (HNE) in different tissues from stressed animals and control group. The presence of the rodlet cell (RCs) was evaluated by histology in both a control and stressed group. Our results show that the real-time PCR method developed is specific for the evaluated target gene and that manipulation and temperature increase are strong stressors for animals. Relative quantification data revealed a gene expression increase of HSP70 in the stressed group of animals compared to the control group. The antibodies used for the immunohistochemical staining were efficient, and it was possible to appreciate the increase of immunoprecipitates in European sea bass either manipulated or stressed by temperature increase. The present study can be a starting point to allow the quantification of HSP70 and the identification of other stress biomarkers in D. labrax.

Loss of EMILIN-1 Enhances Arteriolar Myogenic Tone Through TGF-ß (Transforming Growth Factor-ß)-Dependent Transactivation of EGFR (Epidermal Growth Factor Receptor) and Is Relevant for Hypertension in Mice and Humans.

Objective- EMILIN-1 (elastin microfibrils interface located protein-1) protein inhibits pro-TGF-ß (transforming growth factor-ß) proteolysis and limits TGF-ß bioavailability in vascular extracellular matrix. Emilin1-/- null mice display increased vascular TGF-ß signaling and are hypertensive. Because EMILIN-1 is expressed in vessels from embryonic life to adulthood, we aimed at unravelling whether the hypertensive phenotype of Emilin1-/- null mice results from a developmental defect or lack of homeostatic role in the adult. Approach and Results- By using a conditional gene targeting inactivating EMILIN-1 in smooth muscle cells of adult mice, we show that increased blood pressure in mice with selective smooth muscle cell ablation of EMILIN-1 depends on enhanced myogenic tone. Mechanistically, we unveil that higher TGF-ß signaling in smooth muscle cells stimulates HB-EGF (heparin-binding epidermal growth factor) expression and subsequent transactivation of EGFR (epidermal growth factor receptor). With increasing intraluminal pressure in resistance arteries, the cross talk established by TGF-ß and EGFR signals recruits TRPC6 (TRP [transient receptor potential] classical type 6) and TRPM4 (TRP melastatin type 4) channels, lastly stimulating voltage-dependent calcium channels and potentiating myogenic tone. We found reduced EMILIN-1 and enhanced myogenic tone, dependent on increased TGF-ß-EGFR signaling, in resistance arteries from hypertensive patients. Conclusions- Taken together, our findings implicate an unexpected role of the TGF-ß-EGFR pathway in hypertension with current translational perspectives.

Integrating cardiac PIP3 and cAMP signaling through a PKA anchoring function of p110γ.

Adrenergic stimulation of the heart engages cAMP and phosphoinositide second messenger signaling cascades. Cardiac phosphoinositide 3-kinase p110γ participates in these processes by sustaining ß-adrenergic receptor internalization through its catalytic function and by controlling phosphodiesterase 3B (PDE3B) activity via an unknown kinase-independent mechanism. We have discovered that p110γ anchors protein kinase A (PKA) through a site in its N-terminal region. Anchored PKA activates PDE3B to enhance cAMP degradation and phosphorylates p110γ to inhibit PIP(3) production. This provides local feedback control of PIP(3) and cAMP signaling events. In congestive heart failure, p110γ is upregulated and escapes PKA-mediated inhibition, contributing to a reduction in ß-adrenergic receptor density. Pharmacological inhibition of p110γ normalizes ß-adrenergic receptor density and improves contractility in failing hearts.

Innovative MRI Techniques in Neuroimaging Approaches for Cerebrovascular Diseases and Vascular Cognitive Impairment.

Cognitive impairment and dementia are recognized as major threats to public health. Many studies have shown the important role played by challenges to the cerebral vasculature and the neurovascular unit. To investigate the structural and functional characteristics of the brain, MRI has proven an invaluable tool for visualizing the internal organs of patients and analyzing the parameters related to neuronal activation and blood flow in vivo. Different strategies of imaging can be combined to obtain various parameters: (i) measures of cortical and subcortical structures (cortical thickness, subcortical structures volume); (ii) evaluation of microstructural characteristics of the white matter (fractional anisotropy, mean diffusivity); (iii) neuronal activation and synchronicity to identify functional networks across different regions (functional connectivity between specific regions, graph measures of specific nodes); and (iv) structure of the cerebral vasculature and its efficacy in irrorating the brain (main vessel diameter, cerebral perfusion). The high amount of data obtainable from multi-modal sources calls for methods of advanced analysis, like machine-learning algorithms that allow the discrimination of the most informative features, to comprehensively characterize the cerebrovascular network into specific and sensitive biomarkers. By using the same techniques of human imaging in pre-clinical research, we can also investigate the mechanisms underlying the pathophysiological alterations identified in patients by imaging, with the chance of looking for molecular mechanisms to recover the pathology or hamper its progression.

