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Protective Effects of Pharmacological TPRM2 Inhibition on Ischemia-reperfusion Injury of the liver

(2016) Haas, J. de (Job)

IBsachckemgrioa-urnepde rfusion injury (IRI) of the liver is a common clinical problem after liver surgery
and transplantation and new therapies are required to prevent it. Calcium overload in
hepatocytes plays a central role in the pathogenesis of IRI, but the nature of the Ca+ channels
responsible for this is unknown. Accumulating evidence shows that the Transient Receptor
Potential Melastatin 2 (TRPM2) channel, which is activated in oxidative stress, could play a
major role in Ca2+ overload. This study aims to investigate whether pharmacological inhibition
of TRPM2 could reduce IRI of the liver in rats and mice.
TMweoth doidffse rent types of experiments were conducted. In the first experiment, rats were subjected
to 45 minutes of liver ischemia and 1 hour reperfusion. Each animal randomly received one of
the TRPM2 inhibitors - chlorpromazine (n = 3), N-(p-amylcinnamoyl)anthranilic acid (ACA)
(n = 3) or curcumin (n = 4). The control groups only received the vehicles (n = 3) prior to
ischemia. Bile flow recovery during reperfusion was used to assess final liver damage.
In the second experiment, mice were subjected to 45 minutes of liver ischemia and 24 hours of
reperfusion. Each mouse randomly received either TRPM2 inhibitor curcumin (n = 8) or its
vehicle (n = 7) prior to ischemia and at the start of reperfusion. TRPM2-KO mice were used
as positive control group (n = 4). ALT and AST levels and liver histology after reperfusion
were used to assess final liver damage.
IRne tshuel tesx periments using rats, no significant difference in bile flow recovery was found between
ACA and its vehicle, and between curcumin and its vehicle. Rats treated with chlorpromazine
showed significantly less bile flow recovery compared to the vehicle treated group.
In the experiments using mice, ischemia increased AST and ALT enzyme levels compared to
sham-operated controls. No significant differences in ALT and AST levels were found between
mice treated with curcumin and mice treated with its vehicle only. Interestingly, enzyme levels
in TRPM2-KO mice were not significantly lower compared to levels in WT mice. Comparing
percentages of necrosis, similar results were found between these groups.
TChoenscel udsaitoan d o not show a reduction in liver IRI through pharmacological TRPM2 inhibition.
Further research on the role of TRPM2 channels in liver IRI is needed.





