L. F. Neville

Serum cholesterol is elevated in patients with Achilles tendon ruptures

Abstract Forty-one patients were analyzed after surgical treatment of Achilles tendon ruptures. The following parameters served as the outcome measure: (1) duration of wearing cast, (2) length of hospital stay, (3) outpatient treatment, (4) time of absence from work, (5) complications, (6) re-rupture rate, (7) subjective evaluation by patients, (8) scar condition, (9) ability to stand on tiptoes, (10) Thompson test, (11) movement of talocrural joint, (12) circumference data of lower extremity, (13) radiographs, (14) power measurement of the ankle (in kg), (15) ultrasound examination, (16) blood cholesterol levels, (17) scoring by Trillat’s score. Surgical treatment achieved an excellent or good outcome in 91% of patients as evidenced by the Trillat score. Furthermore, cholesterol levels were found to be elevated in 83% of patients. Given the good results, surgical treatment of Achilles tendon ruptures is recommended, but patients of status post-Achilles tendon rupture should be checked for high cholesterol levels. In the future, controlled, prospective trials need to prove a correlation between Achilles tendon rupture and a pathological blood lipid status.

Locally Produced Tumor Necrosis Factor-α Mediates Interleukin-2Induced Lung Injury

Abstract Interleukin (IL)-2–induced microvascular lung injury is an experimental paradigm commonly used to investigate the pathogenesis of the adult respiratory distress syndrome. Since tumor necrosis factor-α (TNF-α) is known to induce such an injury in vivo and since TNF-α is involved in other models of lung injury, we postulated that it might also mediate pulmonary toxicity after IL-2 administration. The present study tested this hypothesis by evaluating the effect of TNF-α inhibition on IL-2–induced lung injury in the rat. Recombinant human IL-2 (106 U IV per rat, n=6) elevated lung water, myeloperoxidase activity, and protein accumulation in bronchoalveolar lavage fluid and induced tissue hypoxia. Also, IL-2 enhanced lung tissue TNF-α mRNA and peptide (1543±496 pg/g lung wet weight) localized to alveolar macrophages by in situ hybridization. In marked contrast, IL-2 failed to affect serum TNF-α, which remained at undetectable levels. Pretreatment with anti–TNF-α monoclonal antibody (25 mg/kg IV, n=7) or the TNF-α synthesis inhibitor rolipram (200 μg/kg IV, n=7) attenuated lung injury and reverted tissue hypoxia. Furthermore, TNF-α inhibition prevented the upregulation of lung tissue IL-1β, IL-6, cytokine-induced neutrophil chemoattractant, and E-selectin (ELAM-1) but not intercellular adhesion molecule-1 mRNAs in response to IL-2. These data imply that locally produced TNF-α mediates IL-2–induced lung inflammation and tissue injury and point to the potential utilization of TNF-α inhibitors in treating the pulmonary toxicity of IL-2 immunotherapy.

Aspiration-induced lung injury: Role of complement

OBJECTIVES To examine the role of complement in the development of acid aspiration-induced lung injury in the rat. It was postulated that inhibition or depletion of complement attenuates aspiration-induced lung injury. DESIGN Controlled animal trial. SETTING Animal Laboratory, Jefferson Medical College, Philadelphia, PA. SUBJECTS Anesthetized rats. INTERVENTIONS Aspiration was induced by the intratracheal administration of 0.2 mL of 0.1 N hydrochloric acid (n = 7) and lung injury was evaluated by determining water content, myeloperoxidase activity, protein concentration, and leukocyte count in bronchoalveolar lavage fluid. Muscle PO2 was directly measured using a thin-film chamber oxygen sensor and serum tumor necrosis factor-alpha was assayed by enzyme-linked immunosorbent assay. The effect of complement inhibition by recombinant human soluble complement receptor type 1 (n = 8) or complement depletion by cobra venom factor (n = 7) on lung injury was evaluated. MEASUREMENTS AND MAIN RESULTS Acid aspiration induced pulmonary leukosequestration, edema, and a microvascular permeability defect, along with tissue hypoxia. Pretreatment with soluble complement receptor type 1 (complement inhibition) or cobra venom factor (complement depletion) significantly reduced lung edema (-61 +/- 7%; p < .05), eliminated protein accumulation in bronchoalveolar lavage fluid (p < .01), and improved (p < .05) tissue oxygenation. In contrast, there was no effect of soluble complement receptor type 1 or of cobra venom factor on leukosequestration. CONCLUSIONS Acid aspiration induces lung injury through a complement-dependent mechanism that leads to microvascular permeability defects. Therefore, the possibility that complement inhibitors may have a salutary effect in humans with aspiration-induced lung injury should be investigated.

