Age-related inflammatory cytokines and disease

Aging is associated with chronic low-grade increases in circulating levels of inflammatory markers. A wide range of environmental factors, including smoking, infections, and obesity, genetic factors, and the declining function of sex hormones may contribute to systemic low-grade inflammatory activity in older individuals. Age-associated disease may exacerbate this phenomenon. The multifunctional cytokines TNF-alpha and IL-6 have been associated with morbidity and mortality in the elderly. Evidence supports the direct role of TNF-alpha in the pathogeneses of atherosclerosis, type 2 DM, and AD in older individuals. Age-related increases in systemic levels of TNF-alpha could provide a unifying basis for these disorders. Furthermore, TNF-alpha induces a catabolic state that causes frailty. Circulating levels of IL-6 seem to be a strong risk factor for frailty in the elderly, which could reflect its association with increased production of TNF-alpha. IL-6 also may be a risk factor for thromboembolic complications. In healthy, elderly populations, high circulating levels of TNF-alpha and IL-6 predict mortality, independent of comorbidity, indicating that TNF-alpha and IL-6 cause morbidity and mortality. In cohorts of frail, older individuals, TNF-alpha and IL-6 also act as disease markers. Circulating levels of TNF-alpha seem to be the best predictor of mortality in frail, elderly populations with a high mortality rate, whereas IL-6 seems to be the strongest risk marker in healthy, elderly populations. This finding could reflect that in relatively healthy old populations the increase in circulating levels of IL-6 represent a systemic response to local proinflammatory activities; however, when age-related inflammatory diseases progress, levels of TNF-alpha increase in the circulation and become gradually a stronger risk marker than IL-6. In conclusion low-grade elevations in levels of circulating cytokines are strong independent risk factors of morbidity and mortality in the elderly, and lifestyle factors and comorbidities may modulate these levels. Exercise and dietary interventions may be possible strategies to decrease inflammatory activity and improve the health status of the elderly.     

Aging negatively skews macrophage TLR2- and TLR4-mediated pro-inflammatory responses without affecting the IL-2-stimulated pathway

We recently reported that macrophages from aged mice produced less tumor necrosis factor (TNF)-alpha following lipopolysaccharide (LPS) stimulation than macrophages from young animals. This correlated with decreased levels of phosphorylated and total p38 and c-Jun N-terminal kinase (JNK) mitogen-activated protein kinases (MAPKs). Here, we went on to determine if age affects other Toll-like (TLR) and non-TLR signaling pathways. We found that LPS- and zymosan-stimulated TNF-alpha and IL-6 production is attenuated in splenic macrophages from aged mice compared to young. Conversely, LPS-stimulated, but not zymosan-stimulated, IL-10 production from the aged group was elevated over that of the young group. In contrast, IL-2-stimulated TNF-alpha and IL-6 production was not affected by age. The age-associated changes did not correlate with alterations in the cell-surface expression of TLR2, TLR4, or IL-2Rbeta. Macrophages from aged mice demonstrated lower p38 MAPK and MAPK-activated protein kinase (APK)-2 activation. Protein expression of p38, but not MAPK-APK-2, was reduced with age. Additionally, nuclear factor (NF)-kappaB activation was significantly decreased in macrophages from aged mice after exposure to LPS, but not IL-2. These data indicate that age-associated macrophage signaling alterations are pathway-specific and suggest that TLR-mediated pathways are impaired with age at the level of MAPK expression.     

