Acute Phase Response In Humans Research Articles

Efficient expression and purification of rat CRP in Pichia pastoris.

C-reactive protein (CRP) plays a crucial role in the diagnosis and monitoring of the non-specific acute phase response in humans. In contrast, rat CRP (rCRP) is an atypical acute-phase protein that possesses unique features, such as a possible incapacity to trigger the complement system and markedly elevated baseline plasma concentrations. To facilitate in vitro studies on these unique characteristics, obtaining high-quality pure rCRP is essential. Here we explored various strategies for rCRP purification, including direct isolation from rat plasma and recombinant expression in both prokaryotic and eukaryotic systems. Our study optimized the recombinant expression system to enhance the secretion and purification efficiency of rCRP. Compared to traditional purification methods, we present a streamlined and effective approach for the expression and purification of rCRP in the Pichia pastoris system. This refined methodology offers significant improvements in the efficiency and effectiveness of rCRP purification, thereby facilitating further structural and functional studies on rCRP.

Acute phase response and inflammation following pulmonary exposure to low doses of zinc oxide nanoparticles in mice

Inhalation of nanosized zinc oxide (ZnO) induces metal fume fever and systemic acute phase response in humans. Acute phase response activation is a cardiovascular risk factor; we investigated whether pulmonary exposure of mice can be used to assess ZnO-induced acute phase response as well as inflammation and genotoxicity. Uncoated (NM-110) and triethoxycaprylylsilane-coated (NM-111) ZnO nanoparticles were intratracheally instilled once at 0.2, 0.7 or 2 µg/mouse (11, 33 and 100 µg/kg body weight). Serum amyloid A3 mRNA level in lung tissue, bronchoalveolar lavage (BAL) fluid cellularity, and levels of DNA strand breaks in BAL fluid cells, lung and liver tissue were assessed 1, 3 and 28 days post-exposure. Global transcription patterns were assessed in lung tissue using microarrays. The acute-phase response serum amyloid A3 mRNA levels were increased on day 1; for uncoated ZnO nanoparticles at the highest dose and for coated ZnO nanoparticles at medium and highest dose. Neutrophils were increased in BAL fluid only after exposure to coated ZnO nanoparticles. Genotoxicity was observed only in single dose groups, with no dose-response relationship. Most changes in global transcriptional response were observed after exposure to uncoated ZnO nanoparticles and involved cell cycle G2 to M phase DNA damage checkpoint regulation. Although, uncoated and coated ZnO nanoparticles qualitatively exerted similar effects, observed differences are likely explained by differences in solubility kinetics. The finding of serum amyloid A3 induction at low exposure suggests that mouse models can be used to assess the nanoparticle-mediated induction of acute phase responses in humans.

Translational Studies of Lipoprotein-Associated Phospholipase A2 in Inflammation and Atherosclerosis

This study sought to examine the role of lipoprotein-associated phospholipase A₂ (Lp-PLA₂/PLA2G7) in human inflammation and coronary atherosclerosis. Lp-PLA₂ has emerged as a potential therapeutic target in coronary heart disease. Data supporting Lp-PLA₂ are indirect and confounded by species differences; whether Lp-PLA₂ is causal in coronary heart disease remains in question. We examined inflammatory regulation of Lp-PLA₂ during experimental endotoxemia in humans, probed the source of Lp-PLA₂ in human leukocytes under inflammatory conditions, and assessed the relationship of variation in PLA2G7, the gene encoding Lp-PLA₂, with coronary artery calcification. In contrast to circulating tumor necrosis factor-alpha and C-reactive protein, blood and monocyte Lp-PLA₂ messenger ribonucleic acid decreased transiently, and plasma Lp-PLA₂ mass declined modestly during endotoxemia. In vitro, Lp-PLA₂ expression increased dramatically during human monocyte to macrophage differentiation and further in inflammatory macrophages and foamlike cells. Despite only a marginal association of single nucleotide polymorphisms in PLA2G7 with Lp-PLA₂ activity or mass, numerous PLA2G7 single nucleotide polymorphisms were associated with coronary artery calcification. In contrast, several single nucleotide polymorphisms in CRP were significantly associated with plasma C-reactive protein levels but had no relation with coronary artery calcification. Circulating Lp-PLA₂ did not increase during acute phase response in humans, whereas inflammatory macrophages and foam cells, but not circulating monocytes, are major leukocyte sources of Lp-PLA₂. Common genetic variation in PLA2G7 is associated with subclinical coronary atherosclerosis. These data link Lp-PLA₂ to atherosclerosis in humans while highlighting the challenge in using circulating Lp-PLA₂ as a biomarker of Lp-PLA₂ actions in the vasculature.

