Cardiovascular ageing: epidemiology

14 important questions on Cardiovascular ageing: epidemiology

What are NAD+ precursors [caloric restriction mimetics]


NAD+ is a coenzyme that is found and needed in all living cells. Here outlined in red is the niconanamide group, which can exit in two forms: the oxidized form NAD+ and the reduced form NADH. In metabolism, NAD+ can accept electrons, NADH can donate electrons in the redox reactions and thus is necessary for ATP production.

What is the role of NAD in Cardiac Energy Metabolism?

NAD is needed in the substrate utilisation and in the oxidative phosphorylation


We have talked about this 3 components of the cardiac energy metabolism. Component 1 and 2 are the steps that generate ATP. NAD is needed for 1st component and NADH is needed for the 2nd component.

Is NAD+ declining with ageing?

Yes

You can image that if NAD+ is decrased, the energy production will be decreased too. Indeed, as you see from this figure, NAD+ and ATP levels is measure in different ages of mice 6-, 22-, and 30-month-old mice (n = 5, *p < 0.05 versus 6-month-old mice). ATP content of 6-, 22-, and 30-month-old mice (n = 5, *p < 0.05 versus 6-month-old mice). You can see clearly reduction of NAD+ as well as ATP levels in the aged mice.
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How to prevent NAD+ with ageing with diet or nutrition.

Vitamin B3 is a vitamin family that includes three forms: nicotinamide, niacin (nicotinic acid), and nicotinamide riboside. All three forms of vitamin B3 are converted within the body to nicotinamide adenine dinucleotide (NAD).

the role of NAM in the preventing the age-related diastolic dysfunction and also the diastolic heart failure also called HFpEF.

Where is a higher dietary NAD+ intake associated with?

Higher dietary NAD+ intake is associated with lower risk of HFpEF and cardiac death in humans


they also measure the NAD contact in the human heart. They found a rduction of NAD+ in HEpEF pateints. And also the dietatry intake of the vitabmin B3 (niacin) reduced the risk for mortality especially the cardiac mortality. (In the ageing population, cardiac vascular disease is the no.1 cause of death)

What are the risks factors and consequences of AF?

Risk factors
  • ageing
  • obesity
  • diabetes
  • hypertension
  • valvular heart disease

consequences
  • stroke
  • heart failure
  • death
  • decrease the quality of life of the patients, they often may feel palpitation (=hartkloppingen) and have exercise intolerence.

In the clinics, doctors clasify the patients into 4 groups based on the duration of AF episodes. What are these classifications?

  • Normal
  • Paroxysmal (< 1 week)
  • Persistent (>1 week (week to months))
  • Long standing persistent (>12 months)
  • Permanent (not treatable)


currently patients can be treated with electrical cardioversion or pharmacological drugs, but these treatments are only symptomatic treatment, meaning they can only targeting the symptoms such as to slow down the heart rate or restore heart rhythm. These treatment only works for a short period. It does not stop the progression of the disease. Often, patients comes back to the clinics as AF recur.
  • electrical cardio version
  • pharmacological cardio version

What are the causes of atrial remodelling

  • 'lone' AF [<2%]
  • risk factors [>98%]

When/where do these thee types of atrial remodelling take place?
  1. electrical remodelling
  2. structural remodelling
  3. metabolic remodelling

Electrical remodelling in the strict sense, i.e. the shortening of APD and ERP, takes places in the first 1–3 days of AF.


The first signs of structural remodelling do not become apparent until several weeks later.


The period in between (which coincides with a major increase in AF stabilization) is likely to be the most important phase of metabolic remodelling, hallmarked by chronic supply–demand ischaemia and hypoxia. Changing patterns of gene expression in this period reflect a reorientation of metabolism, regression to a foetal phenotype and hibernation.

What does the electrical remodelling do?

It reduced calcium transient in AF patients

You see decreased of CaT amplitude in AF patients.

What is the effect of electrical remodelling in mouse atrial cardiomyocytes?

AF induces electrical remodelling and contractile dysfunction in HL-1 cardiomyocytes

You see reduction of CaT amplitude and also contractile dysfunction measured by cell shortening.

What is the effect of metabolic remodelling: mitochondrial damage and oxidative stress

AF induces metabolic remodelling (mitochondrial dysfunction) in HL-1 cardiomyocytes

What are the major roles of NAD(H) in cellular physiology?

NAD as co-enzyme -->> energy production

NAD as co-substrate -->> cellular signalling

What induces Tachypacing (TP)


Tachypacing (TP) induced PARP activation in HL-1 cardiomyocytes for AF

We checked the activity of PARP in the cellular model of AF by staining the polyADPribosylated protein (PAR) with fluorescence. We saw significantly increase of the PAR in AF, indicating PARP activation by AF.

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