High-Output Heart Failure in Multiple Myeloma: Novel Application of Tc-99m MAA to Identify Intramedullary Shunting.

We introduce the innovative use of technetium-99m-labeled macroaggregated albumin to diagnose high-output heart failure in a patient with multiple myeloma with persistent congestion symptoms. Symptom resolution occurred with lenalidomide and steroids. This marks the first clinical use of technetium-99m-labeled macroaggregated albumin for clarifying high-output heart failure etiology.

Use of Extracorporeal Membrane Oxygenation for Primary Graft Dysfunction After Cardiac Transplantation: Results of an A Priori Ventless Approach.

Primary graft dysfunction (PGD) after cardiac transplantation is a devastating complication with increasing frequency lately in the setting of donation after circulatory death (DCD). Severe PGD is commonly treated with extracorporeal membrane oxygenation (ECMO) using central or peripheral cannulation. We retrospectively reviewed the outcomes of PGD after cardiac transplantation requiring ECMO support at our center from 2015 to 2020, focused on our now preferential approach using peripheral cannulation without a priori venting. During the study period, 255 patients underwent heart transplantation at our center and 26 (10.2%) of them required ECMO for PGD. Of 24 patients cannulated peripherally 19 (79%) were alive at 30 days and 17 (71%) 1 year after transplant; two additional patients underwent central ECMO cannulation due to unfavorable size of femoral vessels and concern for limb ischemia. Successful decannulation with full graft function recovery occurred in 22 of 24 (92%) patients cannulated peripherally. Six of them had an indwelling intra-aortic balloon pump placed before the transplantation. None of the other 18 patients received a ventricular vent. In conclusion, the use of an a priori peripheral and ventless ECMO approach in patients with PGD after heart transplant is an effective strategy associated with high rates of graft recovery and survival.

Predicting Hemodynamic Changes During Intra-Aortic Balloon Pump Support With a Longitudinal Evaluation.

The use of intra-aortic balloon pump (IABP) has decreased in recent years due to negative outcome studies in cardiogenic shock complicating acute myocardial infarction, despite its favorable adverse-event profile. Acute hemodynamic response studies have identified potential super-responders with immediate improvements in cardiac index (CI) in heart failure patients. This single-center retrospective study aimed to predict CI and mean arterial pressure (MAP) changes throughout the entire duration of IABP support. The study analyzed 336 patients who received IABP between 2016 and 2022. Linear mixed-effect regression models were used to predict CI and MAP improvement during IABP support. The results showed that CI and MAP increases during the first days of support, and changes during IABP support varied with time and were associated with baseline parameters. Longitudinal CI change was associated with body surface area, baseline CI, baseline pulmonary artery pulsatility index, baseline need for pressors, and diabetes. Longitudinal MAP change was associated with baseline MAP, baseline heart rate, need for pressors, or inotropes. The study recommends considering these parameters when deciding if IABP is the most appropriate form of support for a specific patient. Further prospective studies are needed to validate the findings.

Impact of narrowing perioperative antibiotic prophylaxis for left ventricular assist device implantation.

BACKGROUND: Although infections are a significant potential complication among patients undergoing left ventricular assist device (LVAD) implantation, standardized surgical infection prophylaxis (SIP) regimens are not well defined. At Montefiore Medical Center, a 4-drug SIP regimen containing fluconazole, ciprofloxacin, rifampin, and vancomycin was previously utilized. In January 2020, the antimicrobial stewardship program implemented a 2-drug SIP regimen of vancomycin and cefazolin to limit exposure to broad-spectrum antibiotics. This study evaluated LVAD-associated infection rates prior to and following the SIP revision. METHODS: A retrospective review of patients who underwent LVAD implantation from 1/2018 to 4/2021 was performed. Infections were classified using the International Society for Heart and Lung Transplantation definitions. Infection rates at 2 weeks, 30 days, and 90 days post-implantation in the 4-drug SIP regimen (1/2018-12/2019) and the 2-drug SIP regimen (1/2020 to 4/2021) were compared. RESULTS: A total of 71 patients were included. The number of patients with LVAD-associated infections (including surgical site infections) was not significantly different in either SIP group at 2 weeks (9% vs. 4%, p = .64), 30 days (9% vs. 11%, p = .99), or 90 days (19% vs. 14%, p = .75). There was no statistically significant difference in 30 or 90-day mortality. LVAD-associated gram-negative (7% vs. 7%; p > .99) and fungal (5% vs. 0%; p = .51) infections were uncommon. The most common organism isolated was Staphylococcus aureus, and the most common type of infection was pneumonia in both SIP groups. CONCLUSION: No significant difference in LVAD-associated infections or infection-related mortality was observed with de-escalation of perioperative antibiotics. Additional studies with larger sample sizes are needed to endorse the findings of this study.