Influence of hypertension, obesity and nicotine abuse on quantitative and qualitative changes in acute-phase proteins in patients with essential hypertension

SummaryBackgroundHypertension is a powerful risk factor for cardiovascular disease and frequently occurs in conjunction with obesity. Accumulative evidence suggests a link between inflammation and hypertension. The aim of study was to evaluate whether blood pressure, obesity and smoking may influence acute-phase response.Material/MethodsNinety-two patients with essential hypertension and 75 healthy volunteers as a control group were studied. In all subjects assessment of hsCRP, α1-acid glycoprotein (AGP), α1-antichymotrypsin, transferrin, α1-antitrypsin, and C3 and C4 complement were performed. Evaluation of glycosylation profile and reactivity coefficient (RC) for AGP was done by means of affinity immunoelectrophoresis with concanavalin A as a ligand.ResultsWhen compared to the controls, hypertensive subjects presented significantly higher hsCRP concentrations and lower transferrin level. Hypertensive patients had elevated AGP-AC. The intensification of the inflammatory reaction was greater in the subgroup of hypertensive patients smoking cigarettes. In obese hypertensives, elevated serum C3 complement level was found.ConclusionsWe conclude that arterial hypertension may evoke the acute-phase response in humans. Markers of acute-phase response are particularly strongly expressed in smokers. Serum C 3 complement, but not other APPs, is elevated in hypertension coexisting with obesity.

High-density lipoprotein and the acute phase response

Inflammation and the concomitant acute phase response induce marked changes in the lipoprotein profile, particularly the high-density lipoprotein (HDL) fraction. The present review describes the transfer proteins and lipases that remodel HDL and regulate its plasma levels, discusses the changes occurring in their activities during inflammation, and the influence of this altered remodeling on HDL function. The review will also discuss the contribution of the ATP-binding-membrane-cassette transporters to the protective actions of HDL. Studies using different models showed that remodeling of acute phase HDL in vitro generates pre-beta migrating particles capable of cholesterol efflux. Induction of the acute phase response in humans resulted in a reduction of HDL phospholipids without a change in HDL-cholesterol. However, the capacity of HDL to promote cholesterol efflux ex vivo was impaired. Studies with ATP-binding-membrane-cassette transporter A1 and ATP-binding-membrane-cassette transporter G1 knockout mice demonstrated anti-inflammatory roles for these transporters by virtue of reducing cell-membrane-free cholesterol and lipid raft content, thus attenuating proinflammatory signaling pathways. It is well known that HDL has anti-inflammatory properties that are diminished during inflammation. Acute phase HDL contains serum amyloid A that can be liberated during remodeling by cholesteryl ester transfer protein and secretory phospholipase A2, or other inflammatory factors. The ability of serum amyloid A and apolipoprotein A-I to promote cholesterol efflux may confer protective effects during the acute phase response.

Clinical influence of vagotomy on postoperative acute phase response

Although there is increasing evidence suggesting that the vagus nerve functions as a connector between the nervous and immune systems in animals, little is known about the role of the vagus nerve in postoperative acute phase response in humans. The extent of fever and acute phase protein response and the production of inflammatory cytokine during the early postoperative period were compared among the patients who had undergone total gastrectomy including truncal vagotomy (n = 13), those having distal gastrectomy with division of vagal branches (n = 14), and the patients with vagal nerve preserving gastrectomy (n = 12). There was no significant difference in serum levels of C-reactive protein, alpha-1-antirypsin, and interleukin-6 among the three groups. Also, postoperative maximum body temperature was similar. Vagotomy did not influence acute phase response after gastric cancer surgery. A multipathway mechanism for acute phase response including the induction of fever is suggested.

