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Biomedical subjects

Lyle L Moldawer

Publications and source records attributed to Lyle L Moldawer.

At least 73 records · Page 4Linked to original sources
PubMed2003

Synthesis of a novel family of diterpenes and their evaluation as anti-inflammatory agents.

The synthesis and biological evaluation of a new family of diterpenes, represented by structures 2 and 3, is presented. These compounds constitute isomeric analogues of acanthoic acid (1) and were examined as potent anti-inflammatory agents. Among them, methyl ester 12 exhibited a low non-specific cytotoxicity, inhibited TNF-alpha synthesis and displayed good specificity in suppressing cytokine expression.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2003

Anti-TNF-alpha therapies: the next generation.

The functioning of the immune system is finely balanced by the activities of pro-inflammatory and anti-inflammatory mediators or cytokines. Unregulated activities of these mediators can lead to the development of serious inflammatory diseases. In particular, enhanced tumour-necrosis factor-alpha (TNF-alpha) synthesis is associated with the development of rheumatoid arthritis, psoriatic arthritis and inflammatory bowel disease. Inhibiting TNF-alpha activities in these diseases has been remarkably successful. However, the current injectable protein therapies have associated risks and limitations. An oral, small molecule that regulates TNF-alpha biology could either replace the injectables or provide better disease control when used alone or in conjunction with existing therapies. In this review, we discuss briefly the present understanding of TNF-alpha-mediated biology and the current injectable therapies in clinical use, and focus on some of the new therapeutic approaches with oral, small-molecule inhibitors.

Animals↗
PubMed2003

Role of endogenous interleukin-10 in local and distant organ injury after visceral ischemia-reperfusion.

The anti-inflammatory cytokine interleukin (IL)-10 has been detected in serum after visceral ischemia-reperfusion injury and exogenous IL-10 administration has been shown to attenuate the associated distant organ injury. This study was designed to examine the role that endogenous IL-10 production plays on both local and distant organ injury after visceral ischemia-reperfusion injury. Wild-type and IL-10(-/-)-null C57BL/6 mice were subjected to 20 min of supraceliac aortic occlusion or sham laparotomy. Serum and lung tissue cytokine levels (tumor necrosis factor alpha, IL-1beta, IL-6, KC/GRO, and IL-10) were measured after reperfusion (1, 2, and/or 4 h) using either enzyme-linked immunoassay or bioassay. Lung neutrophil infiltration and injury were quantified after reperfusion injury using myeloperoxidase concentration (2 h) and mean capillary permeability (4 h), respectively, whereas the direct liver injury was quantified with serum aspartate aminotransferase levels (1, 2, and 4 h). A subset of IL-10(-/-)-null animals was administered human recombinant IL-10 before the visceral ischemia and lung MPO was measured after reperfusion (2 h). Visceral ischemia-reperfusion in the wild-type and IL-10(-/-)-null mice was associated with in an increase in both serum (IL-1beta, KC/GRO, IL-6) and lung tissue (IL-1beta, KC/GRO) cytokine levels and resulted in lung neutrophil infiltration (myeloperoxidase), lung injury (mean capillary permeability) and liver injury (aspartate aminotransferase). The magnitude of the lung tissue cytokine response (IL-1beta, KC/GRO), neutrophil infiltration, and injury were greater in the IL-10(-/-)-null mice. Exogenous IL-10 resulted in a decrease in the lung neutrophil infiltration in the IL-10(-/-)-null mice. The endogenous IL-10 response to visceral ischemia-reperfusion attenuates the associated lung neutrophil infiltration and injury but has no effect upon either the hepatic injury or the magnitude of the systemic inflammatory response. The beneficial effects of IL-10 may be mediated by the inhibition of IL-1beta and KC/GRO through an endocrine rather than paracrine signal.

Animals↗
PubMed2003

Hypothermia induces interleukin-10 and attenuates injury in the lungs of endotoxemic rats.