Common studied polymorphisms do not affect plasma cytokine levels upon endotoxin exposure in humans

The aim of this study was to investigate to what extent single nucleotide polymorphisms (SNPs) in promoter regions of genes of Toll-like receptor (TLR)-4, tumour necrosis factor (TNF)-alpha, interleukin (IL)-18, interferon (IFN)-gamma, IL-6 and IL-10 affect the cytokine response during a controlled low-grade inflammatory response in vivo. Two hundred healthy young male volunteers were genotyped, and cytokine levels were measured in response to a low-dose intravenous bolus of Escherichia coli endotoxin. No association was detected between SNPs (TLR-4299, TLR-4399, TNF-308, IL-18-137, IL-18-607, IFN-gamma+874, IL-6-174, IL-10-592 and IL-10-1082) and endotoxin-induced changes in plasma levels of TNF-alpha, IL-6 and IL-10. IL-18 levels were unaffected by endotoxin. In conclusion, the investigated SNPs did not affect endotoxin-induced low-grade cytokine production of TNF-alpha, IL-6, IL-18 or IL-10 in healthy young men. Previous reports of a major heritability factor in the inflammatory response may be due to other target genes or effects in older age groups or women.     

Increased secretion patterns of interleukin-10 and tumor necrosis factor-alpha in cervical squamous intraepithelial lesions

Cytokines are released in response to infection of the uterine cervix by high-risk HPV. By using enzyme-linked immunosorbent assay, we measured the levels of tumor necrosis factor-alpha (TNF-alpha), interferon-gamma (INF-gamma), interleukin-6 (IL-6), and interleukin-10 (IL-10) in the cervical secretions of 120 cytologically normal or equivocal and 91 abnormal Japanese women. HPV infection of the cervical cells was typed by the LCR-E7 PCR method. The HPV DNA-negative samples were classified as either normal or inflamed, and the HPV DNA-positive samples were classified as HPV positive(+) n-ormal and as low- or high-grade squamous intraepithelial lesions (SILs). Compared with the normal cervices, all of the cytokines tested were elevated in inflamed, HPV+ normal, low-grade SILs (LSIL), and high-grade SILs (HSIL). The level of IL-10 was statistically higher in LSIL, and the level of TNF-alpha was higher in HSIL, relative to the cytokine levels in the inflamed and HPV+ normal samples (P <0.05; Mann-Whitney test). Multivariate analyses confirmed that increased levels of IL-10 were associated with LSIL (relative risk [RR]=3.9, 95% confidence interval [CI]=1.7-8.8) and that increased levels of TNF-alpha (RR=4.6, 95% CI=1.4-15) and age older than 40 years (RR=8.5, 95% CI=1.3-56) were associated with HSIL. The levels of INF-gamma and TNF-alpha (Th1-cytokines) correlated negatively with those of IL-6 and IL-10 (Th2-cytokines) in HPV+ normal and LSIL subjects, whereas no such correlation was observed for HSIL. The up-regulated secretion of IL-10 may inhibit immune responses against HPV infection in early cervical lesions, whereas up-regulated TNF-alpha and uncoordinated cytokine secretion (elevated both Th1 and Th2 cytokines) may reflect impaired or invalid responses in advanced stage lesions. The detection of IL-10 and TNF-alpha in cervical secretions may be a useful indicator of local immune responses and of the stage of the cervical lesions induced by HPV infection.     

Cytokine levels in Crimean-Congo hemorrhagic fever.

BACKGROUND: Crimean-Congo hemorrhagic fever (CCHF) virus causes severe disease in humans with a mortality reaching 30%. A CCHF outbreak took place in Albania in 2003. As in other viral hemorrhagic fevers cytokines may be involved and play a role in the pathogenesis and outcome of the disease. OBJECTIVES: To investigate the levels of TNF-alpha, sTNF-R, IL-6 and IL-10 in serum samples obtained from laboratory confirmed CCHF cases and relate them to the severity of the disease. STUDY DESIGN: A study population of 51 was divided into three groups: group A, consisting of PCR-positive cases; group B, consisting of PCR-negative and serology-positive cases; group C, consisting of doubly negative cases. Concentrations of serum TNF-alpha, sTNF-R, IL-6 and IL-10 were measured during the illness. RESULTS: High levels of all cytokines tested were present in one fatal case. Statistically significant differences between the groups were obtained for TNF-alpha and IL-6: TNF-alpha was detected in 3 cases in group A, and in none of the other groups, while IL-6 was elevated in 10/16 patients in group A, 4/9 in group B, and 4/26 in group C. sTNF-R was not significantly different for the three groups. High concentration of IL-10 was detected only in the fatal case. CONCLUSIONS: TNF-alpha and IL-6 are the cytokines most often detected during a CCHF viral infection. TNF-alpha was associated with the severe form of CCHF, while IL-6 was elevated in both severe and mild cases.     

