Sustained Response to Eculizumab in a Patient With COVID-19-Associated Acute Thrombotic Microangiopathy of the Allograft Kidney: A Case Report.

Acute thrombotic microangiopathy (TMA) developing in association with SARS-CoV-2 infection is a rare but recognized phenomenon in native kidneys. In the allograft kidney, a diagnosis of TMA has a broad etiologic differential, including antibody-mediated rejection and recurrent and de novo causes of TMA that affect the native kidney. Prior case reports have described plasma exchange or eculizumab use in patients with COVID-19-associated TMA. Herein, we describe the course of a kidney transplant patient with COVID-19-associated TMA with response to eculizumab that was sustained after medication withdrawal and review the literature on COVID-19-associated TMA of the allograft kidney.

Prevalence of hypovitaminosis D among children and adolescents of Kabul: a descriptive cross-sectional study.

BACKGROUND: Vitamin D is one of the most important fat-soluble vitamins necessary for normal growth and development of the human body. According to a study done in Kabul shows that economic, racial, and social concerns are thought to be the main impediments to receiving appropriate amounts of this vitamin through dietary sources in countries like Afghanistan. Hypovitaminosis D, on the other hand, is now recognized as a pandemic in both industrialized and developing countries. METHODS: To find out how common hypovitaminosis D is in children aged one month to eighteen years in afghan children Kabul, Afghanistan. Vitamin D deficiency and insufficiency are defined as serum levels of less than 20 ng/mL and 20 to 30 ng/mL, respectively. Children aged between 1 month to 18 years attending our hospital, AMC (Ariana Medical Complex) for health examination were checked for their 25-hydroxyvitamin D [25(OH)D]. Age, gender and address were recorded. 25(OH)D were determined using immunoassay auto analyzers. According to their serum 25(OH)D, the 25(OH)D were categorized into five categories: sufficiency: ≥ 30-100 ng/mL; insufficiency: ≥ 20-29 ng/mL; deficiency: < 20 ng/mL; severe deficiency: < 10 ng/mL; and intoxication: > 150 ng/mL. Participants who were intoxicated with vitamin D were excluded from the study. RESULTS: A total of 4008 children aged 1 month to 18 years participated in this cross-sectional study. Hypovitaminosis D was found to be prevalent in 62.5 percent of the population. When compared to boys, female children were 1.2 times more likely to be vitamin D deficient. When compared to children of illiterate women, the odds of hypovitaminosis D were 1.4, 1.9, and 5.8 times lower in children with mothers educated up to primary school, graduation, and post-graduate. The average vitamin D level was 23 ng/mL, with a median of 15 ng/mL and maximum and minimum values of 135 ng/mL and 3 ng/mL, respectively. In all, 2500 (62.5%) of the children had low levels of vitamin D in their serum. Only 400 (16%) of the patients were sufficient, whereas 917 (36.7%) were severely deficient, 733 (29.3%) were deficient, and 450 (18%) were insufficient. With a female to male ratio of 1.2:1, the majority of those, 1335 (53.4%), were females and 1165 (46.6%) were males. Patients were 8.14 years old on average, with a median age of 7 years. The majority of the patients, 2152 (86.1%), were urban, while 348 (13.9%) were rural. CONCLUSION: The prevalence of hypovitaminosis D was very high in Afghan children. Female sex, higher socio economic status, higher educational status of the mother and living at urban areas were the factors with strong positive association with hypovitaminosis D.

People's attitude towards willingness-to-pay for environmental protection in Pakistan.

Recent environmental research has found that people with higher incomes and in more developed countries are more willing to pay (WTP) to protect their environment than people in developing countries. Based on this assumption, the study investigated Pakistani citizens' attitudes toward environmental protection, precisely their willingness to pay higher prices and taxes to preserve the natural environment. The research was carried out in three Punjab cities (Hasan Abdal, Wah, and Taxila) and four KPK cities (Abbottabad, Havelian, Mansehra, and Haripur). The selected cities are home to knowledgeable people who work in various universities, schools, hospitals, medical colleges, and nearby industrial estates and have a sense of environmental protection and can understand the healthcare issues related to environmental damages. The survey was divided into two sections: one about the participants' socio-demographic information and the other about people's willingness to pay higher prices and taxes to protect the environment. Four hundred and sixty-two people took part in the survey, and the data were analyzed using the bootstrap regression approach. The results show that gender has a detrimental impact, although population density and education positively impact a country's willingness to pay for environmental protection (WTPEP). Women are more likely to engage in pro-environmental behavior than men, resulting in disparities in their perceptions of male and female respondents in the study. People who live in crowded places tend to pay for environmental protection because of population density, healthcare difficulties, and air pollution. The respondents are well-versed in the externalities of environmental pollution; they are hopeful about paying for a better healthcare environment. Other criteria, such as the respondent's income, health status, total pollution level in the country, and per capita income, enable respondents to pay for environmental preservation to achieve long-term sustainable growth. The government must embrace air quality regulations and empower its citizens by offering better healthcare services since they are enthusiastic about paying higher taxes and fees to protect the environment.

