Systemic Hypoxemia Induces Cardiomyocyte Hypertrophy and Right Ventricular Specific Induction of Proliferation

BACKGROUND

A recent study suggests that systemic hypoxemia in adult male mice can induce cardiac myocytes to proliferate. The goal of the present experiments was to confirm these results, provide new insights on the mechanisms that induce adult cardiomyocyte cell cycle reentry, and to determine if hypoxemia also induces cardiomyocyte proliferation in female mice.

METHODS

EdU-containing mini pumps were implanted in 3-month-old, male and female C57BL/6 mice. Mice were placed in a hypoxia chamber, and the oxygen was lowered by 1% every day for 14 days to reach 7% oxygen. The animals remained in 7% oxygen for 2 weeks before terminal studies. Myocyte proliferation was also studied with a mosaic analysis with double markers mouse model.

RESULTS

Hypoxia induced cardiac hypertrophy in both left ventricular (LV) and right ventricular (RV) myocytes, with LV myocytes lengthening and RV myocytes widening and lengthening. Hypoxia induced an increase (0.01±0.01% in normoxia to 0.11±0.09% in hypoxia) in the number of EdU+ RV cardiomyocytes, with no effect on LV myocytes in male C57BL/6 mice. Similar results were observed in female mice. Furthermore, in mosaic analysis with double markers mice, hypoxia induced a significant increase in RV myocyte proliferation (0.03±0.03% in normoxia to 0.32±0.15% in hypoxia of RFP+ myocytes), with no significant change in LV myocyte proliferation. RNA sequencing showed upregulation of mitotic cell cycle genes and a downregulation of Cullin genes, which promote the G1 to S phase transition in hypoxic mice. There was significant proliferation of nonmyocytes and mild cardiac fibrosis in hypoxic mice that did not disrupt cardiac function. Male and female mice exhibited similar gene expression following hypoxia.

CONCLUSIONS

Systemic hypoxia induces a global hypertrophic stress response that was associated with increased RV proliferation, and while LV myocytes did not show increased proliferation, our results minimally confirm previous reports that hypoxia can induce cardiomyocyte cell cycle activity in vivo.

Cortical bone stem cell-derived exosomes' therapeutic effect on myocardial ischemia-reperfusion and cardiac remodeling

Heart failure is the one of the leading causes of death in the United States. Heart failure is a complex syndrome caused by numerous diseases, including severe myocardial infarction (MI). MI occurs after an occlusion of a cardiac artery causing downstream ischemia. MI is followed by cardiac remodeling involving extensive remodeling and fibrosis, which, if the original insult is severe or prolonged, can ultimately progress into heart failure. There is no "cure" for heart failure because therapies to regenerate dead tissue are not yet available. Previous studies have shown that in both post-MI and post-ischemia-reperfusion (I/R) models of heart failure, administration of cortical bone stem cell (CBSC) treatment leads to a reduction in scar size and improved cardiac function. Our first study investigated the ability of mouse CBSC-derived exosomes (mCBSC-dEXO) to recapitulate mouse CBSCs (mCBSC) therapeutic effects in a 24-h post-I/R model. This study showed that injection of mCBSCs and mCBSC-dEXOs into the ischemic region of an infarct had a protective effect against I/R injury. mCBSC-dEXOs recapitulated the effects of CBSC treatment post-I/R, indicating exosomes are partly responsible for CBSC's beneficial effects. To examine if exosomes decrease fibrotic activation, adult rat ventricular fibroblasts (ARVFs) and adult human cardiac fibroblasts (NHCFs) were treated with transforming growth factor β (TGFβ) to activate fibrotic signaling before treatment with mCBSC- and human CBSC (hCBSC)-dEXOs. hCBSC-dEXOs caused a 100-fold decrease in human fibroblast activation. To further understand the signaling mechanisms regulating the protective decrease in fibrosis, we performed RNA sequencing on the NHCFs after hCBSC-dEXO treatment. The group treated with both TGFβ and exosomes showed a decrease in small nucleolar RNA (snoRNA), known to be involved with ribosome stability.NEW & NOTEWORTHY Our work is noteworthy due to the identification of factors within stem cell-derived exosomes (dEXOs) that alter fibroblast activation through the hereto-unknown mechanism of decreasing small nucleolar RNA (snoRNA) signaling within cardiac fibroblasts. The study also shows that the injection of stem cells or a stem-cell-derived exosome therapy at the onset of reperfusion elicits cardioprotection, emphasizing the importance of early treatment in the post-ischemia-reperfusion (I/R) wounded heart.

Abstract P411: Sex-based Differences In A Feline Model Of Hfpef

Rationale: Heart Failure with preserved Ejection Fraction (HFpEF) accounts for approximately 50% of all HF diagnoses with no FDA approved therapies. HFpEF is more prevalent in females versus males, but the mechanisms driving the development of HFpEF as a sex-based disorder are not well understood. We have recently shown that slow progressive pressure overload (PO) in male felines induces a HFpEF phenotype but have not investigated the differences in response to the same physiological stress in females.

Hypothesis: Females will develop a phenotype that is distinct from males in response to PO.

Methods and Results: Male (m) and female (f) domestic short felines (age 2mo) underwent either a sham procedure (m: n=7; f: n=7) or aortic constriction (m: n=11; f: n=10) using a customized pre-shaped band. At baseline (prior to surgery), there was no difference in body weight between groups and echocardiography revealed no significant difference in the ratio of left atrium to aortic root (LA/Ao), LA ejection fraction (LA EF), left ventricle (LV) ejection fraction, LV wall-thickness, and E/A ratio. At 4mo post-surgery, both males and females developed cardiac dysfunction. Females gained significantly less weight than males throughout the study. Despite the size difference, both sexes developed comparable LV wall thickness and changes in E/A ratio vs. sham groups. There was no change in LV EF. Furthermore, there was a decrease in LA EF and increased LA/Ao, indicating LA dysfunction and enlargement. Invasive hemodynamics at 4mo post-surgery showed no differences between sexes for the systolic pressure gradient generated by the aortic banding. Banded males had a significantly higher LV end-diastolic pressure vs. banded females, but there was a trend towards prolongation of tau and lower dp/dt min in banded females, reflective of worse active relaxation. Both sexes had comparable dP/dt max . There were no differences between banded males and females in heart weight to body weight or cardiomyocyte cross-sectional area.

Conclusion: Despite similar pressure gradients as a result of PO and the development of similar cardiac hypertrophy between sexes and a higher LVEDP in males, females had a trend towards worse relaxation. Other causes of HFpEF may have sex-based differences.

Endometrial stromal sarcoma: A review of rare mesenchymal uterine neoplasm

OBJECTIVE

This review aims to analyze the pathological aspects, diagnosis and treatment of rare mesenchymal uterine tumors.

METHODS

On August 2019, a systematic review of the literature was done on Pubmed, MEDLINE, Scopus, and Google Scholar search engines. The systematic review was carried out in agreement with the Preferred Reporting Items for Systematic Reviews and Meta-Analyzes statement (PRISMA). The following words and key phrases have been searched: "endometrial stromal sarcoma", "low-grade endometrial stromal sarcoma", "high-grade endometrial stromal sarcoma", "uterine sarcoma", "mesenchymal uterine tumors" and "uterine stromal sarcoma". Across these platforms and research studies, five main aspects were analyzed: the biological characteristics of the neoplasms, the number of cases, the different therapeutic approaches used, the follow-up and the oncological outcomes.