Interleukin (IL)-8 and growth related oncogene-alpha in severe endotoxemia and the effects of a tumor necrosis factor-alpha/IL-1beta inhibitor on these chemokines

FR167653 inhibits the production of tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta, powerful inducers of CXC chemokines IL-8 and growth related oncogene (GRO)-alpha. The production of IL-8 and GRO-alpha was investigated and the effects of FR167653 were examined in a rabbit model of endotoxin shock. Male New Zealand rabbits were given endotoxin at a dose sufficient to induce DIC. Three groups of rabbits received FR167653 at different doses. TNF-alpha, IL-1beta, IL-8, and GRO-alpha levels were measured, several pathologic features were evaluated, and the results were compared with those obtained in control rabbits, which received only endotoxin. Endotoxin increased serum levels of IL-8 and GRO-alpha, which were associated with hypotension, renal dysfunction, and mortality, peaking at 4 h. FR167653 improved mortality, an event that was associated with decreased levels of not only TNF-alpha and IL-1beta but also IL-8 and GRO-alpha. TNF-alpha peaked at 2 h, at a time point before IL-8 and GRO-alpha reached their peak, and the TNF-alpha level was tightly correlated with that of IL-8 and GRO-alpha. Altogether, these data suggest the possible involvement of IL-8 and GRO-alpha in endotoxin shock, and FR167653 may foster a beneficial outcome in part by modulating the chemokines level by inhibiting TNF-alpha and IL-1beta.     

Inflammatory responses in blood samples of human immunodeficiency virus-infected patients with pulmonary infections

We analyzed the characteristics of the inflammatory response occurring in blood during pulmonary infections in human immunodeficiency virus (HIV)-infected patients. A prospective study of consecutive hospital admissions of HIV-infected patients with new-onset radiologic pulmonary infiltrates was carried out in a tertiary university hospital from April 1998 to May 2001. Plasma cyclic AMP receptor protein (CRP), interleukin 1beta (IL-1beta), IL-6, IL-8, IL-10, and tumor necrosis factor alpha (TNF-alpha) levels were determined at the time of admission and 4, 5, and 6 days later. Patients were included in a protocol addressed to study etiology and outcome of disease. A total of 249 episodes of infection were included, with the main diagnoses being bacterial pneumonia (BP) (118 episodes), Pneumocystis carinii pneumonia (PCP) (41 episodes), and mycobacteriosis (36 episodes). For these three patient groups, at the time of admission the median CRP and cytokine levels were as follows: CRP, 10.2, 3.8 and 5 mg/dl, respectively (P = 0.0001); IL-8, 19, 3, and 2.9 pg/ml (P = 0.045); and TNF-alpha, 46.4, 44, and 75 pg/ml, respectively (P = 0.029). There were no significant differences in levels of IL-1beta, IL-6, or IL-10 among the patient groups. A total of 23 patients died. At the time of admission, HIV-infected patients with BP had higher plasma CRP and IL-8 levels than did PCP and mycobacteriosis patients. TNF-alpha levels were higher in patients with mycobacteriosis. An elevated IL-8 level (>61 pg/ml) at the time of admission was an independent factor associated with higher mortality (odds ratio, 12; 95% confidence interval, 1.2 to 235.5).     

Effect of age and carbon tetrachloride on cytokine concentrations in rat liver.

