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Human internal thoracic artery grafts exhibit severe morphological and functional damage and spasmic vasomotion due to oxidative stress.

Kiss L, Benko R, Kovács E, Szerafin T, Módis K, Szabó C, Lacza Z - Med. Sci. Monit. (2011)

Bottom Line: Functionally, 88.1% reacted to K-Krebs, 68.7% exhibited contraction after 1 µM phenylephrine, 29.9% exhibited relaxation to 30 µM Ach, and all precontracted segments relaxed to 30 µM SNP.High amplitude vasomotion was observed in 47.8% of the segments, which could be abolished by the application of 10 µM SNP.Incubation of the preparations with PJ34 did not improve endothelium-dependent vasodilation.The topical use of SNP to the ITA during the operation may improve vascular functions by dilating the vessels and eliminating the eventual spasmic vasomotion.<br />

View Article: PubMed Central - PubMed

Affiliation: Institute of Human Physiology and Clinical Experimental Research, Semmelweis University, Budapest, Hungary. levente.kiss@eok.sote.hu

ABSTRACT

Background: The internal thoracic artery (ITA) is the first choice for myocardial revascularization, but atherosclerotic lesions and perioperative vasospasm may still limit its functionality. Oxidative stress via the peroxynitrite - poly-(ADP-ribose) polymerase (PARP) cascade plays an important role in the pathogenesis of impaired vascular tone via endothelial injury. We aimed to investigate and describe the histology, PARP activation and functionality of ITA grafts and to assess the possible beneficial effect of PARP-inhibition.

Material/methods: ITA specimens from 47 patients (26 men, mean age 66.2 ± 1.7 years) who underwent coronary bypass surgery were processed for histological and immunohistochemical studies for oxidative stress and PARP activation, and were functionally tested with acetylcholine (ACh) and sodium nitroprusside (SNP) with or without PARP inhibition.

Results: The sections showed atherosclerotic alterations and oxidative and nitrosative stress were evidenced by positive 3-nitrotyrosine, 4-hydroxynonenal and PAR stainings. Functionally, 88.1% reacted to K-Krebs, 68.7% exhibited contraction after 1 µM phenylephrine, 29.9% exhibited relaxation to 30 µM Ach, and all precontracted segments relaxed to 30 µM SNP. High amplitude vasomotion was observed in 47.8% of the segments, which could be abolished by the application of 10 µM SNP.Incubation of the preparations with PJ34 did not improve endothelium-dependent vasodilation.

Conclusions: ITA grafts are severely damaged both morphologically and functionally in patients undergoing coronary artery bypass surgery, but PARP inhibition cannot improve their functional characteristics. The topical use of SNP to the ITA during the operation may improve vascular functions by dilating the vessels and eliminating the eventual spasmic vasomotion.

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Related in: MedlinePlus

Functional characteristics of internal thoracic artery ring segments. (A) Out of 67 segments 59 (88.1%) reacted to K-Krebs, 46 (68.7%) exhibited contraction after 1 μM phenylephrine. All precontracted segments relaxed to SNP, but only 20 (29.9%) had any measurable relaxation to Ach. Data expressed as percentage of all segments. (B) Representative recording of the inhibitory effect of 10 μM sodium-nitroprusside on spasmic vasomotion.
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f2-medscimonit-17-7-cr411: Functional characteristics of internal thoracic artery ring segments. (A) Out of 67 segments 59 (88.1%) reacted to K-Krebs, 46 (68.7%) exhibited contraction after 1 μM phenylephrine. All precontracted segments relaxed to SNP, but only 20 (29.9%) had any measurable relaxation to Ach. Data expressed as percentage of all segments. (B) Representative recording of the inhibitory effect of 10 μM sodium-nitroprusside on spasmic vasomotion.

Mentions: The vasoactive function of the ring segments was very heterogenous even among preparations from the same patient. A total of 67 ring segments were cut from the specimens and 59 (88.1%) reacted to K-Krebs, 46 (68.7%) exhibited contraction after 1 μM phenylephrine, and all of these relaxed to 30 μM SNP. Regarding endothelial-derived vasorelaxation, only 20 ring segments (29.9%) showed at least 20% relaxation to 30 μM Ach (Figure 2A). High amplitude vasomotion, an early sign of spasm, was observed in 32 out of 67 ring segments (47.8%). These large-scale patterns of vasomotion were terminated by 10 μM sodium-nitroprusside (Figure 2B).


