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Telemetry Physical Activity Monitoring in Minipig’s Model of Huntington’s Disease


Abstract and Figures

Animal models represent a key tool for Huntington's disease (HD) research. During the last decade large animal models of HD have been established to improve knowledge of HD under large brain conditions. Transgenic minipig expressing N-terminal part of human huntingtin with 124 CAG/CAA repeats seems to be very promising HD model. Its previous characterization has shown various phenotypes affecting subcellular, cellular as well as organ systems level. The goal of this study was to detect and analyze a pathological pattern in physical activity of transgenic (TgHD) boars at the age of three years using telemetry approach. Into the study we have included five TgHD and five wild type (WT) animals for comparison. The physical activity was measured by the telemetric system rodentPACK2 whereas transmitter was placed into the collar. The analysis have shown significant decrease of total acceleration representing physical activity in TgHD boars between 4:40 and 5:30 a.m. (after night sleep - before morning feeding) in comparison with WT ones which could be explained with disturbed energy metabolism. Telemetry approach will play an important role in the study of physical activity and bio potentials es sential for deeper characterization of large animal HD models in their preclinical and clinical phase.
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Cesk Slov Ne urol N 2015; 78/ 111 (Suppl 2): XXXXXX 2S1
Telemetry Physical Activity Monitor ing in
Minipig’s Model of Huntington’s Disease
Monitorace fyzické aktivity uminiprasečího
modelu pro Huntingtonovu nemoc
Animal models represent a key tool for Huntington’s disease (HD) research. Dur ing the last decade
large animal models of HD have been established to improve knowledge of HD under large brain
conditions . Transgenic minipig expres s ing N-terminal par t of human huntingtin with 124 CAG/
repeats seems to be very promis ing HD model. Its previous characterization has shown various
phenotypes a ect ing subcel lular, cel lular as wel l as organ systems level. The goal of this study was
to detect and analyze a pathological patter in physical activity of transgenic (TgHD) boars at the
age of three years us ing telemetry approach. Into the study we have included five TgHD and five
wild type (WT) animals for comparison. The physical activity was measured by the telemetric sys-
tem rodentPACK2 whereas transmitter was placed into the col lar. The analysis have shown signifi-
cant decrease of total acceleration represent ing physical activity in TgHD boars between 4:40 and
5:30 a. m. (after night sleep –
before morn ing feeding) in comparison with WT ones which could
be explained with dis turbed energy metabolism. Telemetry approach wil l play an important role in
the study of physical ac tivity and bio potentials es sential for deeper characterization of large animal
HD models in their preclinical and clinical phase.
Zvířecí modely představují klíčový nástroj pro studium Huntingtonovy nemoci (HN). V posledním
desetiletí byla snaha vy tvářet velké zvířecí modely této choroby z důvodu zlepšení znalostí o pato-
logických změnách v mozku, který se co nejvíce podobá lidskému. Transgen ní miniprase exprimu-
jící N-terminální část lidského mutovaného huntingtinu se 124 CAG/
CAA repeticemi se zdá být
velmi nadějným modelem pro studium HN. Jelikož předchozí charakterizace tohoto modelu
prokázala rozličné fenotypy postihující subcelulární, buněčnou stejně tak i orgánově-systémovou
úroveň. Cílem této studie bylo detekovat a analyzovat patologický vzorec ve fyzické aktivitě
transgen ních (TgHD) kanců ve věku 3 let pomocí telemetrie. Do experimentu bylo zařazeno pět
TgHD a pro srovnání pět netransgen ních (WT) kanců. Fyzická aktivita byla u kanců měřena pomocí
telemetrického systému rodentPACK2, přičemž transmiter byl umístěn do límce na krku. Na z ákladě
analýzy bylo zjištěno signifikantní snížení totálního zrychlení reprezentujícího fyzickou aktivitu
u TgHD kanců mezi 4:40 a 5:30 ráno (po nočním spánku –
před ran ním krmením) v porovnání s WT
jedinci, které může být v ysvětleno narušeným energetickým metabolizmem. Telemetrická analýza
bude jistě hrát v budoucnosti významnou roli ve studii fyzické aktivity a bio potenclů důležitých
pro podrobnější charakterizaci preklinické a klinické fázi HN u velkých zvířecích modelů.
