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Myocardial interstitial Cajal-like cells (ICLC) and their nanostructural relationships with intercalated discs: shed vesicles as intermediates.

Mandache E, Popescu LM, Gherghiceanu M - J. Cell. Mol. Med. (2007 Sep-Oct)

Bottom Line: Typically, ICLC have several very long, moniliform, cytoplasmic processes which establish closed contacts with nerve fibres, as well as each other.In the last case, electron-dense repetitive nanostructures ('pillars') (35-40 nm high and 100-150 nm wide, similar to adhesion molecules) fasten the ICLC to the myocytes.All these features suggest a juxtacrine and/or paracrine intercellular mutual modulation of ICLC and cardiomyocytes in the microenvironment of ID, possibly monitoring the cardiac functions, particularly the electrical activity.

View Article: PubMed Central - PubMed

Affiliation: Victor Babeçs National Institute of Pathology, Bucharest, Romania.

ABSTRACT
Intercalated discs (ID) are complex junctional units that connect cardiac myocytes mechanically and electrochemically. However, there is limited information concerning the cardiomyocyte interaction with interstitial non-muscle cells. Our previous studies showed that myocardial interstitial Cajal-like cells (ICLC) are located in between cardiomyocytes, blood capillaries and nerve fibres. Typically, ICLC have several very long, moniliform, cytoplasmic processes which establish closed contacts with nerve fibres, as well as each other. We report here ultrastructural evidence concerning the relationships of ICLC processes with ID. The ICLC cytoplasmic prolongations (tens micrometers length) preferentially pass by or stop nearby the ID. Transmission electron microscopy emphasized three distinct connecting features between the tips of ICLC extensions and myocytes at the 'mouth' of ID: free or budding shed vesicles, exocytotic multi-vesicular bodies and direct contacts. In the last case, electron-dense repetitive nanostructures ('pillars') (35-40 nm high and 100-150 nm wide, similar to adhesion molecules) fasten the ICLC to the myocytes. All these features suggest a juxtacrine and/or paracrine intercellular mutual modulation of ICLC and cardiomyocytes in the microenvironment of ID, possibly monitoring the cardiac functions, particularly the electrical activity.

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Oblique section through rat myocardocytes showing the close vicinity between an ICLC extension (11.56 μm long;blue digitally coloured), and two intercalated discs (ID1 and ID2) periphery (arrows). The ICLC process is almost in contact (arrowheads) with the plasma membrane of three different myocytes (M1, M2 and M3). The distance between ICLC and myocytes is less than 45 nm in these points while the mean distance is usually over 100 nm. Ec -endothe-lial cells. The inset shows a direct point contact (arrowhead) between the tip of ICLC process and plasma membrane of a small cytoplasmic protrusion of myocyte M1. The myocyte basal lamina (bl) is disrupted at the site of protrusion.
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fig02: Oblique section through rat myocardocytes showing the close vicinity between an ICLC extension (11.56 μm long;blue digitally coloured), and two intercalated discs (ID1 and ID2) periphery (arrows). The ICLC process is almost in contact (arrowheads) with the plasma membrane of three different myocytes (M1, M2 and M3). The distance between ICLC and myocytes is less than 45 nm in these points while the mean distance is usually over 100 nm. Ec -endothe-lial cells. The inset shows a direct point contact (arrowhead) between the tip of ICLC process and plasma membrane of a small cytoplasmic protrusion of myocyte M1. The myocyte basal lamina (bl) is disrupted at the site of protrusion.


Myocardial interstitial Cajal-like cells (ICLC) and their nanostructural relationships with intercalated discs: shed vesicles as intermediates.

Mandache E, Popescu LM, Gherghiceanu M - J. Cell. Mol. Med. (2007 Sep-Oct)

Oblique section through rat myocardocytes showing the close vicinity between an ICLC extension (11.56 μm long;blue digitally coloured), and two intercalated discs (ID1 and ID2) periphery (arrows). The ICLC process is almost in contact (arrowheads) with the plasma membrane of three different myocytes (M1, M2 and M3). The distance between ICLC and myocytes is less than 45 nm in these points while the mean distance is usually over 100 nm. Ec -endothe-lial cells. The inset shows a direct point contact (arrowhead) between the tip of ICLC process and plasma membrane of a small cytoplasmic protrusion of myocyte M1. The myocyte basal lamina (bl) is disrupted at the site of protrusion.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4401282&req=5

fig02: Oblique section through rat myocardocytes showing the close vicinity between an ICLC extension (11.56 μm long;blue digitally coloured), and two intercalated discs (ID1 and ID2) periphery (arrows). The ICLC process is almost in contact (arrowheads) with the plasma membrane of three different myocytes (M1, M2 and M3). The distance between ICLC and myocytes is less than 45 nm in these points while the mean distance is usually over 100 nm. Ec -endothe-lial cells. The inset shows a direct point contact (arrowhead) between the tip of ICLC process and plasma membrane of a small cytoplasmic protrusion of myocyte M1. The myocyte basal lamina (bl) is disrupted at the site of protrusion.
Bottom Line: Typically, ICLC have several very long, moniliform, cytoplasmic processes which establish closed contacts with nerve fibres, as well as each other.In the last case, electron-dense repetitive nanostructures ('pillars') (35-40 nm high and 100-150 nm wide, similar to adhesion molecules) fasten the ICLC to the myocytes.All these features suggest a juxtacrine and/or paracrine intercellular mutual modulation of ICLC and cardiomyocytes in the microenvironment of ID, possibly monitoring the cardiac functions, particularly the electrical activity.

View Article: PubMed Central - PubMed

Affiliation: Victor Babeçs National Institute of Pathology, Bucharest, Romania.

ABSTRACT
Intercalated discs (ID) are complex junctional units that connect cardiac myocytes mechanically and electrochemically. However, there is limited information concerning the cardiomyocyte interaction with interstitial non-muscle cells. Our previous studies showed that myocardial interstitial Cajal-like cells (ICLC) are located in between cardiomyocytes, blood capillaries and nerve fibres. Typically, ICLC have several very long, moniliform, cytoplasmic processes which establish closed contacts with nerve fibres, as well as each other. We report here ultrastructural evidence concerning the relationships of ICLC processes with ID. The ICLC cytoplasmic prolongations (tens micrometers length) preferentially pass by or stop nearby the ID. Transmission electron microscopy emphasized three distinct connecting features between the tips of ICLC extensions and myocytes at the 'mouth' of ID: free or budding shed vesicles, exocytotic multi-vesicular bodies and direct contacts. In the last case, electron-dense repetitive nanostructures ('pillars') (35-40 nm high and 100-150 nm wide, similar to adhesion molecules) fasten the ICLC to the myocytes. All these features suggest a juxtacrine and/or paracrine intercellular mutual modulation of ICLC and cardiomyocytes in the microenvironment of ID, possibly monitoring the cardiac functions, particularly the electrical activity.

Show MeSH
Related in: MedlinePlus