A History of Heart Failure Is an Independent Risk Factor for Death in Patients Admitted with Coronavirus 19 Disease.

AIMS: The association between cardiovascular diseases, such as coronary artery disease and hypertension, and worse outcomes in COVID-19 patients has been previously demonstrated. However, the effect of a prior diagnosis of heart failure (HF) with reduced or preserved left ventricular ejection fraction on COVID-19 outcomes has not yet been established. METHODS AND RESULTS: We retrospectively studied all adult patients with COVID-19 admitted to our institution from March 1st to 2nd May 2020. Patients were grouped based on the presence or absence of HF. We used competing events survival models to examine the association between HF and death, need for intubation, or need for dialysis during hospitalization. Of 4043 patients admitted with COVID-19, 335 patients (8.3%) had a prior diagnosis of HF. Patients with HF were older, had lower body mass index, and a significantly higher burden of co-morbidities compared to patients without HF, yet the two groups presented to the hospital with similar clinical severity and similar markers of systemic inflammation. Patients with HF had a higher cumulative in-hospital mortality compared to patients without HF (49.0% vs. 27.2%, p < 0.001) that remained statistically significant (HR = 1.383, p = 0.001) after adjustment for age, body mass index, and comorbidities, as well as after propensity score matching (HR = 1.528, p = 0.001). Notably, no differences in mortality, need for mechanical ventilation, or renal replacement therapy were observed among HF patients with preserved or reduced ejection fraction. CONCLUSIONS: The presence of HF is a risk factor of death, substantially increasing in-hospital mortality in patients admitted with COVID-19.

COVID-19 in heart transplant recipients-A seroprevalence survey.

The clinical spectrum of COVID-19 in heart transplant recipients has not been fully defined, because asymptomatic and sub-clinical cases are difficult to capture. Seroprevalence surveys are an important tool to identify not just cases that have come to clinical attention, but all previously infected recipients. We performed a seroprevalence survey of the adult heart transplant program at a large New York City Hospital System. A total of 232 (87% of recipients being followed) subjects were tested, of whom 37 (15.9%) were found to be previously infected. This is comparable to the overall rate of prior infection in the NYC metro area. Disease course tended to be more severe than in the general population; however, this was at least partially driven by traditional risk factors of age and comorbidities. Lastly, 9 of 10 recipients who were initially found to be PCR positive subsequently tested positive for antibodies, confirming the ability of this population to mount a humoral response. In conclusion, prevalence of COVID-19 in heart transplant recipients on immunosuppression was comparable to that in the general population of NYC, and 90% of those with an initially positive viral swab developed antibodies. In those who are infected, disease course tends to be more severe.

Statin Use and In-Hospital Mortality in Patients With Diabetes Mellitus and COVID-19.