RESULTS

Of the 94 studies initially identified, 55 were chosen selecting articles focusing on endometrial stromal sarcoma. Of these fifty-five studies, 46 were retrospective in design, 7 were reviews and 2 randomized phases III trials.

CONCLUSION

Endometrial stromal sarcomas are rare mesenchymal uterine neoplasms and surgery represents the standard treatment. For uterus-limited disease, the remove en bloc with an intact resection of the tumor (without the use of morcellation) is strongly recommended. For advanced-stage disease, the standard surgical treatment is adequate cytoreduction with metastatectomy. Pelvic and para-aortic lymphadenectomy is not recommended in patients with Low-grade Endometrial Stromal Sarcoma (ESS), while is not clear whether cytoreduction of advanced tumors improves patient survival in High-grade ESS. Administration of adjuvant radiotherapy or chemotherapy is not routinely used and its role is still debated.

A low voltage activated Ca2+ current found in a subset of human ventricular myocytes

Low voltage activated (I_Ca-LVA) calcium currents including Cav1.3 and T-type calcium current (I_Ca-T) have not been reported in adult human left ventricular myocytes (HLVMs). We tried to examine their existence and possible correlation with etiology and patient characteristics in a big number of human LVMs isolated from explanted terminally failing (F) hearts, failing hearts with left ventricular assist device (F-LVAD) and nonfailing (NF) human hearts. LVA (I_Ca-LVA) was determined by subtracting L-type Ca²⁺ current (I_Ca-L) recorded with the holding potential of −50 mV from total Ca²⁺ current recorded with the holding potential of −90 mV or −70 mV. I_{Ca- LVA} was further tested with its sensitivity to 100 µM CdCl₂ and tetrodotoxin. Three HLVMs (3 of 137 FHLVMs) from 2 (N = 30 hearts) failing human hearts, of which one was idiopathic and the other was due to primary pulmonary hypertension, were found with I_Ca-LVA. I_Ca-LVA in one FHLVM was not sensitive to 100 µM CdCl₂ while I_Ca-LVA in another two FHLVMs was not sensitive to tetrodotoxin. It peaked at the voltage of −40~-20 mV and had a time-dependent decay faster than I_Ca-L but slower than sodium current (I_Na). I_Ca-LVA was not found in any HLVMs from NF (75 HLVMs from 17 hearts) or F-LVAD hearts (82 HLVMs from 18 hearts) but a statistically significant correlation could not be established. In conclusion, I_Ca-LVA was detected in some HLVMs of a small portion of human hearts that happened to be nonischemic failing hearts.

Differential microRNA-21 and microRNA-221 Upregulation in the Biventricular Failing Heart Reveals Distinct Stress Responses of Right Versus Left Ventricular Fibroblasts

BACKGROUND

The failing right ventricle (RV) does not respond like the left ventricle (LV) to guideline-directed medical therapy of heart failure, perhaps due to interventricular differences in their molecular pathophysiology.

METHODS

Using the canine tachypacing-induced biventricular heart failure (HF) model, we tested the hypothesis that interventricular differences in microRNAs (miRs) expression distinguish failing RV from failing LV.

RESULTS

Severe RV dysfunction was indicated by elevated end-diastolic pressure (11.3±2.5 versus 5.7±2.0 mm Hg; P<0.0001) and diminished fractional area change (24.9±7.1 versus 48.0±3.6%; P<0.0001) relative to prepacing baselines. Microarray analysis of ventricular tissue revealed that miR-21 and miR-221, 2 activators of profibrotic and proliferative processes, increased the most, at 4- and 2-fold, respectively, in RV-HF versus RV-Control. Neither miR-21 or miR-221 was statistically significantly different in LV-HF versus LV-Control. These changes were accompanied by more extensive fibrosis in RV-HF than LV-HF. To test whether miR-21 and miR-221 upregulation is specific to RV cellular response to mechanical and hormonal stimuli associated with HF, we subjected fibroblasts and cardiomyocytes isolated from normal canine RV and LV to cyclic overstretch and aldosterone. These 2 stressors markedly upregulated miR-21 and miR-221 in RV fibroblasts but not in LV fibroblasts nor cardiomyocytes of either ventricle. Furthermore, miR-21/221 knockdown significantly attenuated RV but not LV fibroblast proliferation.

CONCLUSIONS

We identified a novel, biological difference between RV and LV fibroblasts that might underlie distinctions in pathological remodeling of the RV in biventricular HF.

P5996HDAC inhibition improves myofibrillar relaxation and metabolism in a feline model of HFpEF

Background

Heart failure (HF) with preserved ejection fraction (HFpEF) accounts for about 50% of all cases of HF and there are currently no effective therapies.

Purpose

To assess the effects of histone deacetylase (HDAC) inhibition on cardiac and mitochondrial function and the plasma metabolome in a large mammalian model of slow-progressive pressure overload with features of HFpEF.

Methods

Male domestic short hair cats (n=26, aged 2mo), underwent either sham (S) procedures (n=5) or aortic constriction with a customized pre-shaped band (n=21), resulting in slow progressive pressure overload during growth. 2 months post-banding, animals were treated daily with either 10mg/kg suberoylanilide hydroxamic acid (b+SAHA) (n=8), a pan-HDAC inhibitor, or vehicle (b+veh) (n=8) for 2 months. Serial in-vivo cardiopulmonary phenotyping was performed monthly, and invasive hemodynamic and gas exchange parameters were evaluated 4 months post-banding. Ex-vivo myofibril mechanical studies and blood-based metabolomic profiling were performed. Data is presented as mean±SEM.

Results

Echocardiography at 4-months post-banding revealed that b+SAHA animals had a significant reduction in left ventricular hypertrophy (LVH) and LA size vs. b+veh animals. Left ventricular end-diastolic pressure (LVEDP) and mean pulmonary arterial pressure (mPAP) were significantly lower in b+SAHA vs. b+veh. SAHA treatment also improved ex-vivo myofibril relaxation independent of LVH and this effect correlated with in-vivo improvements of LV relaxation. Furthermore, SAHA treatment preserved lung structure, and improved lung compliance and oxygenation, reflected by a decrease in alveolar-capillary wall thickness and intrapulmonary shunt. SAHA treatment also reduced perivascular fluid cuffs around extra-alveolar vessels, suggesting attenuated alveolar-capillary stress failure. Treatment with SAHA caused an increase in both oxygen consumption in-vivo and the percentage of type 1 skeletal muscle fibers (higher oxidative capacity). SAHA also increased mRNA levels of coactivators that regulate mitochondrial function and induced metabolic reprogramming towards mitochondrial oxidation preferentially utilizing fatty acids. SAHA treated HeLa cells showed a significant increase in oxidative phosphorylation and ATP production.

Effects of SAHA

Conclusion

These results show that slow-progressive pressure overload mimics critical features of HFpEF. SAHA can improve cardiac, pulmonary, and metabolic derangements caused by chronic pressure overload. Therefore, HDAC inhibition may be an interesting therapeutic strategy to treat the ever growing HFpEF population.

Acknowledgement/Funding

NIH [HL33921 to S.R.H, HL116848, HL127240 to T.A.M]; AHA [16SFRN31400013 to T.A.M.]; Medical University of Graz [M.W.], Stadt Graz [M.W.]