Relationship of granulocyte colony stimulating factor with other acute phase reactants in man

The non-specific acute phase response in mice is associated with increased resistance to bacterial infection, which is critically mediated by granulocyte colony stimulating factor (G-CSF), but the behaviour of G-CSF in the human acute phase response is not known. Cardiothoracic surgery is a powerful acute phase stimulus and we show here that this procedure caused increased production of G-CSF, in addition to increases in the circulating concentrations of the proinflammatory cytokine interleukin (IL)-6 and the acute phase plasma proteins C-reactive protein (CRP) and serum amyloid A protein (SAA). Values of G-CSF correlated positively with IL-6 concentrations and circulating neutrophil counts, but not with CRP values. These results confirm that G-CSF is a physiological component of the acute phase response in humans that shares some of the same regulatory controls as IL-6, but its downstream effects are on neutrophils, not hepatic acute phase protein synthesis. Our observations are compatible with a protective role against bacterial infection for G-CSF in the human acute phase response, and support investigation of the prophylactic use of G-CSF in at-risk patients.

Elevation of ceramide in serum lipoproteins during acute phase response in humans and mice: role of serine–palmitoyl transferase

Recent studies have indicated that ceramide generated in the liver is secreted into the bloodstream as component of very-low-density lipoproteins (VLDL) and low-density lipoproteins (LDL). This manuscript investigates the effect of host acute phase response to inflammation on lipoprotein ceramide levels. In humans, two different patterns of responses were found. One group of volunteers experienced transient increases in serum ceramide at 1.5 h after LPS administration. Second group showed prolonged increases that reached up to 10-fold above the basal level and continued for up to 24 h. Increases in ceramide were found only in VLDL and LDL particles. LPS administration induced similar increases in mice. These increases were accompanied by activation of secreted sphingomyelinase in serum and serine–palmitoyl transferase in liver. ASMase knockout mice retained LPS-induced increases in serum ceramide, thus suggesting that the elevation of VLDL and LDL ceramide content is attributed at least in part to activation of de novo synthesis of ceramide in the liver.

Nephelometric determination of rat fibrinogen as a marker of inflammatory response

Following tissue injury or infection, the concentrations of several plasma proteins are altered substantially. The characteristic pattern of this change is termed the acute phase response, and can be observed in many different inflammatory situations, including surgical trauma, injury, infections, tissue infarction and several immunologically mediated states such as temporalis arteritis, polymyalgia rheumatica and rheumatoid arthritis. It is often of great clinical value to monitor the acute phase response in humans but the assays used to measure the acute response in man (e.g., erythrocyte sedimentation rate and C-reactive protein) is less well suited for experimental studies in the rat. We have instead developed a nephelometric assay for determination of fibrinogen as a marker of the inflammatory response in rats. The assay was used to monitor the inflammatory response in type II collagen arthritis in rats. This model involves the induction of severe polyarthritis and is a widely used animal model for rheumatoid arthritis (RA). Fibrinogen concentrations increased from 3.1 g/l before immunization to 10.5 g/l 2 weeks after the immunization, after which they gradually declined towards normal levels. This pattern of fibrinogen alterations correlated well with the inflammatory phase of the arthritic response. Plasma fibrinogen may thus represent a rapid and sensitive marker of the acute phase response in the rat.

Formula omitted] and cytokine plasma profiles under different postoperative parenteral nutrition regimens

Both nitric oxide and cytokines are considered mediators of the acute-phase response in humans, and their early postoperative period plasma levels have been found to be of prognostic value. On the other hand, it has been suggested that the fatty emulsions used in total parenteral nutrition (TPN) may induce changes in macrophage function. In the present study we investigated the postoperative evolution of tumor necrosis factor-α (TNF-α), interleukin-1 (IL-1), interleukin-6 (IL-6), and nitrate/nitrite plasma levels under three different TPN regimens. Twenty-one patients diagnosed with upper digestive tract neoplasm, without preoperative TPN, and having undergone radical surgery, were randomly assigned to three groups: Group I, all nonprotein calories supplied by hypertonic glucose solution; Group II, 55% of the nonprotein calories supplied by glucose and 45% by 20% long-chain triacylglycerides emulsion (LCT) (Intralipid 20%, Kabi-Pharmacia); Group III, same as Group II, but a 20% emulsion of a mixture of medium-chain and long-chain triacylglycerides ( MCT LCT ) (Lipofundina MCT LCT 20%, B. Braun) was used instead of LCT. Blood samples were obtained on postoperative Days 1–5 and 10, 3 h after ending the lipid infusion. In all the three groups IL-1, IL-6, and TNF-α levels rose after surgery, peaking at Day 2, whereas NO 2 NO 3 levels had their peak at Day 3. Day-to-day comparison of plasma levels of cytokines and NO 2 NO 3 between the investigated groups did not show any statistical significance. Differences between group means were not found when the areas under the curve over the first 5 postoperative days were compared (1.72 ± 0.25, Group I; 1.88 ± 0.34, Group II; and 2.52 ± 0.50, Group III, for TNF-α; 1.79 ± 0.12, Group I; 1.92 ± 0.18, Group II; and 1.50 ± 0.12, Group III, for NO 2 NO 3 ). We conclude that the different parenteral nutrition regimens studied do not evoke alterations in cytokine and NO 2 + NO 3 levels in the patient groups investigated in this study.