The authors declare they have no potential
conicts of interest concerning drugs, products,
or servi ces used in the study.
Autoři deklaru jí, že v souvislosti s předmětem s tu-
die nemají žád né komerční zájmy.
The Editorial Board declares that the manu-
script met the ICMJE “uniform requirements”
for biomedical papers.
Redakční rada p otvrzuje, že rukopis p ráce splnil
ICMJE krité ria pro publikace zasílan é do biome-
dicínských časopisů.
M. Pokorný1, S. Juhas2,
J. Juhasova2, J. Klima2, J. Motlik2,
J. Klempir3, J. Havlik1
1 Faculty of Electrical Engineering,
Czech Technical University in Prague,
Czech Republic
2 Institute of Animal Physiology and
Genetics, AS CR, v.v.i., Libechov, Czech
3 Institute of Anatomy, Department
of Neurology and Centre of Clinical
Neuroscience, 1st Faculty of Medi-
cine, Charles University and General
University Hospital in Prague, Czech
Ing. Matouš Pokorný
Biomedical Electronics Group
Faculty of Electrical Engineering
Czech Technical University
Technicka 2
166 27 Prague
Czech Republic
Accepted for review:
Accepted for print:
Key words
Huntington‘s disease – minipig – telemetry
– collar – physical activity – acceleration
Klíčová slova
Huntingtonova nemoc – miniprase – tele-
metrie – límec – fyzická aktivita – akcelerace
Cesk Slov Ne urol N 2015; 78/ 111 (Suppl 2): XXXXXX
Aim of the study
Huntington‘s disease (HD) is an inherited
neurodegenerative disorder caused by poly-
glutamine expansion mutations in the hun-
tingtin protein [1].
There is no cure or eff ective treatment for
HD, and death typical ly occurs 15–
20 years
after the onset of HD motor symp toms. Pa-
tients with HD progres sively develop symp-
toms of clinical psychiatric disorders, cog-
nitive deficits, dementia and physical
disability [2,3]. Mutated huntingtin action
as wel l as los s of wild type huntingtin func-
tion aff ect not only the brain structures but
also peripheral tis sues or organ systems
like testes, heart, pancreas, skeletal muscle,
etc. [4–
7]. Deficits in sleep and circadian or-
ganization have been identified as com mon
early features in patients with HD that cor-
relate with symp tom severity and may be
instrumental in disease progres sion. These
observations were also detected in the
most employed mouse model (R6/
2) [8] or
ovine model of HD [9]. Importantly heart
dis ease has been attributed as a major
cause of death in patients with HD. In addi-
tion R6/
1 mice exhibited profound auto-
nomic nervous system cardiac dysfunction
involv ing both sympathetic and parasympa-
thetic limbs as sociated with altered central
autonomic pathways lead ing to cardiac ar-
hythmias and sudden death [2].
The long-term col lection of neurobe-
havioral and other physiologic data us ing te-
lemetry devices represents a critical compo-
nent of diff erently focused animal studies.
Such devices have to be implanted in a lo-
cation that is safe, wel l-tolerated, and func-
tional. Göttingen minipigs (Sus scrofa domes-
ticus) represent an ideal large animal model
for bio medical studies due to their relatively
smal l size, characterized health status, and
ease of train ing and handling [10]. Moreover
Yorkshire pigs were also used in long-term, si-
multaneous telemetric monitor ing of blood
flow, pres sure and heart rate in heart failure
models [11]. EEG, ECG, activity and core tem-
perature monitor ing were succes sful ly mea-
sured in HD mouse models (R6/
2 and R6/
by telemetry devices [2,8].
The aim of study was to find and mea-
sure the physical activity disturbances cha-
racterized by deficit in sleep and circadian
organization of transgenic (TgHD) minipigs
expres s ing human mutated huntingtin in
comparison with wild type boars (WT) by
telemetry approach. The next goal of pre-
sent study was to develop automatic system
for measurement and evaluation of physical
activity in minipigs.
Al l experiments were conducted with the
approval of the State Veterinary Administ-
ration of the Czech Republic and in accor-
dance with Czech regulations and guideli-
nes for animal welfare.