Abstract 707: Cortical-bone Stem Cell Therapy Alters the Inflammatory Response After Myocardial Infarction

Ischemic heart diseases like myocardial infarction are the largest contributors to cardiovascular disease world-wide. The resulting cardiac cell death impairs function of the heart and can lead to heart failure and death. Re-perfusion of the ischemic tissue is necessary but causes damage to the surrounding tissue by re-perfusion injury and initiates a sterile inflammatory response. Cortical bone stem cells (CBSCs) have been shown to increase pump function and decrease scar size in a large animal swine model of myocardial infarction. To explore the potential cause of these changes, we hypothesized that CBSCs were altering the inflammatory response after re-perfusion thereby changing the wound healing process. To test this, we performed serial immune cell analysis of the blood and tissue from Gottingen mini-swine that underwent 90 minutes of lateral anterior descending coronary artery ischemia followed by 7 days of re-perfusion to assess changes in immune cell recruitment and phenotype. Our findings indicate that CBSCs modify the cytokines released by immune cells in the infarct, decrease macrophage infiltration of the infarct 3 days after MI, and increase the recruitment of CD4+ T-cells to the infarct zone 7 days after MI. In addition, these changes reflect a pro-healing inflammatory environment. From this data, we conclude that CBSCs are influencing immune cell recruitment dynamics and phenotype, and these changes may contribute to the decreased scar size and increased pump function seen in CBSC-treated animals.

Abstract 257: Cortical Bone Stem Cell-Derived Exosomes Alter Wound Healing Response in Cardiac Fibroblasts and Cardiac Endothelial Cells

Rationale: Post-myocardial infarction (MI) results in remodeling that leads to the development of heart failure. We have previously seen improvements in post-MI wound healing and scar formation as a result of administration of cortical bone stem cell derived exosomes (CBSC exosomes).

Objectives: We sought to further elucidate the mechanism through which CBSC exosomes improved scar formation and altered wound healing through in vitro experimentation. We continued to explore the unique characteristics of CBSC exosomes in order to understand why they have anti-fibrotic effects.

Methods and Results: We performed migration assays on cardiac endothelial cells and cardiac fibroblasts, and saw alterations in cell migration in both cell types upon treatment with mCBSC CM and mCBSC exosomes. We discovered that migration of CECs was reduced by 20% under the influence of mCBSC CM and mCBSC exosomes, but rescued when exosomes were removed from mCBSC CM. We discovered that the removal of exosomes from mCBSC CM slowed cardiac fibroblast migration by 40%. We saw a decrease in the quantity of pro-fibrotic mRNA in cardiac endothelial cells and cardiac fibroblasts after treatment with mCBSC exosomes. Adult cardiac endothelial cell mRNA levels of VEGFA, Col4A1, and VCAM were reduced nearly two fold from control untreated cell levels following mCBSC exosome treatment. Adult cardiac fibroblast Col1A1, Col3A1, Col4A1, and MMP2 mRNA levels were reduced one-fold from control untreated cell levels following mCBSC exosome treatment.

Conclusions: Our findings show that the wound healing induced by CBSC treatment post-MI involves a mechanism altering the migration of endothelial cells, sustaining the migratory capabilities of fibroblasts, and decreasing the production of pro-fibrotic mRNA in cardiac fibroblasts and cardiac endothelial cells.

Abstract 554: Mechanism of Action for the Beneficial Effects of Cortical Bone Stem Cells on the Heart After Myocardial Infarction

Rationale: Myocardial infarction (MI) causes the death of a portion of the heart and can lead to adverse remodeling that results in poor cardiac pump function and heart failure. We have previously shown that a novel stem cell type, cortical bone stem cells (CBSCs), causes improved repair of cardiac tissue after MI. When injected into the infarct border zone in both mouse and pig hearts, CBSCs reduced infarct size and induced neovascularization via a largely paracrine manner.

Objectives: This study investigates the mechanism involved in the angiogenesis alterations implemented by CBSCs, in particular the wound-healing of endothelial cells. Our goal was to comprehend how mCBSCs affected cardiac repair in an inflammatory environment.

Methods and Results: We performed scratch assays and tubule formation (TF) assays on human umbilical vein endothelial cells (HUVECs) and cardiac endothelial cells (CECs) in mCBSC CM and media controls, and in the presence of pro-inflammatory cytokines such as IL-1β, IL-6, and TNF-α. Both HUVECs and CECs show reduced cell migration and reduced TF. TF was rescued when the cells were plated on Matrigel. We investigated the angiogenesis-related cytokines present within both the mCBSC CM and CM-treated HUVECs and CECs via angiogenesis dot blots. We discovered a significant increase of CXCL-10 and Endostatin/Collagen XVIII relative to murine embryonic fibroblast CM.

Conclusions: Our findings show that part of the mechanism underlying the wound-healing and neovascularization induced by CBSCs post-MI involves secretion of angiogenesis-related cytokines which alter the behavior of cardiac endothelial cells.

Abstract 336: Human Bone Contains Primitive Cells With Angiogenic and Immunomodulatory Properties

Previously, we have shown that treatments of cortical bone derived stem cells (CBSCs) reduce ventricular remodeling and improve cardiac functions in both mouse and pig myocardial infarction (MI) models. The goals of the present study were to isolate and characterize human CBSCs (hCBSCs).

Using bone fragments obtained at the time surgeries, we isolated three morphologically distinctive hCBSC phenotypes; 1) sphere forming (SF); 2) epithelial like monolayer (ELM); and 3) larger and spindle shaped (LSS) phenotype. The hCBSC phenotypes grew without senescence in culture. Mean doubling time (hour) for SF, ELM, and LSS at the passage number 20 (P20) were 19.54, 21.21, and 20.3 respectively and at the P40 were 18.01, 17.13, and 20.56 respectively. All of the phenotypes were found to have surface expression of CD44; however, other markers detected (CD105, CD90, CD73, CD106, CD271, and CD133) on mouse CBSCs (mCBSCs) were not detected along with the markers not detected on the surface of mCBSCs (CD45, CD11b, CD31, CD34, CD117, and CD325). Erythrocytes (CD235a) and immune cell markers (CD2, CD3, CD14, CD16, CD19, and CD56) were also not detected. The hCBSCs were found without histocompatibility antigen Ia (MHC-Ia: HLA-A, HLA-B, and HLA-C) and MHC-II (HLA-DR); instead, they expressed soluble forms of MHC-Ib (HLA-G5, HLA-G6, and HLA-G7), potent inhibitor of natural killer cells and other immune cells. These features are commonly found in immune privileged cells. Further, the hCBSCs produced the immunomodulatory and anti-inflammatory factors (IL-4, IL-1RA, TGF-b and IL-10). Additionally, the hCBSCs secreted angiogenic factors that organize endothelial cells into tube like structures.

From these results, the hCBSCs we isolated have totally different surface marker characteristics compared to any other known cells including mCBSCs. In addition to their angiogenic effects, the hCBSCs have immunomodulatory properties that could make them suitable for cell therapy targeting inflammatory diseases such post myocardial infarction remodeling.

Abstract 249: Cortical-bone Derived Stem Cells Improve Cardiac Outcomes After Myocardial Infarction by Modulating the Inflammatory Response

Rationale: Cortical-bone derived stem cells (CBSCs) improve cardiac pump function and reduce scar size after myocardial infarction (MI) compared to Cardiac-Derived and Mesenchymal Stem Cells. However, the mechanism for these improved outcomes is not known. Recent data in a swine model of MI has demonstrated acute changes to the immune response elicited by MI in CBSC treated animals compared to vehicle controls, suggesting that CBSCs may improve post-MI remodeling by modulation of the immune response.

Objective: Identify the changes in the immune response of CBSC-treated animals and determine the role of these changes in cardiac healing and wound repair.