Real-World Performance of a Comprehensive Genomic Profiling Test Optimized for Small Tumor Samples.

PURPOSE: Tissue-based comprehensive genomic profiling (CGP) is increasingly used for treatment selection in patients with advanced cancer; however, tissue availability may limit widespread implementation. Here, we established real-world CGP tissue availability and assessed CGP performance on consecutively received samples. MATERIALS AND METHODS: We conducted a post hoc, nonprespecified analysis of 32,048 consecutive tumor tissue samples received for StrataNGS, a multiplex polymerase chain reaction (PCR)-based comprehensive genomic profiling (PCR-CGP) test, as part of an ongoing observational trial (NCT03061305). Sample characteristics and PCR-CGP performance were assessed across all tested samples, including exception samples not meeting minimum input quality control (QC) requirements (< 20% tumor content [TC], < 2 mm2 tumor surface area [TSA], DNA or RNA yield < 1 ng/µL, or specimen age > 5 years). Tests reporting ≥ 1 prioritized alteration or meeting TC and sequencing QC were considered successful. For prostate carcinoma and lung adenocarcinoma, tests reporting ≥ 1 actionable or informative alteration or meeting TC and sequencing QC were considered actionable. RESULTS: Among 31,165 (97.2%) samples where PCR-CGP was attempted, 10.7% had < 20% TC and 59.2% were small (< 25 mm2 tumor surface area). Of 31,101 samples evaluable for input requirements, 8,089 (26.0%) were exceptions not meeting requirements. However, 94.2% of the 31,101 tested samples were successfully reported, including 80.5% of exception samples. Positive predictive value of PCR-CGP for ERBB2 amplification in exceptions and/or sequencing QC-failure breast cancer samples was 96.7%. Importantly, 84.0% of tested prostate carcinomas and 87.9% of lung adenocarcinomas yielded results informing treatment selection. CONCLUSION: Most real-world tissue samples from patients with advanced cancer desiring CGP are limited, requiring optimized CGP approaches to produce meaningful results. An optimized PCR-CGP test, coupled with an inclusive exception testing policy, delivered reportable results for > 94% of samples, potentially expanding the proportion of CGP-testable patients and impact of biomarker-guided therapies.

Comprehensive study on transglycosylation of CGTase from various sources.

Transglycosylation is the in-vivo or in-vitro process of transferring glycosyl groups from a donor to an acceptor, which is usually performed by enzymatic reactions because of their simplicity, low steric hindrance, high region-specificity, low production cost, and mild processing conditions. One of the enzymes commonly used in the transglycosylation reaction is cyclodextrin glucanotransferase (CGTase). The transglycosylated products, catalyzed by CGTase, are widely used in food additives, supplements, and personal care and cosmetic products. This is due to improvements in the solubility, stability, bioactivity and length of the synthesized products. This paper's focus is on the importance of enzymes used in the transglycosylation reaction, their characteristics and mechanism of action, sources and production yield, and donor and acceptor specificities. Moreover, the influence of intrinsic and extrinsic factors on the enzymatic reaction, catalysis of glycosidic linkages, and advantages of CGTase transglycosylation reactions are discussed in detail.

ATP sensitive K(+) channels are critical for maintaining myocardial perfusion and high energy phosphates in the failing heart.

