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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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Related in: MedlinePlus

TEM of longitudinal sectioned rat myocardium showing the relationship of ICLC with myocytes and their intercalated disks (ID). The ICLC processes are digitally colour in blue. (A) Two slender and long cytoplasmic extensions of the ICLC (16.16 μm for ICLC1 and 4.5 μm for ICLC2) placed between cardiomyocytes at about 150 nm mean distance. The ICLC processes pass by or stop near the intercalated discs periphery (arrows). Note the overlapping of the ICLC processes in the area next to the ID1 and ID2 (arrowheads). (B) The overlapping of two ICLC processes (ICLC1 and ICLC2), digitally- coloured in two blue tones (between arrowheads) next to the ID is a common feature. The distance between ICLC process and plasma membrane of the cardiomyocytes is 57±10 nm. The red asterisk shows the ID ‘mouth’.
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fig01: TEM of longitudinal sectioned rat myocardium showing the relationship of ICLC with myocytes and their intercalated disks (ID). The ICLC processes are digitally colour in blue. (A) Two slender and long cytoplasmic extensions of the ICLC (16.16 μm for ICLC1 and 4.5 μm for ICLC2) placed between cardiomyocytes at about 150 nm mean distance. The ICLC processes pass by or stop near the intercalated discs periphery (arrows). Note the overlapping of the ICLC processes in the area next to the ID1 and ID2 (arrowheads). (B) The overlapping of two ICLC processes (ICLC1 and ICLC2), digitally- coloured in two blue tones (between arrowheads) next to the ID is a common feature. The distance between ICLC process and plasma membrane of the cardiomyocytes is 57±10 nm. The red asterisk shows the ID ‘mouth’.

Mentions: The transmission electron microscopy (TEM) investigation showed a strong affinity of ICLC for the neighbouring area of ID. The tips of ICLC cytoplasmic processes have been observed in proximity of about 55% of ID (Figs. 1–8). Most of the ICLC processes end up in the extracellular myocyte pockets associated with the ‘mouth'of ID (Figs. 1 and 3).


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)

TEM of longitudinal sectioned rat myocardium showing the relationship of ICLC with myocytes and their intercalated disks (ID). The ICLC processes are digitally colour in blue. (A) Two slender and long cytoplasmic extensions of the ICLC (16.16 μm for ICLC1 and 4.5 μm for ICLC2) placed between cardiomyocytes at about 150 nm mean distance. The ICLC processes pass by or stop near the intercalated discs periphery (arrows). Note the overlapping of the ICLC processes in the area next to the ID1 and ID2 (arrowheads). (B) The overlapping of two ICLC processes (ICLC1 and ICLC2), digitally- coloured in two blue tones (between arrowheads) next to the ID is a common feature. The distance between ICLC process and plasma membrane of the cardiomyocytes is 57±10 nm. The red asterisk shows the ID ‘mouth’.
© Copyright Policy
Related In: Results  -  Collection

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

fig01: TEM of longitudinal sectioned rat myocardium showing the relationship of ICLC with myocytes and their intercalated disks (ID). The ICLC processes are digitally colour in blue. (A) Two slender and long cytoplasmic extensions of the ICLC (16.16 μm for ICLC1 and 4.5 μm for ICLC2) placed between cardiomyocytes at about 150 nm mean distance. The ICLC processes pass by or stop near the intercalated discs periphery (arrows). Note the overlapping of the ICLC processes in the area next to the ID1 and ID2 (arrowheads). (B) The overlapping of two ICLC processes (ICLC1 and ICLC2), digitally- coloured in two blue tones (between arrowheads) next to the ID is a common feature. The distance between ICLC process and plasma membrane of the cardiomyocytes is 57±10 nm. The red asterisk shows the ID ‘mouth’.
Mentions: The transmission electron microscopy (TEM) investigation showed a strong affinity of ICLC for the neighbouring area of ID. The tips of ICLC cytoplasmic processes have been observed in proximity of about 55% of ID (Figs. 1–8). Most of the ICLC processes end up in the extracellular myocyte pockets associated with the ‘mouth'of ID (Figs. 1 and 3).

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