umu.sePublications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Extraocular Muscles in Amyotrophic Lateral Sclerosis
Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy. Umeå University, Faculty of Medicine, Department of Clinical Sciences, Ophthalmology. (Muskelgruppen)ORCID iD: 0000-0003-2369-4319
2017 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Amyotrophic lateral sclerosis (ALS) is an incurable neurodegenerative disease of motor neurons characterized by muscle paralysis and death within 3-5 years of onset. However, due to unknown mechanisms, the extraocular muscles (EOMs) remain remarkably unaffected. The EOMs are highly specialized muscles that differ from other muscles in many respects, including innervation and satellite cells (SCs). Understanding whether these factors play a role in the relative sparing of EOMs in ALS could provide useful clues on how to slow down the progression of ALS in other muscles.

The EOMs and limb muscles from terminal ALS patients and age-matched controls as well as the commonly used SOD1G93A ALS mouse model were studied with immunofluorescence. Antibodies against neurofilament and synaptophysin were used to identify nerves and neuromuscular junctions (NMJs); against Pax7, NCAM, MyoD, myogenin, Ki-67, dystrophin and laminin, to identify SCs and their progeny in EOMs and limb muscles. The proportion and fiber size of myofibers containing myosin heavy chain (MyHC) slow tonic and MyHC slow twitch were also determined in human EOMs.

The abundance of SCs differed extensively along the length of control human EOMs, being twice as abundant in the anterior portion. Pax7-positive cells were also detected in non-traditional SC positions. EOMs from terminal ALS patients showed similar numbers of resting and activated SCs as the controls. In limb muscles of ALS patients, the number of resting and activated SCs ranged from low (similar to normal aged, sedentary individuals) to high numbers, especially in muscles with long duration of disease and varied between the upper and lower limbs. The EOMs maintained a high degree of innervation compared to hindlimb muscles of symptomatic SOD1G93A mice. MyHC slow tonic fibers were less abundant in ALS patients than in controls. The change seemed more pronounced in bulbar onset patients, and in this group of subjects only, there was a strong association between decline in MyHC slow tonic fibers and age of death. Notably, the decline in MyHC slow tonic fibers was unrelated to disease duration.

Our data suggested that SCs play a minor role in the progression of ALS in general and in the sparing of the EOMs in particular. The generally preserved innervation in the EOMs of G93A mice may reflect distinct intrinsic properties relevant for sparing of the oculomotor system.  Even though the EOMs are relatively spared in ALS, MyHC slow tonic myofibers were selectively affected and this may reflect differences in innervation, as these fibers are multiply innervated.

Abstract [sv]

Amyotrofisk lateralskleros (ALS) är en obotlig neurodegenerativ sjukdom som främst påverkar kroppens viljestyrda motoriska nervceller. ALS leder till förlamning, muskelförtvining och slutligen döden genom andningssvikt, vanligen inom tre till fem år efter sjukdomsdebuten. Av okända anledningar så bibehålls ögonmusklernas funktion mycket bättre vid ALS i jämförelse med andra muskler och är hos merparten av patienter i stort sett opåverkade. Ögonmusklerna är mycket specialiserade muskler som skiljer sig från andra muskler i kroppen på flera sätt, bland annat genom deras unika nervförsörjning och genom de satellitceller – muskelspecifika stamceller, som finns i dem. En ökad förståelse för hur dessa faktorer inverkar på ögonmusklernas motståndskraft vid ALS skulle kunna ge värdefulla ledtrådar till hur man skulle kunna sakta ned sjukdomens fortskridande i andra muskler vid ALS.

Ögonmuskler och extremitetsmuskler från avlidna ALS-patienter och åldersmatchade friska kontroller, tillsammans med transgena möss med den sjukdomsalstrande mutationen SOD1G93A, studerades genom immunfluorescens och efterföljande mikroskopering. Antikroppar mot molekylerna Pax7, NCAM, MyoD, myogenin, Ki-67, laminin och dystrofin användes för att identifiera satellitceller och deras dotterceller i ögonmuskler och extremitetsmuskler. Antikroppar mot neurofilament och synaptofysin användes för att identifiera nerver och neuromuskulära synapser hos transgena SOD1-möss. Antikroppar mot toniska (tonic) och ryckande (twitch) muskelmyosinkedjor användes för att bestämma proportionen av och storleken på dessa typer av muskelfibrer i ögonmuskler från avlidna ALS-patienter och friska kontroller.

