Age-related changes in circadian factors and light interventions in healthy and pathological human ageing

Debra J. SKENE

Chronobiology University of Surrey, Guildford, UK

[email protected] 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

Chronobiology University of Surrey, Guildford, UK

[email protected] 2 process model

Borbély, A. A.Hum.Neurobiol., 1982 Daan, 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 - , 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 numbers 7 care homes in south-east England

Total number of residents = 256

Suitable = 131 Not suitable = 125 (51%) (49%)

No = 51 Yes = 80 (39%) (61%)

Wearing AWL = 73 In analysis = 48 (91%) (66%)

Hopkins, S. et al. Current Alz. Res 2017 Not a homogenous group n = 80 Mobility Fully 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 24h activity profiles (7 days) (A) (B)

(C) (D)

(E)

Hourly activity counts mean ± SEM A + C = fully mobile B + D = wheelchair E = walking frame

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 suprachiasmatic nuclei (SCN) of the hypothalamus

Site of circadian oscillator

Courtesy of Dr Michael Hastings The Clock in the Brain

Hz A5

2

0 B7b

4

0 D1

3

0 G3b

4

0 24 48 72 Time (hours) Welsh, Logothetis, Meister & Reppert, Nature 1995

Courtesy of Till Roenneberg Retina-SCN-PVN-SCG-pineal pathway

Stehle, J.H., et al. 2011

SCN rhythmicity drives melatonin rhythm Entrained to 24 h by light/dark via the retina-RHT pathway (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

males n = 14

Gunn et al., 2016 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 endogenous Rhythms 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

DAYTIME NIGHT TIME Leaves are open Leaves are closed

Mimosa pudica

de Marian, 1729 Diurnal versus circadian rhythms 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 Human circadian rhythms - endogenously generated persist in constant conditions

• Melatonin • Cortisol • Rectal temperature • Activity • Sleep • Mood • Performance Circadian rhythms melatonin

core body temp

subjective alertness

task performance

triacylglycerol

Rajaratnam &Arendt 2001 Constant routine protocol versus entrained diurnal sleep/wake

Czeisler & Klerman 1999 Recent Prog Horm Res 54:97-132 Melatonin as a reliable marker of circadian phase

• unaffected by: meals, stress, bathing, sleep

• dim light conditions (< 8 lux) • exclude drugs • control posture, exercise Markers of the melatonin rhythm used to characterise the timing of the circadian clock

80 duration

70 ) l m / 60 g

p acrophase (calculated peak time) (

* 50 n i n o t 40 a l e

m 30 mid-range crossing a * * m 20 s

a 25% rise/fall l p 10 * * onset/offset * * 0 1500 1700 1900 2100 2300 100 300 500 700 900 1100 1300 1500 1700 clock time (h)

‘biological night’

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 Diagnosis Measures 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 metabolome Blood 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 Conclusions

• 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

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 Possible causes of age-related changes in circadian system

Output pathway

RHT Pineal SCN PVN SCG Gland Input pathway cortisol

temperature sleep/wake melatonin ? ? ? ? Output pathway

RHT Pineal SCN PVN SCG Gland Input pathway cortisol

temperature sleep/wake melatonin Possible causes of age-related changes in circadian system 1. Clock disturbance

2. Entrainment abnormalities

3. Insufficient zeitgebers (time cues) Biological rhythms

 Period Phase  

Amplitude

Circadian Terminology T 21 ) l m /

g 18 p ( s l 15 e v e L 12 Amplitude n i n o t 9 a

l Mean e

M Mesor 6  y  r phase angle a v i l 3 bedtime a S 0 12 16 20 24 4 8 12 16 20 24 4 8 12 Clock Hour Courtesy Ken Wright Age-related changes

1. Amplitude 2. Period 3. Phase 4. Phase angle of entrainment 5. Response to light

Phase angle of entrainment = phase relationship between a and the environmental signal entraining the rhythm (e.g. light-dark cycle; sleep onset) Duffy et al., Sleep Med. Clin. , 2016 Possible causes of age-related changes in circadian system 1. Clock disturbance Output pathway

RHT Pineal SCN PVN SCG Gland Input pathway cortisol

temperature sleep/wake melatonin

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 Pre- and postmenopausal women (n=160)

Skene et al., 1990 Pineal melatonin - human postmortem tissue

Skene et al., 1990 Melatonin in CSF

Liu et al., 1999 Possible causes of age-related changes in circadian system

Output pathway

RHT Pineal SCN PVN SCG Gland Input pathway cortisol

temperature sleep/wake melatonin

Concretions, reduced sympathetic innervation, -receptor changes, reduced NAT Age-related changes in melatonin

- reduced melatonin production/amplitude most studies (diurnal, entrained) Constant routine study

65+ Elderly- disease and drug free Dim light, semi-recumbent, sleep deprived, isocaloric meals

Zeitzer et al., 1999 Possible causes of age-related changes in circadian system 1. Clock disturbance

2. Entrainment abnormalities Output pathway

RHT Pineal SCN PVN SCG Gland Input pathway cortisol

temperature sleep/wake melatonin

Reduced amplitude Phase advance of circadian rhythms Age-related change in circadian period?

