Impact of hypoxia, simulated ischemia and reperfusion in HL-1 cells on the expression of FKBP12/FKBP12.6 and intracellular calcium dynamics.

AIMS: To establish a cardiac cell culture model for simulated ischemia and reperfusion and in this model investigate the impact of simulated ischemia and reperfusion on expression of the calcium handling proteins FKBP12 and FKBP12.6, and intracellular calcium dynamics. METHODS: HL-1 cell cultures were exposed to normoxia (as control), hypoxia, simulated ischemia (HEDA) or HEDA+reactive oxygen species (ROS) for up to 24 h and after HEDA, with or without ROS, followed or not by simulated reperfusion (REPH) for 6 h. Viability was analyzed with a trypan blue exclusion method. Cell lysates were analyzed with real-time PCR and Western blot (WB) for FKBP12 and FKBP12.6. Intracellular Ca(2+)measurements were performed using dual-wavelength ratio imaging in fura-2 loaded cells. RESULTS: A time-dependent drop in viability was shown after HEDA (P<0.001). Viability was not further influenced by addition of ROS or REPH. The general patterns of FKBP12 and FKBP12.6 mRNA expression showed upregulation after hypoxia, downregulation after ischemia and normalization after reperfusion, which was partially attenuated if ROS was added during HEDA. The protein contents were unaffected after hypoxia, tended to increase after ischemia and, for FKBP12.6, a further increase after reperfusion was shown. Hypoxia or HEDA, with or without REPH, resulted in a decreased amplitude of the Ca(2+) peak in response to caffeine. In addition, cells subjected to HEDA for 3 h or HEDA for 3 h followed by 6 h of REPH displayed irregular Ca(2+) oscillations with a decreased frequency. CONCLUSION: A threshold for cell survival with respect to duration of ischemia was established in our cell line model. Furthermore, we could demonstrate disturbances of calcium handling in the sarcoplasmic reticulum as well as alterations in the expressions of the calcium handling proteins FKBP12 and FKBP12.6, why this model may be suitable for further studies on ischemia and reperfusion with respect to calcium handling of the sarcoplasmic reticulum.

Myocardial release of FKBP12 and increased production of FKBP12.6 in ischemia and reperfusion experimental models.

BACKGROUND: Coronary artery occlusion and reperfusion may trigger reversible and irreversible ischemic and reperfusion injury. The primary aim of this study was to evaluate protein release into the myocardium in a porcine model during ischemia and reperfusion to search for clarifying models for reperfusion injury and secondarily to investigate release and production of the immunophilins FKBP12/12.6 in this model and in cell cultures. METHODS: In a porcine model local myocardial ischemia was induced during 45min followed by 120min of reperfusion. Microdialysis samples from ischemic and non-ischemic areas were analyzed with surface-enhanced laser desorption ionization (SELDI) mass spectrometry (MS) and Western blotting (WB). Myocardial biopsies from areas at risk and control areas were analyzed with reverse transcription polymerase chain reaction (RT-PCR). Myocardial cell cultures from mice (HL-1 cells) were exposed to hypoxia and then analyzed with WB and RT-PCR. RESULTS: FK binding protein12 (FKBP12), ubiquitin and myoglobin were identified as being released during ischemia and reperfusion in microdialysates. RT-PCR analysis on the biopsies after ischemia revealed a non-significant increase in mRNA expression of FKBP12 and a significant increase in mRNA expression of FKBP12.6. Lysates from HL-1 cells exposed to hypoxia demonstrated increase of FKBP12 and a significant increase in mRNA expression of FKBP12.6. CONCLUSION: In a myocardial ischemic-reperfusion porcine model as well as in hypoxic HL-1 cells, release of FKBP12 and increased production of FKBP12.6 was demonstrated. The findings indicate important mechanisms related to these immunophilins in the reaction to ischemia/hypoxia and reperfusion in the heart.

Infarct evolution in man studied in patients with first-time coronary occlusion in comparison to different species - implications for assessment of myocardial salvage.

BACKGROUND: The time course of infarct evolution, i.e. how fast myocardial infarction (MI) develops during coronary artery occlusion, is well known for several species, whereas no direct evidence exists on the evolution of MI size normalized to myocardium at risk (MaR) in man. Despite the lack of direct evidence, current literature often refers to the "golden hour" as the time during which myocardial salvage can be accomplished by reperfusion therapy. Therefore, the aim of the present study was to investigate how duration of myocardial ischemia affects infarct evolution in man in relation to previous animal data. Consecutive patients with clinical signs of acute myocardial ischemia were screened and considered for enrollment. Particular care was taken to assure uniformity of the patients enrolled with regard to old MI, success of revascularization, collateral flow, release of biochemical markers prior to intervention etc. Sixteen patients were ultimately included in the study. Myocardium at risk was assessed acutely by acute myocardial perfusion single photon emission computed tomography (MPS) and by T2 imaging (T2-STIR) cardiovascular magnetic resonance (CMR) after one week in 10 of the 16 patients. Infarct size was measured by late gadolinium enhancement (LGE) at one week. RESULTS: The time to reach 50% MI of the MaR (T50) was significantly shorter in pigs (37 min), rats (41 min) and dogs (181 min) compared to humans (288 min). There was no significant difference in T50 when using MPS compared to T2-STIR (p = 0.53) for assessment of MaR (288 +/- 23 min vs 310 +/- 22 min, T50 +/- standard error). The transmural extent of MI increased progressively as the duration of ischemia increased (R2 = 0.56, p < 0.001). CONCLUSION: This is the first study to provide direct evidence of the time course of acute myocardial infarct evolution in relation to MaR in man with first-time MI. Infarct evolution in man is significantly slower than in pigs, rats and dogs. Furthermore, infarct evolution assessments in man are similar when using MPS acutely and T2-STIR one week later for determination of MaR, which significantly facilitates future clinical trials of cardioprotective therapies in acute coronary syndrome by the use of CMR.

