Upgrade of The Langendorff Apparatus Using The Infrared Thermo-Control System and An Intelligent Heater

137 Leka a echnika – Clinician and Technology 2020, ol. 50(4), pp. 137–141, DOI: 10.14311/CTJ.2020.4.03 ISSN 0301-5491 (P in ), ISSN 2336-5552 (Online) ORIGINAL RESEARCH UPGRADE OF THE LANGENDORFF APPARATUS USING THE INFRARED THERMO-CONTROL SYSTEM AND AN INTELLIGENT HEATER Jose Skopalík1,6, Jiří Seko a1, Ma in Pešl2,3,4, Ma ké a Béba o á5, Olga Š eco á5, Tomáš Pa ák6, V a isla Čmiel1, I o P o azník1, Edi a Jeklo á7, Jose Mašek7 1Depa men o Biomedical Enginee ing, Facul y o Elec ical Enginee ing and Communica ion, B no Uni e si y o Technology, B no, Czech Republic 2Depa men o Biology, Facul y o Medicine, Masa yk Uni e si y, B no, Czech Republic 3In e na ional Clinical Resea ch Cen e , S . Anne's Uni e si y Hospi al, B no, Czech Republic 4Fi s Depa men o In e nal Medicine – Ca dioangiology Facul y o Medicine, Masa yk Uni e si y, and S . Anne's Uni e si y Hospi al, B no, Czech Republic 5Depa men o Physiology, Facul y o Medicine, Masa yk Uni e si y, B no, Czech Republic 6Depa men o Pha macology and Toxicology, Facul y o Pha macy, Masa yk Uni e si y, B no, Czech Republic 7Ve e ina y Resea ch Ins i u e, B no, Czech Republic Abs ac Biological expe imen s in ol ing isola ed o gans and issues demand p ecise empe a u e moni o ing and egula ion. An au oma ic empe a u e con ol sys em was p oposed and op imised on eal isola ed swine hea s and he p o o ype is desc ibed in his wo k. The adi ional Langendo appa a us consis s o a hea holde , a ese oi o pe usion solu ion lowing o ao ic cannula and a hea ing ba h allowing passi e hea ans e o he ese oi o pe usion solu ion. The comme cial in a ed came a FLIR T62101 was added o his basic se -up and used o e y p ecise moni o ing o he empe a u e kine ic o he o gan and connec ed wi h an elec onic eedback loop, which allowed eal- ime and p ecise egula ion o hea ans e om he hea ing ba h o he pe usion solu ion and in u n indi ec ly o he hea issue. This p o ides eal ime con ol and ac i e egula ion o he myoca dial issue empe a u e. The in a ed came a was es ed in se e al modes and se e al a ian s o de ec ion we e op imised o ideal measu emen o he egion o in e es o he ex i o o gan. The kine ics o he empe a u e changes and empe a u e s abili y o he issue we e eco ded and calib a ed by ex e nal elec onic he mome e s ( ype P 100, inse ed in issue). The ime lapse om he hang-up o he hypo e med o gan (30 °C) un il op imal wa ming (37 °C) was less han eigh minu es in he inal ins umen p o o ype. The inal s abili y o he 37 °C issue empe a u e was app o ed; he empe a u e luc ua ion o le en icle issue was cha ac e ised as 36.8 ± 0.5 °C. This upg aded adi ional ins umen could be used in speci ic p eclinical and clinical ansplan a ion and analy ical p ojec s in u u e. Keywo ds isola ed hea , hea pe usion, issue he mos abili y, he mo con olle , IR he mome y 138 Leka a echnika – Clinician and Technology 2020, ol. 50(4), pp. 137–141, DOI: 10.14311/CTJ.2020.4.03 ISSN 0301-5491 (P in ), ISSN 2336-5552 (Online) ORIGINAL RESEARCH In oduc ion The use o an isola ed bea ing hea has, o e many decades, esul ed in undamen al disco e ies ha imp o ed an unde s anding o he hea ’s physiology and ca dio ascula medicine [1]. A e og ade-pe used hea is a me hod ha was imp o ed by Langendo a he end o he 19 h cen u y [2]. This me hod (scheme on Fig. 1) is based on he pe usion bu e lowing e o- g adely down he ascending ao a. The ao ic al e is closed unde p essu e, and he co ona y a e ies a e hus illed ia he le and igh co ona y os ia (Fig. 1). Fig. 1: O e iew o hea pe usion using he Langendo me hod. The mos commonly used mode o he Langendo appa a us is called ‘cons an hyd os a ic p essu e’. The p essu e is se by he heigh column o he luid ( he ele a ion o solu ion su ace in a ese oi and hyd o- s a ic p essu e di e ence o he ip o he cannula in he ao a). The ex i o bea