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Different Anti-Contractile Function and Nitric Oxide Production of Thoracic and Abdominal Perivascular Adipose Tissues.

Victorio JA, Fontes MT, Rossoni LV, Davel AP - Front Physiol (2016)

Bottom Line: PVAT reduced the contraction evoked by phenylephrine in the absence and presence of endothelium in the thoracic aorta, whereas this anti-contractile effect was not observed in the abdominal aorta.However, Mn-SOD levels were reduced, while CuZn-SOD levels were increased in abdominal PVAT compared with thoracic aortic PVAT.In conclusion, our results demonstrate that the anti-contractile function of PVAT is lost in the abdominal portion of the aorta through a reduction in eNOS-derived NO production compared with the thoracic aorta.

View Article: PubMed Central - PubMed

Affiliation: Department of Structural and Functional Biology, Institute of Biology, University of Campinas Campinas, Brazil.

ABSTRACT
Divergent phenotypes between the perivascular adipose tissue (PVAT) surrounding the abdominal and the thoracic aorta might be implicated in regional aortic differences, such as susceptibility to atherosclerosis. Although PVAT of the thoracic aorta exhibits anti-contractile function, the role of PVAT in the regulation of the vascular tone of the abdominal aorta is not well defined. In the present study, we compared the anti-contractile function, nitric oxide (NO) availability, and reactive oxygen species (ROS) formation in PVAT and vessel walls of abdominal and thoracic aorta. Abdominal and thoracic aortic tissue from male Wistar rats were used to perform functional and molecular experiments. PVAT reduced the contraction evoked by phenylephrine in the absence and presence of endothelium in the thoracic aorta, whereas this anti-contractile effect was not observed in the abdominal aorta. Abdominal PVAT exhibited a reduction in endothelial NO synthase (eNOS) expression compared with thoracic PVAT, without differences in eNOS expression in the vessel walls. In agreement with this result, NO production evaluated in situ using 4,5-diaminofluorescein was less pronounced in abdominal compared with thoracic aortic PVAT, whereas no significant difference was observed for endothelial NO production. Moreover, NOS inhibition with L-NAME enhanced the phenylephrine-induced contraction in endothelial-denuded rings with PVAT from thoracic but not abdominal aorta. ROS formation and lipid peroxidation products evaluated through the quantification of hydroethidine fluorescence and 4-hydroxynonenal adducts, respectively, were similar between PVAT and vessel walls from the abdominal and thoracic aorta. Extracellular superoxide dismutase (SOD) expression was similar between the vessel walls and PVAT of the abdominal and thoracic aorta. However, Mn-SOD levels were reduced, while CuZn-SOD levels were increased in abdominal PVAT compared with thoracic aortic PVAT. In conclusion, our results demonstrate that the anti-contractile function of PVAT is lost in the abdominal portion of the aorta through a reduction in eNOS-derived NO production compared with the thoracic aorta. Although relative SOD isoforms are different along the aorta, ROS formation, and lipid peroxidation seem to be similar. These findings highlight the specific regional roles of PVAT depots in the control of vascular function that can drive differences in susceptibility to vascular injury.

No MeSH data available.


Related in: MedlinePlus

Loss of the anti-contractile effect of perivascular adipose tissue (PVAT) in the abdominal aorta with or without endothelium. Concentration-response curves to phenylephrine (A,B) and acetylcholine (C,D) in rat thoracic (left panel) and abdominal (right panel) aorta with (+) or without (−) endothelium (E) and PVAT. Data are expressed as the means ± SEM; the number of animals (n) is indicated in parentheses. Two-way ANOVA, P < 0.05: *PVAT+/E+ vs. PVAT−/E+; #PVAT+/E− vs. PVAT−/E−.
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Figure 1: Loss of the anti-contractile effect of perivascular adipose tissue (PVAT) in the abdominal aorta with or without endothelium. Concentration-response curves to phenylephrine (A,B) and acetylcholine (C,D) in rat thoracic (left panel) and abdominal (right panel) aorta with (+) or without (−) endothelium (E) and PVAT. Data are expressed as the means ± SEM; the number of animals (n) is indicated in parentheses. Two-way ANOVA, P < 0.05: *PVAT+/E+ vs. PVAT−/E+; #PVAT+/E− vs. PVAT−/E−.

Mentions: To determine the anti-contractile effects of PVAT in thoracic and abdominal aortic tissues, we performed concentration-response curves to phenylephrine in rings with (open symbols) or without (filled symbols) PVAT in intact (circle) or denuded (triangle) endothelium. Thoracic aortic rings with PVAT and intact endothelium (PVAT+E+) presented a significant reduction in potency and maximal response to phenylephrine when compared to rings without PVAT (PVAT−E+; Figure 1A and Table 1). Although the endothelium damage increased the phenylephrine-induced contraction (compare PVAT−/E+ vs. PVAT−/E−, Figure 1A), the anti-contractile effect of PVAT was still observed in endothelium-denuded rings. Thus, the presence of PVAT (PVAT+E−) in endothelium-denuded rings also reduced both the potency and maximal response to phenylephrine when compared to rings without PVAT and endothelium (PVAT−E−; Figure 1A and Table 1). In contrast, the presence of PVAT did not alter the phenylephrine-induced contraction in either intact or denuded endothelium abdominal aortic rings (Figure 1B and Table 1).


