Role of cationic head-group in cytotoxicity of ionic liquids: Probing changes in bilayer architecture using solid-state NMR spectroscopy

Article abstract of DOI:10.1016/j.jcis.2020.08.115

The effect of cationic head-group of ionic liquid on the structure and dynamics of phospholipid bilayer was studied to provide insights into the mechanism of ionic liquid-membrane interaction. The effect was observed using six ionic liquids containing benzimidazolium, imidazolium, pyrrolidinium, piperidinium, ammonium, and morpholinium based amphiphilic cations carrying a dodecyl alkyl chain. Unilamellar and multilamellar vesicles composed of zwitterionic 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) were used. Permeability of POPC bilayer was found to have a strong dependence on ionic liquid head-group structure. To probe the structural details of interaction, ³¹P and ²H based solid-state NMR measurements were performed. The cations differed in terms of their effect on the orientation and disorder in the phosphocholine moiety in lipid head-group as revealed by chemical shift anisotropy of ³¹P. Cations carrying an unshielded charge like benzimidazolium, imidazolium, and ammonium result in strong reorientation of phosphocholine moiety in lipid head-group. Large sized cations like benzimidazolium and piperidinium result in enhanced lipid chain dynamics as revealed by order parameter calculations of deuterated lipid chains. Relatively polar head-group of morpholinium cation neither impacts the phospholipid head-group nor chain packing. Our results suggest that there exists a direct correlation between ionic liquid head-group induced structural changes in bilayer and their ability to permeabilize/disrupt the membrane and be cytotoxic.

Full text of DOI:10.1016/j.jcis.2020.08.115

J O U R N A L O F T H E A M E R I C A N C O L L E G E O F C A R D I O L O G Y , V O L . 6 7 , N O . 1 6 , S U P P L S , 2 0 1 6
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TCTAP C-111
Stent Edge Dissection Caused by Hinge Motion in Tortuous Vessels
Takatoyo Kiko,1 Yoshifumi Kashima,1 Daitarou Kanno,1
Tomohiko Watanabe,1 Yutaka Tadano,1 Takuro Sugie,1 Ken Kobayashi,1
Tsutomu Fujita1
1Sapporo CardioVascular Clinic, Japan
[CLINICAL INFORMATION]
Patient initials or identifier number. M.O.
Relevant clinical history and physical exam. A 67-year-old female with
hypertension and diabetes was admitted to our hospital to be evalu-
ated for chest discomfort on effort. She hadn’t received any cathe-
terization yet. On her physical examination, blood pressure was 140/
70 mmHg and heart rate was 70 bpm.
Relevant test results prior to catheterization. There were no specific
findings on electrocardiography and echocardiography.
Relevant catheterization findings. Coronary angiography revealed focal
75% stenosis at the proximal right coronary artery (RCA) in tortuous
vessels. There was no significant stenosis in left anterior descending
artery and left circumflex artery.
[INTERVENTIONAL MANAGEMENT]
Procedural step. Percutaneous coronary intervention (PCI) was per-
formed from right radial artery. The proximal RCA lesion was dilated
with a 3.0Â15 mm balloon (HiryuPlus, TERUMO) and treated with a
3.0Â18 mm biolimus-eluting stent (NOBORI, TERUMO). Intravascular
ultrasound (IVUS) didn’t show any dissection and intramural hema-
toma. The final angiography was acceptable. In a general ward after
the PCI thirty minutes later, she suddenly got chest pain and nausea
with ST segment elevation in leads II, III and aVF. Emergent coronary
angiography revealed an occlusion of the proximal RCA in the stent.
PCI was performed from femoral artery with a 7 Fr Judkins right
guiding catheter (Launchar, Medtronic) and a guide wire (Sionblue,
ASAHI Intecc). IVUS showed the stent edge dissection and intramural
hematoma expanded to the far distal RCA. The true lumen was com-
pressed by the enlarged, tense, false lumen. We put 2.5Â38 mm and
3.0Â28 mm everolimus-eluting stents (XienceAlpine, Abott) after
making the re-entry point by a 3.0Â10 mm cutting balloon (Flextome,
BostonScientific). Then, RCA flow got TIMI3 and her symptoms were
getting better. The final angiography was acceptable. She was dis-
charged after 2 days with no elevation of cardiac enzyme.
Case Summary. ꢀ Stent loss during PCI occurs infrequently in the
current era (incidence 0.32%) and is more likely to occur in tortuous
and calcified coronary arteries.
ꢀ Lost stents can be successfully retrieved in the majority of cases
using
a variety of retrieval techniques like low pressure balloon
inflation technique, small balloon technique, double wire technique
and loop snare technique.
ꢀ Stent loss is associated with an increased risk of complications,
such as significant bleeding and need for emergency coronary artery
bypass graft surgery.
ꢀ Stents lost in small branches can be left.
ꢀ If stent is not retrieved it may be deployed or crushed.

J O U R N A L O F T H E A M E R I C A N C O L L E G E O F C A R D I O L O G Y , V O L . 6 7 , N O . 1 6 , S U P P L S , 2 0 1 6
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Case Summary. This case represents the possibility that hinge motion
could make coronary artery dissection at the edge of stent. We found the
dissection thirty minutes later despite IVUS couldn’t show any injury in the
first PCI. It may be a risk factor to place stent edge in tortuous vessels with
hinge motion. Additionally, a biolimus-eluting stent (NOBORI, TERUMO)
has thicker strut (125
mm) than other second-generation drug-eluting
stents, which may be also the risk of the phenomenon.
TCTAP C-112
A Complex Calcified Lesion: A Lesson Learnt Twice!
Aaron Wong1
1National Heart Centre Singapore, Singapore
[CLINICAL INFORMATION]
Patient initials or identifier number. DDC
Relevant clinical history and physical exam. 83 year-old man with car-
diovascular risk factors of DM, HTN and HLP. He had past history IHD
with previous PCI done in 2000. He presented 3 years ago with recent
onset of chest tightness on exertion and coronary angiography
showed triple vessel disease. LAD and RCA were both stented with
DES. LCX was calcified and diffusely disease and was left for medical
treatment. 8 months later he presented with exertional angina and he
was admitted for coronary angiography.