Background Severe coronavirus disease 2019 (COVID-19) is characterized by a proinflammatory state with high mortality. Statins have anti-inflammatory effects and may attenuate the severity of COVID-19. Methods and Results An observational study of all consecutive adult patients with COVID-19 admitted to a single center located in Bronx, New York, was conducted from March 1, 2020, to May 2, 2020. Patients were grouped as those who did and those who did not receive a statin, and in-hospital mortality was compared by competing events regression. In addition, propensity score matching and inverse probability treatment weighting were used in survival models to examine the association between statin use and death during hospitalization. A total of 4252 patients were admitted with COVID-19. Diabetes mellitus modified the association between statin use and in-hospital mortality. Patients with diabetes mellitus on a statin (n=983) were older (69±11 versus 67±14 years; P<0.01), had lower inflammatory markers (C-reactive protein, 10.2; interquartile range, 4.5-18.4 versus 12.9; interquartile range, 5.9-21.4 mg/dL; P<0.01) and reduced cumulative in-hospital mortality (24% versus 39%; P<0.01) than those not on a statin (n=1283). No difference in hospital mortality was noted in patients without diabetes mellitus on or off statin (20% versus 21%; P=0.82). Propensity score matching (hazard ratio, 0.88; 95% CI, 0.83-0.94; P<0.01) and inverse probability treatment weighting (HR, 0.88; 95% CI, 0.84-0.92; P<0.01) showed a 12% lower risk of death during hospitalization for statin users than for nonusers. Conclusions Statin use was associated with reduced in-hospital mortality from COVID-19 in patients with diabetes mellitus. These findings, if validated, may further reemphasize administration of statins to patients with diabetes mellitus during the COVID-19 era.

Utilization rates and clinical outcomes of hepatitis C positive donor hearts in the contemporary era.

BACKGROUND: Hepatitis C virus (HCV) donors should be categorized as HCV-viremic (antibody [Ab] negative or positive/Nucleic Acid testing [NAT] positive) or HCV Ab+nonviremic (Ab+/NAT-). Whereas recipients of hearts from HCV-viremic donors will develop viremia but can be cured of HCV shortly after transplant with direct-acting antivirals (DAAs), recipients of hearts from HCV Ab+ nonviremic donors are highly unlikely to become viremic or require DAAs. Given this important difference in risk, we assessed the utilization trends and post-heart-transplantation outcomes of HCV-naive (Ab-/NAT-), HCV-viremic, and HCV Ab+ nonviremic donor hearts. METHODS: A total of 26,572 adult donors (≥18 years) with information on HCV Ab and NAT status were identified in the United Network for Organ Sharing registry between August 2015 and June 2018 for utilization rates. Adult heart transplant recipients of these donors were compared for primary graft failure (PGF) at 90 days and 1-year recipient survival. RESULTS: A total of 96 HCV Ab+ nonviremic and 135 HCV-viremic adult donor hearts were transplanted during the study period. The utilization rates of both HCV Ab+ nonviremic (1.4%-23.4%) and HCV-viremic (0.7%-25.4%) donor hearts increased significantly approaching HCV-naive rates (29.04%). There was no significant difference in rates of PGF and 1-year survival between recipients in the 3 donor HCV groups. We also used (1:3) propensity score matching and found similar 1-year survival in different donor HCV groups (HCV-naive vs HCV Ab+ nonviremic, p = 0.59, and HCV-naive vs HCV-viremic, p = 0.98). CONCLUSIONS: Recipients of HCV-viremic and HCV Ab+ nonviremic donor hearts had equivalent risk of PGF and 1-year mortality compared with recipients of HCV-naive donor hearts. Although only HCV-viremic organs require DAAs and the risk of coronary artery vasculopathy after treated HCV infection has not been defined, the utilization rates of both HCV Ab+ nonviremic and HCV-viremic adult donor hearts have increased at an equal pace now approaching HCV-naive rates.

Hemolysis and Nonhemorrhagic Stroke During Venoarterial Extracorporeal Membrane Oxygenation.

