biology of aging

Question 1

what is aging

Answer 1

Longevity – length of lifespan independent of ageing.​

Ageing – more of a random process arising from the impact of events over the life course.

Question 2

Name 2 physiological changes that occur when humans age

Answer 2

Reduction in brain volume or mass/

Decreased lung capacity/

Question 3

Name 2 psychological changes that occur when humans age

Answer 3

Altered sleep patterns/ Cognitive decline/
increased depression risk

Question 4

Compare program theories of ageing to damage theories of ageing

Answer 4

Program theories of ageing suggest that ageing follows a biological timetable. (1)

Damage theories suggest organisms experience environmental assaults (UV exposure, ROS) throughout their lifespan and that the cumulative impact of these assaults causes ageing (1)​

Question 5

list 3 criteria for hallmarks of ageing- (an attempt to identify biological pathways that contribute to aging)

Answer 5

(i) it should manifest during normal ageing;

(ii) its experimental aggravation should accelerate ageing;

(iii) its experimental improvement should retard the normal ageing process and, hence, increase healthy lifespan

Question 6

9 hallmarks of aging is split into what 3 functional domains

Answer 6

genomic hallmarks
cellular hallmarks
biochemical hallmarks

Question 7

what is in genomic hallmarks

Answer 7

1. genomic instability
2. epigenetic changes
3. telomere attrition

Question 8

what is genomic instability and treatment

Answer 8

[DNA damage over time by environment ie (UV radiation/free radicles) is linked to aging.]

increasing age-> changes in chromosome stability, nuclear architecture, mitochondrial DNA. Failure to remedy these changes-> cellular dysfunction. Accumulation=aging.

treat: elimination of damaged cells

Question 9

what is epigenetic changes and treatment

Answer 9

[Aging is associated with
distinct epigenetic changes,
loss of DNA methylation,]
age-specific patterns of histone modification,
changes in enzymes expression that regulate DNA packaging and chromatin remodelling

impaired DNA repair and chromosome instability

treat: epigenetic drugs

Question 10

what is Telomere attrition and treatment

Answer 10

[Telomeres, repeated DNA sequences at chromosome ends, shorten with each cell division, leading to aging when critical shortness is reached.]

however, some cells, like stem cells, express telomerase, maintaining telomere length. Experimental modulation of telomeres or telomerase can affect lifespan, suggesting a role in aging.

treat- telomerase reactivation

Question 11

what is covered in cellular hallmarks

Answer 11

1.stem cell exhaustion
2. changes in cell signalling
3. cellular senescence

Question 12

what is stem cell exhaustion and treatment

Answer 12

reduced regenerative potential of tissues->hallmark of aging.

reduced cell cycle activity in aged stem cells->divide less frequently -> contribute less to repair + tissue maintenance, resulting in aging.
stem cells accumulate mutations = formation of neoplasias.

treat- stem cell based therapies

Question 13

Stem cell exhaustion- what does changes in HSC/MSC/Satellite cell and IESCs with age lead to

Answer 13

Haematopoietic Stem Cells
-anaemia

Mesenchymal Stem Cells
-osteoporosis

Satellite Cells
-decreased repair of muscle fibres

Intestinal Epithelial Stem Cells
-decreased intestinal function

Question 14

Changes in cell signalling and treatment

Answer 14

[changes in inflammation, hormonal changes, and reduced immune system activity- internal environment is responsible for aging]

Senescent cells can influence the cells around them to enter senescence too (bystander effect)
Prevention of chronic inflammation-> poss inhibiting aging.

treat- anti-inflammatory drugs

Question 15

what is bystander effect

Answer 15

influencing cells around to enter senescence too through communication to neighbouring cells via gap junctions

Question 16

what is cellular senescence and treatment

Answer 16

[suppression of cell cycle]
halts cell cycle in response to DNA damage, preventing proliferation of dysfunctional cells.
removal of senescent cells by the immune system reduces cancer and aging risks.

Aging reduces stem cell activity, impairing replacement of removed cells.
Senescent cells secrete pro-inflammatory cytokines, accelerating aging.

treat- clearance of senescent cells

Question 17

what are considered in the biochemical hallmarks

Answer 17

1. Impaired mitochondrial function
2. Impaired proteostasis
3. Impaired nutrient sensing

Question 18

what is impaired mitochondrial function and treatment

Answer 18

[mother’s mitochondrial DNA damage cause aging]

dysfunction increases ROS damaging cellular macromolecules.

treat- mitophagy

Question 19

what is Impaired proteostasis and treaetment

Answer 19

Proteostasis maintains protein folding via chaperones and targets unfolded proteins for breakdown,

impaired prosteostasis-> their persistence can lead to aggregation, disrupting cell function and contributing to age-related disorders like Alzheimer’s and Parkinson’s.

treat- activation of chaperones and proteolytic systems

Question 20

Impaired nutrient sensing and treatment

Answer 20

Mutations reducing the activity of the GH- like (IGF-1) pathway prolong lifespan in animals, but extremely low levels are deadly. Dietary restriction extends lifespan in animals by activating the AMPK pathway.

treat- dietary restriction

Question 21

What term describes the hallmarks of ageing which are the causes of damage which underpin ageing?

Answer 21

Primary hallmarks
ie. genomic instability

Question 22

what are the 9 hallmarks of aging

Answer 22

1.genomic instability
2.epigenetic changes
3. telomere attrition
4. stem cell exhaustion
5. changes in cell signalling
6. cellular senescence
7. impaired mitochondrial function
8.impaired proteostasis
9. impaired nutrient sensing