We recently reported that hypothermia protects against intrapulmonary nitric oxide overproduction and nitric oxide-mediated lung injury in endotoxemic rats. Few studies have been performed to investigate whether hypothermia reduces inflammation by affecting favorable changes in chemokine and pro- and anti-inflammatory cytokine profiles. In this study, we tested the hypothesis that hypothermia decreases concentrations of growth-related oncogene/cytokine-induced neutrophil chemoattractant-1 (GRO/CINC-1), interleukin (IL)-1beta, IL-6, and myeloperoxidase and increases concentration of IL-10 in the lungs endotoxemic rats. Twelve rats were anesthetized and randomized to treatment with either hypothermia (T = 18-24 degrees C; n = 6) or normothermia (T = 36-38 degrees C, n = 6). Endotoxin (15 mg/kg of Escherichia coli lipopolysaccharide) was administered intravascularly and lung tissue was harvested 150 min later. Three additional rats were sham instrumented and maintained as normothermic but not given endotoxin. Hematoxylin & eosin staining was performed for qualitative inspection of tissues. Quantitative analyses of lung homogenates were performed using enzyme-linked immunosorbent assays for IL-1beta, IL-6, IL-10, and GRO/CINC-1. Myeloperoxidase concentrations were determined using a colorimetric assay. Hypothermia attenuated the induction of intrapulmonary IL-1beta (P < 0.05), IL-6 (P < 0.05), GRO/CINC-1 (P < 0.05), and myeloperoxidase (P < 0.05) caused by endotoxin. Inspection of the lungs revealed that hypothermia similarly attenuated histological signs of injury, such as interstitial edema and neutrophil accumulation. Hypothermia increased the intrapulmonary concentration of IL-10 more than 3-fold over that measured in the normothermia (endotoxin-exposed) group (P < 0.05). Hypothermia inhibits neutrophil recruitment in the lungs of endotoxemic rats in part by decreasing proinflammatory cytokine expression. Additionally, hypothermia induces intrapulmonary IL-10 expression. Further studies are needed to investigate whether IL-10 mediates the anti-inflammatory effects of hypothermia.

Animals↗
PubMed2003

Sepsis and the dendritic cell.

Sepsis is a syndrome of significant morbidity and mortality. Unlike the advances made in other diseases processes, improvements in outcome from sepsis, severe sepsis, and septic shock have been modest. Current research has altered our understanding of sepsis pathogenesis such that present models and definitions are still evolving. One relatively novel cell type, the dendritic cell, is the subject of much current investigation in sepsis. Although our present understanding of dendritic cell biology is incomplete, growing evidence supports the importance of this antigen-presenting cell in the normal and maladaptive responses to microbial invasion and tissue injury. A better understanding of this cell's basic biology as well as its potential as a therapeutic target will undoubtedly play increasing roles in the development of new strategies for the treatment of the septic patient.

Animals↗
PubMed2003

Molecular characterization of the acute inflammatory response to infections with gram-negative versus gram-positive bacteria.

Sepsis caused by gram-negative bacteria and that caused by gram-positive bacteria often manifest similar clinical features. We investigated plasma proinflammatory cytokine profiles in patients with sepsis due to gram-positive and gram-negative bacteria and studied the cytokine production and differential gene regulation of leukocytes stimulated ex vivo with Escherichia coli lipopolysaccharide or heat-killed Staphylococcus aureus. Concentrations of tumor necrosis factor alpha, interleukin 1 receptor antagonist (IL-1Ra), IL-8, IL-10, IL-18 binding protein, procalcitonin, and protein C in plasma did not differ between patients with sepsis due to gram-negative and gram-positive bacteria. However, plasma IL-1beta, IL-6, and IL-18 concentrations were significantly higher in patients with sepsis due to gram-positive bacteria. Ex vivo stimulation of whole blood with heat-killed S. aureus markedly increased IL-1beta and IL-18 levels more than E. coli lipopolysaccharide stimulation. Microarray analysis revealed at least 359 cross-validated probe sets (genes) significant at the P < 0.001 level whose expression discriminated among gram-negative-organism-stimulated, gram-positive-organism-stimulated, and unstimulated whole-blood leukocytes. The host inflammatory responses to gram-negative and gram-positive stimuli share some common response elements but also exhibit distinct patterns of cytokine appearance and leukocyte gene expression.