Congestive heart failure (CHF) is associated with intrinsic alterations of mitochondrial oxidative phosphorylation which lead to increased myocardial cytosolic free ADP. ATP sensitive K(+) channels (KATP) act as metabolic sensors that are important for maintaining coronary blood flow (MBF) and in mediating the response of the myocardium to stress. Coronary adenosine receptors (AdR) are not normally active but cause vasodilation during myocardial ischemia. This study examined the myocardial energetic response to inhibition of KATP and AdR in CHF. CHF (as evidenced by LVEDP>20mmHg) was produced in adult mongrel dogs (n=12) by rapid ventricular pacing for 4weeks. MBF was measured with radiolabeled microspheres during baseline (BL), AdR blockade with 8-phenyltheophylline (8-PT; 5mg/kg iv), and KATP blockade with glibenclamide (GLB; 20µg/kg/min ic). High energy phosphates were examined with (31)P magnetic resonance spectroscopy (MRS) while myocardial oxygenation was assessed from the deoxymyoglobin signal (Mb-δ) using (1)H MRS. During basal conditions the phosphocreatine (PCr)/ATP ratio (1.73±0.15) was significantly lower than in previously studied normal dogs (2.42±0.11) although Mb-δ was undetectable. 8-PT caused ≈21% increase in MBF with no change in PCr/ATP. GLB caused a 33±0.1% decrease in MBF with a decrease in PCr/ATP from 1.65±0.17 to 1.11±0.11 (p<0.0001). GLB did not change the pseudo-first-order rate constant of ATP production via CK (kf), but the ATP production rate via CK was reduced by 35±0.08%; this was accompanied by an increase in Pi/PCr and appearance of a Mb-δ signal indicating tissue hypoxia. Thus, in the failing heart the balance between myocardial ATP demands and oxygen delivery is critically dependent on functioning KATP channels.

A fibrin patch-based enhanced delivery of human embryonic stem cell-derived vascular cell transplantation in a porcine model of postinfarction left ventricular remodeling.

It is unknown how to use human embryonic stem cell (hESC) to effectively treat hearts with postinfarction left ventricular (LV) remodeling. Using a porcine model of postinfarction LV remodeling, this study examined the functional improvement of enhanced delivery of combined transplantation of hESC-derived endothelial cells (ECs) and hESC-derived smooth muscle cells (SMCs) with a fibrin three-dimensional (3D) porous scaffold biomatrix. To facilitate tracking the transplanted cells, the hESCs were genetically modified to stably express green fluorescent protein and luciferase (GFP/Luc). Myocardial infarction (MI) was created by ligating the first diagonal coronary artery for 60 minutes followed by reperfusion. Two million each of GFP/Luc hESC-derived ECs and SMCs were seeded in the 3D porous biomatrix patch and applied to the region of ischemia/reperfusion for cell group (MI+P+C, n = 6), whereas biomatrix without cell (MI+P, n = 5), or saline only (MI, n = 5) were applied to control group hearts with same coronary artery ligation. Functional outcome (1 and 4 weeks follow-up) of stem cell transplantation was assessed by cardiac magnetic resonance imaging. The transplantation of hESC-derived vascular cells resulted in significant LV functional improvement. Significant engraftment of hESC-derived cells was confirmed by both in vivo and ex vivo bioluminescent imaging. The mechanism underlying the functional beneficial effects of cardiac progenitor transplantation is attributed to the increased neovascularization. These findings demonstrate a promising therapeutic potential of using these hESC-derived vascular cell types and the mode of patch delivery.

Effect of acute xanthine oxidase inhibition on myocardial energetics during basal and very high cardiac workstates.

Myocardial ischemia is associated with reduced myocardial adenosine triphosphate (ATP) and increased free adenosine diphosphate (ADP) similar to the normal heart at very high cardiac workstates (HCW). We examined whether acute xanthine oxidase inhibition (XOI) in vivo can decrease myocardial free ADP in normal hearts functioning at basal cardiac workstates (BCW) or very HCW (catecholamine-induced). Myocardial high-energy phosphate ((31)P magnetic resonance spectroscopy), blood flow (radioactive microspheres), and oxygen consumption (MVO(2)) were measured in an open-chest canine model before and after infusion of vehicle or an XO inhibitor (allopurinol or febuxostat; n = 10 in each group) during BCW and infusion of dobutamine + dopamine to induce a very HCW. During BCW, both allopurinol and febuxostat resulted in higher phosphocreatine (PCr)/ATP, corresponding to lower ADP levels. During vehicle infusion, HCW caused a decrease of PCr/ATP and an increase in myocardial free ADP. Although XOI did not prevent an increase in free ADP during catecholamine infusion, the values in the allopurinol or febuxostat groups (0.141 ± 0.012 and 0.136 ± 0.011 µmol/g dry wt, respectively) remained significantly less than in the vehicle group (0.180 ± 0.017; P < 0.05). Thus, at a given rate of ATP synthesis, XOI decreased the free ADP level needed to drive ATP synthesis, suggesting a more energy-efficient status. As contractile dysfunction in ischemia is characterized by increase of myocardial free ADP and energy deficiency, the data suggest that XOI might be a potential therapy for improving energy efficiency during myocardial ischemia.