The transgenic line founder sow “Adela”
expres s ing N-terminal part of human muta-
ted huntingtin with 124CAG/
CAA [12], born
July 2009, as wel l as her off springs (F1, F2,
F3 and F4) are without clinical symp toms of
HD at the present time. However, until now
several phenotypes like the reduced male
reproductive parameters (e. g. fewer sperma-
tozoa per ejaculate), impaired mitochondrial
function in spermatozoa [13], lower level of
total creatine in the brain [14], decrease of re-
lative phosphodiester concentration in testi-
cular parenchyma [15] and blood serum cy-
tokine imbalance [16] have been detected.
We expect the onset of the HD related cli-
nical symp toms in the second half of their
life, i.e., after the 10th year. Transgenic boars
from F2 generation (3 years old) before HD
onset (n = 5) and control WT siblings (n = 5)
we used for telemetry study. The boars
were individual ly held in the neighbor-
ing boxes (al l together in one part of the
Telemetric system
In the experiments we used the telemetric
system rodentPACK2 obtained from emka
TECHNOLOGIES (France). RodentPACK2 has
been primarily designed for rodent stud ies.
This fact has forced us to newly develop
prototype equipment intercon nect ing con-
nectors screwed to external transmitters
with internal electrodes for bio potentials
and temperature measurement fixed into
the minipig’s body pos ses s ing high dura-
bility. Telemetric system consists of smal l
transmitters and central receivers. Every
transmitter can acquire and transmit four
bio potencial signals and/
or core tempe-
rature in combination with x, y, z and total
acceleration. The measurements can be syn-
chronized with video record (infrared came-
ras). We have performed some minipig pilot
experiments (EEG, ECG, EEG, temperature
measurement) complicated with secondary
infection and now we have design a new
type of mount ing approach that wil l be tes-
ted in close future. In present study the acce-
leration chan nels have been used only. Data
were acquired at sampl ing frequency 100 Hz
with resolution ± 2 g. In the learn ing pe-
riod (before activity measurement) the mi-
nipig boars have obtained the empty col lars
(Fig. 1).
Moreover if the measurement was not
run ning, minipigs stil l wore the empty col-
lars. It eliminates the col lar influence on their
behavior. Minipig boars wore a col lar with
Fig. 1. The positioning of the collar for activity measurement in TgHD boar.
Cesk Slov Ne urol N 2015; 78/ 111 (Suppl 2): XXXXXX 2S3
transmitter dur ing experiment. The measu-
rement ses sions started in the morn ing and
ends afternoon. There was minimal ly one
whole day (two nights) between start and
end of the ses sion. Period between indivi-
dual ses sions was approximately one month.
Al l events dur ing the measurement ses sion
were recorded e. g. time of feeding, cleaning,
veterinary and zootechnician intervention or
other activities.
Data analysis
For the statistical analysis we have used the
last ses sion includ ing majority of days dur-
ing weekend without unusual disturb ing
activities. We have decided to analyze the
part of day –
early morn ing just before staff
com ing after night (before morn ing feed) –
which is hypothetical ly daily time with mini-
mal external influences. For data analysis we
have used two software provided by emka
iox2 for data acquisition
and real-
time analysis as wel l as ecgAUTO
for complex analysis. Total acceleration (gra-
vity acceleration –
s2) represent ing phys-
ical activity of animal was proces sed in ec-
gAUTO software. The total physical activity
was sampled at 100 Hz and averaged over
10 min. Generated physical activity (mean
from 10 min) from five TgHD and five WT
boars were consequently averaged and
used for statistical analysis. This simple algo-
rithm for the comparison of WT and TgHD
boars’ physical activity was used for dif-
ferent daily time whereas sophisticated sig-
nal proces s ing wil l be prepared in close
A level p < 0.05 was considered as a statisti-
cal ly significant diff erence. For statistical ana-
lysis of total acceleration of TgHD and WT
group between 4:40 and 5:30 a. m. a one-
ANOVA test with Bonfer roni’s multiple com-
parison post-test were employ ed us ing Gra-
phPad PRISM software (GraphPad Software,
San Diego, CA, USA).
The analysis of total acceleration values from
TgHD and WT animals showed similar dis-
tribution pattern over several days (Fig. 2).
