debra j. skene - european sleep research society · skene et al., pnas, 2018. pathways of...
TRANSCRIPT
Age-related changes in circadian factors and light interventions in healthy and pathological human ageing
Debra J. SKENE
ChronobiologyUniversity of Surrey, Guildford, UK
Metabolomics
• better understanding of circadian and sleep/wake regulation of metabolism
• Powerful tool to elucidate mechanisms linking sleep restriction, circadian misalignment and metabolic disturbances
- peripheral clock phase/function during circadian misalignment
- biomarkers to track sleep and circadian disruption; and monitor recovery
Age-related changes in circadian factors and light interventions in healthy and pathological human ageing
Debra J. SKENE
ChronobiologyUniversity of Surrey, Guildford, UK
2 process model
Borbély, A. A.Hum.Neurobiol., 1982Daan, S., Beersma, D. G. M. and Borbély, A.A. Am. J.Physiol., 1984
Human circadian timing system
Human circadian timing system Circadian rhythms Effect of ageing
Treatment strategies - melatonin, light - in ageing
Challenges Circadian rhythms and ageing research?
Only measure clock outputs (eg melatonin, rest/activity)
Confounded – field studies
Cross-sectional, rarely longitudinal
Older people - medication/mobility issues
Participant numbers7 care homes in south-east England
Total number of residents = 256
Not suitable = 125(49%)
Suitable = 131(51%)
No = 51(39%)
Yes = 80(61%)
Wearing AWL = 73(91%)
In analysis = 48(66%)
Hopkins, S. et al. Current Alz. Res 2017
Not a homogenous group n = 80
MobilityFully mobile 20% Walking stick 11%Walking frame 16%Wheelchair 53%
MMSE score 27 – 30, no impairment 13%21 – 26, mild 26%11 – 20, moderate 53%0 – 10, severe 8%
8 registered blind (2NLP; 6 LP) Hopkins, S. et al. Current Alz. Res 2017
(A)
(C)
(B)
(D)
(E)
Hourly activity counts mean ± SEMA + C = fully mobileB + D = wheelchairE = walking frame
24h activity profiles (7 days)
Hopkins, S. et al. Current Alz. Res 2017
Challenges Circadian rhythms and ageing research?
Only measure clock outputs (eg melatonin, rest/activity)
Confounded – field studies
The suprachiasmaticnuclei (SCN) of the hypothalamus
Site of circadian oscillator
Courtesy of Dr Michael Hastings
The Clock in the Brain
24 48 72
Time (hours)
A5
B7b
D1
G3b
3
4
2
0
0
0
4
0
Hz
Welsh, Logothetis, Meister & Reppert, Nature 1995
Courtesy of Till Roenneberg
Retina-SCN-PVN-SCG-pineal pathway
SCN rhythmicity drives melatonin rhythmEntrained to 24 h by light/dark via the retina-RHT pathway
Stehle, J.H., et al. 2011
(Retina)-SCN-PVN-HPA axis
Courtesy of Andries Kalsbeek
(Retina)-SCN-PVN-ANS
Courtesy of Andries Kalsbeek
SCN-driven melatonin and cortisol rhythms in constant routine conditions
Gunn et al., 2016
males n = 14
Confounders
• Light/dark cycle • Sleep/wake cycle• Activity/exercise• Drugs• Food• Posture• Stress• Menstrual cycle?
Challenges in measurement
Diurnal versus circadian rhythms
Diurnal – exogenous and endogenousRhythms may be influenced, or even driven, by environmental cycles
Circadian – endogenous Rhythms driven by endogenous timing mechanisms (“clocks”)
persist in constant conditions
Early “Clock” Experiments
DAYTIMELeaves are open
NIGHT TIMELeaves are closed
Mimosa pudica
de Marian, 1729
the constant routine protocol
• Designed to remove/minimise effects of external environment and behaviour (e.g. sleep)
• No knowledge of clock time• Constant dim light• Semi-recumbent posture• Minimal social interaction• Regular (e.g. hourly) small
isocaloric snacks
Diurnal versus circadian rhythms
Human circadian rhythms - endogenously generated
persist in constant conditions
• Melatonin• Cortisol• Rectal temperature• Activity• Sleep• Mood• Performance
Circadian rhythms
Rajaratnam &Arendt 2001
melatonin
core body temp
subjective alertness
task performance
triacylglycerol
Czeisler & Klerman 1999 Recent Prog Horm Res 54:97-132
Constant routine protocol versusentrained diurnal sleep/wake
Melatonin as a reliable marker of circadian phase
• unaffected by:meals, stress, bathing, sleep
• dim light conditions (< 8 lux)• exclude drugs• control posture, exercise
0
10
20
30
40
50
60
70
80
1500 1700 1900 2100 2300 100 300 500 700 900 1100 1300 1500 1700
clock time (h)
pla
sma
me
lato
nin
(p
g/m
l)
acrophase (calculated peak time)
mid-range crossing
25% rise/fall
onset/offset
*
**
* ** *
duration
‘biological night’
Markers of the melatonin rhythmused to characterise the timing of the circadian clock
Arendt & Skene, Sleep Medicine Reviews (2005) 9:25-39
Benloucif et al., 2007
SCN extra-SCN brain oscillators peripheral clocks
• synchrony between different internal rhythms• synchrony between internal rhythms and external cycles e.g. for diurnal animals: sleep at night, visual function and metabolic responses optimal in the day
DiagnosisMeasures used to assess - human circadian timing system
- SCN-driven rhythms (melatonin, cortisol)
- Markers of peripheral clocks?