Different Anti-Contractile Function and Nitric Oxide Production of Thoracic and Abdominal Perivascular Adipose Tissues.

Victorio JA, Fontes MT, Rossoni LV, Davel AP - Front Physiol (2016)

Loss of the anti-contractile effect of perivascular adipose tissue (PVAT) in the abdominal aorta with or without endothelium. Concentration-response curves to phenylephrine (A,B) and acetylcholine (C,D) in rat thoracic (left panel) and abdominal (right panel) aorta with (+) or without (−) endothelium (E) and PVAT. Data are expressed as the means ± SEM; the number of animals (n) is indicated in parentheses. Two-way ANOVA, P < 0.05: *PVAT+/E+ vs. PVAT−/E+; #PVAT+/E− vs. PVAT−/E−.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4940415&req=5

Figure 1: Loss of the anti-contractile effect of perivascular adipose tissue (PVAT) in the abdominal aorta with or without endothelium. Concentration-response curves to phenylephrine (A,B) and acetylcholine (C,D) in rat thoracic (left panel) and abdominal (right panel) aorta with (+) or without (−) endothelium (E) and PVAT. Data are expressed as the means ± SEM; the number of animals (n) is indicated in parentheses. Two-way ANOVA, P < 0.05: *PVAT+/E+ vs. PVAT−/E+; #PVAT+/E− vs. PVAT−/E−.
Mentions: To determine the anti-contractile effects of PVAT in thoracic and abdominal aortic tissues, we performed concentration-response curves to phenylephrine in rings with (open symbols) or without (filled symbols) PVAT in intact (circle) or denuded (triangle) endothelium. Thoracic aortic rings with PVAT and intact endothelium (PVAT+E+) presented a significant reduction in potency and maximal response to phenylephrine when compared to rings without PVAT (PVAT−E+; Figure 1A and Table 1). Although the endothelium damage increased the phenylephrine-induced contraction (compare PVAT−/E+ vs. PVAT−/E−, Figure 1A), the anti-contractile effect of PVAT was still observed in endothelium-denuded rings. Thus, the presence of PVAT (PVAT+E−) in endothelium-denuded rings also reduced both the potency and maximal response to phenylephrine when compared to rings without PVAT and endothelium (PVAT−E−; Figure 1A and Table 1). In contrast, the presence of PVAT did not alter the phenylephrine-induced contraction in either intact or denuded endothelium abdominal aortic rings (Figure 1B and Table 1).

Bottom Line: PVAT reduced the contraction evoked by phenylephrine in the absence and presence of endothelium in the thoracic aorta, whereas this anti-contractile effect was not observed in the abdominal aorta.However, Mn-SOD levels were reduced, while CuZn-SOD levels were increased in abdominal PVAT compared with thoracic aortic PVAT.In conclusion, our results demonstrate that the anti-contractile function of PVAT is lost in the abdominal portion of the aorta through a reduction in eNOS-derived NO production compared with the thoracic aorta.

View Article: PubMed Central - PubMed

Affiliation: Department of Structural and Functional Biology, Institute of Biology, University of Campinas Campinas, Brazil.

ABSTRACT
Divergent phenotypes between the perivascular adipose tissue (PVAT) surrounding the abdominal and the thoracic aorta might be implicated in regional aortic differences, such as susceptibility to atherosclerosis. Although PVAT of the thoracic aorta exhibits anti-contractile function, the role of PVAT in the regulation of the vascular tone of the abdominal aorta is not well defined. In the present study, we compared the anti-contractile function, nitric oxide (NO) availability, and reactive oxygen species (ROS) formation in PVAT and vessel walls of abdominal and thoracic aorta. Abdominal and thoracic aortic tissue from male Wistar rats were used to perform functional and molecular experiments. PVAT reduced the contraction evoked by phenylephrine in the absence and presence of endothelium in the thoracic aorta, whereas this anti-contractile effect was not observed in the abdominal aorta. Abdominal PVAT exhibited a reduction in endothelial NO synthase (eNOS) expression compared with thoracic PVAT, without differences in eNOS expression in the vessel walls. In agreement with this result, NO production evaluated in situ using 4,5-diaminofluorescein was less pronounced in abdominal compared with thoracic aortic PVAT, whereas no significant difference was observed for endothelial NO production. Moreover, NOS inhibition with L-NAME enhanced the phenylephrine-induced contraction in endothelial-denuded rings with PVAT from thoracic but not abdominal aorta. ROS formation and lipid peroxidation products evaluated through the quantification of hydroethidine fluorescence and 4-hydroxynonenal adducts, respectively, were similar between PVAT and vessel walls from the abdominal and thoracic aorta. Extracellular superoxide dismutase (SOD) expression was similar between the vessel walls and PVAT of the abdominal and thoracic aorta. However, Mn-SOD levels were reduced, while CuZn-SOD levels were increased in abdominal PVAT compared with thoracic aortic PVAT. In conclusion, our results demonstrate that the anti-contractile function of PVAT is lost in the abdominal portion of the aorta through a reduction in eNOS-derived NO production compared with the thoracic aorta. Although relative SOD isoforms are different along the aorta, ROS formation, and lipid peroxidation seem to be similar. These findings highlight the specific regional roles of PVAT depots in the control of vascular function that can drive differences in susceptibility to vascular injury.

No MeSH data available.


Related in: MedlinePlus