Mängden satellitceller varierade mellan de främre och de mer bakre delarna i friska, humana ögonmuskler och var dubbelt så många i den främre delen av muskeln jämfört med den mellersta och bakre delen av muskeln. Celler som uttryckte satellitcellsmarkören Pax7 hittades även i icke-traditionella satellitcellspositioner i ögonmusklerna. Mängden satellitceller i ögonmusklerna från ALS-patienter var samma som hos friska kontroller. I extremitetsmusklerna hos ALS-patienter varierade mängden satellitceller mellan låga nivåer (liknande de hos friska åldrade, inaktiva individer) till höga nivåer, särskilt i muskler där sjukdomen fortskridit under lång tid. Dessutom varierade mängden satellitceller mellan övre och nedre extremiteter.

Hos symptomatiska SOD1G93A-möss hade ögonmusklerna en mycket välbevarad innervation jämfört med bakbensmusklerna, där många neuromuskulära synapser saknade kontakt mellan nerven och motorändplattan.

Proportionen muskelfibrer med toniska muskelmyosinkedjor var lägre hos ALS-patienter jämfört med friska kontroller. Denna minskning var tydligare hos patienter där sjukdomssymtomen hade debuterat i tugg- och ansiktsmuskulaturen – så kallad bulbär ALS. Dessutom fanns det i den här gruppen, men ingen annan studerad grupp, en stark korrelation mellan nedgången i toniska fibrer och patientens ålder. Värt att notera är att minskningen av toniska muskelfibrer saknade korrelation med hur länge patienten hade varit sjuk i ALS.

Den generellt välbevarade innervationen i ögonmusklerna hos SOD1G93A-möss kan spegla distinkta inneboende egenskaper hos ögonmusklerna som är av vikt för bevarandet av ögonrörligheten vid ALS.

Gällande satellitceller så antyder våra data att satellitceller och deras regenerativa kapacitet spelar en försumbar roll vid ALS i allmänhet och vid ögonmusklernas bevarande i synnerhet.

Slutligen, även om ögonmuskler generellt är välbevarade vid ALS så är toniska muskelfibrer märkbart påverkade och detta kan spegla skillnader mellan olika nervcellsgruppers känslighet vid ALS.

Place, publisher, year, edition, pages
Umeå: Umeå universitet , 2017. , 56 p.
Series
Umeå University medical dissertations, ISSN 0346-6612 ; 1854
Keyword [en]
ALS, EOM, Satellite cells, innervation, neuromuscular disease, neurodegenerative disease
National Category
Other Basic Medicine
Research subject
Human Anatomy
Identifiers
URN: urn:nbn:se:umu:diva-129638ISBN: 978-91-7601-618-3 (print)OAI: oai:DiVA.org:umu-129638DiVA: diva2:1062525
Public defence
2017-01-27, N320, Vån 3, Naturvetarhuset, Umeå universitet, Umeå, 09:00 (English)
Opponent
Supervisors
Funder
Swedish Research Council, 2015-02438
Available from: 2017-01-09 Created: 2017-01-06 Last updated: 2017-01-19Bibliographically approved
List of papers
1. Pax7-Positive Cells/Satellite Cells in Human Extraocular Muscles
Open this publication in new window or tab >>Pax7-Positive Cells/Satellite Cells in Human Extraocular Muscles
2015 (English)In: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, E-ISSN 1552-5783, Vol. 56, no 10, 6132-6143 p.Article in journal (Refereed) Published
Abstract [en]

PURPOSE. We quantified and investigated the distribution of Pax7-positive cells/satellite cells (SCs) in the human extraocular muscles (EOMs). METHODS. An immunofluorescence multiple-marker method simultaneously combining two SC markers (Pax7, NCAM), detection of the basement membrane (laminin) and cell nuclei (4',6-diamidino-2-phenylindole [DAPI]), was used on the anterior, middle, and posterior portions of EOMs from five healthy donors. Pax7-positive cell and SC content, myonuclear content, myofiber cross-sectional area, and myonuclear domain were analyzed in single cross-sections. Between 3915 and 13,536 myofibers per muscle cross-section and myofibers from the entire EOM cross-section were analyzed for quantification of Pax7-positive cells per myofiber (Pax7/F).

RESULTS. The number of Pax7/F in the human EOMs varies along the length of the muscle with twice as high Pax7/F in the anterior part of the EOMs, but within the range of what has been previously reported for normal adult limb muscles. Furthermore, there are Pax7-positive cells in positions other than the classical SC position and the myonuclear domain size of adult EOMs is noticeably smaller than that previously reported for other adult skeletal muscles.

