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. 2019 Aug;26(6):e12527.
doi: 10.1111/micc.12527. Epub 2019 May 7.

Morphological and pharmacological characterization of the porcine popliteal artery: A novel model for study of lower limb arterial disease

Norman E Frederick  1 , Ray Mitchell  1 , Travis W Hein  1 , Pooneh Bagher  1
Affiliations

Morphological and pharmacological characterization of the porcine popliteal artery: A novel model for study of lower limb arterial disease

Norman E Frederick et al. Microcirculation. 2019 Aug.

Abstract

Objective: This study was undertaken to characterize structural and pharmacological properties of the pig popliteal artery in order to develop a novel system for the examination of lower limb blood flow regulation in a variety of cardiovascular pathologies, such as diabetes-induced peripheral artery disease.

Methods: Popliteal arteries were isolated from streptozocin-induced diabetic pigs or age-matched saline-injected control pigs for morphological study using transmission electron microscopy and for examination of vasoreactivity to pharmacological agents using wire myography.

Results: Transmission electron microscopy of the porcine popliteal artery wall revealed the presence of endothelial cell-smooth muscle cell interactions (myoendothelial junctions) and smooth muscle cell-smooth muscle cell interactions, for which we have coined the term "myo-myo junctions." These myo-myo junctions were shown to feature plaques indicative of connexin expression. Further, the pig popliteal artery was highly responsive to a variety of vasoconstrictors including norepinephrine, phenylephrine, and U46619, and vasodilators including acetylcholine, adenosine 5'-[β-thio] diphosphate, and bradykinin. Finally, 2 weeks after streptozocin-induced diabetes, the normalized vasoconstriction of the pig popliteal artery to norepinephrine was unaltered compared to control.

Conclusions: The pig popliteal artery displays structural and pharmacological properties that might prove useful in future studies of diabetes-associated peripheral artery disease and other lower limb cardiovascular diseases.

Keywords: blood flow regulation; diabetes model; myo-myo junction; myoendothelial junction; porcine popliteal artery.

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Figures

Figure 1.
Figure 1.. Schematic outline of the procedure to examine porcine popliteal artery function.
After the gastrocnemius muscle (pink) was isolated from the animal, a bundle of vasculature, nerve fibers, connective tissue, and fat was dissected from the proximal region between the two popliteal muscle heads (blue outline). Extraneous tissue was cleared away from the artery, which was then either left intact or cut into 2 mm segments (pink outline). Segments left intact were fixed for electron microscopy, while 2 mm segments were mounted in a DMT wire myograph using two 40-μm-diameter stainless steel wires (yellow outline).
Figure 2.
Figure 2.. Transmission electron micrographs of structures involved in intercellular communication within the popliteal artery wall.
The myoendothelial junction, a distinct heterocellular signaling microdomain where an endothelial cell (labeled EC) sends a projection (indicated by the white arrowhead) through the internal elastic lamina (IEL; light gray region) to make contact with an adjacent smooth muscle cell (SMC), is present in the pig popliteal artery (A). Black streaks indicate folding of the fragile IEL layer during tissue preparation. Homocellular MMJs are also present in the pig popliteal artery (B-E), which has multiple layers of smooth muscle cells separated by layers of collagen and other connective tissue. An inset (C) displays a plaque at the MMJ (indicated by a white arrow), which classically indicates the presence of connexins.,
Figure 3.
Figure 3.. Response of the porcine popliteal artery to constricting agents.
Constriction of the popliteal artery was elicited by treatment with KCl (A, n=5 vessel segments from 5 different pigs), U4 (B, n=5 vessel segments from 5 different pigs), NE (C, n=11; 34 vessel segments from 11 different pigs), and PE (D, n=5 vessel segments from 5 different pigs). Each panel includes a representative trace from the respective vasoconstrictor.
Figure 4.
Figure 4.. Response of the porcine popliteal artery to dilating agents.
Dilation of the popliteal artery was elicited by treatment with ACh (A, n=8 vessel segments from 5 different pigs, except at 30 μM, at which point n=4 segments from different 4 pigs), DEA (B, n=5 vessel segments from 5 different pigs), CCh (C, n=5 vessel segments from 5 different pigs), and ADPβS (D, n=5 vessel segments from 5 different pigs). In all cases, preconstriction was achieved by adding a dose of NE that produced a tension equal to 70% of the maximum constriction elicited by a previously performed NE dose response curve. Representative traces of each vasodilator are displayed.
Figure 5.
Figure 5.. Response of the porcine popliteal artery to dilating agents.
Dilation of the popliteal artery was elicited by BK (A, n=5 vessel segments from 5 different pigs) and SP (B, n=5 vessel segments from 5 different pigs). Both BK and SP were dissolved in a solution of 0.1 mM acetic acid, so an acetic acid control curve was performed to verify that the solvent did not affect the results. In the control curve, the volume of acetic acid added at each time point was equivalent to the volume added at respective time points of the BK and SP concentration response curves. Preconstriction was achieved by adding a dose of NE that produced a tension equal to 70% of the maximum constriction elicited by a previously performed NE dose response curve. Representative traces of each vasodilator are displayed.
Figure 6.
Figure 6.. Characteristics of STZ-treated and control animals.
STZ-treated animals (n=6 pigs) displayed significantly higher blood glucose levels and significantly decreased body weight compared to control animals (n=5 pigs). The blood glucose reading for one STZ-treated pig exceeded 600 mg/dL, the maximum detectable level with the meter that was used. This animal’s blood glucose level was recorded as 600 mg/dL. *P < 0.05.
Figure 7.
Figure 7.. Constriction to NE is not attenuated in the popliteal artery of diabetic pigs.
In both STZ-injected (n=32 vessel segments from 6 different pigs) and control pigs (n=23 vessel segments from 5 different pigs), increasing concentrations of NE elicited constriction. Without normalizing responses to vessel diameter, STZ-injected diabetic pigs displayed attenuated constriction compared to control pigs (A). However, the popliteal artery diameter of STZ animals was significantly smaller than that of control animals (B). When the data from (A) was re-plotted, but normalized to vessel diameter, all significant differences between control and STZ groups were abolished (C). *P < 0.05 as compared to control.
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References

    1. American Diabetes Association. Peripheral arterial disease in people with diabetes. Diabet Care 26: 3333–3341, 2003. - PubMed
    1. Jude EB, Eleftheriadou I, Tentolouris N. Peripheral arterial disease in diabetes--a review. Diabet Med 27: 4–14, 2010. - PubMed
    1. Faglia E Characteristics of peripheral arterial disease and its relevance to the diabetic population. Int J Low Extrem Wounds 10: 152–166, 2011. - PubMed
    1. Aiello A, Anichini R, Brocco E, Caravaggi C, Chiavetta A, Cioni R, Da Ros R, De Feo ME, Ferraresi R, Florio F, Gargiulo M, Galzerano G, Gandini R, Giurato L, Graziani L, Mancini L, Manzi M, Modugno P, Setacci C, Uccioli L, Italian Society of D, Italian Society of R, Italian Society of Vascular Endovascular S. Treatment of peripheral arterial disease in diabetes: a consensus of the Italian Societies of Diabetes (SID, AMD), Radiology (SIRM) and Vascular Endovascular Surgery (SICVE). Nutr Metab Cardiovasc Dis 24: 355–369, 2014. - PubMed
    1. Tompra N, Foster C, Sanchis-Gomar F, de Koning JJ, Lucia A, Emanuele E. Upper versus lower limb exercise training in patients with intermittent claudication: a systematic review. Atherosclerosis 239: 599–606, 2015. - PubMed

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