Long-term preservation of myocardial energetic in chronic hibernating myocardium.

We previously reported that the myocardial energetic state, as defined by the ratio of phosphocreatine to ATP (PCr/ATP), was preserved at baseline (BL) in a swine model of chronic myocardial ischemia with mild reduction of myocardial blood flow (MBF) 10 wk after the placement of an external constrictor on the left anterior descending coronary artery. It remains to be seen whether this stable energetic state is maintained at a longer-term follow-up. Hibernating myocardium (HB) was created in minipigs (n = 7) by the placement of an external constrictor (1.25 mm internal diameter) on the left anterior descending coronary artery. Function was assessed with MRI at regular intervals until 6 mo. At 6 mo, myocardial energetic in the HB was assessed by (31)P-magnetic resonance spectrometry and myocardial oxygenation was examined from the deoxymyoglobin signal using (1)H-magnetic resonance spectrometry during BL, coronary vasodilation with adenosine, and high cardiac workload with dopamine and dobutamine (DpDb). MBF was measured with radiolabeled microspheres. At BL, systolic thickening fraction was significantly lower in the HB compared with remote region (34.4 ± 9.4 vs. 50.1 ± 10.7, P = 0.006). This was associated with a decreased MBF in the HB compared with the remote region (0.73 ± 0.08 vs. 0.97 ± 0.07 ml · min(-1) · g, P = 0.03). The HB PCr/ATP at BL was normal. DpDb resulted in a significant increase in rate pressure product, which caused a twofold increase in MBF in the HB and a threefold increase in the remote region. The systolic thickening fraction increased with DpDb, which was significantly higher in the remote region than HB (P < 0.05). The high cardiac workload was associated with a significant reduction in the HB PCr/ATP (P < 0.02), but this response was similar to normal myocardium. Thus HB has stable BL myocardial energetic despite the reduction MBF and regional left ventricular function. More importantly, HB has a reduced contractile reserve but has a similar energetic response to high cardiac workload like normal myocardium.

Long-term functional improvement and gene expression changes after bone marrow-derived multipotent progenitor cell transplantation in myocardial infarction.

The study examined the long-term outcome of cardiac stem cell transplantation in hearts with postinfarction left ventricular (LV) remodeling. Myocardial infarction (MI) was created by ligating the first and second diagonal branches of the left anterior descending coronary artery in miniature swine. Intramyocardial injections of 50 million LacZ-labeled bone marrow-derived multipotent progenitor cells (MPC) were performed in the periscar region (Cell, n = 7) immediately after MI, whereas, in control animals (Cont, n = 7), saline was injected. Functional outcome was assessed monthly for 4 mo with MRI and (31)P-magnetic resonance spectroscopy. Engraftment was studied on histology, and gene chip (Affymetrix) array analysis was used to study differential expression of genes in the two groups. MPC treatment resulted in improvement of ejection fraction as early as 10 days after MI (Cell, 43.4 +/- 5.1% vs. Cont, 32.2 +/- 5.5%; P < 0.05). This improvement was seen each month and persisted to 4 mo (Cell, 51.2 +/- 4.8% vs. Cont, 35.7 +/- 5.0%; P < 0.05). PCr-to-ATP ratio (PCr/ATP) improved with MPC transplantation, which was most pronounced at high cardiac work states (subendocardial PCr/ATP was 1.70 +/- 0.10 vs. 1.34 +/- 0.14, P < 0.05). There was no significant difference in scar size (scar/LV area * 100) at 10 days postinfarction. However, at 4 mo, there was a significant decrease in scar size in the Cell group (Cell, 4.6 +/- 1.0% vs. Cont, 8.6 +/- 2.4%; P < 0.05). No significant engraftment of MPC was observed. MPC transplantation was associated with a downregulation of mitochondrial oxidative enzymes and increased levels of myocyte enhancer factor 2a and zinc finger protein 91. In conclusion, MPC transplantation leads to long-term functional and bioenergetic improvement in a porcine model of postinfarction LV remodeling, despite no significant engraftment of stem cells in the heart. MPC transplantation reduces regional wall stresses and infarct size and mitigates the adverse effects of LV remodeling, as seen by a reduction in LV hypertrophy and LV dilatation, and is associated with differential expression of genes relating to metabolism and apoptosis.

Stem cells for myocardial repair with use of a transarterial catheter.