Cytokines↗
PubMed2003

Antineoplastic therapy in colorectal cancer through proteasome inhibition.

Upregulation of nuclear factor (NF)-kappaB is found in many forms of cancer. Activation of NF-kappaB in cancer cells by chemotherapy or radiation can blunt the ability of this therapy to induce cell death. Proteasome inhibitors stimulate apoptosis in part via prevention of NF-kappaB activation. We sought to determine whether constitutive NF-kappaB activity is present in human colon cancer. In addition we studied whether alterations of NF-kappaB activity with a proteasome inhibitor would prevent colon cancer cell growth and induce apoptosis. We demonstrated constitutive transcriptional activation of NF-kappaB in SW48 and SW116 colon cancer cells by luciferase and electromobility shift assays. This was confirmed by p65 immunostaining. This activity was further induced in the presence of chemotherapy. In colon cancer specimens constitutive activation of NF-kappaB was observed in the majority of tumors. Treatment with the proteasome inhibitor (MG-132) inhibited growth and also stimulated apoptosis of colon cancer cells. We conclude that inhibition of NF-kappaB activation may be a logical therapy for certain cancers. This can be done via specific approaches on molecules necessary for keeping NF-kappaB inactivated in the cytoplasm. Other potentially useful ways to promote apoptosis in cancer cells include the utilization of proteasome inhibitors. Such inhibitors are currently being evaluated in clinical trials.

Animals↗
PubMed2002

Direct evidence for tumor necrosis factor-alpha signaling in arteriogenesis.

BACKGROUND: Arteriogenesis serves as an efficient mechanism for flow restoration after arterial occlusion. This process is associated with inflammatory mediators such as tumor necrosis factor-alpha (TNF-alpha), although their role in arteriogenesis remains unclear. We hypothesized that arteriogenesis is reduced in mice lacking functional TNF-alpha or p55 receptor. To test this hypothesis, we developed a novel microsphere-based murine model of hindlimb perfusion measurement. METHODS AND RESULTS: Unilateral femoral arteries of nude (n=9), TNF-alpha(-/-) (n=9), TNF-alpha receptor p55(-/-) (n=8), and p75(-/-) (n=8) mice as well as their appropriate genetic background controls were occluded. The nude mice underwent laser Doppler hindlimb flux measurements preoperatively, postoperatively, and after 7 days. Seven days after ligation, all animals underwent tissue perfusion determinations using fluorescent microspheres. Laser Doppler findings confirmed acute decrease in flux with falsely normal values after 1 week. Microsphere results from control mice showed perfusion restoration to values approximately 50% of normal within 7 days. TNF-alpha(-/-) mice demonstrated a significant reduction (45.1%) in collateral artery perfusion compared with controls (TNF-alpha(-/-) 22.4+/-5.1% versus B6x129 49.7+/-9.3%; P<0.01). p55(-/-) mice exhibited an almost identical 45.8% reduction in collateral artery formation (p55(-/-) 28.3+/-4.3% versus C57BL/6J 61.8+/-9.1%; P<0.01), whereas p75(-/-) mice were equivalent to controls (p75(-/-) 54.5+/-5.5%; P=0.13). CONCLUSIONS: Microsphere techniques in mice offer a tool for the molecular dissection of arteriogenesis mechanisms. These results suggest that TNF-alpha positively modulates arteriogenesis probably via signaling through its p55 receptor.

Animals↗
PubMed2002

Increased survival in sepsis by in vivo adenovirus-induced expression of IL-10 in dendritic cells.