Human internal thoracic artery grafts exhibit severe morphological and functional damage and spasmic vasomotion due to oxidative stress.

Kiss L, Benko R, Kovács E, Szerafin T, Módis K, Szabó C, Lacza Z - Med. Sci. Monit. (2011)

Functional characteristics of internal thoracic artery ring segments. (A) Out of 67 segments 59 (88.1%) reacted to K-Krebs, 46 (68.7%) exhibited contraction after 1 μM phenylephrine. All precontracted segments relaxed to SNP, but only 20 (29.9%) had any measurable relaxation to Ach. Data expressed as percentage of all segments. (B) Representative recording of the inhibitory effect of 10 μM sodium-nitroprusside on spasmic vasomotion.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3539564&req=5

f2-medscimonit-17-7-cr411: Functional characteristics of internal thoracic artery ring segments. (A) Out of 67 segments 59 (88.1%) reacted to K-Krebs, 46 (68.7%) exhibited contraction after 1 μM phenylephrine. All precontracted segments relaxed to SNP, but only 20 (29.9%) had any measurable relaxation to Ach. Data expressed as percentage of all segments. (B) Representative recording of the inhibitory effect of 10 μM sodium-nitroprusside on spasmic vasomotion.
Mentions: The vasoactive function of the ring segments was very heterogenous even among preparations from the same patient. A total of 67 ring segments were cut from the specimens and 59 (88.1%) reacted to K-Krebs, 46 (68.7%) exhibited contraction after 1 μM phenylephrine, and all of these relaxed to 30 μM SNP. Regarding endothelial-derived vasorelaxation, only 20 ring segments (29.9%) showed at least 20% relaxation to 30 μM Ach (Figure 2A). High amplitude vasomotion, an early sign of spasm, was observed in 32 out of 67 ring segments (47.8%). These large-scale patterns of vasomotion were terminated by 10 μM sodium-nitroprusside (Figure 2B).

Bottom Line: Functionally, 88.1% reacted to K-Krebs, 68.7% exhibited contraction after 1 µM phenylephrine, 29.9% exhibited relaxation to 30 µM Ach, and all precontracted segments relaxed to 30 µM SNP.High amplitude vasomotion was observed in 47.8% of the segments, which could be abolished by the application of 10 µM SNP.Incubation of the preparations with PJ34 did not improve endothelium-dependent vasodilation.The topical use of SNP to the ITA during the operation may improve vascular functions by dilating the vessels and eliminating the eventual spasmic vasomotion.<br />

View Article: PubMed Central - PubMed

Affiliation: Institute of Human Physiology and Clinical Experimental Research, Semmelweis University, Budapest, Hungary. levente.kiss@eok.sote.hu

ABSTRACT

Background: The internal thoracic artery (ITA) is the first choice for myocardial revascularization, but atherosclerotic lesions and perioperative vasospasm may still limit its functionality. Oxidative stress via the peroxynitrite - poly-(ADP-ribose) polymerase (PARP) cascade plays an important role in the pathogenesis of impaired vascular tone via endothelial injury. We aimed to investigate and describe the histology, PARP activation and functionality of ITA grafts and to assess the possible beneficial effect of PARP-inhibition.

Material/methods: ITA specimens from 47 patients (26 men, mean age 66.2 ± 1.7 years) who underwent coronary bypass surgery were processed for histological and immunohistochemical studies for oxidative stress and PARP activation, and were functionally tested with acetylcholine (ACh) and sodium nitroprusside (SNP) with or without PARP inhibition.

Results: The sections showed atherosclerotic alterations and oxidative and nitrosative stress were evidenced by positive 3-nitrotyrosine, 4-hydroxynonenal and PAR stainings. Functionally, 88.1% reacted to K-Krebs, 68.7% exhibited contraction after 1 µM phenylephrine, 29.9% exhibited relaxation to 30 µM Ach, and all precontracted segments relaxed to 30 µM SNP. High amplitude vasomotion was observed in 47.8% of the segments, which could be abolished by the application of 10 µM SNP.Incubation of the preparations with PJ34 did not improve endothelium-dependent vasodilation.

Conclusions: ITA grafts are severely damaged both morphologically and functionally in patients undergoing coronary artery bypass surgery, but PARP inhibition cannot improve their functional characteristics. The topical use of SNP to the ITA during the operation may improve vascular functions by dilating the vessels and eliminating the eventual spasmic vasomotion.

Show MeSH
Related in: MedlinePlus