Sodium-glucose cotransporter 2 inhibitor Dapagliflozin attenuates diabetic cardiomyopathy.

BACKGROUND: Diabetes mellitus type 2 (DM2) is a risk factor for developing heart failure but there is no specific therapy for diabetic heart disease. Sodium glucose transporter 2 inhibitors (SGLT2I) are recently developed diabetic drugs that primarily work on the kidney. Clinical data describing the cardiovascular benefits of SGLT2Is highlight the potential therapeutic benefit of these drugs in the prevention of cardiovascular events and heart failure. However, the underlying mechanism of protection remains unclear. We investigated the effect of Dapagliflozin-SGLT2I, on diabetic cardiomyopathy in a mouse model of DM2. METHODS: Cardiomyopathy was induced in diabetic mice (db/db) by subcutaneous infusion of angiotensin II (ATII) for 30 days using an osmotic pump. Dapagliflozin (1.5 mg/kg/day) was administered concomitantly in drinking water. Male homozygous, 12-14 weeks old WT or db/db mice (n = 4-8/group), were used for the experiments. Isolated cardiomyocytes were exposed to glucose (17.5-33 mM) and treated with Dapagliflozin in vitro. Intracellular calcium transients were measured using a fluorescent indicator indo-1. RESULTS: Angiotensin II infusion induced cardiomyopathy in db/db mice, manifested by cardiac hypertrophy, myocardial fibrosis and inflammation (TNFα, TLR4). Dapagliflozin decreased blood glucose (874 ± 111 to 556 ± 57 mg/dl, p < 0.05). In addition it attenuated fibrosis and inflammation and increased the left ventricular fractional shortening in ATII treated db/db mice. In isolated cardiomyocytes Dapagliflozin decreased intracellular calcium transients, inflammation and ROS production. Finally, voltage-dependent L-type calcium channel (CACNA1C), the sodium-calcium exchanger (NCX) and the sodium-hydrogen exchanger 1 (NHE) membrane transporters expression was reduced following Dapagliflozin treatment. CONCLUSION: Dapagliflozin was cardioprotective in ATII-stressed diabetic mice. It reduced oxygen radicals, as well the activity of membrane channels related to calcium transport. The cardioprotective effect manifested by decreased fibrosis, reduced inflammation and improved systolic function. The clinical implication of our results suggest a novel pharmacologic approach for the treatment of diabetic cardiomyopathy through modulation of ion homeostasis.

Online- and offline- monitoring of stem cell expansion on microcarrier.

In the biopharmaceutical industry, adherent growing stem cell cultures gain worldwide importance as cell products. The cultivation process of these cells, such as in stirred tank reactors or in fixed bed reactors, is highly sophisticated. Cultivations need to be monitored and controlled to guarantee product quality and to satisfy GMP requirements. With the process analytical technology (PAT) initiative, requirements regarding process monitoring and control have changed and real-time on-line monitoring tools are recommended. A tool meeting the new requirements may be the dielectric spectroscopy for online viable cell mass determination by measurement of the permittivity. To establish these tools, proper offline methods for data correlation are required. The cell number determination of adherent cells on microcarrier is difficult, as it requires cell detachment from the carrier, which highly increases the statistical error. As an offline method, a fluorescence assay based on SYBR(®)GreenI was developed allowing fast and easy total cell concentration determination without the need to detach the cells from the carrier. The assay is suitable for glass carriers used in stirred tank reactor systems or in fixed bed systems, may be suitable for different cell lines and can be applied to high sample numbers easily. The linear dependency of permittivity to cell concentration of suspended stem cells with the dielectric spectroscopy is shown for even very small cell concentrations. With this offline-method, a correlation of the cell concentration grown on carrier to the permittivity data measured by the dielectric spectroscopy was done successfully.

Process control in cell culture technology using dielectric spectroscopy.