IL-6 stimulates vitronectin gene expression in vivo.

We tested the hypothesis that vitronectin (Vn) is regulated as an acute phase reactant in response to inflammatory stimuli. In initial experiments, Vn levels were measured during the surgically induced acute phase response in humans. The plasma concentration of Vn increased approximately twofold following elective orthopedic surgery and remained elevated up to 5 days. To examine the mechanism(s) of increased Vn synthesis, hepatic Vn mRNA expression and serum levels were examined in three rat models of acute inflammation: LPS (i.v.), CFA (i.p.), or turpentine (s.c.) injection. The serum concentration of Vn increased approximately twofold 24 h following treatment with turpentine. The expression of Vn mRNA in the liver increased markedly as early as 3 h after treatment in these models and remained elevated up to 18 h. Northern blot analysis of RNA isolated from fractionated liver cells derived from rats treated with LPS indicated that Vn was mainly expressed in hepatocytes, but not in the endothelial or nonparenchymal cell fractions. To analyze the individual effects of raised corticosterone and IL-6 levels on the expression of hepatic Vn mRNA, rats were injected (i.p.) with either dexamethasone or purified recombinant rat IL-6. Vn mRNA expression was elevated within 1 h after IL-6 injection, whereas dexamethasone-injected rats showed unchanged Vn expression. Vn mRNA also was increased in rats chronically injected with IL-6. These results indicate that the Vn gene is up-regulated in acute and chronic inflammation, and this induction is primarily mediated by IL-6.

Induction of plasminogen activator inhibitor-1 in HepG2 human hepatoma cells by mediators of the acute phase response.

The liver plays a central role in the systemic acute phase response of an organism to injury. Plasminogen activator inhibitor-1 (PAI-1), a major regulator of fibrinolysis, is an important component of the acute phase response in humans. The source of plasma PAI-1 has been a matter of controversy, but recent in situ hybridization experiments have demonstrated that human hepatocytes express the PAI-1 gene in vivo. However, little is known about regulation of human hepatic PAI-1 gene expression by mediators of the acute phase response. We have analyzed the regulation of PAI-1 mRNA accumulation by interleukin (IL)-1, IL-6, and dexamethasone, known mediators of the acute phase response, in HepG2 cells, a highly differentiated human hepatoma cell line that produces a broad spectrum of acute phase proteins including PAI-1. Incubation of HepG2 cells with IL-1 resulted in a rapid and transient 40-fold induction of the 3.2-kilobase PAI-1 mRNA and a 30-fold induction of the 2.2-kilobase PAI-1 mRNA. Although IL-6 alone had only a modest effect on PAI-1 expression, in combination with IL-1, it caused a synergistic induction of PAI-1 mRNA accumulation. Dexamethasone alone did not increase PAI-1 mRNA accumulation but enhanced it in combination with IL-1. Using nuclear run-on experiments, we determined that the mechanism by which IL-1 alone, or in combination with IL-6, induced PAI-1 mRNA accumulation was to cause a 10-15-fold, transient stimulation of PAI-1 gene transcription. We found no evidence of an effect of these cytokines on PAI-1 mRNA stability. These data demonstrate that mediators of the acute phase response induce the accumulation of PAI-1 mRNA in human hepatoma cells by rapidly and transiently increasing the transcription of the PAI-1 gene.