The minimal activity of animals was de-
tect ed dur ing the night from 19:00–
19:30 to
3:30. This time period is general ly con-
nected with no human activity in the sta-
ble. The staff for morn ing feed ing is com-
ing about 5:00 into the stable with start ing
of feed ing about 5:35–
5:45. Next activity of
animal is as sociated with clean ing proce-
dur e (7:0 0–
9:00) whereas animals are obtain-
ing new straw as a bedd ing that serves also
as a tool for next activity until 11:00 (the time
when the staff is leav ing the stable). It is in
accordance with decrease of animal acti-
vity between 11:00 and 13:00. Afternoon the
staff is com ing again about 15:0 0–
15:30 with
start ing of feed ing between 16:40–
17: 20. Im-
mediately after afternoon feed ing the feed-
boxes are cleaned and the staff is leav ing the
stable about 18:00. This organization pattern
forced us to choose the daily period which
would be minimal ly af fected by external
factors. Thus we have focused on the pe-
riod after long night sleep just before morn-
ing feeding. The analysis of this time interval
5:30) showed decrease of mean total
acceleration of TgHD boars compared to WT
one dur ing al l six days of ses sion. Although
three diff erences weren’t statistical ly signifi-
cant the rest of diff erences in 28th, 29th and
31st August 2015 were (Fig. 3).
In this study we have described six days
last ing telemetry ses sion in which we have
recorded physical activity of TgHD and
WT mini pigs. We have succes sful ly measu-
red and analyzed data as wel l as performed
pilot analysis. Analysis of daily period from
4:40 to 5:30 showed significant decrease of
total acceleration in TgHD animals in com-
parison with WT ones. This data suggest
that 3 years old transgenic animals expres s-
ing human mutated huntingtin more slowly
“starting” everyday faced with wild type sib-
lings. We can hypothesize that this observa-
tion could be in agreement with our pre-
vious study [14] that revealed significant
decrease of total creatine (tCr) in the thala-
mus of TgHD boars (2 years old) measured
by 1H magnetic resonance spectroscopy.
There were also detected other significant
changes in metabolite ratios (increased me-
tabolic ratios tCho/
tCr in the striatum, tha-
lamus, hippocampus as wel l as white mat-
ter) and we had supposed that the majority
of the observed changes were predomi-
nantly related to changes in energy meta-
bolism caused by decrease of tCr in TgHD.
Creatine represents an important marker
for brain energy metabolism. Lower crea-
Fig. 2. Total acceleration (gravity acceleration – m/s2) representing physical activity of TgHD and WT animals over six following days.
Each point (blue – WT, red – TgHD) represents averaged total acceleration of five animals (TgHD or WT) from 10 min sampling. The ellipses
display mark time periods (4:40–5:30) in individual days.
Cesk Slov Ne urol N 2015; 78/ 111 (Suppl 2): XXXXXX
tine levels were reported in striatum of HD
patients suggest ing impaired energy meta-
bolism [17]. Our data are also in accordance
with data obtained from ovine transgenic
model of HD expres s ing ful l length of hun-
tingtin. The authors detected circadian be-
havioural abnormalities in young HD sheep
that worsened with age. This change was
a disturbed even ing behaviour reminiscent
of ‘sundowning’ depend ing upon their so-
cial grouping. That is seen in some patients
with dementia [9].
The telemetric system uses accelerome-
ter for physical activity monitoring. The big
advantage of this system is monitor ing of
transgenic minipigs in their natural envi-
ronment, without disturb ing the study con-
ditions. The system needs only minimal
maintenance and has satisfactory resistant
against aggres sive environment in stable.
Telemetric monitor ing of physical acti-
vity as wel l as other bio potentials (EEG, ECG,
EMG, temperature, etc.) could reveal moto-
ric, behavioral and sleep abnormalities of
TgHD minipigs related to HD. In future we
plan to repeatedly confirm presented data
and focus on analysis of physical activity and
bio potentials of TgHD and WT boars in other
day periods, mainly in the night for complex
sleep analysis. More powerful and sophisti-
cated algorithms wil l be developed as wel l.
This work was supported by the Norwegian Finan-
cial Mechanism 2009
2014 and the Ministry of Edu-
cation, Youth and Sports under Project Contract no.