In the biopharmaceutical industry, mammalian and insect cells as well as plant cell cultures are gaining worldwide importance to produce biopharmaceuticals and as products themselves, for example in stem cell therapy. These highly sophisticated cell-based production processes need to be monitored and controlled to guarantee product quality and to satisfy GMP requirements. With the process analytical technology (PAT) initiative, requirements regarding process monitoring and control have changed and real-time in-line monitoring tools are now recommended. Dielectric spectroscopy (DS) can serve as a tool to satisfy some PAT requirements. DS has been used in the medical field for quite some time and it may allow real-time process monitoring of biological cell culture parameters. DS has the potential to enable process optimization, automation, cost reduction, and a more consistent product quality. Dielectric spectroscopy is reviewed here as a tool to monitor biochemical processes. Commercially available dielectric sensing systems are discussed. The potential of this technology is demonstrated through examples of current and potential future applications in research and industry for mammalian and insect cell culture.

Use of Encapsulated Stem Cells to Overcome the Bottleneck of Cell Availability for Cell Therapy Approaches.

Nowadays cell-based therapy is rarely in clinical practice because of the limited availability of appropriate cells. To apply cells therapeutically, they must not cause any immune response wherefore mainly autologous cells have been used up to now. The amount of vital cells in patients is limited, and under certain circumstances in highly degenerated tissues no vital cells are left. Moreover, the extraction of these cells is connected with additional surgery; also the expansion in vitro is difficult. Other approaches avoid these problems by using allo-or even xenogenic cells. These cells are more stable concerning their therapeutic behavior and can be produced in stock. To prevent an immune response caused by these cells, cell encapsulation (e.g. with alginate) can be performed. Certain studies showed that encapsulated allo- and xenogenic cells achieve promising results in treatment of several diseases. For such cell therapy approaches, stem cells, particularly mesenchymal stem cells, are an interesting cell source. This review deals on the one hand with the use of encapsulated cells, especially stem cells, in cell therapy and on the other hand with bioreactor systems for the expansion and differentiation of mesenchymal stem cells in reproducible and sufficient amounts for potential clinical use.

Production process for stem cell based therapeutic implants: expansion of the production cell line and cultivation of encapsulated cells.

Cell based therapy promises the treatment of many diseases like diabetes mellitus, Parkinson disease or stroke. Microencapsulation of the cells protects them against host-vs-graft reactions and thus enables the usage of allogenic cell lines for the manufacturing of cell therapeutic implants. The production process of such implants consists mainly of the three steps expansion of the cells, encapsulation of the cells, and cultivation of the encapsulated cells in order to increase their vitality and thus quality. This chapter deals with the development of fixed-bed bioreactor-based cultivation procedures used in the first and third step of production. The bioreactor system for the expansion of the stem cell line (hMSC-TERT) is based on non-porous glass spheres, which support cell growth and harvesting with high yield and vitality. The cultivation process for the spherical cell based implants leads to an increase of vitality and additionally enables the application of a medium-based differentiation protocol.

Monitoring lung fluid content in CHF patients under intravenous diuretics treatment using bio-impedance measurements.

A pulmonary edema monitoring system (PulmoTrace, CardioInspect, Tel-Aviv University, Israel) was evaluated for tracking lung resistivity during diuretics treatment in congestive heart failure (CHF) patients. The system incorporates a bio-impedance measurement algorithm and enables, by employing an eight-electrode thoracic belt, the assessment of both the left- and right-lung resistivity values. A clinical study was conducted on a group of 13 CHF patients under intravenous diuretics treatment. The group was measured twice-before the beginning of treatment and following a period of a couple of hours. An increase of 8% of the mean lung resistivity (median value) was found between the two measuring sessions, which indicates a dehydration of the lungs, and a significant correlation (R=0.73, p=0.004) was found between the lung resistivity change and the urine output. In conjunction with previously reported results, which demonstrated the system's reproducibility and long-term monitoring capabilities, this study further supports the diagnostics value of the system.

Parametric EIT for monitoring cardiac stroke volume.