BACKGROUND: Hemolysis, even at low levels, activates platelets to create a prothrombotic state and is common during mechanical circulatory support. We examined the association of low-level hemolysis (LLH) and nonhemorrhagic stroke during venoarterial extracorporeal membrane oxygenation (VA ECMO) support. METHODS: A single-center retrospective review of all adult patients placed on VA ECMO from January 2012 to September 2017 was conducted. To determine the association between LLH and nonhemorrhagic stroke, patients were categorized as those with and without LLH. LLH was defined by 48-hour plasma free hemoglobin (PFHb) of 11 to 50 mg/dL after VA ECMO implantation. RESULTS: Of 201 patients who underwent VA ECMO placement, 150 (75%) met inclusion criteria and comprised the study population. They were 55 ± 14 years of age and 50 (33%) were women. Sixty-two (41%) patients had LLH. Patients with LLH had a higher likelihood of incident nonhemorrhagic stroke during VA ECMO support (20 [32%] versus 4 [5%]; adjusted hazard ratio [HR], 7.6; 95% confidence interval [CI], 2.2 to 25.9; p = 0.001). The severity of LLH was associated with an incrementally higher likelihood of a nonhemorrhagic stroke (PFHb 26 to 50 mg/dL: HR, 11.3; 95% CI, 3.6 to 35.1; p = 0.001; PFHb 11 to 25 mg/dL: HR, 4.4; 95% CI, 1.36 to 14.85; p = 0.014) in comparison with no LLH. Those with LLH had a 2-fold greater increase in mean platelet volume after VA ECMO placement (0.98 ± 1.1 fL versus 0.49 ± 0.96 fL; p = 0.03). Patients with a nonhemorrhagic stroke had a higher operative mortality (20 [83%] versus 57 [45%]; adjusted HR, 3.1; 95% CI, 1.8 to 5.3; p < 0.001). CONCLUSIONS: Hemolysis at low levels during VA ECMO support is associated with subsequent nonhemorrhagic stroke.

Continuous-Flow Left Ventricular Assist Device Survival Improves With Multidisciplinary Approach.

BACKGROUND: Continuous-flow left ventricular assist devices have revolutionized the management of advanced heart failure. Device complications continue to limit survival, but enhanced management strategies have shown promise. This study compared outcomes for HeartMate II recipients before and after implementation of a multidisciplinary continuous support heart team (HTMCS) strategy. METHODS: Between January 2012 and December 2016, 124 consecutive patients underwent primary HeartMate II implantation at our institution. In January 2015, we instituted a HTMCS approach consisting of (1) daily simultaneous cardiology/cardiac surgery/critical care/pharmacy/coordinator rounds, (2) pharmacist-directed anticoagulation, (3) speed optimization echocardiogram before discharge, (4) comprehensive device thrombosis screening and early intervention, (5) blood pressure clinic with pulsatility-adjusted goals, (6) early follow-up after discharge and individual long-term coordinator/cardiologist assignment, and (7) systematic basic/advanced/expert training and credentialing of ancillary in-hospital providers. All patients completed 1-year of follow-up. RESULTS: Demographic characteristics for pre-HTMCS (n = 71) and HTMCS (n = 53) groups, including age (55.8 ± 12.1 versus 52.5 ± 14.1 years, p = not significant), percentage of men (77.5% versus 71.7%, p = not significant), and Interagency Registry for Mechanically Assisted Circulatory Support class 3 (84.5% versus 83.0%, p = not significant), were comparable. One-year survival was 74.6% versus 100% for the pre-HTMCS and HTMCS groups, respectively (p = 0.0002). One-year survival free of serious adverse events (reoperation to replace device or disabling stroke) was 70.4% versus 84.9% for the pre-HTMCS and HTMCS groups, respectively (p = 0.059). Event per patient-year rates for disabling stroke (0.15 versus 0, p = 0.019), gastrointestinal bleeding (0.87 versus 0.51, p = 0.11), and driveline infection (0.24 versus 0.10, p = 0.18) were lower for the HTMCS group, whereas pump thrombosis requiring device exchange was higher (0.09 versus 0.18, p = 0.14). CONCLUSIONS: Implementing a comprehensive multidisciplinary approach substantially improved outcomes for recipients of continuous-flow left ventricular assist devices.

NOX4 (NADPH Oxidase 4) and Poldip2 (Polymerase δ-Interacting Protein 2) Induce Filamentous Actin Oxidation and Promote Its Interaction With Vinculin During Integrin-Mediated Cell Adhesion.

