Immunocytochemical expression of monocarboxylate transporters in the human visual cortex at midgestation.
Lactate and the other monocarboxylates are a major energy source for the developing brain. We investigated the immunocytochemical expression of two monocarboxylate transporters, MCT1 and MCT2, in the human visual cortex between 13 and 26 post-ovulatory weeks. We used immunoperoxidase and immunofluorescence techniques to determine whether these transporters co-localized with markers for blood vessels (CD34), neurons (microtubule-associated protein 2 [MAP2], SMI 311), radial glia (vimentin), or astrocytes (glial fibrillary acidic protein [GFAP], S100beta protein). MCT1 immunoreactivity was visible in blood vessel walls as early as the 13th week of gestation mainly in the cortical plate and subplate. At this stage, less than 10% of vessels in the ventricular layer expressed MCT1, whereas all blood vessels walls showed this immunoreactivity at the 26th gestational week. Starting at the 19th week of gestation, sparse MCT1 positive cell bodies were detected, some of them co-localized with MAP2 immunoreactivity. MCT2 immunoreactivity was noted in astrocytic cell bodies from week 19 and spread subsequently to the astrocyte end-feet in contact with blood vessels. MCTs immunoreactivities were most marked in the subplate and deep cortical plate, where the most differentiated neurons were located. Our findings suggest that monocarboxylate trafficking between vessels (MCT1), astrocytes (MCT2) and some postmitotic neurons (MCT1) could develop gradually toward 20 gestational weeks (g.w.). These data suggest that lactate or other monocarboxylates could represent a significant energy source for the human visual cortex at this early stage.
Fayol
Laurence
L
INSERM E9935, Hôpital Robert Debré, 48, Bd Sérurier 75019, Paris, France.
Baud
Olivier
O
Monier
Anne
A
Pellerin
Luc
L
Magistretti
Pierre
P
Evrard
Philippe
P
Verney
Catherine
C
D018952:Antigens, CD34 / Q000378:metabolism; D001808:Blood Vessels / Q000196:embryology / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000378:metabolism*; D005333:Fetus; D005865:Gestational Age; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D051246:Glucose Transport Proteins, Facilitative; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D027501:Monocarboxylic Acid Transporters / Q000378:metabolism*; D009004:Monosaccharide Transport Proteins / Q000378:metabolism; D009414:Nerve Growth Factors / Q000378:metabolism; D015513:Oncogene Proteins / Q000378:metabolism*; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins / Q000378:metabolism; D014746:Vimentin / Q000378:metabolism; D014793:Visual Cortex / Q000166:cytology / Q000196:embryology / Q000378:metabolism*
D018952:Antigens, CD34; D018797:Cell Cycle Proteins; D005904:Glial Fibrillary Acidic Protein; D051246:Glucose Transport Proteins, Facilitative; C115081:MCTS1 protein, human; D008869:Microtubule-Associated Proteins; D027501:Monocarboxylic Acid Transporters; D009004:Monosaccharide Transport Proteins; D009414:Nerve Growth Factors; D015513:Oncogene Proteins; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins; C490427:SLC16A7 protein, human; C430746:SLC2A10 protein, human; D014746:Vimentin