28 477/
2014 “HUNTINGTON” 7F14308, Pro-
gram Research and Development for In novation
Mi nistry of Education, Youth and Sports ExAM
CZ .1.05. /
03.0124 CHDI Foundation (A-
5378 ,
8248), RVO: 67985904 and SGS14/
13 –
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Fig. 3. Total acceleration of TgHD and WT animals between 4:40–5:30 a.m. during six fol-
lowing days.
Each column (blue – WT, red – TgHD) represents averaged total acceleration of five animals
(TgHD or WT).
... Telemetric studies revealed differences in physical activity patterns of 36-month-old TgHD compared to WT minipigs between 4: 40 and 5: 30 a.m. [30]. The oldest 2 animals, starting at 60 months, manifested motoric defects in limbs and an increase in anxiety behavior [unpubl. ...
Background: Huntington disease (HD) is an incurable neurodegenerative disease caused by the expansion of a polyglutamine sequence in a gene encoding the huntingtin (Htt) protein, which is expressed in almost all cells of the body. In addition to small animal models, new therapeutic approaches (including gene therapy) require large animal models as their large brains are a more realistic model for translational research. Objective: In this study, we describe phenotype development in transgenic minipigs (TgHD) expressing the N-terminal part of mutated human Htt at the age of 24 months. Methods: TgHD and wild-type littermates were compared. Western blot analysis and subcellular fractionation of different tissues was used to determine the fragmentation of Htt. Immunohistochemistry and optical analysis of coronal sections measuring aggregates, Htt expression, neuroinflammation, and myelination was applied. Furthermore, the expression of Golgi protein acyl-CoA binding domain containing 3 (ACBD3) was analyzed. Results: We found age-correlated Htt fragmentation in the brain. Among various tissues studied, the testes displayed the highest fragmentation, with Htt fragments detectable even in cell nuclei. Also, Golgi protein ACBD3 was upregulated in testes, which is in agreement with previously reported testicular degeneration in TgHD minipigs. Nevertheless, the TgHD-specific mutated Htt fragments were also present in the cytoplasm of striatum and cortex cells. Moreover, microglial cells were activated and myelination was slightly decreased, suggesting the development of a premanifest stage of neurodegeneration in TgHD minipigs. Conclusions: The gradual development of a neurodegenerative phenotype, ac-companied with testicular degeneration, is observed in 24- month-old TgHD minipigs.
... The telemetry approach was applied to detect and analyse a pathological pattern in physical activity of TgHD boars at the age of 3 years [80]. In this study, we included five TgHD and five wild-type (WT) animals for comparison. ...
Full-text available
At present, we are probably the only research facility to be breeding transgenic Huntington's disease minipigs (TgHD). These minipigs express N‐terminal part of human mutated huntingtin including 124Q under the control of human huntingtin promoter. The founder animal, born in 2009, gave birth to four subsequent generations with an equal contribution of wild‐type (WT) and transgenic (TgHD) piglets in all litters. We take different approaches, some of which are unique for large animal models, to study the phenotype development comparing WT and TgHD siblings. In this chapter, we review these approaches and the phenotype progression in the minipigs. Additionally, we outline perspectives in generation of new models using novel methodology and the potential of pig models in preclinical HD studies. Keywords: large animal models, pig, huntingtin, transgenic animal, Huntington's disease
Full-text available
Genetically modified rodent models of Huntington's disease (HD) have been especially valuable to our understanding of HD pathology and the mechanisms by which the mutant HTT gene alters physiology. However, due to inherent differences in genetics, neuroanatomy, neurocircuitry and neurophysiology, animal models do not always faithfully or fully recapitulate human disease features or adequately predict a clinical response to treatment. Therefore, conducting translational studies of candidate HD therapeutics only in a single species (i.e. mouse disease models) may not be sufficient. Large animal models of HD have been shown to be valuable to the HD research community and the expectation is that the need for translation studies that span rodent and large animal models will grow. Here, we review the large animal models of HD that have been created to date, with specific commentary on differences between the models, the strengths and disadvantages of each, and how we can advance useful models to study disease pathophysiology, biomarker development and evaluation of promising therapeutics.