The dendritic cell (DC) is the most potent APC of the immune system, capable of stimulating naive T cells to proliferate and differentiate into effector T cells. Recombinant adenovirus (Adv) readily transduces DCs in vitro allowing directed delivery of transgenes that modify DC function and immune responses. In this study we demonstrate that footpad injection of a recombinant Adv readily targets transduction of myeloid and lymphoid DCs in the draining popliteal lymph node, but not in other lymphoid organs. Popliteal DCs transduced with an empty recombinant Adv undergo maturation, as determined by high MHC class II and CD86 expression. However, transduction with vectors expressing human IL-10 limit DC maturation and associated T cell activation in the draining lymph node. The extent of IL-10 expression is dose dependent; transduction with low particle numbers (10(5)) yields only local expression, while transduction with higher particle numbers (10(7) and 10(10)) leads additionally to IL-10 appearance in the circulation. Furthermore, local DC expression of human IL-10 following in vivo transduction with low particle numbers (10(5)) significantly improves survival following cecal ligation and puncture, suggesting that compartmental modulation of DC function profoundly alters the sepsis-induced immune response.

Adenoviruses, Human↗
PubMed2002

Peaks of endogenous G-CSF serum concentrations are followed by an increase in respiratory burst activity of granulocytes in patients with septic shock.

The relationship between peaks of G-CSF serum concentrations and respiratory burst activity of polymorphonuclear cells (PMN) was investigated in patients with postoperative or post-traumatic severe sepsis and septic shock. Over a 12 month period, a longitudinal analysis of G-CSF, TNF-alpha and IFN-gamma serum concentrations, burst activity of PMN, and expression of CD64 on the surface of PMN, were performed by ELISA technique and flow cytometric analysis, respectively, in 58 patients admitted to the intensive care unit (ICU) on a daily basis until discharge from the ICU or death. Out of these 58 patients, 27 with proven infections were in septic shock for at least 4 days' duration. Seventeen of these patients survived, whereas ten died. In 15 out of these 27 patients, 26 episodes of G-CSF peaks were observed, which were followed in most patients (13/15) by an increase in PMN burst activity, from 28% up to 540% (median 188%). Following the G-CSF peaks, CD64 expression on PMN remained at an increased level, followed by a marked decline 3 days later. TNF-alpha serum concentrations were elevated in most episodes (22/26), whereas IFN-gamma serum concentrations were below the detection level in 23/26 episodes. Taken together, peaks in G-CSF serum concentrations are followed by enhanced CD64 expression and increased burst activity of PMN in most patients with severe sepsis and septic shock. Thus, endogenous G-CSF increases neutrophil function in patients with severe sepsis and septic shock, necessary for resolution of bacterial infections in these patients.

Adult↗
PubMed2002

Interleukin-10 fails to modulate low shear stress-induced neointimal hyperplasia.

INTRODUCTION: Overexpression of the anti-inflammatory cytokine interleukin-10 (IL-10) blocks atherosclerotic events in vivo, and IL-10 has been recently hailed as an "immunologic scalpel" for atherosclerosis. Alternatively, mice lacking IL-10 receiving atherogenic diets have increased occlusive lesions. It remains unclear whether such IL-10 modulation broadly applies to other forms of occlusive arterial remodeling. We hypothesized that lack of IL-10 would exacerbate, and exogenous or overexpression of IL-10 would abrogate low shear stress-induced neointimal hyperplasia (NIH). METHODS: Wild-type (WT) and IL-10-deficient (IL-10-/-) mice underwent unilateral common carotid artery (CCA) ligation. Low shear stress in the patent ligated artery results in remodeling and formation of neointima containing BrdU and SMC alpha-actin-positive cells. Additional groups of WT mice underwent CCA ligation and were treated daily with intraperitoneal saline or 1 microg of human IL-10. Chronic delivery gene therapy approaches were also utilized to define the role of IL-10 signaling. WT mice were treated adventitially with 1 x 10(10) adenovirus/green fluorescent protein (Ad/gfp) and an Ad/empty control to confirm the veracity of adventitial delivery. Then, Ad viral IL-10 (vIL-10), Ad/empty, and virus buffer alone were applied directly to the adventitia of the CAA immediately following ligation. In separate experiments, 1 x 10(10) Ad/empty or Ad/vIL-10 was injected intramuscularly. CCAs were perfusion fixed 28 days postligation, the time at which NIH is near maximum. RESULTS: IL-10-/- mice developed identical NIH areas compared to WT controls. Mice receiving IL-10 demonstrated NIH equivalent to saline controls. Mice receiving intramuscular or adventitial Ad/IL-10 developed high serum levels of IL-10 yet formed NIH areas similar to those of controls. Serum IL-10 levels were significantly higher (P = 0.04) with adventitial delivery. Mice treated adventitially with Ad/gfp showed reliable transfection of cells within the adventitia of CAA. No antibody to human IL-10 was found in the sera of intraperitoneal IL-10-treated mice, which failed to attenuate NIH. CONCLUSION: Under the conditions of this experiment, lack of IL-10 does not exacerbate low shear stress-induced NIH, nor does exogenous administration or overexpression of IL-10 attenuate it. Despite high serum levels of vIL-10 in mice treated with ad/vIL-10 adventitially, there appears to be no therapeutic effect despite the confirmed transfection of adventitial cells. Discrepancies between these findings and previous research may be related to IL-10 dosing, inflammation induced by the adenoviral vector, or disparities between the NIH models.