ID 3368
Moeder ID 3084
Volgorde Haas, J. de
Naam HaasJde
Publiceren yes
OAI-naam Student_thesis
Path root/geneeskunde/2016/HaasJde/
Gemaakt op: 2017-03-14 12:57:39
Gemodificeerd op: 2017-03-14 12:57:39
Digitaal ID 58c7e8c3bd8c6
Afstudeerrichting opleiding/afstudeerrichting 1
Studierichting Studierichting 1
Titel Protective Effects of Pharmacological TPRM2 Inhibition on Ischemia-reperfusion Injury of the liver
Ruilverkeer mogelijk no
Printen in opdracht no
Aantal pagina's 45
Publicatiejaar 2016
Taal en
Engelse samenvatting IBsachckemgrioa-urnepde rfusion injury (IRI) of the liver is a common clinical problem after liver surgery
and transplantation and new therapies are required to prevent it. Calcium overload in
hepatocytes plays a central role in the pathogenesis of IRI, but the nature of the Ca+ channels
responsible for this is unknown. Accumulating evidence shows that the Transient Receptor
Potential Melastatin 2 (TRPM2) channel, which is activated in oxidative stress, could play a
major role in Ca2+ overload. This study aims to investigate whether pharmacological inhibition
of TRPM2 could reduce IRI of the liver in rats and mice.
TMweoth doidffse rent types of experiments were conducted. In the first experiment, rats were subjected
to 45 minutes of liver ischemia and 1 hour reperfusion. Each animal randomly received one of
the TRPM2 inhibitors - chlorpromazine (n = 3), N-(p-amylcinnamoyl)anthranilic acid (ACA)
(n = 3) or curcumin (n = 4). The control groups only received the vehicles (n = 3) prior to
ischemia. Bile flow recovery during reperfusion was used to assess final liver damage.
In the second experiment, mice were subjected to 45 minutes of liver ischemia and 24 hours of
reperfusion. Each mouse randomly received either TRPM2 inhibitor curcumin (n = 8) or its
vehicle (n = 7) prior to ischemia and at the start of reperfusion. TRPM2-KO mice were used
as positive control group (n = 4). ALT and AST levels and liver histology after reperfusion
were used to assess final liver damage.
IRne tshuel tesx periments using rats, no significant difference in bile flow recovery was found between
ACA and its vehicle, and between curcumin and its vehicle. Rats treated with chlorpromazine
showed significantly less bile flow recovery compared to the vehicle treated group.
In the experiments using mice, ischemia increased AST and ALT enzyme levels compared to
sham-operated controls. No significant differences in ALT and AST levels were found between
mice treated with curcumin and mice treated with its vehicle only. Interestingly, enzyme levels
in TRPM2-KO mice were not significantly lower compared to levels in WT mice. Comparing
percentages of necrosis, similar results were found between these groups.
TChoenscel udsaitoan d o not show a reduction in liver IRI through pharmacological TRPM2 inhibition.
Further research on the role of TRPM2 channels in liver IRI is needed.
Nederlandse samenvatting IAscchhetemriger-o ennd r eperfusieschade (IRS) van de lever is een veelvoorkomend klinisch probleem
na leverresectie en –transplantatie. IRS kan transplantaat falen en aanzienlijke leverschade
veroorzaken. Gezien het feit dat de patiëntengroep die gevoelig is voor IRS groeit zijn
nieuwe therapieën ter preventie van IRS noodzakelijk. Op celniveau speelt Ca2+-instroom in
hepatocyten een belangrijke rol in de pathogenese van IRS, de Ca2+-kanalen die hiervoor
verantwoordelijk zijn echter tot op heden onbekend. Steeds meer bewijs laat zien dat het
Transient Receptor Melastatin 2 (TRPM2) kationkanaal, dat geactiveerd wordt gedurende
oxidatieve stress, een belangrijke rol zou kunnen spelen in de Ca2+-instroom tijdens IRS. In
deze studie wordt onderzocht of inhibitie van TRPM2 kationkanalen middels medicatie leidt
tot een vermindering van IRS.
TMweethe ovdeernsc hillende experimenten werden uitgevoerd. Tijdens het eerste experiment werd in
ratten onderworpen aan 45 minuten leverischemie en één uur reperfusie. De ratten kregen voor
ischemie willekeurig één van de TRPM2 blokkers chlorpromazine (n = 3), N-(pamylcinnamoyl)
anthranilic acid (ACA, n = 3) of curcumine (n = 4) toegediend. De
controlegroepen kregen voor ischemie alleen de verschillende draagstoffen (n = 3 per draagstof)
toegediend. Het herstel van galproductie door de lever tijdens reperfusie werd gebruikt als maat
voor uiteindelijke leverschade.
Tijdens het tweede experiment werden muizen onderworpen aan 45 minuten leverischemie en
24 uur reperfusie. De muizen ontvingen willekeurig 2 doses (voor ischemie en na ischemie)
van de TRPM2 blokker curcumine (n = 8) of de draagstof daarvan (n = 7). TRPM2-KO muizen
(n = 4) werden in dit experiment gebruikt als positieve controlegroep. AST en ALT
serumwaarden en leverhistologie werden gebruikt als maat voor uiteindelijke leverschade.
TRiejsduelntsa tdeen e xperimenten met ratten werd geen significant verschil in herstel van galproductie
gevonden tussen ACA en alleen de draagstof en tussen curcumine en alleen de draagstof. Ratten
die behandeld werden met chlorpromazine lieten zelfs minder herstel van galproductie zien
vergeleken met ratten die alleen de draagstof kregen.
In de experimenten met muizen zorgde ischemie voor verhoogde leverenzymwaarden ten
opzichte van de controlegroep. Er werd geen significant verschil in leverenzymwaarden
gevonden tussen muizen behandeld met curcumine, en muizen alleen behandeld met de
draagstof. Opvallend genoeg waren de leverenzymwaarden van TRPM2-KO muizen ook niet
significant lager dan de waarden van wild-type muizen. Wat betreft het totaal necroseoppervlak
werden vergelijkbare bevindingen gedaan.
BCoovnecnlustsaiaen de resultaten laten geen vermindering zien van IRS van de lever door TRPM2
blokkade middels medicatie. Verder onderzoek naar de rol van TRPM2 kationkanalen in IRS
is noodzakelijk.
Onderwijsinstelling Medical Sciences
Type embargo abstract openbaar, scriptie op aanvraag
Auteur(s) Haas, J. de (Job)
UMCG begeleider(s) Nieuwenhuis, MD, PhD; Department of Surgery, Isala Zwolle The Netherlands
Begeleider(s) opleidingsinstelling Rychkov, Professor G. PhD; Nutrition and Metabolism, South Australia Health and Medical; Adelaide, Australia; Barritt, Professor G. PhD; Department of Medical Biochemistry, Flinders University, Ade
Auteur(s) Haas, J. de (Job)
UMCG begeleider(s) Nieuwenhuis, MD, PhD; Department of Surgery, Isala Zwolle The Netherlands


 
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