Full-text available
Huntington's disease (HD) is an inherited devastating neurodegenerative disease with no known cure to date. Several therapeutic treatments for HD are in development, but their safety, tolerability and efficacy need to be tested before translation to bedside. The monogenetic nature of this disorder has enabled the generation of transgenic animal models carrying a mutant huntingtin (mHTT) gene causing HD. A large animal model reflecting disease progression in humans would be beneficial for testing the potential therapeutic approaches. Progression of the motor, cognitive and behavioral phenotype was monitored in transgenic Huntington's disease minipigs (TgHD) expressing the N-terminal part of human mHTT. New tests were established to investigate physical activity by telemetry, and to explore the stress-induced behavioral and cognitive changes in minipigs. The longitudinal study revealed significant differences between 6- to 8-year-old TgHD animals and their wild-type (WT) controls in a majority of the tests. The telemetric study showed increased physical activity of 4.6- to 6.5-year-old TgHD boars compared to their WT counterparts during the lunch period as well as in the afternoon. Our phenotypic study indicates progression in adult TgHD minipigs and therefore this model could be suitable for longstanding preclinical studies of HD. This article has an associated First Person interview with the first author of the paper.
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Chronic monitoring of heart rate, blood pressure, and flow in conscious free-roaming large animals can offer considerable opportunity to understand the progression of cardiovascular diseases and can test new diagnostics and therapeutics. The objective of this study was to demonstrate the feasibility of chronic, simultaneous measurement of several hemodynamic parameters (left ventricular pressure, systemic pressure, blood flow velocity, and heart rate) using a totally implantable multichannel telemetry system in swine heart failure models. Two solid-state blood pressure sensors were inserted in the left ventricle and the descending aorta for pressure measurements. Two Doppler probes were placed around the left anterior descending (LAD) and the brachiocephalic arteries for blood flow velocity measurements. Electrocardiographic (ECG) electrodes were attached to the surface of the left ventricle to monitor heart rate. The telemeter body was implanted in the right side of the abdomen under the skin for approximately 4 to 6 weeks. The animals were subjected to various heart failure models, including volume overload (A-V fistula, n = 3), pressure overload (aortic banding, n = 2) and dilated cardiomyopathy (pacing-induced tachycardia, n = 3). Longitudinal changes in hemodynamics were monitored during the progression of the disease. In the pacing-induced tachycardia animals, the systemic blood pressure progressively decreased within the first 2 weeks and returned to baseline levels thereafter. In the aortic banding animals, the pressure progressively increased during the development of the disease. The pressure in the A-V fistula animals only showed a small increase during the first week and remained stable thereafter. The results demonstrated the ability of this telemetry system of long-term, simultaneous monitoring of blood flow, pressure and heart rate in heart failure models, which may offer significant utility for understanding cardiovascular disease progression and treatment.
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Background: Some promising treatments for Huntington's disease (HD) may require pre-clinical testing in large animals. Minipig is a suitable species because of its large gyrencephalic brain and long lifespan. Objective: To generate HD transgenic (TgHD) minipigs encoding huntingtin (HTT)1-548 under the control of human HTT promoter. Methods: Transgenesis was achieved by lentiviral infection of porcine embryos. PCR assessment of gene transfer, observations of behavior, and postmortem biochemical and immunohistochemical studies were conducted. Results: One copy of the human HTT transgene encoding 124 glutamines integrated into chromosome 1 q24-q25 and successful germ line transmission occurred through successive generations (F0, F1, F2 and F3 generations). No developmental or gross motor deficits were noted up to 40 months of age. Mutant HTT mRNA and protein fragment were detected in brain and peripheral tissues. No aggregate formation in brain up to 16 months was seen by AGERA and filter retardation or by immunostaining. DARPP32 labeling in WT and TgHD minipig neostriatum was patchy. Analysis of 16 month old sibling pairs showed reduced intensity of DARPP32 immunoreactivity in neostriatal TgHD neurons compared to those of WT. Compared to WT, TgHD boars by one year had reduced fertility and fewer spermatozoa per ejaculate. In vitro analysis revealed a significant decline in the number of WT minipig oocytes penetrated by TgHD spermatozoa. Conclusions: The findings demonstrate successful establishment of a transgenic model of HD in minipig that should be valuable for testing long term safety of HD therapeutics. The emergence of HD-like phenotypes in the TgHD minipigs will require more study.