Chemokines and interleukin-18 are up-regulated in bronchoalveolar lavage fluid but not in serum of septic surgical ICU patients.

Our objective was to investigate the levels of chemokines (MIP1-alpha, MCP-1, and Gro-alpha), Interleukin-18 (IL-18), and Interleukin (IL-6) in bronchoalveolar lavage (BAL) fluid and serum at the onset and ongoing states of sepsis as defined by the American College of Chest Physicians/Society of Critical Care Medicine in septic surgical ICU patients. Our summary background data was to understand the significance of compartmentalized inflammatory mediator production in an immunologically active organ (lung) in comparison with levels in the systemic circulation. The study group consisted of 20 septic patients and 10 non-septic patients on surgical ICU. At the onset of sepsis, both BAL fluid and serum samples were taken and levels of MIP-1alpha, MCP-1, GRO-alpha, IL-18, and IL-6 were measured by ELISA. Furthermore, over a subsequent 8-day period, levels of these mediators were determined in serum. In some experiments, IL-18 mRNA levels were determined in peripheral blood lymphocytes (PBL) of septic and non-septic patients. At the onset of sepsis, MIP-1alpha, MCP-1, GRO-alpha, IL-18, and IL-6 levels were significantly up-regulated in BAL fluid as compared with non-septic controls. In marked contrast, with the exception of IL-18 mRNA and IL-6 peptide, there was no increase in serum levels of inflammatory mediators determined both at the onset and during the ongoing states of sepsis. Based on the present data, monitoring levels of serum chemokines and IL-18 protein as markers of sepsis might be misleading since despite their non-detection in serum, they were highly up-regulated in the lung tissue compartment. These data might underscore the role of MIP-1alpha, MCP-1, GRO-alpha, and IL-18 in the mediation of local tissue damage. Furthermore, these findings raise the notion that mediator measurement in immunologically active organs might serve as pivotal indicators of sepsis prior to the actual fulfillment of specific clinical criteria that defines the patient as being septic.

Liposome-encapsulated hemoglobin modulates lipopolysaccharide-induced tumor necrosis factor-α production in mice

OBJECTIVE To investigate the effect of liposome-encapsulated hemoglobin, an experimental blood substitute, on the function of the mononuclear phagocytic system in normovolemic mic, in ex vivo murine splenocytes and in a transformed murine monocytic cell line, RAW 264.7. DESIGN Prospective, randomized trial. SETTING Center for Biomolecular Science and Engineering, Naval Research Laboratory, and the Thomas Jefferson University. SUBJECTS Female Balb/c mice (n = 27). INTERVENTIONS Mice were injected into the tail vein with liposome-encapsulated hemoglobin or liposome vehicle and were killed at varying time points for blood sampling and splenocyte isolation and culture. MEASUREMENTS AND MAIN RESULTS Injection of liposome-encapsulated hemoglobin in mice (2.2 of lipid/kg and 0.56 g of hemoglobin/kg, n = 9) did not increase serum tumor necrosis factor (TNF)-alpha concentrations at 2, 8, 15, and 24 hrs after administration. In the ex vivo procedure, lipopolysaccharide (1 microgram/mL)-induced TNF-alpha production by splenocytes from mice injected with liposome-encapsulated hemoglobin was attenuated at 2 and 4 hrs (73%, p = .002 at 2 hrs), compared with TNF-alpha production by splenocytes from sham animals challenged with the same concentration of lipopolysaccharide. In the in vitro procedure, simultaneous exposure of liposome-encapsulated hemoglobin (0.88 to 8.8 mg/mL) and lipopolysaccharide (0.125 to 1 microgram/mL) to the murine-derived, peritoneal monocytic RAW 264.7 cell line showed significantly reduced TNF-alpha peptide, but not messenger RNA, 1 to 4 hrs after exposure as compared with cells challenged with lipopolysaccharide alone. This effect correlated with the rapid phagocytosis (1 hr to 4 hrs) of liposome-encapsulated hemoglobin by RAW 264.7 cells. Phagocytic activity in RAW 264.7 cells exposed to both liposome-encapsulated hemoglobin and lipopolysaccharide showed reduced uptake compared with uptake of liposome-encapsulated hemoglobin. The liposome-induced reduction in TNF-alpha peptide production elicited by lipopolysaccharide was countered by extending the time period to an overnight delay between liposome-encapsulated hemoglobin exposure and lipopolysaccharide challenge. Liposome-encapsulated hemoglobin incubated with lipopolysaccharide in vitro, and subsequently washed to remove free lipopolysaccharide, stimulated TNF-alpha expressed by RAW 264.7 cells. Incubation with liposome-encapsulated hemoglobin alone did not evoke TNF-alpha production in these cells. CONCLUSIONS These data suggest that liposome-encapsulated hemoglobin modulates the response of the mononuclear phagocyte system to endotoxin, possibly through binding of lipopolysaccharide, presentation to macrophages with subsequent phagocytosis, and modulation of cytokine response by a posttranscriptional mechanism. This effect is attenuated by extending the period between exposure to liposome-encapsulated hemoglobin and endotoxin. The clinical relevance of these findings awaits further investigation.

