HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (4) Citing Articles via Google Scholar Google Scholar Articles by Kjellgren, D. Articles by Pedrosa-Domellöf, F. Search for Related Content PubMed PubMed Citation Articles by Kjellgren, D. Articles by Pedrosa-Domellöf, F.

Laminin Isoforms in Human Extraocular Muscles

¹From the Departments of Clinical Science, Section of Ophthalmology and ²Integrative Medical Biology, Section of Anatomy, University of Umeå, Umeå, Sweden; the ³Center for Musculoskeletal Research, University of Gävle, Umeå, Sweden; and the ⁴Department of Anatomy, Institute of Biomedicine, University of Helsinki, Helsinki, Finland.

PURPOSE. To determine the laminin isoform composition of the basement membranes (BMs) in the human extraocular muscles (EOMs) and relate it to the fact that EOMs are spared in laminin 2-chain–deficient congenital muscular dystrophy.

METHODS. Samples from adult human EOMs and limb muscle were processed for immunocytochemistry, with monoclonal antibodies against laminin chains (Ln) 1 to -5, ß1 and -2, and 1. Neuromuscular junctions (NMJs) were identified with acetylcholinesterase reaction. The capillary density was measured in sections stained with anti-Ln5.

RESULTS. The extrasynaptic BM of the EOM muscle fibers contained Ln2, -ß1, -ß2, and -1, and, in contrast to limb muscle, it also contained Ln4 and -5, to some extent. The distinct laminin composition of the EOMs was confirmed by the presence of Lutheran protein, an 5-chain–specific receptor not found in limb muscle. At the NMJs, there was increased expression of Ln4 and expression of Ln2, -5, -ß1, -ß2, and -1 was also maintained. The capillary density was very high (1050 ± 190 capillaries/mm²) in the EOMs and significantly (P < 0.05) higher in the orbital (1170 ± 180 capillaries/mm²) than in the global (930 ± 110 capillaries/mm²) layer.

CONCLUSIONS. The human EOMs showed important differences in laminin isoform composition and capillary density when compared with human limb muscle and muscles of other species. The presence of additional laminin isoforms other than laminin-2 in the BM of the extrasynaptic sarcolemma could partly explain the sparing of the EOMs in Ln2-deficient congenital muscular dystrophy.

This article has been cited by other articles:

				B. Bystrom, I. Virtanen, P. Rousselle, D. Gullberg, and F. Pedrosa-Domellof Distribution of laminins in the developing human eye. Invest. Ophthalmol. Vis. Sci., March 1, 2006; 47(3): 777 - 785. [Abstract] [Full Text] [PDF]

				M. D. Fischer, M. T. Budak, M. Bakay, J. R. Gorospe, D. Kjellgren, F. Pedrosa-Domellof, E. P. Hoffman, and T. S. Khurana Definition of the unique human extraocular muscle allotype by expression profiling Physiol Genomics, August 11, 2005; 22(3): 283 - 291. [Abstract] [Full Text] [PDF]