ing hea is an excellen model sys em o obse ing hea physiology o hea elec o- physiology on he mac oscopic and mic oscopic le el, he co ona y ascula unc ion and p incipals o egula ion, and also o simula ing o medical in e - en ion in p eclinical es s [1, 2]. The pe used hea is also used o he ex ac ion o single li ing ca dio- myocy es om a speci ic si e o he hea muscle o isola ion o issue en i ies, which a e being conside ed by many biomedical eams [3, 4]. Expe imen s on isola ed hea s demand a p ecise se ing and con ol o he empe a u e o he hea issue. Ne e heless, di e ence be ween pe usa e em- pe a u e and local epica dial empe a u e can be se e al uni s o Celsius deg ees. We p esen a echnological concep in ol ing adding he mosenso s o he adi ional Langendo appa a- us. This upg aded sys em can be used o p ecise he mo-con ol o he issue, especially he le en i- cle. Ou p o o ype was es ed in expe imen s on pig hea s; howe e , he applica ion could be easily modi- ied o smalle o bigge isola ed hea s. Ma e ial and Me hods Basic design and edesign o he Langendo appa a us The basic Langendo se up was modi ied. T adi- ional componen s (shown in Fig. 2) we e supple- men ed using a Fo wa d Looking In a ed IR (FLIR) de ec o came a FLIR-T62101 (FLIR Sys ems, Inc., Wilson ille, USA) and compu e connec i i y o he FLIR came a and he powe supply o hea ing he ba h (de ails in Fig. 3). Fig. 2: Componen s o he basic Langendo se up. T1 is empe a u e o he he mos a ba h, T2 is empe a- u e o he pe usion solu ion nea he en ance o he ao a. The compu e was equipped wi h Uni e sal Se ial Bus (USB e sion 3.1, 10 Gbi /s) designed o high- speed upload o da a packe s om he FLIR came a. The u ili y c ea ed on MATLAB pla o m (Ma h- Wo ks, Na ick, Massachuse s, USA) was able o iden i y he empe a u e o he le en icle ( he cen al ield o he hea – 320×256 pixels) and eco d i in he o m o a da a ma ix in eal ime. The u ili y was se o compu e he minimal, maximal and mean alue o he empe a u e poin s on he 320×256 ma ix and com- mand he powe supply o he hea ing elemen s in he ba h in eal ime (see Fig. 3 and Fig. 4). The illus a i e isualisa ion o he da a ma ix (le en icle) is p esen ed in he o m o a pseudocolou ame, as shown in Fig. 5. A e ca ying ou a basic es o unc ionali y wi h espec o he se ing o he came a and compu ing sys em, h ee impo an enginee ing asks had o be esol ed: (i) es ing o an e ec i e ime lap be ween de ec ing he issue empe a u e (ΔTIR espec i ely) and change in he empe a u e o he pe usion luids (poin wi h ‘T1 he mome e ’, as shown in Fig. 3); (ii) es ing o he ime laps be ween de ec ing he issue empe a u e and su icien compensa ion o empe a u e T2 and he eal empe a u e o he le en icle; (iii) assessing he empe a u e measu ed by he IR came a (a compa ison wi h con ac needle he mome e s). 139 Leka a echnika – Clinician and Technology 2020, ol. 50(4), pp. 137–141, DOI: 10.14311/CTJ.2020.4.03 ISSN 0301-5491 (P in ), ISSN 2336-5552 (Online) ORIGINAL RESEARCH Fig. 3: Langendo se up modi ied by he IR came a and compu e o elec onic egula ion o he hea ing elemen s o he ba h. Au oma ic sc eening o hea issue is ollowed h ough image p ocessing using a compu e and he ope a ion o he hea ing elemen s ( espec i ely he pump a e). The eple ion o he came a scan and commanding o he hea ing elemen is 1 Hz. Fo each small a ea o 4×4 pixels he a e age empe a u e TIR and di e ence ΔTIR = 37 - TIR (in deg ees o Celsius) a e compu ed. The mass o he es ed expe imen al pig hea was 0.35 kg, he hea issue was ob ained du ing slaugh e p ocessing o he pigs. Fig. 4: The scheme o geome ical a angemen o componen s: 1 – isola ed hea , 2 – holde and cannula, 3 – he mome e used o he luids in oduced in o he ao a, 4 – IR came a ( ocused on he le en icle). Resul s Time lap be ween he IR came a’s de ec ion o TLV and eadjus ing T1 The s abili y o he empe a u e o he wa e in he ba h is he main limi ing ac o o egula ing he