Objective- Actin cytoskeleton assembly and organization, as a result of focal adhesion (FA) formation during cell adhesion, are dependent on reactive oxygen species and the cellular redox environment. Poldip2 (polymerase δ-interacting protein 2), a novel regulator of NOX4 (NADPH oxidase 4), plays a significant role in reactive oxygen species production and cytoskeletal remodeling. Thus, we hypothesized that endogenous reactive oxygen species derived from Poldip2/NOX4 contribute to redox regulation of actin and cytoskeleton assembly during integrin-mediated cell adhesion. Approach and Results- Using vascular smooth muscle cells, we verified that hydrogen peroxide (H2O2) levels increase during integrin-mediated cell attachment as a result of activation of NOX4. Filamentous actin (F-actin) was oxidized by sulfenylation during cell attachment, with a peak at 3 hours (0.80±0.04 versus 0.08±0.13 arbitrary units at time zero), which was enhanced by overexpression of Poldip2. Depletion of Poldip2 or NOX4 using siRNA, or scavenging of endogenous H2O2 with catalase, inhibited F-actin oxidation by 78±26%, 99±1%, and 98±1%, respectively. To determine the consequence of F-actin oxidation, we examined the binding of F-actin to vinculin, a protein involved in FA complexes that regulates FA maturation. Vinculin binding during cell adhesion as well as migration capacity were inhibited after transfection with actin containing 2 oxidation-resistant point mutations (C272A and C374A). Silencing of Poldip2 or NOX4 also impaired actin-vinculin interaction, which disturbed maturation of FAs and inhibited cell migration. Conclusions- These results suggest that integrin engagement during cell attachment activates Poldip2/Nox4 to oxidize actin, which modulates FA assembly.

Digoxin Is Associated With a Decreased Incidence of Angiodysplasia-Related Gastrointestinal Bleeding in Patients With Continuous-Flow Left Ventricular Assist Devices.

BACKGROUND: Gastrointestinal bleeding (GIB) is one of the principal adverse events affecting patients with continuous-flow left ventricular assist devices (CF-LVADs). Despite the early recognition that GIB is commonly because of gastrointestinal angiodysplasia (GIAD), the exact pathophysiology of this process remains elusive. It has been postulated that the abnormal hemodynamic profile in CF-LVAD patients may activate the angiogenesis signaling cascade via the HIF (hypoxia-inducible factor)-1α/angiopoietin-2 pathway leading to formation of GIADs. Digoxin is a potent inhibitor of HIF-1α synthesis, and we hypothesized that its use reduces the incidence of GIAD and GIB in patients with CF-LVAD. METHODS AND RESULTS: Charts of all adult patients implanted with CF-LVAD between February 2006 and February 2017 were reviewed with particular emphasis on occurrence and cause of GIB. Fifty-four of 199 patients (27%) experienced a GIB. Overall frequency of GIB was lower in the 64 patients receiving digoxin compared with the 135 patients not receiving digoxin (16% versus 33%, P=0.01). Multivariable-adjusted Cox regression analysis confirmed that digoxin use was independently associated with a reduced risk for overall GIB (hazard ratio, 0.49; 95% CI, 0.24-0.98; P=0.045). GIBs were then categorized as non-GIAD, GIAD, or likely GIAD. Although the incidence of non-GIAD was similar in both groups (11% versus 7%, P=0.41), the frequency of GIAD/likely GIAD bleeding was significantly reduced in the digoxin group (5% versus 25%, P=0.0003). Multivariable-adjusted analysis confirmed that digoxin use was independently associated with a reduced risk for GIAD/likely GIAD bleeding (hazard ratio, 0.18; 95% CI, 0.06-0.6; P=0.005). However, digoxin use was not associated with reduced risk for non-GIAD GIB (hazard ratio, 1.54; 95% CI, 0.58-4.08; P=0.39). CONCLUSIONS: Use of digoxin was associated with a significant reduction in GIAD-related GIB in patients with CF-LVAD.

Cardiac transplantation from non-viremic hepatitis C donors.