Methods and Results: Using multi-color flow cytometry, we found that murine bone marrow-derived macrophages (BMDMs) cultured and exposed to CBSC conditioned culture medium in vitro express higher levels of the mannose receptor CD206 than controls, indicating alternative “M2” activation. In addition, CD86 expression on BMDMs exposed to the classical (M1) activators interferon-γ (INF-γ) and lipopolysaccharide (LPS) in conditioned CBSC media was significantly lower than cells treated only with INF-γ and LPS. Blocking the IL-4 receptor on the BMDMs with a monoclonal antibody in conditioned media decreased CD206 expression, increased CD86 expression, and failed to mitigate the activation elicited by INF-γ and LPS. Exposing the BMDMs to conditioned media also increased the amount of the anti-inflammatory cytokine IL-1 receptor antagonist (IL1-RA) released compared to controls, matching previous data from a swine-model of MI that showed increased IL-1RA blood levels in CBSC-treated swine 72 hours post-MI. Together these data implicate IL-4 as a possible mechanism through which CBSCs influence the inflammatory response raised to MI.

Conclusion: Soluble factors secreted by CBSCs change the phenotype of immune cells in vitro and in vivo . A possible mechanism for the beneficial effects of CBSCs on cardiac wound healing after MI may come from their ability to modulate the monocyte/macrophage response to preserve cardiac structure and function.

Abstract 227: Inhibition of Histone Deacetylase Catalytic Activity Improves Cardiac and Pulmonary Function in a Feline Model of Heart Failure with Preserved Ejection Fraction

Rationale: Heart Failure with preserved Ejection Fraction (HFpEF) accounts for about 50% of all heart failure cases but has no effective therapies.

Hypothesis: Inhibition of histone deacetylase (HDAC) catalytic activity exerts beneficial effects on the cardiopulmonary system in a feline model of HFpEF.

Methods and Results: Male domestic short hair cats (n=21, aged 2mo), underwent either a sham procedure (n=5) or aortic constriction (n=16) using a customized pre-shaped band, resulting in slow progressive pressure overload during growth. 2 months post-banding, banded cats were treated daily with either 10mg/kg suberoylanilide hydroxamic acid ( b+SAHA ) (n=8), a pan-HDAC inhibitor, or vehicle ( b+veh ) (n=8) for 2 months. At 4 months post-banding, b+SAHA cats showed significantly reduced LV wall thickness and LA size (LA/Ao) compared to b+veh cats (Fig). Invasively measured left ventricular end-diastolic pressure (Fig. LVEDP) at 4 months was significantly elevated in b+veh cats compared to b+SAHA and sham cats (Fig). After dobutamine infusion, the increase in dp/dt max was significantly attenuated in b+veh , but not in b+SAHA cats (Fig). In vivo measurements of pulmonary function at 4 months post-banding demonstrated marked improvement in b+SAHA cats, reflected by an increase in lung compliance and a decrease in alveolar-arterial oxygen gradient (A-aDO 2 ) and intrapulmonary shunt (Fig). Efficacy of SAHA in vivo correlated with enhanced ex vivo myofibril relaxation.

Conclusion: HDAC inhibition rescues the established HFpEF phenotype by reducing LV hypertrophy, LVEDP, LA size, and enhancing myofibril relaxation, which ultimately results in improved pulmonary function.

Abstract 465: Short Term Hypoxia Can Induce Adult Feline Cardiomyocytes to Re-enter the Cell Cycle and Divide

Rationale: The mammalian adult heart has a very limited capacity to regenerate cardiomyocytes that die from pathological damage. Most recent studies suggest that those few new myocytes found after injury are derived from pre-existing cardiomyocytes. A recent study in mice suggest that systemic hypoxemia in adult animals can induce cardiac myocyte cell cycle reentry and myocyte proliferation. In the present experiments we evaluate the ability of adult feline cardiomyocytes to reenter the cell cycle and proliferate in hypoxic environments.

Hypothesis: To determine if hypoxia induces adult feline cardiomyocytes to regenerate.

Methods and results: Adult ventricular cardiomyocytes were isolated from adult felines and maintained in culture. For acute hypoxia, cultures were placed in a hypoxic chamber on day 1, 3, 5, 7, 10, or 14 following isolation and subjected to 1% O 2 , 5% CO 2 , and the balance was N 2 for 24 hours. For chronic hypoxia, adult cardiomyocytes were subjected to 1% O 2 , 5% CO 2 with the balance of N 2 at day 1 after isolation and kept at continuous hypoxia for 3, 5, 7, 10, or 14 days. Prior to hypoxia, cells were treated with 10uM EdU to identify new DNA in cardiomyocytes. Acute hypoxia was shown to promote cell division in cardiac myocytes at all time points except at day 1 post isolation when compared to control cultures. However, chronic hypoxia caused cardiomyocyte damage and increased cell death in all time points as compared to control and acute hypoxia cultures.

Conclusion: Short term hypoxia can induce adult feline cardiomyocytes to proliferate, while long term exposure leads to injury and apoptosis.

Class I Histone Deacetylase Inhibition for the Treatment of Sustained Atrial Fibrillation

Current therapies are less effective for treating sustained/permanent versus paroxysmal atrial fibrillation (AF). We and others have previously shown that histone deacetylase (HDAC) inhibition reverses structural and electrical atrial remodeling in mice with inducible, paroxysmal-like AF. Here, we hypothesize an important, specific role for class I HDACs in determining structural atrial alterations during sustained AF. The class I HDAC inhibitor N-acetyldinaline [4-(acetylamino)-N-(2-amino-phenyl) benzamide] (CI-994) was administered for 2 weeks (1 mg/kg/day) to Hopx transgenic mice with atrial remodeling and inducible AF and to dogs with atrial tachypacing-induced sustained AF. Class I HDAC inhibition prevented atrial fibrosis and arrhythmia inducibility in mice. Dogs were divided into three groups: 1) sinus rhythm, 2) sustained AF plus vehicle, and 3) sustained AF plus CI-994. In group 3, the time in AF over 2 weeks was reduced by 30% compared with group 2, along with attenuated atrial fibrosis and intra-atrial adipocyte infiltration. Moreover, group 2 dogs had higher atrial and serum inflammatory cytokines, adipokines, and atrial immune cells and adipocytes compared with groups 1 and 3. On the other hand, groups 2 and 3 displayed similar left atrial size, ventricular function, and mitral regurgitation. Importantly, the same histologic alterations found in dogs with sustained AF and reversed by CI-994 were also present in atrial tissue from transplanted patients with chronic AF. This is the first evidence that, in sustained AF, class I HDAC inhibition can reduce the total time of fibrillation, atrial fibrosis, intra-atrial adipocytes, and immune cell infiltration without significant effects on cardiac function.

Abstract 34: STIM1 Increases Calcium Stores in the Sarcoplasmic Reticulum of Adult Feline Ventricular Myocytes

Background: STIM1 is a Sarcoplasmic Reticulum (SR) membrane resident protein implicated in sensing and maintaining SR Ca2+ levels. The role of STIM1 in the regulation of SR Ca2+ stores in the normal and diseased heart is not well described. Previous reports confirm that STIM1 is present at low levels in the healthy adult heart, but expression levels increase after cardiac injury.

Objective: To determine if increased STIM1 expression after cardiac injury may be involved in the disturbed Ca2+ cycling present within diseased cardiomyocytes.