BACKGROUND: Using a swine model of postinfarction left ventricle (LV) remodeling, we investigated marrow-derived, multipotent progenitor cell (MPC) transplantation into hearts with acute myocardial infarction (AMI) via a novel transarterial catheter. METHODS AND RESULTS: The left anterior descending coronary artery was balloon-occluded after percutaneous transluminal angiography to generate AMI (60-minute no-flow ischemia). The transarterial catheter was then placed in the same coronary artery, and either 50x10(6) MPCs (cell group, n=6) or saline (control, n=6) was injected into the border zone (BZ) myocardium. LV function was assessed by magnetic resonance imaging before AMI and at 1 and 4 weeks after AMI, whereas myocardial energy metabolism was assessed by (31)P-magnetic resonance spectroscopy at week 4. One week after AMI, the ejection fraction was significantly reduced in both groups from a baseline of approximately 50% to 31.3+/-3.9% (cell group) and 33.3+/-3.1% (control). However, at week 4, the cell group had a significant recovery in ejection fraction. The functional improvements were accompanied by a significant improvement in myocardial bioenergetics. Histologic data demonstrated a 0.55% cell engraftment rate 4 weeks after MPC transplantation. Only 2% of engrafted cells were costaining positive for cardiogenic markers. Vascular density in the BZ was increased in the cell group. Conditioned medium from cultured MPCs contained high levels of vascular endothelial growth factor, which was increased in response to hypoxia. MPCs cocultured with cardiomyocytes inhibited changes in cardiomyocyte mitochondrial membrane potential and cytochrome c release induced by tumor necrosis factor-alpha. CONCLUSIONS: Thus, a paracrine effect may contribute significantly to the observed therapeutic effects of MPC transplantation.

Novel strategy for measuring creatine kinase reaction rate in the in vivo heart.

In the heart, the creatine kinase (CK) system plays an important role in the cascade of ATP production, transportation, and utilization. The forward pseudo-first-order rate constant for the CK reaction can be measured noninvasively by the (31)P-magnetic resonance (MR) spectroscopy magnetization saturation transfer (MST) techniques. However, the measurement of MST in the in vivo heart is limited by the lengthy data acquisition time, especially for studies requiring spatial localization. This technical report presents a new method for measuring ATP production rate via CK that can reduce the MST data acquisition time by 82%. This method is validated using an in vivo pig model to evaluate the forward pseudo-first-order rate constant of myocardial CK reaction noninvasively.

Gender differences in KAP related to HIV/AIDS among freshmen in Afghan universities.

This cross-sectional study aimed to describe the level of knowledge, perception/ attitude, and practices related to HIV among 1,054 freshmen students in four Afghan universities differences between genders. A probability, two stage sampling method was used. Data were collected by a self administered structured questionnaire. SPSS software was used for data analysis. Descriptive and inferential statistics were performed. Most of respondents were male (72.1%), their average age was 20.1 +/- 2 years, and most were unmarried (93.4%). The majority (90.8%) were aware of HIV but only 28.3% had a good level of knowledge. Around one-third (35.6%) had a positive level of attitude toward HIV. Approximately 30% had at least one risk practice; therefore, they were counted as high-risk behavior group members. Females were statistically more knowledgeable than males, and high-risk behaviors were significantly more prevalent among males; p = 0.01 and p = 0.001, respectively. However, general awareness, and attitude were not statistically different between genders. A considerable proportion of students (14.6%), as compared to peer-countries, were sexually active. A very high level of sharing injecting needles (4.5%) and shaving sets (20.8%) were also reported among informants.

Transmural distribution of metabolic abnormalities and glycolytic activity during dobutamine-induced demand ischemia.