Human peripheral clocks
• Buccal tissue (Cajochen et al., 2006)
• Blood cells (Archer et al., 2008; O’Neill and Reddy, 2011; Ackermann et al., 2013)
• Skin fibroblasts (Brown et al., 2005; 2008)
• Hair follicles (Akashi et al., 2010)
• Adipose tissue (Otway et al., 2011)
• Skeletal muscle (van Moorsel et al., 2016)
SCN extra-SCN brain oscillators peripheral clocks
Markers of human peripheral clocks? Plasma metabolomeBlood cells, buccal tissue, skin fibroblasts, hair follicles, adipose tissue, muscle
Skene et al., PNAS, 2018
Effects of Prior Simulated Shift Work on Metabolite Rhythms (Examples)
Sphingolipid SM C20:2
24/27 (89%) had significantly shifted (reversed) rhythms
Skene et al., PNAS, 2018
• Rhythms in most metabolites dissociated from the SCN pacemaker rhythm
• Vast majority aligning with the preceding sleep/wake and feeding/fasting cycles
• Metabolic profiling (metabolomics) in plasma may provide a window onto peripheral clocks and the biobehavioral factors orchestrating them
Conclusions
Skene et al., PNAS, 2018
Pathways of peripheral clock entrainment
From Mohawk et al. Annu. Rev. Neurosci. 2012
Human circadian timing system
Human circadian timing system Circadian rhythms Effect of ageing
Possible causes of age-related changes in circadian system
PinealGland
SCN PVN SCG
Output pathway
melatonin temperature sleep/wake
RHT
Input pathway
cortisol
Possible causes of age-related changes in circadian system
PinealGland
SCN PVN SCG
Output pathway
melatonin temperature sleep/wake
RHT
Input pathway
cortisol
? ?
??
Possible causes of age-related changes in circadian system
1. Clock disturbance
2. Entrainment abnormalities
3. Insufficient zeitgebers (time cues)
Biological rhythms
Amplitude
Period Phase
Mesor
Courtesy Ken Wright
phase angle
0
3
6
9
12
15
18
21
TCircadian Terminology
Mean
bedtime
Amplitude
12 16 20 24 4 8 12 16 20 24 4 8 12
Sal
iva
ry M
ela
ton
in L
eve
ls (
pg
/ml)
Clock Hour
Age-related changes
1. Amplitude2. Period3. Phase 4. Phase angle of
entrainment5. Response to light
Duffy et al., Sleep Med. Clin. , 2016
Phase angle of entrainment = phase relationship between a circadian rhythm and the environmental signal entraining the rhythm (e.g. light-dark cycle; sleep onset)
Possible causes of age-related changes in circadian system
1. Clock disturbance
PinealGland
SCN PVN SCG
Output pathway
melatonin temperature sleep/wake
RHT
Input pathway
cortisol
Reduced amplitude
1. Clock disturbance
Human SCN- reduced number of vasopressin neurons- reduced amplitude of rhythm
- alterations in the neural and temporal organization of the SCN
Hofman and Swaab, 1988; review 2006
Hofman and Swaab, 1988; review 2006
Age-related changes in melatonin
- reduced melatonin amplitude
Plasma melatonin
Waldhauser et al., 1988
Urinary 6-sulphatoxymelatonin (aMT6s)
Bojkowski and Arendt, 1990
Skene et al., 1990
Pre- and postmenopausal women (n=160)
Skene et al., 1990
Pineal melatonin - human postmortem tissue
Melatonin in CSF
Liu et al., 1999
PinealGland
SCN PVN SCG
Output pathway
melatonin temperature sleep/wake
RHT
Input pathway
cortisol
Possible causes of age-related changes in circadian system
Concretions, reduced sympathetic innervation, -receptor changes, reduced NAT
Age-related changes in melatonin
- reduced melatonin production/amplitude most studies (diurnal, entrained)
Zeitzer et al., 1999
65+ Elderly- disease and drug freeDim light, semi-recumbent, sleep deprived, isocaloric meals
Constant routine study
Possible causes of age-related changes in circadian system
1. Clock disturbance
2. Entrainment abnormalities
PinealGland
SCN PVN SCG
Output pathway
melatonin temperature sleep/wake
RHT
Input pathway
cortisol
Reduced amplitudePhase advance of circadian rhythms
Age-related change in circadian period?