BACKGROUND: Hepatitis C (HCV) donors are rarely used for cardiac transplantation due to historically poor outcomes. In 2015, nucleic acid testing (NAT) for viral load was added to the routine work-up of organ donors, allowing for the distinction between subjects who remain viremic (HCV Ab+/NAT+) and those who have cleared HCV and are no longer viremic (HCV Ab+/NAT-). The American Society of Transplantation recently recommended that HCV Ab+/NAT- donors be considered non-infectious and safe for transplantation. We present our initial experience with such donors. METHODS: All patients were counseled regarding donor HCV antibody (Ab) and NAT. Transplant recipients were tested post-transplant at 1 week and at 1, 3, and 6 months for HCV seropositivity and viremia. We also analyzed the UNOS database to determine the potential impact of widespread acceptance of HCV Ab+/NAT- organs. RESULTS: Fourteen HCV Ab‒ subjects received hearts from HCV Ab+/NAT- donors in 2017. Over a median follow-up of 256 (192 to 377) days, 3 patients developed a reactive HCV Ab, yet none had a detectable HCV viral load during prospective monitoring at any time. Analysis of the UNOS database for the calendar year 2016 revealed that only 7 (3%) of 220 HCV Ab+/NAT- donors were accepted for heart transplantation. CONCLUSIONS: We have demonstrated the feasibility of utilizing HCV Ab+/NAT- donors for cardiac transplantation without recipient infection. A small percentage of recipients developed HCV Ab without evidence of viremia, possibly consistent with a biological false reactive test, as has been seen in other settings. Large-scale validation of our data may have a significant impact on transplantation rates.

Stress Signals, Mediated by Membranous Glucocorticoid Receptor, Activate PLC/PKC/GSK-3ß/ß-catenin Pathway to Inhibit Wound Closure.

Glucocorticoids (GCs), key mediators of stress signals, are also potent wound healing inhibitors. To understand how stress signals inhibit wound healing, we investigated the role of membranous glucocorticoid receptor (mbGR) by using cell-impermeable BSA-conjugated dexamethasone. We found that mbGR inhibits keratinocyte migration and wound closure by activating a Wnt-like phospholipase (PLC)/ protein kinase C (PKC) signaling cascade. Rapid activation of mbGR/PLC/PKC further leads to activation of known biomarkers of nonhealing found in patients, ß-catenin and c-myc. Conversely, a selective inhibitor of PKC, calphostin C, blocks mbGR/PKC pathway, and rescues GC-mediated inhibition of keratinocyte migration in vitro and accelerates wound epithelialization of human wounds ex vivo. This novel signaling mechanism may have a major impact on understanding how stress response via GC signaling regulates homeostasis and its role in development and treatments of skin diseases, including wound healing. To test tissue specificity of this nongenomic signaling mechanism, we tested retinal and bronchial human epithelial cells and fibroblasts. We found that mbGR/PLC/PKC signaling cascade exists in all cell types tested, suggesting a more general role. The discovery of this nongenomic signaling pathway, in which glucocorticoids activate Wnt pathway via mbGR, provides new insights into how stress-mediated signals may activate growth signals in various epithelial and mesenchymal tissues.

Skin Metabolite, Farnesyl Pyrophosphate, Regulates Epidermal Response to Inflammation, Oxidative Stress, and Migration.

Skin produces cholesterol and a wide array of sterols and non-sterol mevalonate metabolites, including isoprenoid derivative farnesyl pyrophosphate (FPP). To characterize FPP action in epidermis, we generated transcriptional profiles of primary human keratinocytes treated with zaragozic acid (ZGA), a squalene synthase inhibitor that blocks conversion of FPP to squalene resulting in endogenous accumulation of FPP. The elevated levels of intracellular FPP resulted in regulation of epidermal differentiation and adherens junction signaling, insulin growth factor (IGF) signaling, oxidative stress response and interferon (IFN) signaling. Immunosuppressive properties of FPP were evidenced by STAT-1 downregulation and prominent suppression of its nuclear translocation by IFNγ. Furthermore, FPP profoundly downregulated genes involved in epidermal differentiation of keratinocytes in vitro and in human skin ex vivo. Elevated levels of FPP resulted in induction of cytoprotective transcriptional factor Nrf2 and its target genes. We have previously shown that FPP functions as ligand for the glucocorticoid receptor (GR), one of the major regulator of epidermal homeostasis. Comparative microarray analyses show significant but not complete overlap between FPP and glucocorticoid regulated genes, suggesting that FPP may have wider transcriptional impact. This was further supported by co-transfection and chromatin immunoprecipitation experiments where we show that upon binding to GR, FPP recruits ß-catenin and, unlike glucocorticoids, recruits co-repressor GRIP1 to suppress keratin 6 gene. These findings have many clinical implications related to epidermal lipid metabolism, response to glucocorticoid therapy as well as pleiotropic effects of cholesterol lowering therapeutics, statins. J. Cell. Physiol. 231: 2452-2463, 2016. © 2016 Wiley Periodicals, Inc.

Poldip2 controls vascular smooth muscle cell migration by regulating focal adhesion turnover and force polarization.

Polymerase-δ-interacting protein 2 (Poldip2) interacts with NADPH oxidase 4 (Nox4) and regulates migration; however, the precise underlying mechanisms are unclear. Here, we investigated the role of Poldip2 in focal adhesion turnover, as well as traction force generation and polarization. Poldip2 overexpression (AdPoldip2) in vascular smooth muscle cells (VSMCs) impairs PDGF-induced migration and induces a characteristic phenotype of long cytoplasmic extensions. AdPoldip2 also prevents the decrease in spreading and increased aspect ratio observed in response to PDGF and slightly impairs cell contraction. Moreover, AdPoldip2 blocks focal adhesion dissolution and sustains H2O2 levels in focal adhesions, whereas Poldip2 knockdown (siPoldip2) significantly decreases the number of focal adhesions. RhoA activity is unchanged when focal adhesion dissolution is stimulated in control cells but increases in AdPoldip2-treated cells. Inhibition of RhoA blocks Poldip2-mediated attenuation of focal adhesion dissolution, and overexpression of RhoA or focal adhesion kinase (FAK) reverses the loss of focal adhesions induced by siPoldip2, indicating that RhoA and FAK mediate the effect of Poldip2 on focal adhesions. Nox4 silencing prevents focal adhesion stabilization by AdPoldip2 and induces a phenotype similar to siPoldip2, suggesting a role for Nox4 in Poldip2-induced focal adhesion stability. As a consequence of impaired focal adhesion turnover, PDGF-treated AdPoldip2 cells are unable to reduce and polarize traction forces, a necessary first step in migration. These results implicate Poldip2 in VSMC migration via regulation of focal adhesion turnover and traction force generation in a Nox4/RhoA/FAK-dependent manner.

Deregulation of epidermal stem cell niche contributes to pathogenesis of nonhealing venous ulcers.

The epidermis is maintained by epidermal stem cells (ESCs) that reside in distinct niches and contribute to homeostasis and wound closure. Keratinocytes at the nonhealing edges of venous ulcers (VUs) are healing-incompetent, hyperproliferative, and nonmigratory, suggesting deregulation of ESCs. To date, genes which regulate ESC niches have been studied in mice only. Utilizing microarray analysis of VU nonhealing edges, we identified changes in expression of genes harboring regulation of ESCs and their fate. In a prospective clinical study of 10 VUs, we confirmed suppression of the bone morphogenetic protein receptor (BMPR) and GATA binding protein 3 (GATA3) as well as inhibitors of DNA-binding proteins 2 and 4 (ID2 and ID4). We also found decreased levels of phosphorylated glycogen synthase kinase 3 (GSK3), nuclear presence of ß-catenin, and overexpression of its transcriptional target, c-myc, indicating activation of the Wnt pathway. Additionally, we found down-regulation of leucine-rich repeats and immunoglobulin-like domains protein 1 (LRIG1), a gene important for maintaining ESCs in a quiescent state, and absence of keratin 15 (K15), a marker of the basal stem cell compartment suggesting local depletion of ESCs. Our study shows that loss of genes important for regulation of ESCs and their fate along with activation of ß-catenin and c-myc in the VU may contribute to ESC deprivation and a hyperproliferative, nonmigratory healing incapable wound edge.

Apical ballooning syndrome associated with isolated severe hyponatremia: case report and suggested pathophysiology.

An 82-year-old woman who presented to her primary care physician for preoperative evaluation was incidentally found to have severe hyponatremia (sodium = 118 mmol/L). The patient was then admitted for workup and treatment of hyponatremia. On day 2 of the admission, the patient was found to have new T-wave inversions on a telemetry monitor. Further workup, including an electrocardiogram, cardiac markers, echocardiogram, and a cardiac catheterization were consistent with the diagnosis of apical ballooning syndrome (ABS). Mechanisms of how severe hyponatremia may lead to ABS are discussed as well as a possible approach to the management of severe hyponatremia in postmenopausal women.