Improved outcome with standardized plan for clinical management of acute decompensated chronic heart failure.

BACKGROUND: Our overall goal is to improve clinical care for inpatients with chronic heart failure (CHF). A retrospective assessment of CHF patients admitted to our hospital over the past decade (2005 vs. 2014) indicated a need for better strategies to evaluate clinical treatment, implement best practices and achieve optimal patient outcome. To that purpose, we developed a standardized plan to improve in-hospital treatment of acute decompensated CHF patients. METHODS & RESULTS: Retrospective chart reviews were conducted to compare three cohorts of CHF patients admitted to the University Hospital of Lund at different time points over a 12-year period: 2005 (365 patients), 2014 (172 patients) and 2017-2018 (57 patients). Little improvement was seen between 2005 and 2014 with respect to one-year mortality (35% vs. 34%) and adequate treatment with recommended medications, e.g., use of renin-angiotensin system blockers (45% vs. 51%). A standardized treatment plan was devised to improve outcomes. A third cohort, treated under the plan (2017-2018), was compared with the 2014 cohort. One-year mortality (18% vs. 34%) and 30-day readmission (5% vs. 30%) were dramatically decreased, and adherence to medication guidelines was achieved. Key elements of the plan included well-defined treatment procedures, enhanced communication and teamwork, education, adequate time for treatment (5 days) and post-discharge follow-up as necessary. Natriuretic peptide (NT-proBNP) levels were useful for assessing patient status, prognosis and response to treatment. CONCLUSION: Development of a standard plan for clinical management of acute decompensated CHF patients resulted in significant improvements in patient outcome, as reflected in decreased rates of 30-day readmission and one-year mortality.

The impact of general usage of stents on short- and long-term health care costs following percutaneous coronary intervention.

BACKGROUND: The general usage of stents during percutaneous coronary intervention (PCI) reduces the need for subsequent repeated revascularizations when compared with balloon dilatation. The aim was to evaluate the impact of stenting on short- and long-term in-hospital care costs after PCI. METHOD AND RESULTS: Patients who underwent PCI from July 1992 to June 1993 (group A, n = 166; 4.2% stents) and from July 1996 to June 1997 (group B, n = 233; 61.4% stents) were included. The clinical outcome and all in-hospital care costs during 2.5 years following the procedures were analyzed. During the study period the number of deaths and acute myocardial infarctions was similar in the groups, but repeated revascularization occurred more often in group A than in group B (53.6 vs. 39.5%; p = 0.007). The initial procedural cost per patient was higher in group B than in group A (EUR 7,653 +/- 5,071 vs. EUR 6,048 +/- 3,242; p = 0.002), but after 2.5 years the costs were similar in the 2 groups (not significant). CONCLUSION: General usage of stents increases immediate health care cost compared with balloon dilatation, but despite reduction in subsequent revascularization, there is no reduction in long-term in-hospital costs.

Initial results of inflammatory response, matrix remodeling, and reactive oxygen species following PCI in acute ischemic myocardial injury in man.

BACKGROUND: Neutrophils and reactive oxygen species (ROS) are suggested to be involved in irreversible myocardial reperfusion injury and stunning. We investigated the relations between circulating biochemical markers and myocardium at risk (MaR), myocardial infarct (MI) size, salvage, and recovery of function in man. METHODS AND RESULTS: In patients undergoing PCI serial blood samples were acquired for markers of inflammatory response (myeloperoxidase [MPO], neutrophil-gelatinase-associated lipocalin [NGAL], interleukins 6 and 8 [IL-6/8], tumor necrosis factor-a [TNF-a], high-sensitive C-reactive protein [hsCRP]), matrix remodeling (matrixmetalloproteinase-9 [MMP-9]) and ROS (malondialdehyde [MDA], isoprostane [IsoP]). Samples were obtained before PCI and 1.5, 3, and 24 hours after reperfusion. Myocardial perfusion SPECT (MPS) was used to assess MaR. Late gadolinum-enhanced cardiac magnetic resonance imaging was performed for regional function in the acute setting, at 1 week and 6 months, and at 1 week also for MI size. Sixteen patients (15 men; 42-78 years) were enrolled, 12 of whom underwent MPS. Peak and cumulative NGAL and cumulative MMP-9 showed inverse correlations to MaR. No correlation was found for MI size. Peak MPO correlated inversely to salvage and to recovery of regional function in the infarcted segments at 1 week and 6 months. CONCLUSIONS: This is the first study in man to show inverse relations between circulating NGAL and MMP-9 and MaR. The current results do not support that ROS has a role in stunning in man. MI size showed no significant correlation to any parameter, challenging inflammatory treatment in reperfusion.