The bio-impedance technique appears appropriate for non-invasive cardiac stroke volume (SV) measurement, as the thoracic conductivity distribution is altered during the cardiac cycle due to the heart contraction and blood perfusion. In the present work, the feasibility of a parametric electrical impedance tomography (EIT) for assessing the cardiac SV was studied. An impedance model of the thorax was constructed from segmented axial MRI images along 19 phases of the cardiac cycle. The heart was simulated as an ellipsoid, with its axes' lengths set as the reconstruction parameters, while all other tissues' geometry and conductivity values were kept fixed. A Newton-Raphson parametric optimization scheme was utilized, yielding a correlation between the reconstructed and anatomical left ventricular volumes of 0.97 (p = 2 x 10(-11)). An analysis of noise sensitivity showed that the proposed algorithm requires an SNR greater than 65 dB. The simulation results were compared to physical data, collected with a portable EIT system (PulmoTrace, CardioInspect). The validation study was employed for a group of N = 28 healthy patients, and a comparison with impedance cardiography measurements (BioZ, Cardiodynamics) was made, showing a correlation of r = 0.86 (p = 4 x10(-9)). The preliminary results demonstrate that parametric EIT has the potential to measure SV, and may be applicable for both clinical and home environment usage.

Does total orthotopic heart transplantation offer improved hemodynamics during cellular rejection events?

BACKGROUND: We hypothesized that total orthotopic heart transplantation (TOHT) improves hemodynamics during cellular rejection compared with biatrial transplantation (SOHT). METHODS: We reviewed 1942 biopsies from 134 patients (pts) and right heart catheterization data obtained at endomyocardial biopsy. Biopsies that displayed cellular rejection grade 1B as classified according to International Society for Heart and Lung Transplantation (ISHLT) criteria were analyzed. Pts with pacemakers, atrial fibrillation, or beta-blocker therapy at the time of biopsy were excluded. Twenty-three pts after TOHT and 38 after SOHT were identified to match these criteria. RESULTS: Demographic data and pretransplant hemodynamics were similar. TOHT pts had a higher mean cardiac index than SOHT recipients (3.3 +/- 0.8 vs 2.7 +/- 0.5 L/min/m(2); P =.002). Right atrial mean pressure was lower after TOHT (8 +/- 4 vs 11 +/- 4 mm Hg; P =.006). Pulmonary pressures, pulmonary vascular resistance, and heart rate were similar. CONCLUSIONS: TOHT offers improved hemodynamics during cellular rejection grade 1B as evidenced by higher cardiac output and index with lower right atrial pressures. Future studies must examine the potential benefits of TOHT during more severe rejection events.

Improved prognosis of patients presenting with clinical markers of spontaneous reperfusion during acute myocardial infarction.

OBJECTIVE: To describe the clinical features, management, and prognosis of patients presenting with clinical markers of spontaneous reperfusion (SR) during acute myocardial infarction (AMI). DESIGN: Cohort study. SETTING: National registry of 26 coronary care units. PATIENTS: 2382 consecutive patients with AMI. MAIN OUTCOME MEASURES: Patient characteristics, management, and mortality. RESULTS: The incidence of SR was 4% of patients (n = 98) compared with thrombolytic treatment (n = 1163, 49%), primary angioplasty (n = 102, 4%), and non-reperfusion (n = 1019, 43%). SR patients were more likely to develop less or no myocardial damage as indicated by a higher percentage of non-Q wave AMI (58% v 32%, 47%, and 44%, respectively, p < 0.0001), aborted AMI (25% v 9%, 8%, and 12%, p < 0.001), and lower peak creatine kinase (503 v 1384, 1519, and 751 IU, p < 0.0001). SR patients, however, were more likely to develop recurrent ischaemic events (35% v 17%, 12%, and 16%, respectively; p < 0.001) and subsequently were more likely to be referred to coronary angiography (67%), angioplasty (41%), or bypass surgery (16%, p < 0.001). Mortality at 30 days (1% v 8%, 7%, and 13%, respectively, p < 0.0001) and one year (6% v 11%, 12%, and 19%, p < 0.0001) was significantly lower for SR patients than for the other subgroups. By multivariate analysis, SR remained a strong determinant of 30 day survival (odds ratio (OR) 0.16, 95% confidence interval (CI) 0.01 to 0.74). At one year, the association between SR and survival decreased (OR 0.49, 95% CI 0.18 to 1.13). CONCLUSIONS: Clinical markers of SR are associated with greater myocardial salvage and favourable prognosis. The vulnerability of SR patients to recurrent ischaemic events suggests that they need close surveillance and may benefit from early intervention.