Explain phase advance of circadian rhythmsi.e shorter period as age?
Forced desynchrony
Sighted
Czeisler et al., Science, 1999
= 24.18 0.02 h
n = 11 youngn = 13 old
Human circadian period ()
23.9
24
24.1
24.2
24.3
24.4
24.5
24.6
24.7
24.8
24.9
25
0 10 20 30 40 50 60 70 80
aMT6stau (h)
Age (yrs)
aMT6s Period and Age
r = -0.02n = 23
Skene et al., unpublished
Totally blind
Real life
Age-related changes in melatonin
1. decreased melatonin production - decline in amplitude
2. phase advance of melatonin rhythm
16-20 21-30 31-40 41-50 51-60 61-70 71-81 16-810
1
2
3
4
5
6
7aM
T6s
acr
op
has
e m
ean
S
D
18 83 18 13 4 136 n
years
Earlier aMT6s peak time with ageing
English et al., unpublished
Duffy et al., Sleep Med. Clin. , 2016
solid line - older group
Earlier wrt clock time
Later wrt to biological timei.e. sleep/darkness
Older compared to young adults
Possible causes of age-related changes in circadian system
1. Clock disturbance
2. Entrainment abnormalities
PinealGland
SCN PVN SCG
Output pathway
melatonin temperature sleep/wake
RHT
Input pathway
cortisol
Age-related changes in the eye
Age-related changes in the eye
Adapted from Weale, 1988
pupil size
lens transmission
S-cones melanopsin RCGs
Lerman, 1980
25 years
91 years82 years70 years
60 years47 years
increased lens density reduced transmission of light
Age-related changes in the eye
Age-related changes in the lens reduce transmittance of short wavelength blue light
Average spectral density of the lens (adapted from Pokorny et al., 1987)
-0.5
0.5
1.5
2.5
380 420 460 500 540 580 620 660
Wavelength (nm)
Op
tica
l Den
sity
20 yrs
60 yrs
80 yrs
20 yrs
60 yrs
80 yrs
Spectral sensitivity?
Arendt, 1995
0
20
40
60
80
100
120
140
n
n
nn n
n
n
nnO
O
O
O O
O OO
Oo
o
o
o
o
o oo
o
23:00 23:30 0:00 0:30 1:00 1:30 2:00
Clock time (hours)
Pla
sma
mel
aton
in (
pg/m
l)Suppression by short wavelength light
o 424 nm 16 W/cm2
O 472 nm 36 W/cm2
Thapan, Arendt & Skene, J Physiol, 535, 261-67, 2001
Spectral sensitivity of light-induced melatonin suppression
Melatonin suppression as a function of wavelength and irradiance
Me
lato
nin
su
pp
res
sio
n (
%)
Photons/cm2/sec
548 nm£ 520 nm 496 nm 472 nml 456 nmn 424 nm
0
10
20
30
40
50
60
70
1E+11 1E+12 1E+13 1E+14 1E+15 5E+15
n
n
n
nn
l
l
l
l
t tt
t
t t t
u
u
u
u
uu
££
£
£
£
£
££
l
l
l
l l
Thapan, Arendt & Skene, J Physiol, 535, 261-267, 2001
Age-related changes in the eye
Effect on non-visual light responses?