Adenoviridae↗
PubMed2002

Pro- and antiinflammatory cytokine production after radiofrequency ablation of unresectable hepatic tumors.

BACKGROUND: Experience using radiofrequency ablation (RFA) for treating unresectable hepatic malignancies is expanding, with promising outcomes and fewer complications compared with cryotherapy. STUDY DESIGN: This study examined systemic inflammatory responses after RFA as measured by the appearance of postoperative symptoms and cytokine production. Seventeen patients (11 men, 6 women) aged 40 to 85 years (mean 64.2 years) with unresectable primary and metastatic hepatic tumors underwent RFA. Mean liver volume treated with RFA was 35.3% +/- 3.6% (SEM) (median 36.8%). Plasma cytokines (tumor necrosis factor-alpha, interleukin [IL]-1beta, IL-1ra, IL-6, IL-8, IL-10, p55, and p75) were measured from anesthesia induction through 48 hours after RFA. Ex vivo whole-blood cytokine production was measured at baseline, 24 hours, and 48 hours after RFA. RESULTS: Cytokine and cytokine-receptor production were not notably altered by RFA. Ex vivo whole-blood endotoxin stimulation indicated that intrinsic cellular immune function remained intact after treatment, although modest decreases in stimulated tumor necrosis factor alpha production were observed 24 to 48 hours after RFA. Variceal bleeding, hepatic failure, and death occurred in one patient 30 days after RFA. None of the remaining patients exhibited tachycardia or hypotension. Fevers (> or = 38.5 degrees C) developed in three patients during the first 48 hours postoperatively. There was no association between plasma cytokines and postoperative complications. CONCLUSIONS: In contrast to previous reports using cryotherapy, systemic inflammatory responses as measured by increased cytokines were not observed after RFA. The cryotherapy-induced "cryoshock" phenomenon was not observed in patients undergoing RFA in our study. We conclude that RFA ablation is fundamentally different than cryotherapy and apparently does not stimulate Kupffer and other hepatic macrophages to produce proinflammatory cytokines.

Adult↗
PubMed2002

Bioglass attenuates a proinflammatory response in mouse peritoneal endotoxicosis.

Bioglass is a bioactive, resorbable ceramic particle that was developed to assure binding to living tissues. Bioglass is currently employed to fill osseus defects in oral surgery, and it possesses both unique anti-inflammatory and antimicrobial properties. In an effort to determine whether Bioglass may be useful as an adjunct anti-inflammatory device in local inflammatory processes, we examined whether exposure of the peritoneal cavity to Bioglass would induce a pro- or anti-inflammatory response, and then modulate a subsequent proinflammatory response to endotoxin. Three- to fifty-milligram doses of 5 pm Bioglass were administered intraperitoneally in C57BL/6 mice. Total leukocyte, myeloperoxidase, and cytokine levels in the peritoneal wash fluid were determined. In addition, the peritoneal cavity was preexposed to Bioglass, and was then subjected to a subsequent endotoxin administration. All doses of Bioglass were found to induce a significant peritoneal IL-6 response; however, Bioglass did not induce a TNF-alpha, IL-1alpha, IL-10, or a white cell recruitment into the peritoneal lavage fluid. Pretreatment of the peritoneal cavity with Bioglass produced a transient reduction in the proinflammatory response to endotoxin. We conclude that exposure to Bioglass produces an IL-6 response without concurrent expression of TNF-alpha or IL-1alpha. Bioglass appears to transiently suppress the inflammatory response to endotoxin, possibly through the early induction of IL-6. These findings suggest that Bioglass may offer a unique approach in modifying the inflammatory response in local tissue compartments.