speed o he empe a u e o he pe using solu ion (blood subs i u e - Ty od solu ion) en e ing he ao a. This he modynamic ac was immedia ely ob ious a he beginning o he expe imen . The ba h con ains wo li es o dis illed wa e , and he hea ing elemen s ha e maximal ou pu Pmax = 2 kW. We es ed he se e al p og amming o mulas o commanding he hea ing elemen s, he op imised so wa e se ing o he ac i a ion o ou pu P o he hea ing elemen s was adjus ed o he ollowing o mula: IF ΔTIR ≥ 3 THEN se P = 1×Pmax IF 3 ≥ ΔTIR ≥ 0 THEN se P = 0.5×Pmax This se ing gi es he ollowing ime laps (Table 1) o s abilising he empe a u e o he ba h ( inal 37 °C). Table 1: S abilisa ion o T1. S a ing T IR Final T IR Time (s) 30 °C 37 °C 138 32 °C 37 °C 69 34 °C 37 °C 35 36 °C 37 °C 8 These ime laps a e su icien o s abilising he hea issue empe a u e o la ge se o biological applica ions. A B Fig. 5: Typical ame om he IR came a isualised by he MATLAB u ili y (A). The co esponding pho o o he le en icle (B). 140 Leka a echnika – Clinician and Technology 2020, ol. 50(4), pp. 137–141, DOI: 10.14311/CTJ.2020.4.03 ISSN 0301-5491 (P in ), ISSN 2336-5552 (Online) ORIGINAL RESEARCH Quan i ica ion o he ime lap be ween he IR came a’s de ec ion o TLV and eadjus ing o T2 The e ec i e ans e o hea om he ba h o he luids in he p oximi y o he ao a is ano he p oblem. A p ima y se ing in ol ing ope a ing he hea ele- men s has been ound o be insu icien o ans e ing he hea quickly. An ope a ion also had o be ca ied ou o he pump a e: he pump was upg aded h ough an elec onical connec ion o he compu e , whe e he mo o o he pump was ope a ed by his op imised di ec ion: IF ΔTIR ≥ 3 THEN se V = 1×Vmax IF 3 ≥ ΔTIR ≥ 0 THEN se V = 0.5×Vmax (whe e he maximal ou pu Vmax is he maximal pump ou pu 0.3 li es pe second; V is he ac ual pump ou pu ). This se ing gi es he ollowing ime laps o s abilising he empe a u e T2 and TIR (Table 2; o his pu pose measu ed as he a e age empe a u e in he cen al 2×2 cm o he le en icle). Table 2: S abilisa ion o T2 and TIR. S a ing TIR Time T2 (s) Time TIR (s) 30 °C 246 382 32 °C 97 199 34 °C 52 85 36 °C 17 32 Assessmen o he accu acy o he empe a u e measu emen using he IR came a The e alua ion o he accu acy o he empe a u e measu emen using he IR came a can be spli in o wo s eps. Fi s s ep (calib a ion o FLIR came a sys em i sel ); he pa ame e s o e lec ance in he IR came a se up was adjus ed o he mois ened su ace o he skin model (hea ed body) by a FLIR se ice echnician. Second s ep (checking o de ec ion alidi y on eal cada e ); he co ela ion be ween he eal pig issue empe a u e (cada e p ehea ed in he mos a ic ba h, con ol needle empe a u e a dep h o 3 mm) and empe a u e alue om display o IR came a was checked using. The mome e (P 1000, ype VOLTCRAFT TPT-206 VC-8603650) connec ed o Vol age-me e and PC was used (Fig 6A). In o de o minimize he in luences o he cable esis ance and i s empe a u e dependan luc ua ions, he 3-wi e ci cui was used o connec ing o P 100 senso s (Fig 6B). The hea was imme sed in he ba h o 20 minu es a empe a u es o 30, 34, 37 o 38 °C in an a emp o ob ain a uni o m dis ibu ion o he empe a u es ac oss he issue. The esul s om ou independen measu e- men s (Table 3) show a high co ela ion o TIR and Tcon ol. Fig. 6: (A) Con ol he mome e s a wo poin s o he issue o compa ison wi h he IR non-con ac came a measu emen . (B) Scheme o he 3-wi e ci cui o connec ing o P 100. Table 3: Co ela ion o he empe a u es (a e age alue and s anda d de ia ion om 4 expe imen s). Hea ba h T con ol (°C) T IR (°C) 30 °C 29.9 ±0.6 29.5 ±0.8 34 °C 33.9 ±0.4 33.8 ±0.5 37 °C 37.0 ±0.3 36.8 ±0.5 38 °C 37.9 ±0.4 37.9 ±0.6 The e alua ion o he accu acy o he empe a u e measu emen on eal issue using he non-con ac IR came a is e y impo an o all u u e biological expe imen s. The IR came a was calib a ed ( eadjus ed o he mois ened su ace o he o gan) by calib a ion p o ocol o FLIR company. A e ha , he co ela ion be ween he