Light-induced melatonin suppression
max 456 nm max 548 nm
1. A significantly reduced response to the short
wavelength light (456 nm) in the older group
2. No difference between age groups in response to
medium wavelength light (548 nm)
Hypotheses
- 0.5
0.5
1.5
2.5 20 yrs60 yrs80 yrs
- 0.5
0.5
1.5
2.5 20 yrs60 yrs80 yrs
- 0.5
0.5
1.5
2.5
380 420 460 500 540 580 620 660
20 yrs60 yrs80 yrs
Average spectral density of the lens (adapted from Pokorny et al., 1987)
- 0.5
0.5
1.5
2.5
Wavelength (nm)
Op
tica
l D
ensi
ty
20 yrs60 yrs80 yrs
Age-related changes in short wavelength blue light sensitivity
Reduced responsiveness in the elderly
Exp Gerontol 40, 237-242, 2005
Time: F = 4.68, p < 0.0001Age: F = 35.76, p < 0.0001
Increased alertness in young during and after blue (456 nm) light
morealert
Su
bje
cti
ve a
lert
ness
Time from start of light (h)
(norm
alised
to b
aselin
e)
moresleep
y
young (n = 11)
older (n = 15)
Sletten et al., J. Biol. Rhythms, 2009
0 1 2 3 4 5 6 7
-2
-1
0
1
2
3
4
5
No effect of age on alertness during and after green (548 nm) light
Time: F = 4.84, p < 0.0001
Time from start of light (h)
Su
bje
cti
ve a
lert
ness
(norm
alised
to b
aselin
e)
young (n = 11)
older (n = 10)morealert
moresleep
y0 1 2 3 4 5 6 7
-2
-1
0
1
2
3
4
5
Sletten et al., J. Biol. Rhythms, 2009
Conclusions
AGEING• Acute responses to blue light are impaired- melatonin suppression, alerting effect
• Phase advancing effects of blue light retained
• Acute and phase shifting responses: Differentially affected by age?
- Different photopigment contribution?- Different melanopsin RGCs (M1 and M2)?
Herljevic et al., 2005; Ackermann et al., 2009; Jud et al., 2009; Sletten et al., 2009
Age-related changes
1. Amplitude2. Period3. Phase 4. Phase angle of
entrainment5. Response to light
reducedshorter (faster)? Noearlier clock timesleep at earlier biological timereduced acute effectsphase shifting effects?
Duffy et al., Sleep Med. Clin. , 2016
Possible causes of age-related changes in circadian system
1. Clock disturbance
2. Entrainment abnormalities
3. Insufficient zeitgebersocular light, ↓ melatonin signalling
PinealGland
SCN PVN SCG
Output pathway
melatonin temperature sleep/wake
RHT
Input pathway
cortisol
LIGHT MELATONIN
LIGHT MELATONIN
Phase shift circadian rhythms
Chronotherapy to hasten adaptation
Light Melatonin
• shifts circadian rhythmssleep timing
melatonin
temperature
cortisol
Management/Treatment of
Circadian Rhythm Sleep-wake Disorders
Increase zeitgeber strength
Increase circadian amplitude
Light Melatoninsupplementation
Age-related ocular changes
Reduced sensitivity to blue light**
Reduced environmental light exposure
- reduced mobility
- homes poorly lit
Older people require 3-5 times more light
**Herljevic et al., 2005; Jud et al., 2009; Sletten et al., 2009
Why light supplementation for older people?
Optimisation of lighting for the elderly
increase blue light content
increase longer wavelengths - enhance any M- and L-cone input- melanopsin photoreversal
Revell and Skene, 2009
Light treatment shown some benefits
- older demented patients Van Someren et al., 1997; Fetveit et al., 2003; Riemersma-van der Lek et al., 2008
Blue-enriched 17000 K lights
- office workers; living environments Francis et al., 2008; Viola et al., 2008; van Hoof et al., 2008; Vetter et al., 2011
Why light supplementation for older people?
Spectral compositionBlue-enriched white light Control white light high colour temperature low colour temperature 17000 K 4000 K
400 450 500 550 600 650 700
-100
0
100
200
300
17000 K lights
4000 K lights
Wavelength (nm)
Re
lati
ve
sp
ec
tra
lp
ow
er
dis
trib
uti
on
Effect of blue-enriched and control white light
on sleep quality and daytime alertness
in older people?
- in the community
- in care homes
EU FP6 Marie Curie RTNESRC New Dynamics of Ageing/Philips Lighting
Field studies
week
week
Baseline
Light exposureA or B
Washout period
Light exposureA or B
Washout period
week
week
week
1
2
3
4
5
6
7
8
9
10
11
light exposure A or B
week
week
week
week
week
week
Community study - skeleton photoperiods
Effect of blue-enriched and control white light
on sleep quality and daytime alertness
in older people?