Results: We used adenovirus to express either STIM1 or red fluorescent protein (RFP) in freshly isolated adult feline ventricular myocytes (AFMs). After 48 hours in culture, STIM1 induced cell death in 60% of myocytes versus only 5% in RFP controls. Addition of nifedipine rescued the cell death caused by STIM1, but block of transient receptor potential canonical (TRPC) channels was unable to improve viability. AFMs expressing STIM1 exhibited increased fractional shortening and Ca2+ transient amplitude, which was associated with increased SR load. Interestingly, high SR load levels caused by STIM1 were not reduced by nifedipine addition. We also found that baseline L-type channel current amplitude was significantly reduced by 20%, but no difference in current amplitude was found after Bay K8644 addition.

Conclusions: In this study, we found that STIM1 caused Ca2+ overload leading to cell death. This process was L-type channel dependent, but TRPC channels were not involved. STIM1 also caused increased SR load at rest, which was not altered by nifedipine revealing that STIM1 mediated Ca2+ influx does not require L-type channel activity but Ca2+ influx through L-type channels is essential for STIM1 induced cellular death. Furthermore, STIM1 reduced L-type current activity but did not alter channel availability. These data show that after cardiac injury, STIM1 is likely to play a role in regulating cell survival as well as excitation-contraction coupling.

Hyperhomocysteinemia suppresses bone marrow CD34+/VEGF receptor 2+ cells and inhibits progenitor cell mobilization and homing to injured vasculature-a role of β1-integrin in progenitor cell migration and adhesion

Hyperhomocysteinemia (HHcy) impairs re-endothelialization and accelerates vascular remodeling. The role of CD34(+)/VEGF receptor (VEGFR) 2(+) progenitor cells (PCs) in vascular repair in HHcy is unknown. We studied the effect of HHcy on PCs and its role in vascular repair in severe HHcy (∼150 μM), which was induced in cystathionine-β synthase heterozygous mice fed a high-methionine diet for 8 weeks. Vascular injury was introduced by carotid air-dry endothelium denudation. CD34(+)/VEGFR2(+) cells were examined by flow cytometry. HHcy reduced bone marrow (BM) CD34(+)/VEGFR2(+) cells and suppressed replenishment of postinjury CD34(+)/VEGFR2(+) cells in peripheral blood (PB). Donor green fluorescent protein-positive PC homing to the injured vessel was reduced in HHcy after CD34(+) PCs from enhanced green fluorescent protein mice were adoptively transferred following carotid injury. CD34(+) PC transfusion partially reversed HHcy-suppressed re-endothelialization and HHcy-induced neointimal formation. Furthermore, homocysteine (Hcy) inhibited proliferation, adhesion, and migration and suppressed β1-integrin expression and activity in human CD34(+) endothelial colony-forming cells (ECFCs) isolated from PBs in a dose-dependent manner. A functional-activating β1-integrin antibody rescued Hcy-suppressed adhesion and migration in CD34(+) ECFCs. In conclusion, HHcy reduces BM CD34(+)/VEGFR2(+) generation and suppresses CD34(+)/VEGFR2(+) cell mobilization and homing to the injured vessel via β1-integrin inhibition, which partially contributes to impaired re-endothelialization and vascular remodeling.

T-type Ca²⁺ channels regulate the exit of cardiac myocytes from the cell cycle after birth

T-type Ca(2+) channels (TTCCs) are expressed in the fetal heart and then disappear from ventricular myocytes after birth. The hypothesis examined in this study was the α1G TTCCs' influence in myocyte maturation and their rapid withdrawal from the cell cycle after birth.

METHODS

Cardiac myocytes were isolated from neonatal and adult wild type (WT), α1G-/- and α1G over expressing (α1GDT) mice. Bromodeoxyuridine (BrdU) uptake, myocyte nucleation, cell cycle analysis, and T-type Ca(2+) currents were measured.

RESULTS

All myocytes were mono-nucleated at birth and 35% of WT myocytes expressed functional TTCCs. Very few neonatal myocytes had functional TTCCs in α1G-/- hearts. By the end of the first week after birth no WT or α1G-/- had functional TTCCs. During the first week after birth about 25% of WT myocytes were BrdU+ and became bi-nucleated. Significantly fewer α1G-/- myocytes became bi-nucleated and fewer of these myocytes were BrdU+. Neonatal α1G-/- myocytes were also smaller than WT. Adult WT and α1G-/- hearts were similar in size, but α1G-/- myocytes were smaller and a greater % were mono-nucleated. α1G over expressing hearts were smaller than WT but their myocytes were larger.

CONCLUSIONS

The studies performed show that loss of functional TTCCs is associated with bi-nucleation and myocyte withdrawal from the cell cycle. Loss of α1G TTCCs slowed the transition from mono- to bi-nucleation and resulted in an adult heart with a greater number of small cardiac myocytes. These results suggest that TTCCs are involved in the regulation of myocyte size and the exit of myocytes from the cell cycle during the first week after birth.

Abstract 168: Does Calcium Influx Through TTCC Induce Cardiomyocyte Proliferation?

T-type Ca²[[Unable to Display Character: + ]] channels (TTCC) are primarily expressed in fetal/neonatal cardiomyocytes and their functional role is not well defined. Here we explored the idea that Ca 2+ influx through TTCC regulates myocyte proliferation. The fact that Mibefradil (TTCC and L-type calcium channel (LTCC) antagonist) inhibits smooth muscles proliferation supports this idea. Our hypothesis is: Blocking TTCC will reduce neonatal cardiomyocyte proliferation.

Wild type (WT) and α1G TTCC knockout (α1G-/-) neonatal mice ventricular myocytes (NMVMs) were used. Patch clamp was used to measure TTCC. Flow cytometry was used to determine cell cycle distribution. 1. On day 1 (after birth), TTCC was detected in 35% WT NMVMs (n=31), whereas only 4% α1G-/- NMVMs have TTCC (n=25). On day 7, no TTCC was detected in both WT (n=16) and α1G-/- (n=27). 2. In vivo: On day 1 there’s no significant difference in cell cycle distribution: [88.2%±2.7% in G1/G0, 8.1%±2.8% in G2/M, 3.2%±0.1% in S; n=12] in WT vs. [90.6%±1.6% in G1/G0, 5.7%±1.5% in G2/M, 3.7%±0.3% in S; n=20] in α1G-/-. On day 7 there’s a significant difference: [52.3%±1.6% in G1/G0, 47.7%±1.6% in G2/M; n=28] in WT vs. [68.2%±2.1% in G1/G0, 31.9%±2.1% in G2/M; n=20] in α1G-/-, p<0.05. 3. In vitro: Mono and binucleated myocytes percentage was measured: On day 1 there’s no significant difference. On day 7 there were more binucleated cells in WT: 51%±4% mono and 49%±4% binucleated in WT (n=495) vs. 80%±3% mono and 20%±3% binucleated in α1G-/- (n=1107), p<0.05. Cell surface area (CSA) (um²) in α1G-/- (n=164) was smaller than WT (n=109): 860.3±323.3 in WT vs. 716.7±274.9 in α1G-/- in mono (p<0.005), 1333.9±534.0 in WT vs. 1016.6±315.4 in α1G-/- in binucleated (p<0.001). In 2-month old mice there’s a difference in percentage of mono and binucleated myocytes: [7.3%±3.7% mono, 92.7%±3.6% binucleated; n=687] in WT vs. [30.8%±6.1% mono, 69.2%±6.1% binucleated; n=793] in α1G-/-, p<0.05. CSA in α1G-/- was smaller than in WT: 2267.4±1119.7 in WT vs. 1784.6±683.9 in α1G-/- in mononulceated (p<0.0001), 2419.2±712.4 in WT vs. 2048.3±671.1 in α1G-/- in binucleated (p<0.0001).