The Interactions of the Immune System and the Brain in Hypertension.

PURPOSE OF REVIEW: Hypertension still represents a huge health problem, causing death and disability and rising at epidemic levels worldwide. The availability of a vast array of antihypertensive therapeutic strategies still fails to adequately treat significant fractions of refractory patients. The possible explanation to this disappointing evidence should be ascribed to the fact that myriad of mechanisms contribute to onset and maintenance of hypertension. Although we have been able to develop strategies aimed at counteracting the single mechanisms identified as master regulators of blood pressure, we still lack strategies capable to approach at the complex interactions established among the different pathophysiological mechanisms. RECENT FINDINGS: One of the most intriguing pathophysiological interactions in hypertension emerged in the very last years is the one established between the autonomic nervous system and immunity. Here we briefly review the most important contributions revealing neural modulation of immunity in hypertension and how this novel concept is integrated in the already known multitude of regulations exerted by the autonomic nervous system in typical organs involved in blood pressure regulation.

PI3Kinases in Diabetes Mellitus and Its Related Complications.

Recent studies have shown that phosphoinositide 3-kinases (PI3Ks) have become the target of many pharmacological treatments, both in clinical trials and in clinical practice. PI3Ks play an important role in glucose regulation, and this suggests their possible involvement in the onset of diabetes mellitus. In this review, we gather our knowledge regarding the effects of PI3K isoforms on glucose regulation in several organs and on the most clinically-relevant complications of diabetes mellitus, such as cardiomyopathy, vasculopathy, nephropathy, and neurological disease. For instance, PI3K α has been proven to be protective against diabetes-induced heart failure, while PI3K γ inhibition is protective against the disease onset. In vessels, PI3K γ can generate oxidative stress, while PI3K ß inhibition is anti-thrombotic. Finally, we describe the role of PI3Ks in Alzheimer's disease and ADHD, discussing the relevance for diabetic patients. Given the high prevalence of diabetes mellitus, the multiple effects here described should be taken into account for the development and validation of drugs acting on PI3Ks.

The Spleen: A Hub Connecting Nervous and Immune Systems in Cardiovascular and Metabolic Diseases.

Metabolic disorders have been identified as major health problems affecting a large portion of the world population. In addition, obesity and insulin resistance are principal risk factors for the development of cardiovascular diseases. Altered immune responses are common features of both hypertension and obesity and, moreover, the involvement of the nervous system in the modulation of immune system is gaining even more attention in both pathophysiological contexts. For these reasons, during the last decades, researches focused their efforts on the comprehension of the molecular mechanisms connecting immune system to cardiovascular and metabolic diseases. On the other hand, it has been reported that in these pathological conditions, central neural pathways modulate the activity of the peripheral nervous system, which is strongly involved in onset and progression of the disease. It is interesting to notice that neural reflex can also participate in the modulation of immune functions. In this scenario, the spleen becomes the crucial hub allowing the interaction of different systems differently involved in metabolic and cardiovascular diseases. Here, we summarize the major findings that dissect the role of the immune system in disorders related to metabolic and cardiovascular dysfunctions, and how this could also be influenced by neural reflexes.

The Multifaceted Roles of PI3Kγ in Hypertension, Vascular Biology, and Inflammation.

PI3Kγ is a multifaceted protein, crucially involved in cardiovascular and immune systems. Several studies described the biological and physiological functions of this enzyme in the regulation of cardiovascular system, while others stressed its role in the modulation of immunity. Although PI3Kγ has been historically investigated for its role in leukocytes, the last decade of research also dedicated efforts to explore its functions in the cardiovascular system. In this review, we report an overview recapitulating how PI3Kγ signaling participates in the regulation of vascular functions involved in blood pressure regulation. Moreover, we also summarize the main functions of PI3Kγ in immune responses that could be potentially important in the interaction with the cardiovascular system. Considering that vascular and immune mechanisms are increasingly emerging as intertwining players in hypertension, PI3Kγ could be an intriguing pathway acting on both sides. The availability of specific inhibitors introduces a perspective of further translational research and clinical approaches that could be exploited in hypertension.

Hypertension and Dementia: Epidemiological and Experimental Evidence Revealing a Detrimental Relationship.