- in the community
- in care homes
EU FP6 Marie Curie RTNESRC New Dynamics of Ageing/Philips Lighting
Field studies
Weeks
1 2 3 4 5 6 7 8 9 10 11 12
Weeks
1 2 3 4 5 6 7 8 9 10 11 12
Care home study - protocol
base line care home lights ~ 60 lux
17000 K light ~ 900 lux
4000 K light ~ 200 lux
wash out period care home lights ~ 60 lux
12-week study, randomised, crossover design September - April in 2008/2009 and 2009/2010
Aims• To increase light levels and light exposure in
older people
• To test if increasing light levels will affect sleep, activity, alertness and mood
Hypothesis
high intensity blue-enriched (17000 K, 900 lux) > control (4000 K, 200 lux)
Care room original light conditions
Dimly lit, not uniform59 ± 52 lux (mean ± SD, n = 20 rooms)
Indoor lighting measured weekly (lux meter), after sunsetIn direction of gaze (vertical plane)
Supplementing light in care homes
Care home #1, 4000 K lights Care home #8, 17000 K light
More uniform, higher light levels
4000 K 195 ± 31 lux17000 K894 ± 129 luxCare home 59 ± 52 lux
Hopkins, S. et al. Current Alz. Res 2017
24 hour light profiles
17000 K vs washout
4000 K vs washout
17000 KWashout
4000 KWashout
0 4 8 12 16 20 240
500
1000
1500 17kWO
Time (Hours)
Mea
nlu
x le
vel
0 4 8 12 16 20 240
500
1000
1500 WO4K
Time (Hours)
Mea
nlu
x le
vel
Conclusions
Blue-enriched light supplementation - well tolerated - positive effects
reduced anxietyincreased daytime activityadvanced activity rhythm
- negative effects increased night-time activityreduced sleep efficiencyreduced sleep quality
Hopkins, S. et al. Current Alz. Res 2017
Using Light: ChallengesControlled laboratory studies
practical real life situations?
Need more large, randomised, placebo controlled studies for light optimisation
Adapt to specific subjects groups e.g. older people (shiftworkers etc)
Caution with high intensity “activating” blue-enriched light
Melatonin• shifts circadian rhythms
sleep timing
melatonin
temperature• acute effects
lowers temperature
lowers alertness, transient sleepiness
improves sleep (mood, performance)
Time (h)
Melatonin
36.2
36.4
36.6
36.8
37
37.2
20
40
60
80
100
Meal17:00 19:00 21:00 23:00 01:00
Core body temperature
Alertness
Acute effects of 5mg melatonin
100
PlaceboSubjective Alertness
(%)
Rectal Temperature
( C)
Deacon et al., 1994
Melatonin as a “sleep aid”• Not a classical sedative hypnotic
Reduces sleep latency
Increases total sleep time?
Reduces night awakenings?
• Older adults with sleep problems• (Children with neurodevelopmental disorders
autism, ADHD)
reducing sleep onset latency
in primary insomnia (p = 0.002)
in delayed sleep phase syndrome (p < 0.0001)
regulating the sleep-wake patterns in blind patients compared with placebo.
Auld et al., Sleep Med Rev. 2017
Melatonin receptor agonists
TASIMELTEON – HETLIOZ®
Selective MT1/MT2 agonist
FDA approved for non-24 h S/W disorder
Vanda Pharmaceuticalsmelatonin
Takeda
Sleep-onset insomnia
Valdoxan ®
ServierMajor depressive disorder
Acknowledgements
LIGHTKavita Thapan Victoria RevellMirela HerljevicTracey SlettenHelen ThorneKatharina Lederle
MELATONINSteven LockleyLisa HackJosephine Arendt
Benita Middleton
Lloyd Morgan
Samantha Hopkins
Daniel Barrett
Katrin Ackermann
Shelagh Hampton
FOODSophie Wehrens
Cheryl Isherwood
Skevoulla Christou
Simon Archer
Michelle Gibbs
Jonathan Johnston
AcknowledgementsCurrent and recent funding EU Marie Curie RTN EU FP6 IP
Past fundingBHF, EU Biomed, EU FP5, MRC, Pfizer, Servier R & D, Wellcome Trust
STOCKGRAND LTDSTOCKGRAND LTD
ESRC New Dynamics of Ageing
References - Reviews
References - Reviews
References - Reviews