Animals↗
PubMed2002

Interleukin-10: a complex role in the pathogenesis of sepsis syndromes and its potential as an anti-inflammatory drug.

Interleukin (IL)-10 is a pleiotropic cytokine produced by both T cells and macrophages and possesses both anti-inflammatory and immunosuppressive properties. IL-10 circulates in the blood of patients with sepsis syndromes, and increased concentrations of IL-10 have been associated with an adverse clinical outcome. Experimental studies in rodents and primates have demonstrated that endogenously produced and exogenously administered IL-10 can reduce the magnitude of the inflammatory response and improve outcome, primarily in models of endotoxemic and bacteremic shock. However, endogenous IL-10 production and systemic administration can also exacerbate T-cell dysfunction, decrease T-cell apoptosis, reduce antimicrobial function, and increase mortality in other less acute bacterial models of sepsis or after thermal injury. Targeted delivery of IL-10 to individual tissues may obviate the adverse effects of systemic delivery. The potential anti-inflammatory properties of IL-10 will have to be carefully weighed against its immunosuppressive properties when considering its use in patients with acute inflammation and sepsis syndromes.

Animals↗
PubMedDate not supplied

Analysis of gene expression patterns in human postburn hypertrophic scars.

Hypertrophic scars cause cosmetic disfigurement and limited mobility in burn patients. To better understand the molecular pathophysiology of hypertrophic scar formation, microarray analyses were performed on normal skin and hypertrophic scars from four burn patients. Microarray analyses were determined in an effort to identify genes whose expression discriminated between normal skin and mature, hypertrophic scars. Surgical biopsies were obtained from two pediatric and two adult patients 6 to 15 months after burn injury. Total RNA was isolated from the samples and subjected to microarray analysis using the Affymetrix U95Av2 GeneChip. Results from this analysis revealed 31 probe sets representing genes that were consistently up-regulated at least two-fold in hypertrophic scar specimens from all four patients and four probe sets that were down-regulated. The significance analysis of microarrays algorithm also identified 35 probe sets whose increased expression resulted in the hierarchal clustering of the hypertrophic scar and normal tissue, seven of which were identical to the six genes identified by paired analyses. These six genes all displayed elevated levels of expression in the scar tissue. Proteins encoded by the genes identified included germline oligometric matrix protein, matrix metalloproteinase-16, collagen type 1alpha, pleiotrophin, and thrombospondin-4. Although the results presented here suggest that there may be unique patterns of gene expression in hypertrophic scars that may be important in the evaluation and treatment of hypertrophic scarring, the results must be confirmed with larger datasets.

Adult↗
PubMedDate not supplied

Cytokines and wound healing: the role of cytokine and anticytokine therapy in the repair response.

Wound healing is an integrated and complex process involving a large number of regulatory molecules, including proinflammatory cytokines and growth factors, and an orchestrated tissue response. Dysregulation in cytokine or growth factor expression dramatically alters the normal wound healing process, and blocking the inappropriate production of specific proinflammatory cytokines or supplementing the milieu with increased quantities of growth factors has demonstrated the central role played by these mediators. Both protein-based and DNA-based (gene transfer) therapies are currently under clinical development as tools to improve the healing process. Although there has been some success with these approaches in both experimental models and in patients, only through a better understanding of the complexity and diversity of the wound healing process, as well as an improved comprehension of the time-dependent and concentration-dependent responses to individual proinflammatory cytokines or growth factors, will further development in the therapeutic treatment of healing wounds be attained.

Cytokines↗