Evidence for fractal correlation properties in variations of peripheral arterial tone during REM sleep.

Previous studies utilizing detrended fluctuation analysis (DFA) of heart rate variability during sleep revealed a higher fractal exponent during rapid eye movement (REM) sleep than non-REM sleep. The aim of this study was to determine whether the same difference exists in the variations of peripheral arterial tone (PAT). Finger pulse wave measured by a novel plethysmographic technique was monitored during sleep in 12 chronic heart failure patients, 8 heavy snorers, and 12 healthy volunteers. For each subject, at least two 15-min time series were constructed from the interpulse intervals and from pulse wave amplitudes during REM and non-REM sleep. Fractal scaling exponents of both types of time series were significantly higher for REM than non-REM sleep in all groups. In each of the groups and in both sleep stages, the fractal scaling exponents based on pulse wave amplitude were significantly higher than those based on pulse rate variability. A repeat of the analysis for short-, intermediate-, and long-term intervals revealed that the fractal-like exponents were evident only in the short- and intermediate-term intervals. Because PAT is a surrogate of sympathetic activation, our results indicate that variations in sympathetic activation during REM sleep have a fractal-like behavior.

[Cheyne-Stokes breathing disorder in patients with congestive heart failure: incidence, pathophysiology, treatment and prognosis].

Cheyne-Stokes Respiration (CSR) is a breathing disorder characterized by recurrent central sleep apneas, mainly during sleep, alternating with a crescendo-decrescendo pattern of tidal volume. The pathophysiology of CSR, which involves both the cardiovascular system, the pulmonary system and the sympathetic nervous system, is still not well understood. Although it is well recognized that congestive heart failure (CHF) patients suffer from CSR, only in recent years have studies been undertaken in order to determine the prevalence of this phenomenon and its implications regarding the patients life expectancy and quality. In a few studies it was found that 50% of moderate to severe CHF patients suffer significant CSR and other studies suggested that CSR has a negative prognostic value upon CHF patients. In order to treat CSR, novel therapeutic approaches have been tried, including oxygen delivery during the night, various pharmacological treatments aiming to stabilize the ventilatory system and other pharmacological treatments aiming to improve the ejection fraction of the left ventricle. However, none of these treatments has proved to be adequately efficient. This review tries to summarize current knowledge regarding CSR pathophysiology, prevalence, prognostic implications and current available treatments.

The significance of persistent ST elevation versus early resolution of ST segment elevation after primary PTCA.

OBJECTIVES: To determine the prevalence and clinical significance of early ST segment elevation resolution after primary percutaneous transluminal coronary angioplasty (PTCA) for acute myocardial infarction (AMI). BACKGROUND: Despite angiographically successful restoration of coronary flow early during AMI, adequate myocardial reperfusion might not occur in a substantial portion of the jeopardized myocardium due to microvascular damage. This phenomenon comprises the potentially beneficial effect of early recanalization of the infarct related artery (IRA). METHODS: Included in the study were 117 consecutive patients who underwent angiographically successful [Thrombolysis in Myocardial Infarction (TIMI III)] primary PTCA. The patients were classified based on the presence or absence of reduction > or =50% in ST segment elevation in an ECG performed immediately upon return to the intensive cardiac care unit after the PTCA in comparison with ECG before the intervention. RESULTS: Eighty-nine patients (76%) had early ST segment elevation resolution (Group A) and 28 patients (24%) did not (Group B). Group A and B had similar clinical and hemodynamic features before referring to primary PTCA, as well as similar angiographic results. Despite this, ST segment elevation resolution was associated with better predischarge left ventricular ejection fraction (LVEF) (44.7 +/- 8.0 vs. 38.2 +/- 8.5, p < 0.01). Group B patients, as compared with those of Group A, had a higher incidence of in-hospital mortality (11% vs. 2%, p = 0.088), congestive heart failure (CHF) [28% vs. 19%, odds ratio (OR) = 4, 95% confidence interval (CI) 1 to 15, p = 0.04], higher long-term mortality (OR = 7.3, 95% CI 1.9 to 28, p = 0.004 with Cox proportional hazard regression analysis) and long-term CHF rate (OR = 6.5, 95% CI 1.3 to 33, p = 0.016 with logistic regression). CONCLUSIONS: Absence of early ST segment elevation resolution after angiographically successful primary PTCA identifies patients who are less likely to benefit from the early restoration of flow in the IRA, probably because of microvascular damage and subsequently less myocardial salvage.