There is large amount of DNA synthesis in NMVMs after birth, by day 7 most of the WT NMVMs are arrested in G2 and become binucleated. Myocyte without α1G TTCCs did not exit from the cell cycle normally.

Abstract P074: Loss of Function of TRPC4 Protects Against Cardiac Dysfunction Progression After Myocardial Infarction

The source of Ca 2+ to hypertrophic signaling after myocardial infarction (MI) is not clearly defined. Transient Receptor Potential Canonical (TRPC) channels could be an important source of hypertrophic Ca 2+ after MI. The objective of this study was to determine if TRPC 4 is a major source of Ca 2+ influx mediating cardiac dysfunction after MI.

Methods: Cardiac-specific transgenic mice that express a dominant-negative (dn) TRPC4 that reduces the activity of the TRPC1/4/5 subfamily of channels in the heart were used. MI was produced and in-vivo cardiac function was measured with ECHO. Myocytes were isolated and isoproterenol (ISO) effects on LTCC Current ( I Ca-L ), fractional shortening (FS) and Ca 2+ transients were measured 6 weeks after MI.

Results: Baseline ejection fraction (EF) and fractional shortening (FS) were greater in (dn) TRPC4 vs. WT mice. Two weeks after MI, EF and FS were significantly decreased in all animals (WT: 37.1% and 18.2%; (dn) TRPC4: 41.7% and 20.5%), but there was no significant difference between WT and (dn) TRPC4 mice. Six weeks after MI, EF and FS were significant greater in (dn) TRPC4 compared with WT mice (WT: 37.4% and 18.2%; (dn) TRPC4: 52.2% and 27.4%). Heart weight and lung weight were significantly increased after 2 weeks MI, but there were significant lower heart and lung weight in (dn) TRPC4 vs. WT mice after 6 weeks MI. I Ca-L [[Unsupported Character - Codename &shy;]] after 6 weeks MI was smaller than that in sham myocytes, and there was no significant difference between (dn) TRPC4 and WT myocytes. Contractions and Ca 2+ transients were significantly greater in sham and post-MI (dn) TRPC4 vs. WT myocytes. ISO increased contractions and Ca 2+ transients to a similar extent in all myocytes.

Conclusions: (dn) TRPC4 mice have greater baseline cardiac and myocyte function. While initial effects of MI were similar to control, there was improved function in these mice by 6 weeks. These results suggest that blocking TRPC4 after MI may reduce pathological cardiac remodeling.

Correlation between fetal movement revealed in actography and fetal-neonatal well-being: observational study on 3,805 pregnancies followed in a Northern Italy tertiary care hospital

PURPOSE OF INVESTIGATION

To evaluate the correlation between fetal movement revealed in cardiotocography and fetal-neonatal well-being as well as to assess the value of cardiotocography in our clinical practice.

METHODS

Retrospective analysis of 3,805 pregnancies followed at Parma General Hospital. Exclusion criteria were cesarean section, preterm delivery, and stillbirth. We analyzed the predictive power of actography during the dilating and expulsive phases of labor by establishing a correlation between number of fetal movements and our neonatal indexes of well being, i.e., cardiotocographic score, Apgar index and neonatal pH value. Statistical tests used were Fisher's test, chi-square test (X2), Pearson correlation and Spearman Rho; p value was considered significant if it was less than 0.05.

RESULTS

We considered 2,389 vaginal deliveries. Analyzing the correlation between fetal movement and cardiotocographic score in the two different phases of labor, the comparison among subpopulations identified by different cardiotocograph scores revealed no statistical difference.

CONCLUSION

Cardiotocography is reconfirmed as a good instrument to evaluate neonatal outcome, while actigraphy cannot be used alone to define fetal well-being, mainly due to the inability to standardize assessment of the actographic study.

Increasing cardiac contractility after myocardial infarction exacerbates cardiac injury and pump dysfunction

RATIONALE

Myocardial infarction (MI) leads to heart failure (HF) and premature death. The respective roles of myocyte death and depressed myocyte contractility in the induction of HF after MI have not been clearly defined and are the focus of this study.

OBJECTIVES

We developed a mouse model in which we could prevent depressed myocyte contractility after MI and used it to test the idea that preventing depression of myocyte Ca(2+)-handling defects could avert post-MI cardiac pump dysfunction.

METHODS AND RESULTS

MI was produced in mice with inducible, cardiac-specific expression of the β2a subunit of the L-type Ca(2+) channel. Myocyte and cardiac function were compared in control and β2a animals before and after MI. β2a myocytes had increased Ca(2+) current; sarcoplasmic reticulum Ca(2+) load, contraction and Ca(2+) transients (versus controls), and β2a hearts had increased performance before MI. After MI, cardiac function decreased. However, ventricular dilation, myocyte hypertrophy and death, and depressed cardiac pump function were greater in β2a versus control hearts after MI. β2a animals also had poorer survival after MI. Myocytes isolated from β2a hearts after MI did not develop depressed Ca(2+) handling, and Ca(2+) current, contractions, and Ca(2+) transients were still above control levels (before MI).

CONCLUSIONS

Maintaining myocyte contractility after MI, by increasing Ca(2+) influx, depresses rather than improves cardiac pump function after MI by reducing myocyte number.

CaMKII negatively regulates calcineurin-NFAT signaling in cardiac myocytes

RATIONALE

Pathological cardiac myocyte hypertrophy is thought to be induced by the persistent increases in intracellular Ca(2+) needed to maintain cardiac function when systolic wall stress is increased. Hypertrophic Ca(2+) binds to calmodulin (CaM) and activates the phosphatase calcineurin (Cn) and CaM kinase (CaMK)II. Cn dephosphorylates cytoplasmic NFAT (nuclear factor of activated T cells), inducing its translocation to the nucleus where it activates antiapoptotic and hypertrophic target genes. Cytoplasmic CaMKII regulates Ca(2+) handling proteins but whether or not it is directly involved in hypertrophic and survival signaling is not known.

OBJECTIVE

This study explored the hypothesis that cytoplasmic CaMKII reduces NFAT nuclear translocation by inhibiting the phosphatase activity of Cn.

METHODS AND RESULTS

Green fluorescent protein-tagged NFATc3 was used to determine the cellular location of NFAT in cultured neonatal rat ventricular myocytes (NRVMs) and adult feline ventricular myocytes. Constitutively active (CaMKII-CA) or dominant negative (CaMKII-DN) mutants of cytoplasmic targeted CaMKII(deltac) were used to activate and inhibit cytoplasmic CaMKII activity. In NRVM CaMKII-DN (48.5+/-3%, P<0.01 versus control) increased, whereas CaMKII-CA decreased (5.9+/-1%, P<0.01 versus control) NFAT nuclear translocation (Control: 12.3+/-1%). Cn inhibitors were used to show that these effects were caused by modulation of Cn activity. Increasing Ca(2+) increased Cn-dependent NFAT translocation (to 71.7+/-7%, P<0.01) and CaMKII-CA reduced this effect (to 17.6+/-4%). CaMKII-CA increased TUNEL and caspase-3 activity (P<0.05). CaMKII directly phosphorylated Cn at Ser197 in CaMKII-CA infected NRVMs and in hypertrophied feline hearts.

CONCLUSION

These data show that activation of cytoplasmic CaMKII inhibits NFAT nuclear translocation by phosphorylation and subsequent inhibition of Cn.

