11 CARDIOVASCULAR HEALTH Flashcards
What is CVD?
Cardiovascular Disease is a general term for conditions affecting the heart and blood vessels such as atherosclerosis, hypertension, angina, myocardial infarction and stroke.
What percentage of global deaths are attributed to CVD?
32%
TRUE or FALSE:
CVD is the most common non-communicable disease worldwide.
TRUE
What percentage of premature CVD is preventable?
75%
What are some lifestyle factors that increase CVD risk?
Unhealthy diet, lack of exercise, excess body fat, stress, smoking
What can damage the GX?
The GX is easily damaged by inflammation, hyperglycaemia, endotoxemia, oxidised low-density lipoproteins and abnormal blood shear stress.
What is the glycocalyx (GX)?
The glycocalyx (GX), a carbohydrate-rich protective layer covering the ED, regulates permeability, controls NO production and acts as a mechanosensor of blood shear stress.
What is shear stress in relation to Endothelium (ED) cells?
Frictional force of blood
What are the key functions of the ED?
• Semi-permeable barrier: Role in fluid balance, host defence and selective movement of substances e.g., glucose and oxygen.
• Regulates vascular tone: Secretes vasodilators (e.g., NO) and vasoconstrictors (e.g., endothelin).
• Enzymes: Contains angiotensin-converting enzyme (ACE) ― plays a key role in regulating blood pressure.
• Angiogenesis: ED cells are the origin of all new blood vessels.
• Haemostasis: The luminal surface of ED prevents platelet adherence and coagulation (non-thrombotic, anticoagulant).
• Immune defence: Healthy ED cells deflect leukocyte adhesion and oppose local inflammation.
Where are Vascular Smooth Muscle Cells (VSMCs) located and what is their role?
Located in the tunica media and play a key role in vessel contraction and dilation (regulate blood circulation and pressure).
What happens to VSMCs under pathological conditions (e.g., inflammation, oxidative stress, telomere damage?
VSMCs undergo phenotypic modulation, altering cell structure and function.
What is phenotype modulation?
Altering physical form/structure through the interaction of the genotype and environment
What is the result of reduced Nitric Oxide?
Reduced NO contributes to atheroma formation and CVD.
What are the physiological effects of NO?
- Regulates vascular tone
- reduces platelet aggregation and VSMC proliferation
- inhibits leukocyte adhesion and inflammatory cytokines
- opposes oxidation of LDLs.
How is NO generated?
It is continuously generated from L-arginine by endothelial nitric oxide synthase (eNOS).
What regulates NO synthesis?
Vitamin D regulates NO synthesis by mediating eNOS.
Characteristics and function of normal endothelial cells
• Impermeable to large molecules, anti-inflammatory, deflects leukocyte adhesion.
• Enhances vasodilation.
• Resists thrombosis.
Impact of oxidative stress and inflammation on endothelial cells (activated state)
• ↑ permeability, inflammatory cytokines and leukocyte adhesion.
• Reduced vasodilator (NO, prostacyclin) molecules.
• Increased risk of thrombosis.
Location of VSMCs in arteries
Tunica media
Characteristics and function of normal VSMCs
• Normal contractile function, maintains extracellular matrix.
• Contained within the tunica media.
Impact of activation on VSMCs
• Increased inflammatory cytokines and extracellular matrix synthesis.
• Migration into the tunica intima and proliferation of VSMCs.
What are PPARs?
Peroxisome proliferator-activated receptor (PPARs) are nuclear transcription factors that control gene expression involved in:
* adipogenesis
* lipid and glucose metabolism
* cellular proliferation and apoptosis.
What is the role of PPARα in cardiovascular health?
↑ HDL-C, ↓TGs and inflammation, anti-atherosclerotic
List natural PPAR-α agonists.
Green tea, resveratrol, oregano, thyme, rosemary, naringenin, omega-3
What effect does PPAR-γ have?
Name 3 natural PPAR-γ agonists.
Reduces blood glucose, fatty acids, insulin.
Apigenin, hesperidin, curcumin, resveratrol, EGCG
What overall benefits do PPARs provide?
Decrease inflammation, promote ED health
What is the risk increase for offspring of parents with premature CVD?
60–75%
Which genetic polymorphisms are associated with CVD risk?
MnSOD, NOS3, MTHFR, ACE
Which ethnicities have an enhanced risk of CVD?
South Asian, sub-Saharan African
Why is CVD risk in women often underestimated?
Vague symptoms, mistaken for menopause or heartburn
Dyslipidemia is a largely preventable risk factor for CVD. Which lifestyle and dietary factors can underlie this?
Associated with sedentary lifestyle, excess alcohol, smoking, obesity, high intake of saturated and trans fat, menopause. Risk increases in T2DM, hypothyroidism and chronic kidney disease.
Why is mitochondrial dysfunction a CVD risk factor?
ATP is required to pump Ca ions out of myocardial cells, allows relaxation and maintains electrochemical gradient across myocardial cell membrane. Consider statins/CoQ10.
Why is elevated homocysteine regarded as a CVD risk factor?
Associated with LDL oxidation, monocyte adhesion and ED dysfunction
Deficiency of which vitamins can lead to elevated homocysteine?
Folate, B12, B6
What genetic polymorphisms impact homocysteine levels?
MTHFR, FUT2, TCN, MTR, MTRR
Which two nutrients apart from B vitamins are needed for the methylation of homocysteine?
Choline, betaine
How could the thyroid be implicated in cardiovascular disease risk?
Thyroid Hormone receptors are present in the myocardium and vascular tissue and minor TH changes can alter CV homeostasis. Hypo and hyperthyroidism are linked with ED dysfunction, dyslipidaemia and BP changes.