Acute myocardial infarction with isolated ST-segment elevation in posterior chest leads V7-9: "hidden" ST-segment elevations revealing acute posterior infarction.

OBJECTIVES: This study was done to determine whether electrocardiographic (ECG) isolated ST-segment elevation (ST) in posterior chest leads can establish the diagnosis of acute posterior infarction in patients with ischemic chest pain and to describe the clinical and echocardiographic characteristics of these patients. BACKGROUND: The absence of ST on the standard 12-lead ECG in many patients with acute posterior infarction hampers the early diagnosis of these infarcts and thus may result in inadequate triage and treatment. Although 4% of all acute myocardial infarction (AMI) patients reveal the presence of isolated ST in posterior chest leads, the significance of this finding has not yet been determined. METHODS: We studied 33 consecutive patients with ischemic chest pain suggestive of AMI without ST in the standard ECG who had isolated ST in posterior chest leads V7 through V9. All patients had echocardiographic imaging within 48 h of admission, and 20 patients underwent coronary angiography. RESULTS: Acute myocardial infarction was confirmed enzymatically in all patients and on discharge ECG pathologic Q-waves appeared in leads V7 through V9 in 75% of the patients. On echocardiography, posterior wall-motion abnormality was visible in 97% of the patients, and 69% had evidence of mitral regurgitation (MR), which was moderate or severe in one-third of the patients. Four patients (12%), all with significant MR, had heart failure, and one died from free-wall rupture. The circumflex coronary artery was the infarct related artery in all catheterized patients. CONCLUSIONS: Isolated ST in leads V7 through V9 identify patients with acute posterior wall myocardial infarction. Early identification of those patients is important for adequate triage and treatment of patients with ischemic chest pain without ST on standard 12-lead ECG.

Synergistic effects of prothrombotic polymorphisms and atherogenic factors on the risk of myocardial infarction in young males.

Several recent studies evaluated a possible effect of the prothrombotic polymorphisms such as 5,10 methylenetetrahydrofolate reductase (MTHFR) nt 677C --> T, factor V (F V) nt 1691G --> A (F V Leiden), and factor II (F II) nt 20210 G --> A on the risk of myocardial infarction. In the present study, we analyzed the effect of these prothrombotic polymorphisms, as well as apolipoprotein (Apo) E4, smoking, hypertension, diabetes mellitus, and hypercholesterolemia, on the risk of myocardial infarction in young males. We conducted a case-control study of 112 young males with first acute myocardial infarction (AMI) before the age of 52 and 187 healthy controls of similar age. The prevalences of heterozygotes for F V G1691A and F II G20210A were not significantly different between cases and controls (6.3% v 6.4% and 5.9% v 3.4% among cases and controls, respectively). In contrast, the prevalence of MTHFR 677T homozygosity and the allele frequency of Apo E4 were significantly higher among patients (24.1% v 10.7% and 9.4% v 5.3% among cases and controls, respectively). Concomitant presence of hypertension, hypercholesterolemia, or diabetes and one or more of the four examined polymorphisms increased the risk by almost ninefold (odds ratio [OR] = 8.66; 95% confidence interval [CI], 3.49 to 21.5) and concomitant smoking by almost 18-fold (OR = 17.6; 95% CI, 6.30 to 48.9). When all atherogenic risk factors were analyzed simultaneously by a logistic model, the combination of prothrombotic and Apo E4 polymorphisms with current smoking increased the risk 25-fold (OR = 24.7; 95% CI, 7.17 to 84.9). The presented data suggest a synergistic effect between atherogenic and thrombogenic risk factors in the pathogenesis of AMI, as was recently found in a similar cohort of women.

The clinical significance of antibodies to human vascular endothelial cells after cardiac transplantation.