Pelvic lymphadenectomy in endometrial cancer: our current experience

OBJECTIVE

Lymph node involvement is the single most important factor in the prognosis of endometrial cancer, because it is predictive of locoregional and distant metastases. The purpose of our study was to determine whether lymphadenectomy is useful in the surgical staging of endometrial cancer and if it may help establish a more accurate prognosis and reduce the need for postoperative therapy in patients without surgical complications.

STUDY DESIGN

We conducted a retrospective study on 55 patients with diagnosis of endometrial cancer.

RESULTS

Surgical staging of patients undergoing pelvic lymphadenectomy (47/55) showed that 59.6% of cases (n = 28) had Stage I cancer (IA in 4, IB in 16, IC in 8), 17.02% (n = 8) Stage II (IIA in 3, IIB in 5), 21.2% (n = 10) Stage III (IIIB in 5, IIIC in 5), and 2.1% (n = 1) Stage IVA. In the remaining eight patients with a very high anesthesiologic risk (ASA 4), surgical staging was incomplete because they underwent only node palpation.

CONCLUSION

In conclusion, as we wait for the sentinel lymph node technique to demonstrate satisfactory results and be standardized also for endometrial cancer, we believe that surgical lymph node dissection plays a crucial role in debulking this type of cancer. When performed by a good surgical oncology team, it does not entail a significantly increased operative risk.

Incidence of port-site metastasis after laparoscopic management of borderline ovarian tumors: a series of 22 patients

PURPOSE

The aim of this work was to evaluate the incidence of port-site metastasis in patients undergoing laparoscopy for borderline ovarian carcinoma (BOT).

METHODS

Twenty-two patients who underwent laparoscopy from 2004 to 2008 for BOT were evaluated retrospectively.

RESULTS

In 15 patients an ultraconservative procedure with enucleation of the annexal neoplasia was carried out, while in five (23%) unilateral salpingo-oophorectomy was performed and in two cases (9%) bilateral salpingo-oophorectomy was done.

CONCLUSION

The literature data report few cases of port-site metastasis in BOT patients. Residual cutaneous metastases have been reported to occur within 12 months from the first surgery, generally in association with serous histology. In our analysis, we found 17 out of 22 cases of serous BOT, three mucinous and two endometriod. In no case was cutaneous metastasis revealed after an average of 30 months of follow-up.

A perspective study on correlation between HPV DNA and lymph nodes in surgically treated cervical carcinoma patients. Preliminary data

The purpose of this study was to analyze the presence of HPV DNA in lymph nodes in patients with cervical cancer.

STUDY DESIGN

A prespective study was performed on a total of 18 patients with cervical cancer in FIGO Stage I-II. The surgical procedure consisted of systematic pelvic lymphadenectomy with removal of the common/external/internal (obturator) iliac lymph node chains, followed by radical hysterectomy depending on the clinical stage, or by Piver's type II radical laparohysterectomy for Stage IA2 carcinoma and Piver's type-III laparohysterectomy for Stage IB or Stage II carcinoma. After removal by a technique not yet described in the literature, the lymph nodes were processed directly in the operating room. HPV DNA testing was done using a cytobrush device. At the end of this operation, the lymph nodes were sent to the hospital's pathologist for metastasis detection.

RESULTS

The correlation between a positive HPV DNA test in the cervix and lymph node metastasis was non significant (p < 0.63). By contrast, the correlation between a positive HPV DNA test in the lymph nodes and lymph node metastasis was highly significant (p < 0.005), as was the correlation between positive HPV DNA tests in the cervix and lymph nodes (p < 0.005). Finally, the correlation between disease stage and positive HPV DNA testing in the lymph nodes was also significant (p < 0.05).

CONCLUSIONS

In conclusion, the technique that we used for HPV DNA extraction appears safe and reproducible. The results are comparable with, if not better, than those obtained with other techniques reported in the literature. The presence of HPV DNA in the lymph nodes is probably an early indicator of metastasis and as such it could be used as a predictor of relapse. Normally untreated patients who have this marker could then receive adjuvant therapy.

Ca2+ influx through T- and L-type Ca2+ channels have different effects on myocyte contractility and induce unique cardiac phenotypes

T-type Ca(2+) channels (TTCCs) are expressed in the developing heart, are not present in the adult ventricle, and are reexpressed in cardiac diseases involving cardiac dysfunction and premature, arrhythmogenic death. The goal of this study was to determine the functional role of increased Ca(2+) influx through reexpressed TTCCs in the adult heart. A mouse line with cardiac-specific, conditional expression of the alpha1G-TTCC was used to increase Ca(2+) influx through TTCCs. alpha1G hearts had mild increases in contractility but no cardiac histopathology or premature death. This contrasts with the pathological phenotype of a previously studied mouse with increased Ca(2+) influx through the L-type Ca(2+) channel (LTCC) secondary to overexpression of its beta2a subunit. Although alpha1G and beta2a myocytes had similar increases in Ca(2+) influx, alpha1G myocytes had smaller increases in contraction magnitude, and, unlike beta2a myocytes, there were no increases in sarcoplasmic reticulum Ca(2+) loading. Ca(2+) influx through TTCCs also did not induce normal sarcoplasmic reticulum Ca(2+) release. alpha1G myocytes had changes in LTCC, SERCA2a, and phospholamban abundance, which appear to be adaptations that help maintain Ca(2+) homeostasis. Immunostaining suggested that the majority of alpha1G-TTCCs were on the surface membrane. Osmotic shock, which selectively eliminates T-tubules, induced a greater reduction in L- versus TTCC currents. These studies suggest that T- and LTCCs are in different portions of the sarcolemma (surface membrane versus T-tubules) and that Ca(2+) influx through these channels induce different effects on myocyte contractility and lead to distinct cardiac phenotypes.

Uterine smooth muscle tumor of uncertain malignant potential: a three-case report

Based on the degree of cytologic atypia, mitotic activity, and other features, uterine smooth muscle tumors have historically been grouped into two classes: benign leiomyomas and malignant leiomyosarcomas. However, this separation holds true more in principle than in practice because the tumor's biological potential may not always be determined with certainty, complicating diagnosis, and therapy. We report three cases of patients with uterine smooth muscle tumors of uncertain malignant potential. Surgery was radical in two and conservative in one. During the follow-up, one patient developed diffuse lung metastases. The two other patients have not shown any signs of relapse to date. Uterine smooth muscle tumors of uncertain malignant potential may have an unpredictable clinical course and may metastasize to seemingly low-grade neoplasms in distant sites even after several years and even in the absence of important negative prognostic predictors, such as coagulative tumor cell necrosis. At present, no final consensus has been reached on the choice of the best strategy for surgery and adjuvant therapy

Calcineurin inhibition normalizes beta-adrenergic responsiveness in the spontaneously hypertensive rat

Calcineurin, a Ca(2+)-regulated protein phosphatase, links myocardial Ca(2+) signaling with hypertrophic gene transcription. Calcineurin abundance increases in pressure-overload hypertrophy and may reduce agonist-mediated phospholamban (PLB) phosphorylation to underlie blunted beta-adrenergic receptor (beta-AR) responsiveness in hypertension. This hypothesis was tested by measuring the effects of calcineurin inhibition on changes in cardiac contractility caused by beta-adrenergic stimulation in spontaneously hypertensive rats (SHR). Female SHR (age: 7 mo) and age-matched female Wistar-Kyoto rats (WKY) were studied. Heart weight-to-body weight ratio (P < 0.01) and systolic blood pressure (P < 0.01) were greater in SHR compared with WKY and were associated with increased myocardial calcineurin mRNA (CnAbeta) and activity (P < 0.05). beta-AR stimulation with isoproterenol (Iso) increased calcineurin activity (P < 0.05) in both WKY and SHR hearts, and this activity was suppressed with cyclosporin A (CsA) treatment. In SHR, CsA improved left ventricular whole heart and isolated myocyte beta-AR responsiveness by normalizing PLB phosphorylation at Ser(16) and Thr(17) (P < 0.05). These CsA-induced, PLB-mediated effects were associated with an augmentation in cardiomyocyte peak Ca(2+) and a reduced rate (time constant of isovolumic pressure relaxation, tau) and magnitude of diastolic Ca(2+) during beta-AR stimulation. In conclusion, CsA normalized the blunted beta-AR responsiveness associated with hypertension, in part, by mitigating calcineurin activity while improving PLB phosphorylation and subsequent sarcoplasmic reticulum Ca(2+) regulation.