Why is inflammation a CVD risk factor?
Inflammation has various origins including dyslipidaemia, dysbiosis and intestinal permeability, ROS, diabetes, excess adipose tissue and smoking. Inflammation contributes to ED dysfunction. In turn, ED dysfunction, subintimal cholesterol accumulation and recruitment of monocytes and T-cells drives the inflammatory response.
Why is obesity a CVD risk factor?
Excess adipose tissue perpetuates inflammation contributing to vascular breakdown and metabolic complications:
- Inflammation = Elevated ET-1 = fibrosis of VSMCs and ↑ ROS.
- ↓ Adiponectin = disrupted expression of ED cells = less protection against CVD
- ↑ Leptin = ↑ SNS = sodium retention, vasoconstriction & ↑ blood pressure.
Inflammation is linked with an increase in which vasoconstrictor peptide?
Endothelin-1 (ET-1)
Which gene polymorphisms may increase Endothelin-1 and CVD risk?
Polymorphisms of EDN1
Why is insulin resistance a CVD risk factor?
IR generates chronic hyperglycaemia leading to oxidative stress, inflammation and cellular damage:
- IR contributes to the lipid triad and dyslipidaemia.
- Dysfunctional insulin signalling → ED damage + Dyslipidaemia = leads to atherosclerotic plaque formation.
- IR → glucose is not cleared from the bloodstream as quickly as needed = ↑ risk of glycosylation reactions & AGEs.
What is the Lipid triad?
- high plasma TGs
- low HDL
- small dense LDLs
What are advanced glycation end products (AGEs)?
Harmful compounds formed when protein or lipids become glycated after exposure to glucose.
Via which two main mechanisms do AGEs exert their effects?
Via receptor-mediated and non-receptor mediated mechanisms.
What is the receptor-mediated mechanism of AGEs?
AGEs bind to the cell receptor RAGE, increasing inflammatory cytokines and ROS via NADPH activation.
What is the non-receptor mediated mechanism of AGEs?
Increased EC matrix synthesis, trapping ED LDL and cross binding with collagen.
What does AGE/RAGE signaling lead to?
Induces fibroblast differentiation and downregulates intracellular detoxifying mechanisms.
What does glycation refer to?
The chemical addition of glucose molecule to lipids or proteins
What causes an increase in AGEs?
Advancing age, high refined carbohydrates, processed foods, meat, dairy, high heat cooking, smoking, sedentary lifestyle
What is the result of renal accumulation of AGEs?
Kidney dysfunction
What does the AGER gene encode?
RAGE
Which nutrient can ameliorate AGE-mediated complications?
Vitamin D
How does smoking impact cardiovascular health?
- ↑ oxidative stress (ROS react with NO to form harmful peroxynitrite)
- Lowers antioxidants (1 cigarette = 25 mg loss of vitamin C)
- Nicotine over-stimulates SNS and increases BP.
How can exercise contribute to cardiovascular health?
Positive effect on lipid profile, blood pressure, insulin sensitivity, and NO production
How does chronic stress impact cardiovascular health?
- May cause ED dysfunction (especially with other risks e.g., smoking).
- Activates SNS and HPA-axis, ultimately ↑ inflammatory cytokines.
- ↑ heart rate and blood pressure through the SNS.
- Raised activity of the amygdala increases arterial inflammation.
How does stress increase heart rate and blood pressure?
Through SNS activation
What is the effect of periodontal disease on systemic inflammation?
↑ TNF, IL-1, IL-6, CRP
Why is periodontal disease a CVD risk factor?
Periodontal disease increase systemic inflammation (↑ TNF, IL-1, IL-6, CRP) which impair vasodilation. It promotes endothelial dysfunction, arterial stiffness, ↑ fibrinogen
How does heavy metals increase CVD risk?
Heavy metals induce oxidative stress, lipid peroxidation and inflammatory cytokines.
Cadmium and lead compete with zinc. A zinc deficiency increases atherosclerosis risk.
How does melatonin affect cardiovascular health?
Melatonin is a potent antioxidant with anti-hypertensive properties that protects against coronary artery disease.
Which harmful metabolite could result from alterations in gut microbiota and how does this relate to CVD risk?
Trimethylamine-N-oxide (TMAO), which is a proinflammatory metabolite that originates from the bacterial metabolism of choline-rich foods.
TMAO is associated with endothelial dysfunction and increased risk of CVD.
Which metabolites produced by gut microbiota reduces the risk of metabolic endotoxaemia and thus CVD and IR?
SCFAs.
They reduce serum lipids by inhibiting cholesterol synthesis or redirecting lipids to the liver.
Which foods have a high potential renal acid load (PRAL) and what is the impact of high PRAL foods on health?
Foods rich in protein such as meat and cheese. They may induce low-grade metabolic acidosis = risk for IR and CVD
How do trans fats affect health?
Promote dyslipidaemia, inflammation, ED dysfunction, visceral adiposity and IR risk
What is the consequence of high fructose intake on lipid metabolism?
Promotes de novo lipogenesis and ↑ fatty acids, especially palmitic acid which ↑ uptake of oxidised LDL (major driver of atherosclerosis and CAD).
Which nutrient deficiencies can be linked to cardiovascular health risks?
Vitamin C, D, E, CoQ10, Mg
What is a cardiac risk tool?
Calculates score based on CV risks such as age, BMI, smoking. (e.g. QRISK)
What is hs-cTnT and hs-cTnI?
Cardiac troponin proteins released when heart muscle is damaged (such as in Myocardial Infarction)
What is a normal TC level?
< 5 mmol / L
What is a normal HDL level for men?
> 1 mmol / L
What is a normal HDL level for women?
> 1.2 mmol / L