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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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An ICLC extension in the vicinity of an intercalated disc (ID) with a multi-vesicular body (mvb) in between. A free vesicle can be seen near by (arrow). Inset–The multi-vesicular body seems to release electron-lucent vesicles (diameter 50–90 nm) (*). Electron-dense structures connect the multi-vesicular body envelope to the plasma membrane of cardiomyocyte (arrowheads). A tiny connection with ICLC (double arrow) can be seen. Scale bar = 0.5 μm.
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fig04: An ICLC extension in the vicinity of an intercalated disc (ID) with a multi-vesicular body (mvb) in between. A free vesicle can be seen near by (arrow). Inset–The multi-vesicular body seems to release electron-lucent vesicles (diameter 50–90 nm) (*). Electron-dense structures connect the multi-vesicular body envelope to the plasma membrane of cardiomyocyte (arrowheads). A tiny connection with ICLC (double arrow) can be seen. Scale bar = 0.5 μm.

Mentions: We have noticed free vesicles with electron-lucent content or even multi-vesicular body structures in the extracellular space between the ICLC endings and the periphery of ID (Fig. 4). The mean diameter of these free vesicles was 78 ‘B1 10 nm (min = 50 nm, max = 91 nm).


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)

An ICLC extension in the vicinity of an intercalated disc (ID) with a multi-vesicular body (mvb) in between. A free vesicle can be seen near by (arrow). Inset–The multi-vesicular body seems to release electron-lucent vesicles (diameter 50–90 nm) (*). Electron-dense structures connect the multi-vesicular body envelope to the plasma membrane of cardiomyocyte (arrowheads). A tiny connection with ICLC (double arrow) can be seen. Scale bar = 0.5 μm.
© Copyright Policy
Related In: Results  -  Collection

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

fig04: An ICLC extension in the vicinity of an intercalated disc (ID) with a multi-vesicular body (mvb) in between. A free vesicle can be seen near by (arrow). Inset–The multi-vesicular body seems to release electron-lucent vesicles (diameter 50–90 nm) (*). Electron-dense structures connect the multi-vesicular body envelope to the plasma membrane of cardiomyocyte (arrowheads). A tiny connection with ICLC (double arrow) can be seen. Scale bar = 0.5 μm.
Mentions: We have noticed free vesicles with electron-lucent content or even multi-vesicular body structures in the extracellular space between the ICLC endings and the periphery of ID (Fig. 4). The mean diameter of these free vesicles was 78 ‘B1 10 nm (min = 50 nm, max = 91 nm).

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