Acute phase proteins and prognosis in multiple myeloma.

Serum IL-6 levels have been shown to correlate with disease severity and prognosis in patients with plasma cell dyscrasias. Among its pleiotropic actions, IL-6 is also the major regulator of the acute phase response in humans. The possible impact on survival of the major serum acute phase proteins (s.APP) [C-reactive protein (s.CRP), alpha-1-antitrypsin (s.AAT), haptoglobin, acid alpha-1-glycoprotein and alpha-2-macroglobulin (used as control)] was assessed on a population of 103 consecutive, previously untreated myeloma patients. Univariate analysis showed that among the acute phase proteins only s.AAT (P = 0.015) and s.CRP (P = 0.027) were significantly correlated with survival. The multivariate Cox proportional hazard model applied to s.APP and other common parameters showed that s.beta-2-microglobulin (s.b2M), s.calcium, s.creatinine, BM plasma cell percentage, age and s.AAT correlated significantly with survival. Combining s.b2M and s.AAT allowed stratification of myeloma patients: those with low levels of s.b2M (< or = 3 mg/l) and of s.AAT (< or = 3 g/l) presented an excellent prognosis (median survival exceeding 10 years) while those presenting higher values of the two parameters presented a median survival of 2.5 years (P = 0.002).

Formula omitted] and cytokine plasma profiles under different postoperative parenteral nutrition regimens

Both nitric oxide and cytokines are considered mediators of the acute-phase response in humans, and their early postoperative period plasma levels have been found to be of prognostic value. On the other hand, it has been suggested that the fatty emulsions used in total parenteral nutrition (TPN) may induce changes in macrophage function. In the present study we investigated the postoperative evolution of tumor necrosis factor-a ( TNF-a ) , interleukin-1 (IL- 1) , interleukin-6 (IL-6)) and nitrate/nitrite plasma levels under three different TPN regimens. Twenty-one patients diagnosed with upper digestive tract neoplasm, without preoperative TPN, and having undergone radical surgery, were randomly assigned to three groups: Group I, all nonprotein calories supplied by hypertonic glucose solution; Group II, 55% of the nonprotein calories supplied by glucose and 45% by 20% long-chain triacylglycerides emulsion (LCT) (Intralipid 20%. Kabi-Pharmacia); Group III, same as Group II, but a 20% emulsion of a mixture of medium-chain and long-chain triacylglycerides (MCT/LCT) (Lipofundina MCT/LCT 20%, B. Braun) was used instead of LCT. Blood samples were obtained on postoperative Days l-5 and 10, 3 h after ending the lipid infusion. In all the three groups IL-l, IL-6, and TNF-(Y levels rose after surgery, peaking at Day 2, whereas NOZ/NO, levels had their peak at Day 3. Day-to-day comparison of plasma levels of cytokines and N02/N03 between the investigated groups did not show any statistical significance. Differences between group means were not found when the areas under the curve over the first 5 postoperative days were compared (1.72 t- 0.25, Group I; 1.88 5 0.34, Group II; and 2.52 + 0.50, Group III, for TNF-(Y; 1.79 -t 0.12, Group I; 1.92 2 0.18, Group II; and 1.50 + 0.12, Group III, for N01/N03). We conclude that the different parenteral nutrition regimens studied do not evoke alterations in cytokine and NO1 + NO3 levels in the patient groups investigated in this study. Nutrition 1996; 12539-92

A family of lipopolysaccharide binding proteins involved in responses to gram-negative sepsis.

The lipopolysaccharides (LPS) of Gram-negative bacteria initiate potentially fatal processes in many host organisms. Recently published amino acid sequence data suggest that there is a family of LPS binding proteins that may participate in the host response to Gram-negative bacteremia. The first two members of the family to be identified are an LPS binding protein present in serum after an acute phase response in humans, mice, rabbits, and rats and a bactericidal/permeability increasing protein present in the primary granules of human and rabbit neutrophils. LPS binding protein and bactericidal/permeability increasing protein share an ability to bind to LPS, have homologous NH2-terminal amino acid sequences, and are immunologically cross-reactive. Nevertheless, these two molecules differ in their effects on LPS and Gram-negative bacteria, in their sites of biosynthesis, and localization in vivo.