Interleukin-1beta (IL-1beta), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha) concentrations were measured in livers of young-adult and old rats administered carbon tetrachloride or vehicle. IL-1beta levels were higher and IL-6 levels were lower in old rats than in young-adult rats. Carbon tetrachloride treatment increased IL-1beta and decreased TNF-alpha and IL-6. The elevation in IL-1beta was diminished by aging. These results indicate that the increase in carbon tetrachloride hepatotoxicity that occurs in old age could be related to a dysregulation of inflammatory cytokines.     

Biological variations, genetic polymorphisms and familial resemblance of TNF-alpha and IL-6 concentrations: STANISLAS cohort

Cytokines are involved in the development of several inflammatory diseases and atherosclerosis. Their variations in healthy individuals are not well defined. The aims of this study were: firstly, to identify factors affecting biological variation of interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-alpha); secondly, to study their family resemblance; and thirdly, to evaluate the effect of two TNF-alpha (-308G/A and -238G/A) and two IL-6 polymorphisms (174G/C and -572G/C) on their corresponding circulating levels. A total of 171 healthy families selected from the STANISLAS cohort were studied. Age was negatively related to TNF-alpha concentrations in offspring only (both sons and daughters). Additionally, IL-6 and TNF-alpha levels were differently influenced by gender, white blood cells, tobacco consumption, and HDL-cholesterol level. A weak significant familial resemblance for TNF-alpha concentration was observed in siblings only. There was no significant familial resemblance for IL-6 levels. The TNF-alpha -308A allele was associated with decreased TNF-alpha concentrations in both offspring aged less than 18 and males without overweight (BMI<25 kg/m(2)). Fathers carrying the IL-6 -174CC genotype had higher IL-6 levels than those with the IL-6 -174G allele. Parents with the IL-6 -572GG genotype had higher IL-6 concentrations than the C allele carriers. In this sample of healthy families, plasma levels of IL-6 and TNF-alpha were differently affected by biological parameters including age, gender and smoking, and the impact of their respective polymorphisms was influenced by gender, age and BMI.     

1267 HSP70-2 polymorphism as a risk factor for carotid plaque rupture and cerebral ischaemia in old type 2 diabetes-atherosclerotic patients

Patients with type 2 diabetes mellitus (NIDDM) are at risk for macrovascular disease complications, such as myocardial infarction (MI) or stroke from plaque rupture. Cytokines play a key role in plaque vulnerability. IFN-gamma inhibits collagen synthesis thereby affecting plaque stability. High IL-6, TNF-alpha, and dyslipidemia are risk factors for thrombosis. Abnormal increments of HSP70 in atherosclerotic plaques might lead to plaque instability and rupture caused by chronic inflammation, which up-regulates the expression of pro-inflammatory cytokines (IL-6 and TNF-alpha) in human monocytes. Studies of a polymorphic PstI site lying in the coding region at position 1267 of the HSP70-2 gene have shown that the BB genotype is associated with NIDDM. We screened 60 old NIDDM patients with carotid stenosis and 107 old healthy controls for 1267 HSP70-2 polymorphism in order to establish if an association with plaque frailty exists. Different genotypic distributions were observed between patients and healthy controls. An increased relative risk was associated with the B allele (p = 0.0107; odds ratio = 1.861). HSP70-2, IL-6, IFN-gamma, TNF-alpha gene expressions within the plaques and serum levels of triglyceride, total cholesterol and LDL cholesterol were tested from patients stratified according to their B+ (AB and BB) and B- (AA) genotypes. Plaque morphology (soft or fibrous-calcified) and the incidence of cerebral ischaemia were also assessed. B+ patients showed increased HSP70-2, IL-6, IFN-gamma, TNF-alpha and dyslipidemia as compared to B- carriers. The frequency of soft plaques increased in B+ in comparison to B- patients (67% versus 13%; odds ratio 13.0, p = 0.0006). A higher frequency of cerebral ischaemia (ictus or transient ischaemic attack (TIA)) was present in B+ than in B- genotype (53% versus 20%; odds ratio 4.57, p < 0.05) Hence, 1267 HSP70-2 polymorphism may be of use in identifying B+ NIDDM patients at risk for carotid plaque rupture and cerebral ischaemia.     