The heterogeneity across the left ventricular wall is characterized by higher rates of oxygen consumption, systolic thickening fraction, myocardial perfusion, and lower energetic state in the subendocardial layers (ENDO). During dobutamine stimulation-induced demand ischemia, the transmural distribution of energy demand and metabolic markers of ischemia are not known. In this study, hemodynamics, transmural high-energy phosphate (HEP), 2-deoxyglucose-6-phosphate (2-DGP) levels, and myocardial blood flow (MBF) were determined under basal conditions, during dobutamine infusion (DOB: 20 microg x kg(-1) x min(-1) iv), and during coronary stenosis + DOB + 2-deoxyglucose (2-DG) infusion. DOB increased rate pressure products (RPP) and MBF significantly without affecting the subendocardial-to-subepicardial blood flow ratio (ENDO/EPI) or HEP levels. During coronary stenosis + DOB + 2-DG infusion, RPP, ischemic zone (IZ) MBF, and ENDO/EPI decreased significantly. The IZ ratio of creatine phosphate-to-ATP decreased significantly [2.30 +/- 0.14, 2.06 +/- 0.13, and 2.04 +/- 0.11 to 1.77 +/- 0.12, 1.70 +/- 0.11, and 1.72 +/- 0.12 for EPI, midmyocardial (MID), and ENDO, respectively], and 2-DGP accumulated in all layers, as evidenced by the 2-DGP/PCr (0.55 +/- 0.12, 0.52 +/- 0.10, and 0.37 +/- 0.08 for EPI, MID, and ENDO, respectively; P < 0.05, EPI > ENDO). In the IZ the wet weight-to-dry weight ratio was significantly increased compared with the normal zone (5.9 +/- 0.5 vs. 4.4 +/- 0.4; P < 0.05). Thus, in the stenotic perfused bed, during dobutamine-induced high cardiac work state, despite higher blood flow, the subepicardial layers showed the greater metabolic changes characterized by a shift toward higher carbohydrate metabolism, suggesting that a homeostatic response to high-cardiac work state is characterized by more glucose utilization in energy metabolism.

The energetic state within hibernating myocardium is normal during dobutamine despite inhibition of ATP-dependent potassium channel opening with glibenclamide.

Within hibernating myocardium, it is uncertain whether a normal energetic state is present at baseline and whether maintaining that energy state during a catecholamine challenge is dependent on ATP-dependent potassium channel opening. In this study, 16 swine underwent a thoracotomy with placement of an external constrictor on the left anterior descending coronary artery (LAD) (hibernation model). Seven additional swine underwent a sham operation. At 10 wk, the myocardial energetic state in the LAD region was assessed by (31)P-NMR spectroscopy, and the ratio of phosphocreatine to ATP (PCr/ATP) was determined at baseline, during glibenclamide treatment (0.5 mg/kg bolus with 50 microg/min iv), and during addition of dobutamine (40 microg x kg(-1) x min(-1) iv). At baseline, transmural blood flow in the LAD and remote region was 0.75 +/- 0.11 and 0.88 +/- 0.09 ml x min(-1) x g(-1), respectively (P < 0.01), in hibernating hearts and 0.83 +/- 0.12 and 0.88 +/- 0.15 ml x min(-1) x g(-1), respectively (not significant), in sham-operated hearts. Under basal conditions, PCr/ATP in the LAD region of hibernating and sham pigs was 2.15 +/- 0.04 and 2.11 +/- 0.05, respectively (not significant). In sham pigs, addition of dobutamine to glibenclamide increased the double product from 10.4 +/- 0.8 to 23.9 +/- 4.0 mmHg x beats x min(-1) x 1,000 (P < 0.05) and decreased transmural PCr/ATP from 2.06 +/- 0.06 to 1.69 +/- 0.06 (P < 0.05). Dobutamine increased the double product in hibernating pigs in a similar fashion and, despite a 40% lower blood flow response, induced an equivalent decrease in PCr/ATP from 2.04 +/- 0.04 to 1.73 +/- 0.08 (P < 0.05). In conclusion, we found that, in chronic hibernating swine myocardium with reduced basal blood flow and perfusion reserve, the transmural energetic state, defined by PCr/ATP, is normal during addition of dobutamine, despite inhibition of ATP-dependent potassium channel opening with glibenclamide. These data suggest that important adaptations other than the ATP-dependent potassium channel opening allow hibernating myocardium to operate over a lower range of the oxygen supply-demand relationship to protect against myocardial ischemia.

Functional and bioenergetic modulations in the infarct border zone following autologous mesenchymal stem cell transplantation.

Preclinical and clinical studies have demonstrated that stem cell transplantation can improve the left ventricular (LV) contractile performance, yet the underlying mechanisms remain unknown. We examined whether mesenchymal stem cell (MSC) transplantation-induced beneficial effects are secondary to paracrine-associated improvements in LV contractile performance, wall stress, and myocardial bioenergetics in hearts with postinfarction LV remodeling. Myocardial contractile function and bioenergetics were compared 4 wk after acute myocardial infarction in normal pigs (n = 6), untreated pigs with myocardial infarction (MI group; n = 6), and pigs receiving autologous MSC transplantation (MI + MSC group; n = 5). A distal occlusion of the left anterior descending coronary artery instigated significant myocardial hypertrophy. Ejection fraction decreased from 55.3 +/- 3.1% (normal) to 30.4 +/- 2.3% (MI group; P < 0.01) and to 45.4 +/- 3.1% (MI + MSC group; P < 0.01 vs. MI). Hearts in the MI group developed severe contractile dyskinesis in the infarct zone and border zone (BZ). MSC transplantation significantly improved contractile performance from dyskinesis to active contraction (P < 0.01 vs. MI). BZ systolic wall stress was severely increased in MI hearts but significantly improved after MSC transplantation (P < 0.01 vs. MI). The BZ demonstrated profound bioenergetic abnormalities in MI pigs; this was significantly improved after MSC transplantation (P < 0.01 vs. MI). Patchy spared myocytes were found in the infarct zone of hearts receiving MSC transplantation but not in control hearts. These data demonstrate that MSC transplantation into the BZ causes significant improvements in myocardial contractile performance and reduction in wall stress, which ultimately results in significant bioenergetic improvements. Low cell engraftment indicates that MSCs did not provide a structural contribution to the damaged heart and that the observed beneficial effects likely resulted from paracrine repair mechanisms.