Explain phase advance of circadian rhythms i.e shorter period as age? Human circadian period () Forced desynchrony n = 11 young Sighted n = 13 old

 = 24.18  0.02 h

Czeisler et al., Science, 1999 aMT6s Period and Age

Totally blind 25 24.9  Real life 24.8   24.7    24.6    aMT6s 24.5   tau (h) 24.4    24.3    24.2 24.1  r = -0.02 24 n = 23 23.9  0 10 20 30 40 50 60 70 80 Age (yrs) Skene et al., unpublished Age-related changes in melatonin

1. decreased melatonin production - decline in amplitude

2. phase advance of melatonin rhythm

Earlier aMT6s peak time with ageing 7 D

S 6

 n a

e 5 m e s 4 a h p o r 3 c a s 6

T 2 M a 1

0 16-20 21-30 31-40 41-50 51-60 61-70 71-81 16-81 years

18 83 18 13 4 136 n English et al., unpublished Older compared to young adults

Earlier wrt clock time

Later wrt to biological time i.e. sleep/darkness

solid line - older group Duffy et al., Sleep Med. Clin. , 2016 Possible causes of age-related changes in circadian system 1. Clock disturbance

2. Entrainment abnormalities Output pathway

RHT Pineal SCN PVN SCG Gland Input pathway cortisol

temperature sleep/wake melatonin

Age-related changes in the eye Age-related changes in the eye

 pupil size  S-cones  melanopsin RCGs

 lens transmission

Adapted from Weale, 1988 Age-related changes in the eye increased lens density  reduced transmission of light

25 years 47 years 60 years

70 years 82 years 91 years

Lerman, 1980 Age-related changes in the lens reduce transmittance of short wavelength blue light

2.5 20 yrs 60 yrs y t i 80 yrs s 1.5 n e D

l a c i t

p 0.5 O

-0.5 380 420 460 500 540 580 620 660 Wavelength (nm)

Average spectral density of the lens (adapted from Pokorny et al., 1987) Spectral sensitivity?

Arendt, 1995 Spectral sensitivity of light-induced melatonin suppression

Suppression by short wavelength light

2 140 o 424 nm 16 W/cm n n ) l n m 120 n 2 /

g O 472 nm 36 W/cm O p O n O ( o o 100 O

n o o i

n O n n

o 80 t n Oo

a no Oo l

e o 60 m o a O O m 40 s a l

P 20

0 23:00 23:30 0:00 0:30 1:00 1:30 2:00 Clock time (hours)

Thapan, Arendt & Skene, J Physiol, 535, 261-67, 2001 Melatonin suppression as a function of wavelength and irradiance

70 t t £ t l

) £

% 60 uu ( n £ n t u o nl i 50

s l u£ l s n 424 nm e r 40 l 456 nm p p n l  472 nm u l

s u

30 496 nm

n  i £ £ 520 nm n n o 20 t t l  548 nm a u l l t

e t 10 n M £ £ l £ 0 1E+11 1E+12 1E+13 1E+14 1E+15 5E+15 Photons/cm2/sec 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 Hypotheses 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)

2.5 20 yrs 60 yrs y

t 80 yrs i s n

e 1.5 D

l a c i t

p 0.5 O

- 0.5 380 420 460 500 540 580 620 660 Wavelength (nm)

Average spectral density of the lens (adapted from Pokorny et al., 1987) Age-related changes in short wavelength blue light sensitivity

Reduced responsiveness in the elderly

Exp Gerontol 40, 237-242, 2005 Increased alertness in young during and after blue (456 nm) light

more 5 young ) s e

alert s n 4 (n = 11) i e l e n t s 3 r a e b l 2 a o

t

e

d 1 v i e t s i c l 0 e a j m b older more r -1 u o S sleep n (n = 15) ( -2 y 0 1 2 3 4 5 6 7 Time from start of light (h)

Time: F = 4.68, p < 0.0001 Sletten et al., J. Biol. Rhythms, 2009 Age: F = 35.76, p < 0.0001 No effect of age on alertness during and after green (548 nm) light

young (n = 11) more 5 ) older (n = 10) s e

alert s n 4 i e l e n t s 3 r a e b l 2 a o

t

e d

v 1 e i t s i c l 0 a e j m b more r -1 u o S sleep n y ( -2 0 1 2 3 4 5 6 7 Time from start of light (h)