Levels of proinflammatory cytokines in plasma after pneumoccoccal immunization in human immunodeficiency virus type 1-infected patients

To ascertain if immunization with pneumococcal polysaccharide vaccine is associated with rises in the levels of proinflammatory cytokines in the plasma of human immunodeficiency virus type 1 (HIV-1)-infected patients, the levels of tumor necrosis factor alpha (TNF-alpha) and interleukin-6 (IL-6) were measured serially after immunization. IL-6 levels rose an average of 2.2- and 2.1-fold 6 and 8 h after immunization, respectively, but TNF-alpha levels remained unchanged. The levels of these cytokines were stable in unimmunized controls. Immunization with pneumococcal polysaccharide vaccine induces increases in the levels of IL-6 in the plasma of persons with HIV-1 infection.     

Ageing is associated with a prolonged fever response in human endotoxemia

The purpose of this study was to investigate whether an age-associated impaired acute-phase response exists. Nine healthy elderly volunteers (median, 66 years; range, 61 to 69 years) and eight young controls (median, 24 years; range, 20 to 27 years) were given an intravenous bolus of endotoxin (2 ng/kg). The rectal temperature was monitored continuously, and blood samples for cytokine measurements were obtained before endotoxin administration as well as 0.5, 1, 1.5, 2, 3, 4, 8, 12, and 24 h after the injection. The elderly subjects showed a more prolonged fever response compared to the young controls. Levels of tumor necrosis factor alpha (TNF-alpha), soluble TNF receptors (sTNFR-I), interleukin-6 (IL-6), IL-8, IL-10, and IL-1 receptor antagonist (IL-1ra) in plasma increased markedly following endotoxin administration in both groups. The elderly group showed larger initial increases in TNF-alpha and sTNFR-I levels and prolonged increased levels of sTNFR-I. Monocyte concentrations decreased in both groups, with the elderly group showing a more rapid decrease and a slower subsequent increase than did the young group. Furthermore, the elderly group had a more rapid increase in C-reactive protein levels than did the young group. In conclusion, ageing is associated with an altered acute-phase response including initial hyperreactivity, prolonged inflammatory activity, and prolonged fever response.     

Age-associated changes in immune and inflammatory responses: impact of vitamin E intervention

Aging is associated with dysregulated immune and inflammatory responses. Declining T cell function is the most significant and best-characterized feature of immunosenescence. Intrinsic changes within T cells and extrinsic factors contribute to the age-associated decline in T cell function. T cell defect seen in aging involves multiple stages from early receptor activation events to clonal expansion. Among extrinsic factors, increased production of T cell-suppressive factor PGE(2) by macrophages (Mphi) is most recognized. Vitamin E reverses an age-associated defect in T cells, particularly na?ve T cells. This effect of vitamin E is also reflected in a reduced rate of upper respiratory tract infection in the elderly and enhanced clearance of influenza infection in a rodent model. The T cell-enhancing effect of vitamin E is accomplished via its direct effect on T cells and indirectly by inhibiting PGE(2) production in Mphi. Up-regulated inflammation with aging has attracted increasing attention as a result of its implications in the pathogenesis of diseases. Increased PGE(2) production in old Mphi is a result of increased cyclooxygenase 2 (COX-2) expression, leading to higher COX enzyme activity, which in turn, is associated with the ceramide-induced up-regulation of NF-kappaB. Similar to Mphi, adipocytes from old mice have a higher expression of COX-2 as well as inflammatory cytokines IL-1beta, IL-6, and TNF-alpha, which might also be related to elevated levels of ceramide and NF-kappaB activation. This review will discuss the above age-related immune and inflammatory changes and the effect of vitamin E as nutritional intervention with a focus on the work conducted in our laboratory.     