Bioenergetic and functional consequences of bone marrow-derived multipotent progenitor cell transplantation in hearts with postinfarction left ventricular remodeling.

BACKGROUND: The present study examined whether transplantation of adherent bone marrow-derived stem cells, termed pMultistem, induces neovascularization and cardiomyocyte regeneration that stabilizes bioenergetic and contractile function in the infarct zone and border zone (BZ) after coronary artery occlusion. METHODS AND RESULTS: Permanent left anterior descending artery occlusion in swine caused left ventricular remodeling with a decrease of ejection fraction from 55+/-5.6% to 30+/-5.4% (magnetic resonance imaging). Four weeks after left anterior descending artery occlusion, BZ myocardium demonstrated profound bioenergetic abnormalities, with a marked decrease in subendocardial phosphocreatine/ATP (31P magnetic resonance spectroscopy; 1.06+/-0.30 in infarcted hearts [n=9] versus 1.90+/-0.15 in normal hearts [n=8; P<0.01]). This abnormality was significantly improved by transplantation of allogeneic pMultistem cells (subendocardial phosphocreatine/ATP to 1.34+/-0.29; n=7; P<0.05). The BZ protein expression of creatine kinase-mt and creatine kinase-m isoforms was significantly reduced in infarcted hearts but recovered significantly in response to cell transplantation. MRI demonstrated that the infarct zone systolic thickening fraction improved significantly from systolic "bulging" in untreated animals with myocardial infarction to active thickening (19.7+/-9.8%, P<0.01), whereas the left ventricular ejection fraction improved to 42.0+/-6.5% (P<0.05 versus myocardial infarction). Only 0.35+/-0.05% donor cells could be detected 4 weeks after left anterior descending artery ligation, independent of cell transplantation with or without immunosuppression with cyclosporine A (with cyclosporine A, n=6; no cyclosporine A, n=7). The fraction of grafted cells that acquired an endothelial or cardiomyocyte phenotype was 3% and approximately 2%, respectively. Patchy spared myocytes in the infarct zone were found only in pMultistem transplanted hearts. Vascular density was significantly higher in both BZ and infarct zone of cell-treated hearts than in untreated myocardial infarction hearts (P<0.05). CONCLUSIONS: Thus, allogeneic pMultistem improved BZ energetics, regional contractile performance, and global left ventricular ejection fraction. These improvements may have resulted from paracrine effects that include increased vascular density in the BZ and spared myocytes in the infarct zone.

Functional and bioenergetic consequences of AT1 antagonist olmesartan medoxomil in hearts with postinfarction LV remodeling.

The structural left ventricular (LV) remodeling and contractile dysfunction of hearts with postinfarction LV remodeling are benefited by angiotensin II type 1 receptor (AT1) blocker. However, the myocardial bioenergetic consequences of AT1 blocker in these hearts are not known. To investigate, we used a porcine model of postinfarction LV remodeling produced by ligation of the left circumflex coronary artery. After infarction, 7 pigs received olmesartan medoxomil (2 mg/kg) for comparison against 9 untreated and 10 normal pigs. Measurements of hemodynamics, myocardial perfusion, and myocardial bioenergetics were taken 7 weeks postinfarction. The treated group had an LV-to-body weight ratio significantly lower than the untreated group (2.69 +/- 0.70, 2.96 +/- 0.51, 3.66 +/- 0.60 g/kg for control, treated, and untreated groups, respectively). The untreated group had a mean aortic pressure significantly higher than the control (73 +/- 16, 86 +/- 14, and 94 +/- 20 mm Hg, respectively). The subendocardial phosphocreatine-to-ATP ratios of the treated group were significantly higher than that of the untreated group. The untreated group, but not the treated group, had significant reductions in mitochondrial F0F1-ATPase subunits compared with controls. Congestive heart failure as evidenced by significant ascites (100 to 2000 mL) developed in 4 of the 9 untreated animals, but was absent in the treated group. Animals with heart failure demonstrated reductions in both mitochondrial F0F1-ATPase expression and myocardial high-energy phosphate levels. Thus, severe LV dysfunction and accompanying abnormal myocardial bioenergetic phenotype were prevented by the AT1 antagonist olmesartan medoxomil.