su ace empe a u e measu ed by he came a and he empe a u es o he issue (a a dep h o 0–5 mm) was checked using a he mome e P 1000. The a e age di e ence be ween IR measu ed empe a- u e and P 100 measu ed empe a u e was de ec ed as 0.2 °C o a ge empe a u e 37 °C. Discussion The Oska Langendo model o isola ed hea has been going h ough nume ous modi ica ions, o e he decades he concep p o ed i s simplici y and p ac i- cabili y, e en acing wo king hea sys em [5]. The empe a u e o he hea issue has always been he key pa ame e [6] and he impo ance has g own due o u iliza ion o sophis ica ed echniques o ex ac ion o myocy es, ex ac ion o ex acellula componen s o in usion o gene-deli e y sys em [7]. Rep oducible esul s o all hese expe imen al me hods depend on oxygen, nu ien s deli e y, pe usion p essu e, bu o emos on he s able empe a u e. This is usually kep by he mocouples wi hin he ba h i sel , ne e heless his is applicable only when whole o gan is subme ged. Ou me hods eplaced adi ional con ac he mome e by non-con ac IR came a. The selec ion o he came a was based on knowledge o IR imaging, 141 Leka a echnika – Clinician and Technology 2020, ol. 50(4), pp. 137–141, DOI: 10.14311/CTJ.2020.4.03 ISSN 0301-5491 (P in ), ISSN 2336-5552 (Online) ORIGINAL RESEARCH which has been used p edominan ly in he e alua ion o spo s inju ies and he p og ession o he apy o in disease e alua ion ill oday [8]. The eedback loop in many a ian s o his o ical Langendo sys ems was ep esen ed by he mos a s wi h smalle o longe esponse impe ec ion. Ou me hods eplaced he he mos a s by he so wa e u ili y commanding he hea ing and ci cula ing sys em. The inal s abili y o empe a u e in ou p o o ype is excellen in compa ison wi h some p e ious a ian o he mocouple sys em [9]. The ocus on he adequa e a ea o measu ed hea is he impo an aspec o ou s udy, applica ion o con olled condi ion will allow p ecise p epa a ion o he hea issue o expe imen al deli e y, physiological simula ion o ha es ing o mul iple cell ypes (p ogeni o cells, ca diomyocy es, e c.), which a e commonly dissocia ed by he mo- esponsi e enzymes om ex ac ed hea s [10]. Conclusion Ou p o o ype o he lab sys em based on he adi ional Langendo appa a us p o ides p ecise moni o ing and egula ion o he empe a u e o he isola ed hea . The possibili y o as and p ecise he mo egula ion o he pe usa e and hea issue en e ing he ao a was documen ed. The ime lap om he hang-up o he hypo e med o gan and op imal wa ming o 37 °C was less han eigh minu es ( he ini ial empe a u e was 30 °C). The s abili y o he issue empe a u e was app o ed. Ou aim o u u e upg ades is o se e an au oma ic sys em wi h con ol so wa e o ou ine use - iendly applica ions o bo h clinical and esea ch use. Acknowledgemen The wo k has been suppo ed by esea ch g an MUNIA/A/1255/2018 and suppo ed by he Minis y o Educa ion, You h and Spo s p ojec “FIT” (Pha macology, Immuno he apy, nanoToxicology) CZ.02.1.01/0.0/0.0/15 003/0000495, by he Minis y o Ag icul u e o he Czech Republic - g an numbe RO0518, and by he Speci ic Uni e si y Resea ch p ojec numbe MUNI/A/1307/2019 p o ided by he Minis y o Educa ion, You h and Spo s o he Czech Republic. Re e ences [1] Bell RM, Mocanu MM, Yellon DM. Re og ade hea pe usion: he Langendo echnique o isola ed hea pe usion. Jou nal o molecula and cellula ca diology. 2011 Jun 1;50(6):940–50. 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DOI: 10.1152/ajphea .00333.2012 [10] Pesl M, Jelinko a S, Caluo i G, Holicka M, K ejci J, Nemec P, Kohu o a A, Zampacho a V, D o ak P, Ro ekl V. Ca dio- ascula p ogeni o cells and issue plas ici y a e educed in a myoca dium a ec ed by Becke muscula dys ophy. O phane jou nal o a e diseases. 2020 Dec;15(1):1–8. DOI: 10.1186/s13023-019-1257-4 Jose Skopalík, Ph.D. Dep . o Pha macology and Toxicology Facul y o Pha macy – Masa yk Uni e si y Palackého řída 1946/1, CZ 602 00 B no E-mail: [email protected] Phone: +420 541 562 890