The mycotoxins citrinin and gliotoxin differentially affect production of the pro-inflammatory cytokines tumour necrosis factor-α and interleukin-6, and the anti-inflammatory cytokine interleukin-10

BACKGROUND: Microbial growth is considered one of the major causes of indoor air problems. Moulds have been associated with asthma, allergy and a wide range of diffuse indoor air-related symptoms. However, mechanisms of the adverse health effects are not well understood. OBJECTIVE: We hypothesized that the mycotoxins citrinin and gliotoxin could cause an imbalance between the secretion of the pro-inflammatory cytokines TNF-alpha and IL-6 and the anti-inflammatory cytokine IL-10. METHODS: We investigated the influence of citrinin and gliotoxin on the human monocytic cell line Mono-Mac-6 (MM6) with and without lipopolysaccharide -stimulation. The levels of IL-10, IL-6 and TNF-alpha were analysed in cell culture supernatants by ELISA. Cell viability and cell apoptosis were measured by flow cytometry. RESULTS: The strongest inhibition of cytokine secretion was found for IL-10. IL-6 levels were found to decrease in a dose-dependent manner along with reduced cell viability. TNF-alpha levels increased with low gliotoxin exposure (less than 100 ng/mL), but decreased significantly at 375 ng/mL and higher along with increased cell apoptosis and reduced cell viability. TNF-alpha levels were not reduced by citrinin exposure. CONCLUSION: We observed a cytokine imbalance with a more pronounced reduction of IL-10 concentrations compared with those of TNF-alpha and IL-6. We suggest that low exposure doses of citrinin and gliotoxin (corresponding to less than 100 ng/mL gliotoxin and less than 10 mug/mL citrinin) may inhibit IL-10 and lead to increased risk of an inflammatory response with relative overproduction of TNF-alpha and IL-6. The findings and their clinical implications must be verified by human studies. However, we speculate that the observed biological effects may be of importance as they may partly explain the occurrence of diffuse general indoor air-related symptoms as well as the worsening of asthmatic inflammatory reactions experienced in mouldy environments.     

Cytokine appearance and effects of anti-tumor necrosis factor alpha antibodies in a neonatal rat model of group B streptococcal infection.

Cytokines are suspected of playing an important role in the pathophysiology of septic shock. This study was undertaken to determine whether tumor necrosis factor alpha (TNF-alpha) induces the production of other cytokines and mediates mortality in a neonatal rat model of sepsis caused by group B streptococci (GBS). We have measured TNF-alpha, interleukin-1 alpha (IL-1 alpha), interleukin-6 (IL-6), and gamma interferon (IFN-gamma) levels in neonatal rats infected with different strains (H738, 259, and 90) and doses (1 50% lethal dose [LD50] and 5 90% lethal doses [LD90]) of type III GBS. TNF-alpha and IL-6 were detected by the L929 cytotoxicity and the B9 proliferation assays, respectively, in serial plasma samples. IL-1 alpha and IFN-gamma were measured in spleen homogenates by enzyme-linked immunosorbent assay kits by using antibodies raised against the corresponding mouse cytokines. Plasma TNF-alpha levels significantly rose above baseline values within 12 h after intraperitoneal challenge with 5 LD90 of GBS strain H738, corresponding to 3 x 10(3) CFU. A mean peak TNF-alpha concentration of 232 +/- 124 U/ml was reached at 20 h. Peak IL-1 alpha and IL-6 levels of 766 +/- 404 U/g and 1,033 +/- 520 U/ml, respectively, were reached at 24 h after bacterial challenge. Maximal spleen concentrations of IFN-gamma (449 +/- 283 U/g) were measured at 36 h. Concentrations of TNF-alpha, but not other cytokines, remained significantly elevated at 72 h, a time when mortality approached 100%. Significant correlations were found between concentrations of each of the cytokines tested and the logs of CFU concentrations in the blood. In order to ascertain whether TNF-alpha influenced the production of other cytokines, rat pups received two injections of anti-murine TNF-alpha or normal rabbit serum at 2 h before and at 26 h after challenge with live GBS. Plasma TNF-alpha bioactivity was undetectable in anti-TNF-alpha-treated animals, while IL-6 and IFN-gamma, but not IL-1 alpha, levels were significantly reduced, compared with normal serum controls. Rat pups pretreated with anti-TNF-alpha serum and infected with 1 and 5 LD90 of strains H738 and 259 showed enhanced early (48 to 72 h) survival. However, by 96 h this protection was no longer apparent.     