In vitro and in vivo properties of a fully human IgG1 monoclonal antibody that combats multidrug resistant Pseudomonas aeruginosa

The development of an anti-bacterial drug in the form of a monoclonal antibody (mAb) targeting an exposed virulence factor, represents an innovative therapeutic strategy. Consequently, a fully human IgG1 mAb (LST-007) targeting Pseudomonas aeruginosa (PA) flagellin type b was recombinantly expressed and characterized in vitro and in an infection model driven by a multidrug resistant (MDR) PA strain. LST-007 demonstrated a highly specific binding towards whole PA bacteria harboring flagellin type b and its recombinant counterpart, with a KD of 7.4×10−10 M. In bioactivity assays, LST-007 or titers of Cmax sera derived from pharmacokinetic studies, markedly attenuated PA motility in an equipotent manner. In vivo, parenteral LST-007 (20 mg/kg) given as a single or double-dosing paradigm post-infection, afforded survival (up to 75% at Day 7) in a lethal model of pneumonia driven by the intratracheal (i.t.) instillation of an LD80 of the MDR PA isolate. This protective effect was markedly superior to that of imipenem (30% survival at Day 7) and totally devoid with an irrelevant, human isotype mAb. These data lay credence that LST-007 may be a valuable adjunct to the limited list of anti-bacterials that can tackle MDR PA strains, thereby warranting its continued development for eventual clinical evaluation.

Effect of liposome-encapsulated hemoglobin on the development of endotoxin-induced shock in the rat

ABSTRACT Liposome-encapsulated hemoglobin (LEH) is an experimental oxygen-carrying resuscitation fluid. Because LEH is cleared from the circulation primarily by the reticuloendothelial system, its effect on the development of sepsis remains a major concern. Thus, the present study aimed to evaluate whether LEH modifies consequences of endotoxemia in the conscious normovolemic rat. LEH infusion at 10% of estimated blood volume (n = 10) did not affect mortality (30%, p < .05) and serum tumor necrosis factor-a levels (6204 ± 414, p < .05) induced by 3.6 mg/kg Escherichia coli endotoxin administered (intravenous bolus) 22 h later. In contrast, when a shorter LEH-endotoxin time interval (<12 h, n = 10) or a higher dose of endotoxin (14.4 mg/kg, n = 20) was tested, LEH enhanced endotoxin-induced mortality (90% and 100%, respectively, p < .05) and broadened serum tumor necrosis factor-a response without modifying its peak levels. LEH (n = 20) did not exacerbate the endotoxin-induced tachycardia, leukopenia, and thrombocy-topenia. Therefore, in this model, the effect of LEH on endotoxin-induced responses was dependent on the time interval between LEH and endotoxin administration as well as the endotoxin dose. The clinical relevance of these results should be further investigated.

Effect of Liposome-Encapsulated Hemoglobin on Triglyceride, Total Cholesterol, Low-Density Lipoprotein, and High-Density Lipoprotein Cholesterol Measurements

The present study investigated the effect of liposome-encapsulated hemoglobin (LEH), an experimental oxygen-carrying resuscitation fluid, on triglyceride, total cholesterol, and low density lipoprotein (LDL), and high density lipoprotein (HDL) cholesterol measurements. In vivo, the intravenous infusion of LEH (5.6 mL/kg, n=6) elevated serum triglycerides (+92% vs. baseline, P<.05), total cholesterol (+25% vs. baseline, P<.01), LDL cholesterol (+72% vs. baseline, P<.01) and had no effect on serum HDL cholesterol. In addition, LEH did not alter the elevation in serum triglycerides (+302% vs. baseline, P<.01) and LDL cholesterol (+86% vs. baseline, P<.01) induced by lipopolysaccharide (3.6 mg/kg, i.v., n=6). Ex vivo, measurements of triglycerides and total cholesterol as well as LDL and HDL cholesterol in whole blood from naive rats were not changed by the addition of LEH (0–50%, n=6). In vitro, the addition of a fixed concentration of LEH (50%, n=6) to varying concentrations of cholesterol solution (0–50%), or vice versa, had no effect on cholesterol determination. It is therefore concluded that LEH only minimally affects serum levels of triglycerides, total cholesterol, LDL cholesterol, and HDL cholesterol and does not interfere with their measurement.