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Deficits in sleep and circadian organization have been identified as common early features in patients with Huntington's disease that correlate with symptom severity and may be instrumental in disease progression. Studies in Huntington's disease gene carriers suggest that alterations in the electroencephalogram may reflect underlying neuronal dysfunction that is present in the premanifest stage. We conducted a longitudinal characterization of sleep/wake and electroencephalographic activity in the R6/2 mouse model of Huntington's disease to determine whether analogous electroencephalographic 'signatures' could be identified early in disease progression. R6/2 and wild-type mice were implanted for electroencephalographic recordings along with telemetry for the continuous recording of activity and body temperature. Diurnal patterns of activity and core body temperature were progressively disrupted in R6/2 mice, with a large reduction in the amplitude of these rhythms apparent by 13 weeks of age. The diurnal variation in sleep/wake states was gradually attenuated as sleep became more fragmented and total sleep time was reduced relative to wild-type mice. These genotypic differences were augmented at 17 weeks and evident across the entire 24-h period. Quantitative electroencephalogram analysis revealed anomalous increases in high beta and gamma activity (25-60 Hz) in all sleep/wake states in R6/2 mice, along with increases in theta activity during both non-rapid eye movement and rapid eye movement sleep and a reduction of delta power in non-rapid eye movement sleep. These dramatic alterations in quantitative electroencephalographic measures were apparent from our earliest recording (9 weeks), before any major differences in diurnal physiology or sleep/wake behaviour occurred. In addition, the homeostatic response to sleep deprivation was greatly attenuated with disease progression. These findings demonstrate the sensitivity of quantitative electroencephalographic analysis to identify early pathophysiological alterations in the R6/2 model of Huntington's disease and suggest longitudinal studies in other preclinical Huntington's disease models are needed to determine the generality of these observations as a potential adjunct in therapeutic development.
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Huntington's disease (HD) is a complex and severe disorder characterized by the gradual and the progressive loss of neurons, predominantly in the striatum, which leads to the typical motor and cognitive impairments associated with this pathology. HD is caused by a highly polymorphic CAG trinucleotide repeat expansion in the exon-1 of the gene encoding for huntingtin protein. Since the first discovery of the huntingtin gene, investigations with a consistent number of in-vitro and in-vivo models have provided insights into the toxic events related to the expression of the mutant protein. In this review, we will summarize the progress made in characterizing the signaling pathways that contribute to neuronal degeneration in HD. We will highlight the age-dependent loss of proteostasis that is primarily responsible for the formation of aggregates observed in HD patients. The most promising molecular targets for the development of pharmacological interventions will also be discussed.
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Huntington disease (HD) is a dominantly inherited neurodegenerative disorder that results from expansion of the polyglutamine repeat in the huntingtin (HTT) gene. There are currently no effective treatments for this devastating disease. Given its monogenic nature, disease modification therapies for HD should be theoretically feasible. Currently, pharmacological therapies aimed at disease modification by altering levels of HTT protein are in late-stage preclinical development. Here, we review current efforts to develop new treatments for HD based on our current understanding of HTT function and the main pathological mechanisms. We emphasize the need to enhance translational efforts and highlight the importance of aligning the clinical and basic research communities to validate existing hypotheses in clinical studies. Human and animal therapeutic trials are presented with an emphasis on cellular and molecular mechanisms relevant to disease progression.
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Huntington's disease (HD) is one of a class of inherited progressive neurodegenerative disorders that are caused by a CAG/polyglutamine repeat expansion. We have previously generated mice that are transgenic for exon 1 of the HD gene carrying highly expanded CAG repeats which develop a progressive movement disorder and weight loss with similarities to HD. Neuronal inclusions composed of the exon 1 protein and ubiquitin are present in specific brain regions prior to onset of the phenotype, which in turn occurs long before specific neurodegeneration can be detected. In this report we have extended the search for polyglutamine inclusions to non-neuronal tissues. Outside the central nervous system (CNS), inclusions were identified in a variety of post-mitotic cells. This is consistent with a concentration-dependent nucleation and aggregation model of inclusion formation and indicates that brain-specific factors are not necessary for this process. To possibly gain insights into the wasting that is observed in the human disease, we have conducted a detailed analysis of the timing and progression of inclusion formation in skeletal muscle and an investigation into the cause of the severe muscle atrophy that occurs in the mouse model. The formation of inclusions in non-CNS tissues will be particularly useful with respect to in vivo monitoring of pharmaceutical agents selected for their ability to prevent polyglutamine aggregation in vitro, without the requirement that the agent can cross the blood-brain barrier in the first instance.