BACKGROUND: Vascular endothelial cells are primary targets for injury during both cellular and humoral allograft rejection (AR). In cardiac transplantation, the role of humoral immunity in mediating AR has not been extensively characterized. METHODS: Antibodies against human vascular endothelial cells (AECA) were measured using a cellular ELISA developed from human umbilical vein endothelial cells in 80 consecutive patients after cardiac transplantation. The aim was to determine the incidence of AECA formation after transplantation and their association with different types of AR, graft survival, and development of cardiac allograft vasculopathy (CAV). At least eight serum samples obtained from each patient were examined for AECA and an endomyocardial biopsy was performed at regular intervals during the first year after transplantation. RESULTS: Of the 80 patients examined, 31 were AECA (+) and 49 patients were AECA (-). There were no significant differences between the AECA (+) and (-) groups when examined for age, sex, and pretransplantation ischemia time. A significant correlation was found between the presence of AECA and humoral AR (P<0.015). AECA positivity did not correlate with the presence of cellular AR or the number of rejection episodes. In addition, allograft survival at 2 years after transplantation was significantly better in the AECA (-) group compared with that in the AECA (+) group (89.8% vs. 71.0%, P<0.0004). The persistence of AECA positivity during the first year after transplantation was also associated with a significantly greater incidence of CAV when compared with the patients who were AECA (-) (25.8% vs. 14.3%, P<0.004). CONCLUSIONS: AECA may be important in the mediation of humoral AR, may decrease allograft survival, and may identify a high-risk group for CAV.

The distinction between coronary and myocardial reperfusion after thrombolytic therapy by clinical markers of reperfusion.

OBJECTIVES: We sought to examine the hypothesis that rapid resolution of ST-segment elevation in acute myocardial infarction (AMI) patients with early peak creatine kinase (CK) after thrombolytic therapy differentiates among patients with early recanalization between those with and those without adequate tissue (myocardial) reperfusion. BACKGROUND: Early recanalization of the epicardial infarct-related artery (IRA) during AMI does not ensure adequate reperfusion on the myocardial level. While early peak CK after thrombolysis results from early and abrupt restoration of the coronary flow to the infarcted area, rapid ST-segment resolution, which is another clinical marker of successful reperfusion, reflects changes of the myocardial tissue itself. METHODS: We compared the clinical and the angiographic results of 162 AMI patients with early peak CK (< or =12 h) after thrombolytic therapy with (group A) and without (group B) concomitant rapid resolution of ST-segment elevation. RESULTS: Patients in groups A and B had similar patency rates of the IRA on angiography (anterior infarction: 93% vs. 93%; inferior infarction: 89% vs. 77%). Nevertheless, group A versus B patients had lower peak CK (anterior infarction: 1,083+/-585 IU/ml vs. 1,950+/-1,216, p < 0.01; and inferior infarction: 940+/-750 IU/ml vs. 1,350+/-820, p=0.18) and better left ventricular ejection fraction (anterior infarction: 49+/-8, vs. 44+/-8, p < 0.01; inferior infarction: 56+/-12 vs. 51+/-10, p=0.1). In a 2-year follow-up, group A as compared with group B patients had a lower rate of congestive heart failure (1% vs. 13%, p < 0.01) and mortality (2% vs. 13%, p < 0.01). CONCLUSIONS: Among patients in whom reperfusion appears to have taken place using an early peak CK as a marker, the coexistence of rapid resolution of ST-segment elevation further differentiates among patients with an opened culprit artery between the ones with and without adequate myocardial reperfusion.

Rescue coronary angiography after failed thrombolysis: a real-life experience.

Failed thrombolysis in acute myocardial infarction (AMI) patients is associated with a high risk of morbidity and mortality. Rescue or salvage percutaneous transluminal coronary angioplasty (PTCA) in this group of patients is still controversial. We report our experience with early emergency angiography and rescue PTCA in 27 patients who were hemodynamically unstable or had a large area of myocardium at risk after failed thrombolysis. Rescue PTCA was successful in 95% of attempted PTCA. Three patients were referred to emergency CABG. Early 'rescue angiography' with or without rescue PTCA after failed thrombolysis in a selected patient population, is an important tool for early risk stratification and decision-making during the hyperacute phase of AMI, while it may also serve in restoring coronary artery patency of the infarct-related artery with a high success rate.