Benchmarking a memetic algorithm for ordering microarray data

This work introduces a new algorithm for "gene ordering". Given a matrix of gene expression data values, the task is to find a permutation of the gene names list such that genes with similar expression patterns should be relatively close in the permutation. The algorithm is based on a combined approach that integrates a constructive heuristic with evolutionary and Tabu Search techniques in a single methodology. To evaluate the benefits of this method, we compared our results with the current outputs provided by several widely used algorithms in functional genomics. We also compared the results with our own hierarchical clustering method when used in isolation. We show that the use of images, corrupted with known levels of noise, helps to illustrate some aspects of the performance of the algorithms and provide a complementary benchmark for the analysis. The use of these images, with known high-quality solutions, facilitates in some cases the assessment of the methods and helps the software development, validation and reproducibility of results. We also propose two quantitative measures of performance for gene ordering. Using these measures, we make a comparison with probably the most used algorithm (due to Eisen and collaborators, PNAS 1998) using a microarray dataset available on the public domain (the complete yeast cell cycle dataset).

Periostin and periostin-like factor in the human heart: possible therapeutic targets

BACKGROUND

Although numerous signaling pathways have been identified in adult heart disease, our ability to diagnose and treat human cardiomyopathies remains limited. A family of proteins, which includes periostin and periostin-like factor (PLF), has been identified during heart development and disease. Based on recent findings, these proteins are candidate therapeutic agents for heart disease.

METHODS

Affymetrix GeneChip Expression Analysis as well as northern and western blot analyses were used to determine periostin and PLF expression in humans. Periostin-like factor levels were determined, by western blot analysis, in the rat animal model used to study myocardial loading and unloading. In vivo and in vitro effects of overexpressing PLF by infection with adenovirus were assessed by calculating cardiac myocyte cross-sectional area and determining the level of protein synthesis, respectively.

RESULTS AND CONCLUSIONS

Our findings on PLF suggest that this periostin isoform plays a crucial role in adult cardiac myocyte growth following mechanical overload, thus, implicating its potential as a therapeutic target. In addition, we believe that the differences between the periostin and PLF are of functional significance.

Ca 2+ Influx–Induced Sarcoplasmic Reticulum Ca 2+ Overload Causes Mitochondrial-Dependent Apoptosis in Ventricular Myocytes

Increases in Ca 2+ influx through the L-type Ca 2+ channel (LTCC, Cav1.2) augment sarcoplasmic reticulum (SR) Ca 2+ loading and the amplitude of the cytosolic Ca 2+ transient to enhance cardiac myocyte contractility. Our hypothesis is that persistent increases in Ca 2+ influx through the LTCC cause apoptosis if the excessive influx results in SR Ca 2+ overload. Feline ventricular myocytes (VMs) in primary culture were infected with either an adenovirus (Ad) containing a rat Cav1.2 β 2a subunit-green fluorescent protein (GFP) fusion gene (Adβ 2a ) to increase Ca 2+ influx or with AdGFP as a control. Significantly fewer β 2a -VMs (21.4±5.6%) than GFP-VMs (99.6±1.7%) were viable at 96 hours. A fraction of β 2a -VMs (20.8±1.8%) contracted spontaneously (SC-β 2a -VMs), and viability was significantly correlated with the percentage of SC-β 2a -VMs. Higher percentages of apoptotic nuclei, DNA laddering, and cytochrome C release were detected in β 2a -VMs. This apoptosis was prevented with pancaspase or caspase-3 or caspase-9 inhibitors. L-type calcium current (I Ca-L ) density was greater in β 2a -VMs (23.4±2.8 pA/pF) than in GFP-VMs (7.6±1.6 pA/pF). SC-β 2a -VMs had higher diastolic intracellular Ca 2+ (Indo-1 ratio: 1.1±0.1 versus 0.7±0.03, P <0.05) and systolic Ca 2+ transients (1.89±0.27 versus 0.80±0.08) than GFP-VMs. Inhibitors of Ca 2+ influx, SR Ca 2+ uptake and release, mitochondrial Ca 2+ uptake, mitochondrial permeation transition pore, calpain, and Bcl-2-associated X protein protected β 2a -VMs from apoptosis. These results show that persistent increases in Ca 2+ influx through the I Ca-L enhance contractility but lead to apoptosis through a mitochondrial death pathway if SR Ca 2+ overload is induced.

Radioguided sentinel lymph node detection in vulvar cancer

Lymph node status is the most important prognostic factor in vulvar cancer. Histologically, sentinel nodes may be representative of the status of the other regional nodes. Identification and histopathologic evaluation of sentinel nodes could then have a significant impact on clinical management and surgery. The aim of this study was to evaluate the feasibility and diagnostic accuracy of sentinel lymph node detection by preoperative lymphoscintigraphy with technetium-99 m-labeled nanocolloid, followed by radioguided intraoperative detection. Nine patients with stage T1, N0, M0, and 11 patients with stage T2, N0, M0 squamous cell carcinoma of the vulva were included in the study. Only three cases had lesions exceeding 3.5 cm in diameter. Sentinel nodes were detected in 100% of cases. A total of 30 inguinofemoral lymphadenectomies were performed, with a mean of 10 surgically removed nodes. Histological examination revealed 17 true negative sentinel nodes, 2 true positive, and 1 false negative. In our case series, sentinel lymph node detection had a 95% diagnostic accuracy, with only one false negative. Based on literature evidence, the sentinel node procedure is feasible and reliable in vulvar cancer; however, the value of sentinel node dissection in the treatment of early-stage vulvar cancer still needs to be confirmed.

Radioguided sentinel lymph node detection in vulvar cancer

Lymph node status is the most important prognostic factor in vulvar cancer. Histologically, sentinel nodes may be representative of the status of the other regional nodes. Identification and histopathologic evaluation of sentinel nodes could then have a significant impact on clinical management and surgery. The aim of this study was to evaluate the feasibility and diagnostic accuracy of sentinel lymph node detection by preoperative lymphoscintigraphy with technetium-99 m–labeled nanocolloid, followed by radioguided intraoperative detection. Nine patients with stage T1, N0, M0, and 11 patients with stage T2, N0, M0 squamous cell carcinoma of the vulva were included in the study. Only three cases had lesions exceeding 3.5 cm in diameter. Sentinel nodes were detected in 100% of cases. A total of 30 inguinofemoral lymphadenectomies were performed, with a mean of 10 surgically removed nodes. Histological examination revealed 17 true negative sentinel nodes, 2 true positive, and 1 false negative. In our case series, sentinel lymph node detection had a 95% diagnostic accuracy, with only one false negative. Based on literature evidence, the sentinel node procedure is feasible and reliable in vulvar cancer; however, the value of sentinel node dissection in the treatment of early-stage vulvar cancer still needs to be confirmed.