Sletten et al., J. Biol. Rhythms, 2009 Time: F = 4.84, p < 0.0001 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. Amplitude reduced 2. Period shorter (faster)? No 3. Phase earlier clock time 4. Phase angle of sleep at earlier biological entrainment time 5. Response to light reduced acute effects phase 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 zeitgebers ocular light, ↓ melatonin signalling Output pathway

RHT Pineal SCN PVN SCG Gland Input pathway cortisol

temperature sleep/wake melatonin

LIGHT MELATONIN Chronotherapy to hasten adaptation LIGHT MELATONIN

Phase shift circadian rhythms Light Melatonin

• shifts circadian rhythms sleep timing melatonin temperature cortisol Management/Treatment of Circadian Rhythm Sleep-wake Disorders Light Melatonin supplementation Increase zeitgeber strength

Increase circadian amplitude Why light supplementation

for older people? 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 Optimisation of for the elderly

increase blue light content

increase longer wavelengths - enhance any M- and L-cone input - melanopsin photoreversal

Revell and Skene, 2009 Why light supplementation

for older people? 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 Spectral composition Blue-enriched white light Control white light high colour temperature low colour temperature 17000 K 4000 K

300 n l

a o 200 i r t t 17000 K lights u c b e i p r t s 4000 K lights

s 100 i e d v i r t e a l w e

o 0 R

p 400 450 500 550 600 650 700

-100 Wavelength (nm) Field studies

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 RTN ESRC New Dynamics of Ageing/Philips Lighting Community study - skeleton photoperiods

Baseline week 1

week 2 Light exposure week A or B 3 week 4

week Washout period 5 week 6

week 7 Light exposure week 8 A or B week 9

week Washout period 10 week 11

light exposure A or B Field studies

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 RTN ESRC New Dynamics of Ageing/Philips Lighting Care home study - protocol 12-week study, randomised, crossover design September - April in 2008/2009 and 2009/2010 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

wash out base line 4000 K light period care home 17000 K light ~ 200 care home lights ~ 900 lux lux lights ~ 60 lux ~ 60 lux 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 uniform 59 ± 52 lux (mean ± SD, n = 20 rooms)

Indoor lighting measured weekly (lux meter), after sunset In 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 lux Care home 59 ± 52 lux Hopkins, S. et al. Current Alz. Res 2017 24 hour light profiles

17000 K vs washout 1500 1700017k K WO

l Washout e 1000 n v a e l e

x M u l 500

0 0 4 8 12 16 20 24 Time (Hours)

4000 K vs washout 1500 WO 40004K K l

e 1000 Washout n v a e l e

x M u l 500

0 0 4 8 12 16 20 24 Time (Hours) Conclusions Blue-enriched light supplementation - well tolerated - positive effects reduced anxiety increased daytime activity advanced activity rhythm - negative effects increased night-time activity reduced sleep efficiency reduced sleep quality

Hopkins, S. et al. Current Alz. Res 2017 Using Light: Challenges Controlled 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) Acute effects of 5mg melatonin Core body temperature 37.2

37 Rectal Temperature 36.8 ( C) 36.6

36.4 Alertness 10010036.2

80 Placebo Subjective Melatonin Alertness 60 (%) 40

20 17:00 19:00 21:00 23:00 01:00 Meal Time (h) 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

Valdoxan ® Takeda

Servier Sleep-onset insomnia Major depressive disorder TASIMELTEON – HETLIOZ® Selective MT1/MT2 agonist FDA approved for non-24 h S/W disorder

melatonin Vanda Pharmaceuticals Acknowledgements

LIGHT Benita Middleton Kavita Thapan Lloyd Morgan Victoria Revell Samantha Hopkins Mirela Herljevic Daniel Barrett Tracey Sletten Katrin Ackermann Helen Thorne Katharina Lederle Shelagh Hampton MELATONIN FOOD Steven Lockley Sophie Wehrens Lisa Hack Cheryl Isherwood Josephine Arendt Skevoulla Christou Simon Archer Michelle Gibbs Jonathan Johnston Acknowledgements Current and recent funding EU Marie Curie RTN EU FP6 IP

ESRC New Dynamics of Ageing

STOCKGRAND LTD STOCKGRAND LTD

Past funding BHF, EU Biomed, EU FP5, MRC, Pfizer, Servier R & D, Wellcome Trust

k you Than [email protected]

@debrajskene References - Reviews References - Reviews References - Reviews