Profound bioenergetic abnormalities in peri-infarct myocardial regions.

Regions of myocardial infarct (MI) are surrounded by a border zone (BZ) of normally perfused but dysfunctional myocardium. Although systolic dysfunction has been attributed to elevated wall stress in this region, there is evidence that intrinsic abnormalities of contractile performance exist in BZ myocardium. This study examined whether decreases of high-energy phosphates (HEP) and mitochondrial F(1)F(0)-ATPase (mtATPase) subunits typical of failing myocardium exist in BZ myocardium of compensated postinfarct remodeled hearts. Eight pigs were studied 6 wk after MI was produced by ligation of the left anterior descending coronary artery (LAD) distal to the second diagonal. Animals developed compensated LV remodeling with a decrease of ejection fraction from 54.6 +/- 5.4% to 31 +/- 2.1% (MRI) 5 wk after LAD occlusion. The remote zone (RZ) myocardium demonstrated modest decreases of ATP and mtATPase components. In contrast, BZ myocardium demonstrated profound abnormalities with ATP levels decreased to 42% of normal, and phosphocreatine-to-ATP ratio ((31)P-magnetic resonance spectroscopy) decreased from 2.06 +/- 0.19 in normal hearts to 1.07 +/- 0.10, with decreases in alpha-, beta-, OSCP, and IF(1) subunits of mtATPase, especially in the subendocardium. The reduction of myocardial creatine kinase isoform protein expression was also more severe in the BZ relative to the RZ myocardium. These abnormalities were independent of a change in mitochondrial content because the mitochondrial citrate synthase protein level was not different between the BZ and RZ. This regional heterogeneity of ATP content and expression of key enzymes in ATP production suggests that energetic insufficiency in the peri-infarct region may contribute to the transition from compensated LV remodeling to congestive heart failure.

Bioenergetic and functional consequences of stem cell-based VEGF delivery in pressure-overloaded swine hearts.

In an established swine model of severe left ventricular (LV) hypertrophy (LVH), the bioenergetic and functional consequences of transplanting autologous mesenchymal stem cells (MSCs) overexpressing vascular endothelial growth factor (VEGF-MSCs) into the LV were evaluated; transplantation was accomplished by infusion of VEGF-MSCs into the interventricular cardiac vein. Specifically, the hypertrophic response to aortic banding was compared in seven pigs treated with 30 million VEGF-MSCs, eight pigs treated with 30 million MSCs without VEGF modification, and 19 untreated LVH pigs. Eight pigs without banding or cell transplantation (normal) were also studied. Four weeks postbanding, LV wall thickening (MRI), myocardial blood flow (MBF), high-energy phosphate levels ((31)P magnetic resonance spectroscopy), and hemodynamic measurements were obtained under basal conditions and during a catecholamine-induced high cardiac workstate (HCW). Although 9 of 19 untreated banded pigs developed clinical evidence of biventricular failure, no MSCs-treated animal developed heart failure. MSCs engraftment was present in both cell transplant groups, and both baseline and HCW MBF values were significantly increased in hearts receiving VEGF-MSCs compared with other groups (P < 0.05). During HCW, cardiac inotropic reserve (defined as the percent increase of rate pressure product at HCW relative to baseline) was normal in the VEGF-MSCs group and significantly decreased in all other banded groups. Additionally, during HCW, the myocardial energetic state [reflected by the phosphocreatine-to-ATP ratio (PCr/ATP)] of VEGF-MSCs-treated hearts remained stable, whereas in all other groups, PCr/ATP decreased significantly from baseline values (P < 0.05, each group). Myocardial von Willebrand factor and VEGF mRNA expressions and myocardial capillary density were significantly increased in VEGF-MSCs-treated hearts (P < 0.05). Hence, in the pressure-overloaded LV, transplantation of VEGF-MSCs prevents LV decompensation, induces neovascularization, attenuates hypertrophy, and improves MBF, myocardial bioenergetic characteristics, and contractile performance.