Hypertension and dementia represent two major public health challenges worldwide, notably in the elderly population. Although these two conditions have classically been recognized as two distinct diseases, mounting epidemiological, clinical and experimental evidence suggest that hypertension and dementia are strictly intertwined. Here, we briefly report how hypertension profoundly affects brain homeostasis, both at the structural and functional level. Chronic high blood pressure modifies the cerebral vasculature, increasing the risk of Aß clearance impairment. The latter, excluding genetic etiologies, is considered one of the main causes of Aß deposition in the brain. Studies have shown that hypertension induces cerebral arterial stiffening and microvascular dysfunction, thus contributing to dementia pathophysiology. This review examines the existing and the updated literature which has attempted to explain and clarify the relationship between hypertension and dementia at the pathophysiological level.

Nitroxyl (HNO) for treatment of acute heart failure.

The loss of contractile function is a hallmark of heart failure. Although increasing intracellular Ca(2+) is a possible strategy for improving contraction, current inotropic agents that achieve this by raising intracellular cAMP levels, such as ß-agonists and phosphodiesterase inhibitors, are generally deleterious when administered as long-term therapy due to arrhythmia and myocardial damage. Nitroxyl donors have been shown to improve cardiac function in normal and failing dogs, and in isolated cardiomyocytes they increase fractional shortening and Ca(2+) transients, independently from cAMP/PKA or cGMP/PKG signaling. Instead, nitroxyl targets cysteines in the EC-coupling machinery and myofilament proteins, reversibly modifying them to enhance Ca(2+) handling and myofilament Ca(2+) sensitivity. Phase I-IIa trials with CXL-1020, a novel pure HNO donor, reported declines in left and right heart filling pressures and systemic vascular resistance, and increased cardiac output and stroke volume index. These findings support the concept of nitroxyl donors as attractive agents for the treatment of acute decompensated heart failure.

A translational perspective on the interplay between hypertension, inflammation and cognitive impairment.

Hypertension represents the major risk factor in the onset of cardiovascular disease worldwide. Preclinically, manifold mouse models of hypertension have been developed to investigate the pathophysiological link between hypertension and vascular impairment. Specifically, Angiotensin-II (Ang II) infusion, transverse aortic constriction (TAC), deoxycorticosterone-acetate (DOCA) - salt, and L-NAME administration as hypertensive stimuli at the preclinical level permit the unveiling of a pro-inflammatory response driven by the innate and adaptive immune system as well leading to vascular injury in terms of structural and functional alterations. Vascular impairment seems to be particularly critical at the cerebral level wherein arterioles, venules, and capillaries finely tune blood supply across the whole brain leading to the onset of a well-known clinical condition named cerebral small vessel disease (cSVD) characterized by extensive brain injury, which culminates in the decline of cognitive functions. Advances in magnetic resonance imaging (MRI) permit identification and accurate diagnosis of specific cSVD biomarkers including white matter hyperintensities (WMHs), lacunar strokes (LS), cerebral microbleeds (CMBs), and enlarged perivascular spaces (ePVSs), each of which proved to be associated with a specific cognitive domain impairment. Such an approach in combination with pharmacological interventions targeted both to the lowering of blood pressure and the prevention of vascular thrombosis formation represents a solid strategy in the prevention and the management of cSVD cognitive decay.

Advanced Magnetic Resonance Imaging to Define the Microvascular Injury Driven by Neuroinflammation in the Brain of a Mouse Model of Hypertension.

BACKGROUND: Hypertension is one of the main risk factors for dementia and cognitive impairment. METHODS: We used the model of transverse aortic constriction to induce chronic pressure overload in mice. We characterized brain injury by advanced translational applications of magnetic resonance imaging. In parallel, we analyzed peripheral target organ damage induced by chronic pressure overload by ultrasonography. Microscopical characterization of brain vasculature was performed as well, together with the analysis of immune and inflammatory markers. RESULTS: We identified a specific structural, microstructural, and functional brain injury. In particular, we highlighted a regional enlargement of the hypothalamus, microstructural damage in the white matter of the fimbria, and a reduction of the cerebral blood flow. A parallel analysis performed by confocal microscopy revealed a correspondent tissue damage evidenced by a reduction of cerebral capillary density, paired with loss of pericyte coverage. We assessed cognitive impairment and cardiac damage induced by hypertension to perform correlation analyses with the brain injury severity. At the mechanistic level, we found that CD8+T cells, producing interferon-γ, infiltrated the brain of hypertensive mice. By neutralizing this proinflammatory cytokine, we obtained a rescue of the phenotype, demonstrating their crucial role in establishing the microvascular damage. CONCLUSIONS: Overall, we have used translational tools to comprehensively characterize brain injury in a mouse model of hypertension induced by chronic pressure overload. We have identified early cerebrovascular damage in hypertensive mice, sustained by CD8+IFN-γ+T lymphocytes, which fuel neuroinflammation to establish the injury of brain capillaries.