Huntington's disease (HD) is an inherited autosomal neurodegenerative disorder characterized by motor dysfunctions, behavioral and cognitive disturbances. It affects predominantly the brain, however, changes were found also in peripheraltis sues. Some of these changes can result from direct expression of mutant huntingtin; its highest levels have been found in the brain and testes. In 2009 we established a minipig model of HD (TgHD) expressing N-terminal (548aa) part of human mutated huntingtin encod ed 124 CAG/CAA repeats. Previous research has revealed the presence of reduced fertility and fewer spermatozoa perejaculate in TgHD boars started at 13 months of age. The aim of this study was to determine changes in the testes of 24 months old transgenic boars (F2 generation in vivo) using non-invasive methodology of ³¹P magnetic resonance (MR) spectroscopy as well as to perform imunohistochemical analysis of TgHD sperm collected from-form F1 and F3 generation before HD onset. The results have shown significant reduction of relative phosphodiester concentration in testicular parenchyma of TgHD boars compared to wild type (WT) ones of the same ages. Moreover im munohistochemical analysis of sperm collected from TgHD and WT have revealed exclusive anti-polyQ specific (clone 3B5H10) as well as significantly increased anti-huntingtin (clone EPR5526) staining in transgenic spermatozoa tails in comparison with WT counterparts. Thus, our results are suggestive of the negative impact of human mutated huntingtin on testes metabolism as well as sperm abnormalities.
Huntington's disease (HD) is an inherited autosomal neurodegenerative disorder affecting predominantly the brain, characterized by motor dysfunctions, behavioral and cognitive disturbances. The aim of this study was to determine changes in the brain of transgenic minipigs before HD onset using (1)H magnetic resonance (MR) spectroscopy. Measurements were performed on a 3T MR scanner using a single voxel spectroscopy sequence for spectra acquisition in the white matter and chemical shift imaging sequence for measurement in the striatum, hippocampus and thalamus. A decrease of (phospho)creatine (tCr) concentration was found only in the thalamus (p=0.002) of transgenic minipigs, nevertheless we found significant changes in metabolite ratios. Increase of the ratio choline compounds (tCho)/tCr was found in all examined areas: striatum (p=0.010), thalamus (p=0.011) as well as hippocampus (p=0.027). The ratio N-acetylaspartate+N-acetylaspartylglutamate (tNAA)/tCr (p=0.043) and glutamate+glutamine (Glx)/tCr(p=0.039) was elevated in the thalamus, the ratio myo-inositol (Ins)/tCr (p=0.048) was significantly increased in the hippocampus. No significant differences were observed in the metabolite concentrations in the white matter, however we found significant increase of ratios tNAA/tCr (p=0.018) and tCho/tCr (p=0.003) ratios in transgenic boars. We suppose that the majority of the observed changes are predominantly related to changes in energy metabolism caused by decrease of tCr.
Huntington's disease (HD) is an inherited neurodegenerative disorder caused by polyglutamine expansion mutations in the huntingtin protein. Despite its ubiquitous distribution, expression of mutant huntingtin (mHtt) is particularly detrimental to medium spiny neurons within the striatum. Mitochondrial dysfunction has been associated with HD pathogenesis. Here we review the current evidence for mHtt-induced abnormalities in mitochondrial dynamics and quality control, with a particular focus on brain and neuronal data pertaining to striatal vulnerability. We address mHtt effects on mitochondrial biogenesis, protein import, complex assembly, fission and fusion, mitochondrial transport, and on the degradation of damaged mitochondria via autophagy (mitophagy). For an integrated perspective on potentially converging pathogenic mechanisms, we also address impaired autophagosomal transport and abnormal mHtt proteostasis in HD.