Cyclosporine does not reduce myocardial infarct size in a porcine ischemia-reperfusion model.

Cyclosporine A (CsA) has been shown to protect against myocardial ischemia and reperfusion (I/R) injury in small animal models. The aim of the current study was to evaluate the effects of CsA on myocardial I/R injury in a porcine model. Pigs were randomized between CsA (10mg/kg; n = 12) or placebo (n = 15) and anesthetized with either isoflurane (phase I) or pentobarbital (phase II). By catheterization, the left descending coronary artery was occluded for 45 minutes, followed by reperfusion for 2 hours. Hearts were stained to quantify area at risk (AAR) and infarct size (IS). Myocardial biopsies were obtained for terminal dUTP nick end labeling and immunoblot analysis of proapoptotic proteins (apoptosis-inducing factor [AIF], BCL2/adenovirus E1B 19-kd interacting protein 3 [BNIP-3], and active caspase-3). Cyclosporine A did not reduce IS/AAR compared with placebo (49% vs 41%, respectively; P = .21). Pigs anesthetized with isoflurane had lower IS/AAR than pigs anesthetized with pentobarbital (39% vs 51%, respectively; P = .03). This reduction in IS/AAR seemed to be attenuated by CsA. Apoptosis-inducing factor protein expression was higher after CsA administration than after placebo (P = .02). Thus, CsA did not protect against I/R injury in this porcine model. The data suggest a possible deleterious interaction of CsA and isoflurane.

Dissociation of the Inflammatory Reaction following PCI for Acute Myocardial Infarction.

OBJECTIVES: Neutrophils are activated and infiltrate the myocardium after ischemia and reperfusion. The involvement of neutrophils in irreversible reperfusion injury is suggested by numerous experimental studies. The aim of this study was to investigate markers of neutrophil activation following reperfusion of acute myocardial infarction (AMI) accomplished with percutaneous coronary intervention (PCI) and their relationship to markers of lipid peroxidation, cytokines and highly-sensitive C-reactive protein (hsCRP). DESIGN: Non-consecutive patients with their first myocardial infarction were evaluated. Setting. University hospital as primary referral center, single center. PATIENTS AND METHODS: Forty-nine patients with AMI were evaluated. All were treated with primary PCI and infusion of abciximab. Reperfusion was verified by angiography. Blood samples for analyses of myeloperoxidase (MPO), neutrophil gelatinase-associated lipocalin (NGAL), matrix metalloproteinase-9 (MMP-9), malondialdehyde (MDA), 8-isoprostane-prostaglandin F2alpha (Iso-P), interleukin 6 (IL-6), interleukin 8 (IL-8), tumor necrosis factoralpha (TNFalpha), hsCRP, creatine kinase-monobasic fraction (CK-MB) and troponin-T (TnT) were obtained at baseline with the occluded coronary vessel, and subsequently after verified reperfusion at 1.5, 3 and 24 hours. RESULTS: Significant increases in MMP-9, IL-6, IL-8, TNFalpha and hsCRP were observed, and a significant decrease in MPO and MDA was also observed over the same period. No significant changes in Iso-P and NGAL were found. CONCLUSION: We found a dissociation of the inflammatory reaction after PCI for AMI: a decrease of markers of neutrophil activation and MDA, but an increase in cytokines and hsCRP. An antineutrophil effect of the PCI procedure including treatment with abciximab, an antiplatelet drug and a modulator of inflammation, is conceivable.

Peak CKMB and cTnT accurately estimates myocardial infarct size after reperfusion.

OBJECTIVES: To find the time-to-peak for creatine kinase MB(mass) (CKMB) and cardiac troponin T (cTnT) after acute reperfusion, to compare peak and cumulative values to estimate infarct size (IS), and to evaluate clinical routine sampling for assessment of IS. DESIGN: Acute primary percutaneous coronary intervention (PCI) was performed in 38 patients with first-time myocardial infarction. In 21 patients, CKMB and cTnT were acquired before PCI and at 1.5, 3, 6, 12, 18, 24, and 48 hours thereafter. In 17 patients, clinical routine samples were acquired at arrival, and at 10 and 20 h. IS was assessed by delayed contrast-enhanced MRI (DE-MRI). RESULTS: Time-to-peak was 7.6+/-3.6 h for CKMB and 8.1+/-3.4 h for cTnT. Peak values correlated strongly to cumulative values (r(s)=0.97-0.98) as well as to DE-MRI (r(s)=0.8-0.82). Clinical routine sampling showed lower rs values (0.47-0.60). CONCLUSIONS: Peak values are likely captured if CKMB and cTnT are acquired at 3, 6, and 12 h after acute PCI. These peak values can be used to estimate myocardial infarct size after acute PCI.