CONCLUSIONS. Previous data on differences in Pax7-positive cell/SC abundance between EOMs and limb muscles must be reconsidered and the characteristics of different Pax7-positive cell populations further investigated. Higher numbers of Pax7-positive cells in the anterior portion of the EOMs may have a bearing for strabismus surgery involving sectioning of the muscle fibers.

Keyword
satellite cell, myoprogenitor cell, Pax7
National Category
Microbiology in the medical area
Identifiers
urn:nbn:se:umu:diva-116774 (URN)10.1167/iovs.15-16544 (DOI)000368426300057 ()26393672 (PubMedID)
Funder
Swedish Research Council, K2012-63x-20399-06-3
Available from: 2016-02-15 Created: 2016-02-11 Last updated: 2017-01-06Bibliographically approved
2. Satellite cells and other muscle progenitor cells in extraocular muscles and limb muscles of ALS donors
Open this publication in new window or tab >>Satellite cells and other muscle progenitor cells in extraocular muscles and limb muscles of ALS donors
Show others...
(English)Manuscript (preprint) (Other academic)
National Category
Cell and Molecular Biology
Research subject
Human Anatomy
Identifiers
urn:nbn:se:umu:diva-129640 (URN)
Note

Manuscript

Available from: 2017-01-06 Created: 2017-01-06 Last updated: 2017-01-09
3. Unaffected motor endplate occupancy in eye muscles of ALS G93A mouse model
Open this publication in new window or tab >>Unaffected motor endplate occupancy in eye muscles of ALS G93A mouse model
2012 (English)In: Frontiers in bioscience (Scholar edition), ISSN 1945-0524, Vol. 4, 1547-1555 p.Article in journal (Refereed) Published
Abstract [en]

Amyotrophic lateral sclerosis (ALS) is a progressive, lethal neurodegenerative disorder characterised by selective loss of motor neurons with accompanying muscle paralysis and respiratory failure. Despite progressive paralysis in trunk and extremity muscles, disturbed eye motility is not a hallmark of ALS. Extraocular muscles (EOMs) of terminal ALS patients show far less morphological signs of disease than their limb muscles. One of the earliest signs of the disease in the transgenic G93A SOD1 mouse model of ALS is loss of motor neuron contact at the neuromuscular junctions (NMJ) in limb muscles. We used immunohistochemistry to identify NMJs and evaluate innervation in EOMs and limb muscles of G93A mice. In G93A limb muscles, loss of axonal contact was seen in 6-82 percent of the NMJs. On the contrary, the degree of endplate occupancy in the EOMs did not differ between transgenic mice and wild-type controls. We propose that EOM-specific properties make these muscles more resistant to the underlying pathophysiological process of ALS and that the EOMs are a useful model to advance our understanding of ALS.

Place, publisher, year, edition, pages
Frontiers in Bioscience, 2012
Keyword
Amyotropic lateral sclerosis, Neuromuscular junction, Extraocular muscle, SOD1, G93A, Denervation, Synaptophysin
National Category
Basic Medicine
Identifiers
urn:nbn:se:umu:diva-73222 (URN)22652891 (PubMedID)
Available from: 2013-06-19 Created: 2013-06-19 Last updated: 2017-01-09Bibliographically approved
4. Impact of ALS on slow tonic myofiber composition in human extraocular muscles
Open this publication in new window or tab >>Impact of ALS on slow tonic myofiber composition in human extraocular muscles
Show others...
(English)Manuscript (preprint) (Other academic)
National Category
Cell and Molecular Biology
Research subject
Human Anatomy
Identifiers
urn:nbn:se:umu:diva-129641 (URN)
Available from: 2017-01-06 Created: 2017-01-06 Last updated: 2017-01-06

Open Access in DiVA

Fulltext(975 kB)100 downloads
File information
File name FULLTEXT01.pdfFile size 975 kBChecksum SHA-512
4b067d2ae41dd9e4dacd512fe01527de3d871985686bfb36a8aac5faca956e1490920b67b0d4073571fbc4951ccb6dd5068eaa02968f7aa2d14e107d202dd43e
Type fulltextMimetype application/pdf
spikblad(75 kB)10 downloads
File information
File name SPIKBLAD02.pdfFile size 75 kBChecksum SHA-512
bff23f24e926edc841ea2174a925fb2d494ab33e7f14465b20df8330903a658a88106c1938e5d39f02cadd89fd60d85f03cb8dc258709510f24de981b38ce968
Type spikbladMimetype application/pdf

Search in DiVA

By author/editor
Tjust, Anton
By organisation
AnatomyOphthalmology
Other Basic Medicine

Search outside of DiVA

GoogleGoogle Scholar
Total: 100 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 1265 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf