Experimentally Induced Peripheral Venous Congestion Exacerbates Inflammation, Oxidative Stress, and Neurohormonal and Endothelial Cell Activation in Patients With Systolic Heart Failure

BACKGROUND

Venous congestion (VC) is a hallmark of symptomatic heart failure (HF) requiring hospitalization; however, its role in the pathogenesis of HF progression remains unclear. We investigated whether peripheral VC exacerbates inflammation, oxidative stress and neurohormonal and endothelial cell (EC) activation in patients with HF with reduced ejection fraction (HFrEF).

METHODS AND RESULTS

Two matched groups of patients with HFrEF and with no peripheral VC vs without recent HF hospitalization were studied. We modeled peripheral VC by inflating a cuff around the dominant arm, targeting ∼ 30 mmHg increase in venous pressure (venous stress test [VST]). Blood and ECs were sampled before and after 90 minutes of VST. We studied 44 patients (age 53 ± 12 years, 32% female). Circulating endothelin-1, tumor necrosis factor-α, interleukin-6, isoprostane, angiotensin II (ang-2), angiopoietin-2, vascular cell adhesion molecule-1, and CD146 significantly increased after the VST. Enhanced endothelin-1 and angiopoietin-2 responses to the VST were present in patients with vs without recent hospitalization and were prospectively associated with incident HF-related events; 6698 messenger ribonucleic acid (mRNA probe sets were differentially expressed in ECs after VST.

CONCLUSIONS

Experimental VC exacerbates inflammation, oxidative stress, neurohormonal and EC activation and promotes unfavorable transcriptome remodeling in ECs of patients with HFrEF. A distinct biological sensitivity to VC appears to be associated with high risk for HF progression.

Levels of Trimethylamine N-Oxide Remain Elevated Long Term After Left Ventricular Assist Device and Heart Transplantation and Are Independent From Measures of Inflammation and Gut Dysbiosis

BACKGROUND

Trimethylamine N-oxide (TMAO)-a gut-derived metabolite-is elevated in heart failure (HF) and linked to poor prognosis. We investigated variations in TMAO in HF, left ventricular assist device (LVAD), and heart transplant (HT) and assessed its relation with inflammation, endotoxemia, oxidative stress, and gut dysbiosis.

METHODS

We enrolled 341 patients. TMAO, CRP (C-reactive protein), IL (interleukin)-6, TNF-α (tumor necrosis factor alpha), ET-1 (endothelin-1), adiponectin, lipopolysaccharide, soluble CD14, and isoprostane were measured in 611 blood samples in HF (New York Heart Association class I-IV) and at multiple time points post-LVAD and post-HT. Gut microbiota were assessed via 16S rRNA sequencing among 327 stool samples. Multivariable regression models were used to assess the relationship between TMAO and (1) New York Heart Association class; (2) pre- versus post-LVAD or post-HT; (3) biomarkers of inflammation, endotoxemia, oxidative stress, and microbial diversity.

RESULTS

ln-TMAO was lower among HF New York Heart Association class I (1.23 [95% CI, 0.52-1.94] µM) versus either class II, III, or IV (1.99 [95% CI, 1.68-2.30], 1.97 [95% CI, 1.71-2.24], and 2.09 [95% CI, 1.83-2.34] µM, respectively; all P<0.05). In comparison to class II-IV, ln-TMAO was lower 1 month post-LVAD (1.58 [95% CI, 1.32-1.83] µM) and 1 week and 1 month post-HT (0.97 [95% CI, 0.60-1.35] and 1.36 [95% CI, 1.01-1.70] µM). ln-TMAO levels in long-term LVAD (>6 months: 1.99 [95% CI, 1.76-2.22] µM) and HT (>6 months: 1.86 [95% CI, 1.66-2.05] µM) were not different from symptomatic HF. After multivariable adjustments, TMAO was not associated with biomarkers of inflammation, endotoxemia, oxidative stress, or microbial diversity.

CONCLUSIONS

TMAO levels are increased in symptomatic HF patients and remain elevated long term after LVAD and HT. TMAO levels were independent from measures of inflammation, endotoxemia, oxidative stress, and gut dysbiosis.

Association of preoperative infections, nasal Staphylococcus aureus colonization and gut microbiota with left ventricular assist device outcomes

AIMS

Infections are common following left ventricular assist device (LVAD) implantation and predict adverse events. Infections are frequent prior to LVAD implantation although their impact on postoperative outcomes remains unknown. Gut and nasal microbial imbalance may predispose to mucosal colonization with pathogens. Herein, we investigated the predictive role of pre-LVAD infections, and explored the association of nasal Staphylococcus aureus (SA) colonization and gut microbiota, on postoperative outcomes.

METHODS AND RESULTS

Overall, 254 LVAD patients were retrospectively categorized based on pre-LVAD infection status: Group 1, bacterial/fungal bloodstream infection (BSI); Group 2, other bacterial/fungal; Group 3, viral; and Group 4, no infection. In a subset of patients, nasal SA colonization (n = 140) and pre-LVAD stool (n = 25) were analysed using 16S rRNA sequencing. A total of 75 (29%) patients had a pre-LVAD infection [Group 1: 22 (29%); Group 2: 41 (55%); Group 3: 12 (16%)]. Pre-LVAD BSIs were independent predictors of 1-year postoperative mortality and infections [Group 1 vs. 4: hazard ratio (HR) 2.70, P = 0.036 vs. HR 1.8, P = 0.046]. In an unadjusted analysis, pre-LVAD infections other than BSIs, INTERMACS profile ≤2, higher serum creatinine, lower serum albumin and nasal SA colonization were also significantly associated with postoperative infections. Patients with early post-LVAD infections exhibited decreased microbial diversity (P < 0.05).

CONCLUSIONS

Pre-LVAD infections are common. BSIs independently predict postoperative mortality and infections. Additional studies are needed to confirm our findings that pre-LVAD SA nasal colonization and gut microbial composition can help stratify patients' risk for infectious complications after LVAD implantation.

Gut microbial diversity, inflammation, and oxidative stress are associated with tacrolimus dosing requirements early after heart transplantation

Introduction

Effective tacrolimus (TAC) dosing is hampered by complex pharmacokinetics and significant patient variability. The gut microbiome, a key mediator of endotoxemia, inflammation and oxidative stress in advanced heart failure (HF) patients, is a possible contributor to interindividual variations in drug efficacy. The effect of alterations in the gut microbiome on TAC dosing requirements after heart transplant (HT) has not been explored.

Methods

We enrolled 24 patients (mean age = 55.8 ±2.3 years) within 3 months post-HT. Biomarkers of endotoxemia ((lipopolysaccharide (LPS)), inflammation (tumor necrosis factor-α (TNF-α)) and oxidative stress (8,12-iso-Isoprostane F-2alpha-VI) were measured in 16 blood samples. 22 stool samples were analyzed using 16S rRNA sequencing. TAC dose and serum trough level were measured at the time of stool and blood collection. TAC doses were reported in mg/kg/day and as level-to-dose (L/D) ratio, and categorized as ≤ vs. > median.

Results

The median TAC dose was 0.1 mg/kg/day and L/D ratio was 100.01. Above the median daily weight-based TAC dose was associated with higher gut microbial alpha diversity (p = 0.03); similarly, TNF-α and 8,12-iso-Isoprostane F-2alpha-VI levels were lower and LPS levels were higher in the above median TAC group, although these findings were only marginally statistically significant and dependent on BMI adjustment. We observed n = 37 taxa to be significantly enriched among patients with > median TAC dose (all FDR<0.05), several of which are potential short-chain fatty acid producers with anti-inflammatory properties, including taxa from the family Subdoligranulum.

Conclusions

Our pilot study observed gut microbial alpha diversity to be increased while inflammation and oxidative stress were reduced among patients requiring higher TAC doses early after HT.

Peripheral venous congestion causes time- and dose-dependent release of endothelin-1 in humans

Endothelin‐1 (ET‐1) is a pivotal mediator of vasoconstriction and inflammation in congestive states such as heart failure (HF) and chronic kidney disease (CKD). Whether peripheral venous congestion (VC) increases plasma ET‐1 at pressures commonly seen in HF and CKD patients is unknown. We seek to characterize whether peripheral VC promotes time‐ and dose‐dependent increases in plasma ET‐1 and whether these changes are sustained after decongestion. We used a randomized, cross‐over design in 20 healthy subjects (age 30 ± 7 years). To experimentally model VC, venous pressure was increased to either 15 or 30 mmHg (randomized at first visit) above baseline by inflating a cuff around the subject's dominant arm; the nondominant arm served as a noncongested control. We measured plasma ET‐1 at baseline, after 20, 60 and 120 min of VC, and finally at 180 min (60 min after cuff release and decongestion). Plasma ET‐1 progressively and significantly increased over 120 min in the congested arm relative to the control arm and to baseline values. This effect was dose‐dependent: ET‐1 increased by 45% and 100% at VC doses of 15 and 30 mmHg, respectively (P < 0.05), and declined after 60 min of decongestion though remaining significantly elevated compared to baseline. In summary, peripheral VC causes time‐ and dose‐dependent increases in plasma ET‐1. Of note, the lower dose of 15 mmHg (more clinically relevant to HF and CKD patients) was sufficient to raise ET‐1. These findings support the potentially contributory, not merely consequential, role of VC in the pathophysiology of HF and CKD.

Soluble CD146 Is a Novel Marker of Systemic Congestion in Heart Failure Patients: An Experimental Mechanistic and Transcardiac Clinical Study

BACKGROUND

Soluble CD146 (sCD146), is an endothelial marker with similar diagnostic power as natriuretic peptides in decompensated heart failure (HF). While natriuretic peptides are released by the failing heart, sCD146 may be released by veins in response to stretch induced by systemic congestion in HF. This study investigated the source, effects of vascular stress on release and prognostic properties of sCD146 in HF.

METHODS

In a peripheral venous stress study, plasma concentrations of sCD146 and N-terminal probrain natriuretic-peptide (NT-proBNP) were measured in 44 HF patients at baseline and after 90 min of unilateral forearm venous congestion. In addition, sCD146 and NT-proBNP were measured in peripheral vein (PV) and coronary sinus (CS) blood samples of 137 HF patients and the transcardiac gradient was calculated. Those patients were followed for major adverse cardiovascular events (MACE) during 2 years.

RESULTS

The induction of venous stress was associated with a pronounced increase in circulating concentrations of sCD146 in the congested arm (+60 μg/L) compared to the control arm (+16 μg/L, P = 0.025), while no difference in NT-proBNP concentrations was seen. In contrast to positive transcardiac gradient for NT-proBNP, median sCD146 concentrations were lower in CS than in PV (396 vs 434, P &lt; 0.001), indicating a predominantly extracardiac source of sCD146. Finally, increased PV concentrations of sCD146 were associated with higher risk of MACE at 2 years.

CONCLUSIONS

Soluble CD146 is released from the peripheral vasculature in response to venous stretch and may reflect systemic congestion in chronic HF patients.

Venous congestion, endothelial and neurohormonal activation in acute decompensated heart failure: cause or effect?

Venous congestion and endothelial and neurohormonal activation are known to occur in acute decompensated heart failure (ADHF), yet the temporal role of these processes in the pathophysiology of decompensation is not fully understood. Conventional wisdom presumes congestion to be a consequence of worsening cardiovascular function; however, the biomechanically driven effects of venous congestion are biologically plausible contributors to ADHF that remain largely unexplored in vivo. Recent experimental evidence from human models suggests that fluid accumulation and venous congestion are not simply consequences of poor cardiovascular function, but rather are fundamental pro-oxidant, pro-inflammatory, and hemodynamic stimuli that contribute to acute decompensation. The latest advances in the monitoring of volume status using implantable devices allow for the detection of venous congestion before symptoms arise. This may ultimately lead to improved treatment strategies including not only diuretics, but also specific, adjuvant interventions to counteract endothelial and neurohormonal activation during early preclinical decompensation.

Peripheral venous congestion causes inflammation, neurohormonal, and endothelial cell activation

AIMS

Volume overload and venous congestion are typically viewed as a consequence of advanced and of acute heart failure (HF) and renal failure (RF) although it is possible that hypervolaemia itself might be a critical intermediate in the pathophysiology of these diseases. This study aimed at elucidating whether peripheral venous congestion is sufficient to promote changes in inflammatory, neurohormonal, and endothelial phenotype similar to those observed in HF and RF.

METHODS

To experimentally model peripheral venous congestion, we developed a new method (so-called venous stress test) and applied the methodology on 24 healthy subjects (14 men, age 35 ± 2 years). Venous arm pressure was increased to ∼30 mmHg above the baseline level by inflating a tourniquet cuff around the dominant arm (test arm). Blood and endothelial cells (ECs) were sampled from test and control arm (lacking an inflated cuff) before and after 75 min of venous congestion, using angiocatheters and endovascular wires. Magnetic beads coated with EC-specific antibodies were used for EC separation; amplified mRNA was analysed by Affymetrix HG-U133 Plus 2.0 Microarray.

RESULTS

Plasma interleukin-6 (IL-6), endothelin-1 (ET-1), angiotensin II (AII), vascular cell adhesion molecule-1 (VCAM-1), and chemokine (C-X-C motif) ligand 2 (CXCL2) were significantly increased in the congested arm. A total of 3437 mRNA probe sets were differentially expressed (P < 0.05) in venous ECs before vs. after testing, including ET-1, VCAM-1, and CXCL2.

CONCLUSION

Peripheral venous congestion causes release of inflammatory mediators, neurohormones, and activation of ECs. Overall, venous congestion mimicked, notable aspects of the phenotype typical of advanced and of acute HF and RF.

Evaluation of changes in biologic markers ER, PR, HER 2 and Ki-67 index in breast cancer with administration of neoadjuvant dose dense doxorubicin, cyclophosphamide followed by paclitaxel chemotherapy

PURPOSE

The aim of this study was to assess the changes in biologic markers of breast cancer ER, PR, HER 2 and Ki-67 in locally advanced breast cancer patients after neoadjuvant chemotherapy.

METHODS

Data from 63 locally advanced breast cancer patients (stage II or III), whose histological diagnosis was made by core biopsies were retrospectively evaluated. The patients were given 4 cyles of 600 mg/m(2) cyclophosphamide, 60 mg/m(2) doxorubicin every 15 days followed by 4 cycles of paclitaxel 175 mg/m(2) every 15 days, and they underwent surgery within two weeks after the last chemotherapy cycle. Expressions in the preoperative and postoperative status of ER, PR, HER 2 and Ki-67 were compared.

RESULTS

The patient mean age was 49.2 ±10.7 years and most (57.1%) were premenopausal. Clinical stages of patients ranged between T2N1 and T3N2. The pathological complete response (pCR) rate was 14.9 % (N=9). Two (5.7%) patients who were ER positive prior to treatment showed ER negativity after treatment. In 7 (21.17percnt;) patients PR became negative after neoadjuvant chemotherapy and in 3 (9.0%) patients PR became positive. Changes in ER and PR receptors were not statistically significant (ER p=0.500 and PR p=0.549, respectively), whereas in 2 (5. 8%) patients hormonal status changed significantly when compared to initial biopsies (p=0.003). In addition, median value for PR intensity decreased from 20 to 10% (p=0.003) and Ki-67 values decreased from 10 to 1% (p<0.001) following neoadjuvant therapy. Six (17%) patients exhibited some changes in HER 2 staining. HER 2 expression became 2+ in 3 patients who were HER 2 negative prior to treatment, and HER 2 expression became negative in two patients with HER 2 1+ and 2+ prior to treatment following neoadjuvant chemotherapy.

CONCLUSION

The biological markers ER, PR, HER 2 and Ki- 67 index demonstrated differences after neoadjuvant treatment in breast cancer patients. These changes may affect the treatment decision.

Inflammatory activation: cardiac, renal, and cardio-renal interactions in patients with the cardiorenal syndrome

Although inflammation is a physiologic response designed to protect us from infection, when unchecked and ongoing it may cause substantial harm. Both chronic heart failure (CHF) and chronic kidney disease (CKD) are known to cause elaboration of several pro-inflammatory mediators that can be detected at high concentrations in the tissues and blood stream. The biologic sources driving this chronic inflammatory state in CHF and CKD are not fully established. Traditional sources of inflammation include the heart and the kidneys which produce a wide range of pro-inflammatory cytokines in response to neurohormones and sympathetic activation. However, growing evidence suggests that non-traditional biomechanical mechanisms such as venous and tissue congestion due to volume overload are also important as they stimulate endotoxin absorption from the bowel and peripheral synthesis and release of pro-inflammatory mediators. Both during the chronic phase and, more rapidly, during acute exacerbations of CHF and CKD, inflammation and congestion appear to amplify each other resulting in a downward spiral of worsening cardiac, vascular, and renal functions that may negatively impact patients' outcome. Anti-inflammatory treatment strategies aimed at attenuating end organ damage and improving clinical prognosis in the cardiorenal syndrome have been disappointing to date. A new therapeutic paradigm may be needed, which involves different anti-inflammatory strategies for individual etiologies and stages of CHF and CKD. It may also include specific (short-term) anti-inflammatory treatments that counteract inflammation during the unsettled phases of clinical decompensation. Finally, it will require greater focus on volume overload as an increasingly significant source of systemic inflammation in the cardiorenal syndrome.

Evaluation of changes of biologic markers ER, PR, HER 2 and Ki-67 in breast cancer with administration of neoadjuvant dose-dense doxorubicin, cyclophosphamide followed by paclitaxel

PURPOSE

To assess the changes of biologic markers estrogen receptors (ER), progesterone receptors (PR), HER 2 and Ki-67 in locally advanced breast cancer patients after neoadjuvant chemotherapy.

METHODS

Data from 63 locally advanced breast cancer patients (stage II or III), whose histological diagnosis was made by core biopsies were retrospectively evaluated. The patients were given 4 cycles of 600 mg/m(2) cyclophosphamide, 60 mg/m(2) doxorubicin every 15 days, followed by 4 cycles of paclitaxel 175 mg/m(2), followed by mastectomy within 2 weeks after the last chemotherapy cycle. The changes in ER, PR, HER 2 and Ki-67 status of the operated tumor tissue were compared with the material obtained by initial core biopsies.

RESULTS

The patient mean age was 49.2±10.7 years. Most (57.1%) were premenopausal. Clinical disease stages ranged between T2N1 and T3N2. Pathological complete response (pCR) rate was 14.9 7 percent; (n=9). Two (5.7%) patients who were ER positive prior to treatment showed ER negativity after treatment. In 7 (21.1%) patients PR became negative and in 3 (9.0%) became positive after neoadjuvant chemotherapy. Changes in ER and PR receptors were not statistically significant (p=0.500 and PR p=0.549, respectively), whereas in 2 (5.8%) patients hormonal status changed significantly when compared to initial biopsies (p=0.003). In addition, the median value of PR intensity decreased from 20 to 10% (p=0.003) and Ki-67 decreased from 10 to 1% (p<0.001) following neoadjuvant therapy. Five (14.1%) patients exhibited some changes in HER 2 expression: HER 2 expression became 2+ in 3 patients previously being HER 2 negative, and in 2 patients HER 2 became negative whilst it was 1+ and 2+ prior to neoadjuvant chemotherapy.

CONCLUSION

It was observed that the biologic markers ER, PR, HER 2 and Ki-67, from the same tumor material demonstrated differences after neoadjuvant treatment in breast cancer patients. These changes may affect the treatment decision.

Human vascular endothelial cells: a model system for studying vascular inflammation in diabetes and atherosclerosis

The vascular endothelium is the inner lining of blood vessels serving as autocrine and paracrine organ that regulates vascular wall function. Endothelial dysfunction is recognized as initial step in the atherosclerotic process and is well advanced in diabetes, even before the manifestation of end-organ damage. Strategies capable of assessing changes in vascular endothelium at the preclinical stage hold potential to refine cardiovascular risk. In vitro cell culture is useful in understanding the interaction of endothelial cells with various mediators; however, it is often criticized due to the uncertain relevance of results to humans. Although circulating endothelial cells, endothelial microparticles, and progenitor cells opened the way for ex vivo studies, a recently described method for obtaining primary endothelial cells through endovascular biopsy allows direct characterization of endothelial phenotype in humans. In this article, we appraise the use of endothelial cell-based methodologies to study vascular inflammation in diabetes and atherosclerosis.

Venous congestion and endothelial cell activation in acute decompensated heart failure

Despite accumulating clinical evidence supporting a key role for venous congestion in the development of acute decompensated heart failure (ADHF), there remain several gaps in our knowledge of the pathophysiology of ADHF. Specifically, the biomechanically driven effects of venous congestion on the vascular endothelium (the largest endocrine/paracrine organ of the body), on neurohormonal activation, and on renal and cardiac dysfunction remain largely unexplored. We propose that venous congestion is a fundamental, hemodynamic stimulus for vascular inflammation, which plays a key role in the development and possibly the resolution of ADHF through vascular, humoral, renal, and cardiac mechanisms. A better understanding of the role of venous congestion and endothelial activation in the pathophysiology of ADHF may provide a strong rationale for near-future testing of treatment strategies that target biomechanically driven inflammation. Targeting vascular and systemic inflammation before symptoms arise may prevent progression to overt clinical decompensation in the ADHF syndrome.

Inflammation, oxidative stress, and repair capacity of the vascular endothelium in obstructive sleep apnea

BACKGROUND

Indirect evidence implicates endothelial dysfunction in the pathogenesis of vascular diseases associated with obstructive sleep apnea (OSA). We investigated directly whether dysfunction and inflammation occur in vivo in the vascular endothelium of patients with OSA. The effects of continuous positive airway pressure (CPAP) therapy on endothelial function and repair capacity were assessed.

METHODS AND RESULTS

Thirty-two patients with newly diagnosed OSA and 15 control subjects were studied. Proteins that regulate basal endothelial nitric oxide (NO) production (endothelial NO synthase [eNOS] and phosphorylated eNOS) and inflammation (cyclooxygenase-2 and inducible NOS) and markers of oxidative stress (nitrotyrosine) were quantified by immunofluorescence in freshly harvested venous endothelial cells before and after 4 weeks of CPAP therapy. Vascular reactivity was measured by flow-mediated dilation. Circulating endothelial progenitor cell levels were quantified to assess endothelial repair capacity. Baseline endothelial expression of eNOS and phosphorylated eNOS was reduced by 59% and 94%, respectively, in patients with OSA compared with control subjects. Expression of both nitrotyrosine and cyclooxygenase-2 was 5-fold greater in patients with OSA than in control subjects, whereas inducible NOS expression was 56% greater. Expression of eNOS and phosphorylated eNOS significantly increased, whereas expression of nitrotyrosine, cyclooxygenase-2, and inducible NOS significantly decreased in patients who adhered to CPAP > or = 4 hours daily. Baseline flow-mediated dilation and endothelial progenitor cell levels were lower in patients than in control subjects, and both significantly increased in patients who adhered to CPAP > or = 4 hours daily.

CONCLUSIONS

OSA directly affects the vascular endothelium by promoting inflammation and oxidative stress while decreasing NO availability and repair capacity. Effective CPAP therapy is associated with the reversal of these alterations.

Vascular endothelial sampling and analysis of gene transcripts: a new quantitative approach to monitor vascular inflammation

BACKGROUND

Limited access to endothelial tissue is a major constraint when investigating the cellular mechanisms of vascular inflammation in patients with cardiovascular and metabolic diseases. We introduce venous endothelial sampling coupled to quantitative analysis of gene transcripts by real-time PCR, as a novel approach to study endothelial gene expression in human subjects.

METHODS

Endothelial cells were collected from a superficial forearm vein using five guide wires sequentially inserted through a 20-gauge angiocatheter in seven patients with history of cardiovascular events related to advanced vascular disease and in 17 healthy subjects. Endothelial cells were purified using magnetic beads coated with endothelial specific antibodies. Endothelial mRNA was amplified using RiboAmp HS RNA Amplification kit (Molecular Devices, Sunnyvale, CA). Amplified RNA was analyzed by real-time PCR.

RESULTS

Linearity of RNA amplification was validated by real-time PCR using RNA from 1,000 human umbilical endothelial cells (HUVECs) before and after amplification. In human subjects, vascular disease was associated with significant induction of proatherosclerotic genes: early growth response gene product (Egr-1) and monocyte chemoattractant protein-1 (MCP-1).

CONCLUSION

Venous endothelial sampling coupled to real-time PCR analysis is a minimally invasive, safe, and reliable technique to monitor vascular inflammation in human subjects. Expression of genes implicated in the atherosclerotic process is increased in the venous endothelium of patients with arterial vascular disease. Venous endothelial sampling and quantitative analysis of gene expression may help develop new vascular-targeted biomarkers to identify and track the impact of disease states and therapeutic interventions in vascular diseases.

Reliability of nesiritide infusion via non-primed tubing and heparin-coated catheters

BACKGROUND

Prescribing information for nesiritide mandates priming of intravenous tubing prior to connecting to the patient's intravenous access because the drug may adsorb to the line. As of this writing, no published study has quantified the binding effect of nesiritide to intravenous tubing.

OBJECTIVE

To investigate whether priming of peripheral intravenous tubing is necessary and whether nesiritide can be reliably delivered through central intravenous lines, including heparin-coated catheters, where priming cannot occur.

METHODS

A 23.3-mL bolus of nesiritide followed by a 7-mL/h 2-hour infusion were run through (1) polyvinylchloride (PVC) peripheral intravenous tubing primed with nesiritide, (2) non-primed PVC peripheral intravenous tubing, (3) non-primed polyethylene peripheral intravenous tubing, (4) non-primed PVC peripheral intravenous tubing connected to a central intravenous polyurethane catheter, and (5) non-primed PVC peripheral intravenous tubing connected to a heparin-coated pulmonary artery PVC catheter. Nesiritide concentrations were measured in the intravenous bags and in samples collected from the 5 intravenous settings.

RESULTS

Priming of intravenous tubing with nesiritide did not increase drug recovery: at least 94% of the bolus dose and 96% of the total drug were recovered from all intravenous sets.

CONCLUSIONS

Infusion of nesiritide via non-primed peripheral and central intravenous tubing, including heparin-coated pulmonary catheter, is reliable. Changes in nesiritide labeling appear to be warranted.

A key angiogenic role of monocyte chemoattractant protein-1 in hemangioendothelioma proliferation

Angiomatous lesions are common in infants and children. Hemangioendotheliomas (HE) represent one type of these lesions. Endothelial cell proliferation and the development of vascular/blood cell-filled spaces are inherent in the growth of HE. Therefore, understanding mechanisms that regulate the proliferation of these lesions should provide key insight into mechanisms regulating angiogenesis. A murine model was used to test the significance of monocyte chemoattractant protein (MCP)-1 in HE proliferation. EOMA cells, a cell line derived from a spontaneously arising murine HE, generate these lesions with 100% efficiency when injected subcutaneously into syngeneic mice. MCP-1 produced by EOMA cells recruit macrophages, which were shown to induce angiogenic behavior in EOMA cells by stimulating transwell migration and inducing sprout formation on type I collagen gels. When EOMA cells were injected into MCP-1(-/-) mice, only 50% of the mice developed tumors, presumably because the low levels of MCP-1 expressed by the injected EOMA cells were enough to overcome any host deficits of this chemokine. When EOMA cells were coinjected with a neutralizing antibody to MCP-1, tumors failed to develop in any of the treated mice, including syngeneic 129P3, C57Bl/6 (wild type), and MCP-1(-/-). These results present the first evidence that MCP-1 is required for HE proliferation and may promote the growth of these lesions by stimulating angiogenic behavior of endothelial cells. This study has produced the first in vivo evidence of a complete response for any neoplasm, specifically a vascular proliferative lesion, to anti-MCP-1 therapy in animals with intact immune systems.

Stimulation of gap junctional intercellular communication by thalidomide and thalidomide analogs in human fetal skin fibroblasts (HFFF2) and in rat liver epithelial cells (WB-F344)

Gap junction channels maintain cell-cell communication and are essential for the coordination of tissues, playing a pivotal role in embryonal development. Gap junctional intercellular communication (GJIC), studied here in human fetal skin fibroblasts (HFFF2) and in rat liver epithelial cells (WB-F344), was almost doubled upon exposure to thalidomide (10 microM) in the presence of NADH or NADPH (20 microM). Neither in HFFF2 nor in WB-F344 cells did any detectable alteration in GJIC occur with the thalidomide analog EM 16 (10 microM), known as a non-teratogenic compound. The thalidomide analog EM 364 (10 microM) increased GJIC without prior metabolic activation. It is suggested that GJIC modification may be related to the pharmacological and toxicological properties of thalidomide.

Diagnosis and treatment of uncomplicated hydatid cyst of the liver

Hydatid disease of the liver is still endemic in certain parts of the world. The diagnosis of noncomplicated hydatid cyst of the liver depends on clinical suspicion. Ultrasonography and computed tomography, the most important diagnostic tools, are helpful for determining the complications and planning treatment. The modern treatment of hydatid cyst of the liver varies from surgical intervention to percutaneous drainage or medical therapy. Surgery is still the treatment of choice and can be performed by the conventional or laparoscopic approach. Percutaneous drainage and treatment of the cyst with hypertonic saline or alcohol seems to be a good alternative to surgery in selected cases. Currently, we treat types I and II by ultrasound-guided percutaneous drainage and types IV and V (excluding totally calcified cysts) surgically. Type III cysts can be managed either way depending on the presence of drainable content. We believe that the laparoscopic approach should be limited to noncomplicated cysts.

Effect of persistently elevated intraabdominal pressure on healing of colonic anastomoses

BACKGROUND

The adverse effects of elevated intraabdominal pressure (IAP) on abdominal organs are realized, but its influence on anastomotic healing has not been studied. The aim of this study was to evaluate the effect of elevated IAP on healing of colonic anastomoses.

METHODS

Thirty rats, which all had right colonic anastomoses, were divided into five groups. Group 1 was the control group, and group 2 had fecal peritonitis. IAP was maintained between 4 to 6 mm Hg in group 3, 8 to 12 mm Hg in group 4, and 14 to 18 mm Hg in group 5 until all rats were sacrificed on day 4. Bursting pressures and tissue hydroxyproline concentrations of anastomoses were then analyzed and compared.

RESULTS

Mean +/- SEM of bursting pressures were 143+/-2.9 mm Hg in group 1, 72+/-14.4 mm Hg in group 2, 77.3+/-7.9 mm Hg in group 3, 57.5+/-11.2 mm Hg in group 4, and 40.1+/-9.6 mm Hg in group 5 (P<0.0001, one-way analysis of variance [ANOVA]). Mean +/- SEM of tissue hydroxyproline concentrations were 5.3+/-0.3 microg/mg in group 1, 4.7+/-0.5 microg/mg in group 2, 4.6+/-0.6 microg/mg in group 3, 3.6+/-0.5 microg/mg in group 4, and 2.4+/-0.2 microg/mg in group 5 (P = 0.0026, one-way ANOVA). The bursting pressure and hydroxyproline concentrations had good correlation (P<0.001, r = 0.76).

CONCLUSIONS

Elevated IAP delays healing of colonic anastomoses and 4 to 6 mm Hg IAP delays healing as much as fecal peritonitis. More elevated IAP delays healing more than fecal peritonitis. These events may be clinically important and may result from local-systemic effects of IAP.

A case of renal artery stenosis secondary to chronic pancreatitis

We report a case of renal artery stenosis most probably secondary to chronic pancreatitis. The patient had a traumatic pancreatic fistula. This was followed by numerous attacks of pancreatitis in the following years. At a relatively young age, he developed hypertension. Examinations revealed a right renal artery stenosis which was successfully treated by a percutaneous angioplasty. This rare complication should be kept in mind as a possible complication of pancreatitis.

Effect of alpha-tocopherol and silibin dihemisuccinate on the proliferation of human skin fibroblasts

Cell proliferation is a complex and important event in atherosclerosis, aging and cancer, and is under the control of signalling pathways. These signalling pathways in turn are effected by the presence of a number of chemicals. For this purpose, we have checked the effect of two chemicals on the proliferation of skin fibroblasts. alpha-Tocopherol and silibin dihemisuccinate (SDH) negatively regulate proliferation of human skin fibroblasts. To check the cell-cycle time intervals, a [3H]thymidine incorporation assay was performed, showing DNA replication at around 24 h; this indicated the time required for the incubation with the chemicals. When alpha-tocopherol was added to the growth medium at a physiological concentration of 50 microM, cell proliferation was inhibited by 40% in 72 h. A similar inhibitory effect of cell proliferation was achieved when 500 microM SDH was used (39% inhibition in 72 h). From the dose-response curves obtained it was concluded that both duration of treatment and the concentration of the chemicals are important parameters. The actual mechanism of the inhibition of cell proliferation may be due to the anti-oxidative potential of these chemicals as well as another mechanism effecting signal transduction pathways.

Effects of laparotomy, and carbon dioxide and air pneumoperitoneum, on cellular immunity and peritoneal host defences in rats

OBJECTIVE

To assess the effects of laparotomy, and insufflation of carbon dioxide and air, on the immune system in rats.

DESIGN

Randomised laboratory study.

SETTING

Teaching hospital, Turkey.

ANIMALS

77 Wistar rats randomly allocated to 2 groups one of which was sensitised with dinitrofluorobenzene (DNFB, n = 43) and one of which was not (n = 34).

INTERVENTIONS

The DNFB group was sensitised and subdivided into control (n = 8), laparotomy alone (n = 7), and insufflation with carbon dioxide (CO2) for 30 and 60 mins (n = 7 in each) or room air for 30 and 60 mins (n = 7 in each). A week later DNFB was reapplied to the ears. In the group not sensitised with DNFB the animals were subdivided similarly, the corresponding numbers in each group being, 6, 6, 6, 6, 5, and 5.

MAIN OUTCOME MEASURES

Delayed type hypersensitivity (DTH) measured by ear swelling in the DNFB group, and peritoneal bactericidal activity, total free peritoneal cell counts (TPC), and cell types in the non-sensitised group.

RESULTS

There were significant differences in the degree of ear swelling in the DNFB group between control and laparotomy groups (p = 0.0001) and between control and both insufflations of air (p = 0.002 and p = 0.0003, respectively). In the non-sensitised group peritoneal bactericidal activity was significantly increased after 7 hours in the 60 mins air insufflation group (p = 0.04). At 24 hours there were no differences among the groups. TPC were not affected. The number of peritoneal polymorphonuclear leucocytes (PMN) was significantly higher in the laparotomy alone group than in the control or any of the insufflation groups (p < 0.05).

CONCLUSIONS

Laparotomy and air insufflation depressed cell-mediated immunity. Peritoneal bactericidal activity was affected only after 60 minutes of air insufflation.

An experimental study of the effect of aprotinin on intestinal adhesion formation

BACKGROUND

Depression of fibrinolysis is known to be a major mechanism for postoperative adhesion formation. Because aprotinin inhibits fibrinolysis it may lead to an increase in adhesion formation whereas its anti-inflammatory effects may lead to a decrease in adhesion formation. Our aim is to clarify conflicting results in previous literature.

METHODS

Basal levels of intestinal hydroxyproline (OHP) content and local fibrinolytic activity (LFA) were determined using naive groups. In the experiment groups, adhesions were created by scraping and creating a transient ischemia of a segment of terminal ileum. Group I and II rats were injected subcutaneous (s.c.) normal saline (NS) for 3 days and single dose intraperitoneal (i.p.) NS, respectively. Group III and IV rats were injected s.c. aprotinin for 3 days and single dose i.p. aprotinin, respectively. Group V rats were injected intramuscular methylprednisolone (MP) for 3 days. LFA and OHP levels were determined on the second and fifth postoperative days. The severity of adhesion formation was graded on the fifth day.

RESULTS

Aprotinin decreased both the severity of adhesions and OHP levels whereas MP decreased only the severity of adhesions. There was an early depression of LFA at the second day in both NS and MP groups increasing to basal levels at the fifth day. OHP levels showed significant correlation with adhesion severity.

CONCLUSION

Results showed that aprotinin decreased intra-abdominal adhesion formation probably by preventing early depression of LFA.

Effects of polyglycolic acid and polypropylene meshes on postoperative adhesion formation in mice

The purpose of this study was to investigate the effects of polyglycolic acid (PGA), an absorbable (ABS) mesh, and polypropylene (PP), a nonabsorbable (NA) mesh, on intestinal adhesion formation. Altogether 72 mice were divided into a control group of 24, an ABS mesh group of 23, and an NA mesh group of 25. All three groups were divided into two subgroups for evaluation of adhesion severity at postoperative (po) days 5 and 90. Adhesion severity was measured with adhesion grading and tissue hydroxyproline (OHP) levels. Adhesion degree was minimal (1) in all subjects on day 5. Also there was no difference in tissue OHP levels between three groups on day 5 (p > 0.05). Adhesion degree and tissue OHP levels as determinants of adhesion severity were higher in the PGA mesh group than the control group and the PP mesh group on day 90 (p < 0.001). There was no difference between the control group and the PP mesh groups (p > 0.05). Adhesion degree was higher on day 90 than on day 5 in the control group and the PGA mesh group (p < 0.05), whereas tissue OHP level was higher on day 90 than on day 5 in all three groups (p < 0.001). Also there was linear correlation between adhesion degree and tissue OHP levels (r = 0.86, p < 0.001). The study demonstrates that ABS PGA mesh has higher potential for adhesion formation than the NA PP mesh, probably related to the increased foreign body and inflammatory reactions during the absorption process of the mesh.

Restoration of bactericidal activity of peritoneal fluid by cimetidine but not ranitidine or famotidine in burned mice

OBJECTIVE

To find out the effect of 20%, third degree burns and H2 receptor antagonists on peritoneal bactericidal activity.

DESIGN

Animal experiment.

SETTING

Research laboratory of university school of medicine.

SUBJECTS

52 mice in five groups.

INTERVENTIONS

Sham burn (n = 5, group I), burned, and received subcutaneous injections of saline (0.3 ml/kg day, n = 14, group II); ranitidine (10 ml/kg/day, n = 15, group III); cimetidine (10 mg/kg/day, n = 8, group IV); or famotidine (0.7 mg/kg/day, n = 10, group V); for 14 days.

MAIN OUTCOME MEASURE

Peritoneal bactericidal activity in all groups measured 15 days after the burn.

RESULTS

There was a significant difference in peritoneal bactericidal activity between the control and burned mice, but no significant difference between the control group and the burned mice that were given cimetidine and famotidine.

CONCLUSION

Peritoneal bactericidal activity is suppressed in mice after 20% third degree burns and this effect may be partly reversed by cimetidine and famotidine.

Factors affecting postoperative mortality in abdominal trauma

Records of 345 patients in whom laparatomies were performed because of blunt and penetrating abdominal trauma were reviewed retrospectively with respect to factors affecting mortality. One hundred and twenty-eight patients had blunt abdominal trauma (Group I), 114 patients had gunshot wounds of the abdomen (Group II), and 103 patients had stab wounds of the abdomen (Group III). Mortality rates were 14.8%, 12.3% and 1.9% in groups I, II and III respectively. The presence of head trauma especially if accompanied by hypotension in group I, and the presence of chest trauma (hemothorax and/or pneumothorax) and hypotension (less than 90 mmHg) in group II were associated with a high mortality rate (p less than 0.05). Of the two patients who died in group III, one had septic shock due to massive intestinal necrosis and the other had hemorrhagic shock due to multiple organ injury and bleeding from an injured internal thoracic artery as the cause of death.

Risk factors in perforated peptic ulcer disease: comparison of a new score system with the Mannheim Peritonitis Index

OBJECTIVE

To construct a score that would accurately predict outcome for patients with perforated peptic ulcers.

DESIGN

Retrospective study.

SETTING

University Hospital.

SUBJECTS

173 patients who were operated on for perforated peptic duodenal ulcers over a 14 year period.

MAIN OUTCOME MEASURES

Results of multivariate discriminant function analysis of derived set of clinical variables known to be associated with high mortality, and comparison with the Mannheim Peritonitis Index.

RESULTS

Serious coexisting medical illness, acute renal failure, white cell count of more than 20 x 10(9)/l, and male sex were the most significant factors influencing mortality. The Hacettepe score for perforated peptic ulcer was established using these four variables. The sensitivity was 83%, the specificity 94%, and the overall predictive accuracy 93%. The corresponding figures for the Mannheim Peritonitis Index were 75%, 96%, and 94% respectively.

CONCLUSION

The Hacettepe score is useful in predicting whether a patient will survive after perforation of a peptic duodenal ulcer.