Elevated butyrylcholinesterase and acetylcholinesterase may predict the development of type 2 diabetes mellitus and Alzheimer's disease

Plasma levels of C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), and lipid peroxides are elevated and concentrations of endothelial nitric oxide (eNO) decreased in type 2 diabetes mellitus and Alzheimer's disease. This suggests that both these diseases are low-grade systemic inflammatory conditions and are closely associated with each other. Recent studies revealed that plasma and tissue concentrations of enzymes butyrylcholinesterase and acetylcholinesterase are elevated in type 2 diabetes and Alzheimer's disease. Acetylcholine has anti-inflammatory actions. Hence, elevated butyrylcholinesterase and acetylcholinesterase concentrations will lead to a decrease in the levels of acetylcholine that could trigger the onset of low-grade systemic inflammation seen in type 2 diabetes and Alzheimer's disease. In view of this, we propose that butyrylcholinesterase and acetylcholinesterase will not only serve as therapeutic targets but also may serve as markers to predict the development of type 2 diabetes mellitus and Alzheimer's disease.     

LPS-induced release of IL-1beta, IL-1Ra, IL-6, and TNF-alpha in whole blood from patients with familial hypercholesterolemia: no effect of cholesterol-lowering treatment.

Proinflammatory cytokines, such as interleukin-1beta (IL-1beta), IL-6, and tumor necrosis factor-alpha (TNF-alpha), are suggested to have an important role in the process of atherosclerosis. Patients with heterozygous familial hypercholesterolemia (FH) have a marked elevation in the plasma level of low-density lipoproteins (LDL), and they show early development of atherosclerosis. The aim of the present study was to test with a whole blood culture system if hyperlipoproteinemia is associated with increased cytokine production capacity in these patients and if treatment with 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors influences this production capacity of blood cells, at both the protein and mRNA levels. The capacity of blood cells in a whole blood culture to produce IL-1beta, IL-6, TNF-alpha, IL-12, IL-18, and IL-1 receptor antagonist (IL-1Ra) in response to lipopolysaccharide (LPS) appeared to be similar for heterozygous FH patients and healthy volunteers. Furthermore, the capacity to produce IL-1beta, IL-6, and TNF-alpha in response to LPS was not modified by cholesterol synthesis inhibitors at the level of mRNA expression or at the level of release. On the other hand, the release of IL-1Ra was significantly increased after treatment with HMG-CoA reductase inhibitors, although only at the protein level. This suggests a possible beneficial anti-inflammatory role for this therapy.     

Circulating levels of TNF-alpha and IL-6-relation to truncal fat mass and muscle mass in healthy elderly individuals and in patients with type-2 diabetes

The purpose of the current study was to test the hypothesis that an altered fat distribution in elderly healthy subjects and in patients with type-2 diabetes contributes to high circulating levels of interleukin (IL)-6 and tumor necrotic factor (TNF)-alpha, which secondly is related to lower muscle mass. Twenty young controls, (20-35 yr), 20 healthy elderly subjects (65-80 yr) and 16 elderly patients with type 2 diabetes (65-80 yr) were included in a cross sectional study. Plasma levels of TNF-alpha and IL-6 were measured after an overnight fast. Dual-energy X-ray absorptiometry and total body potassium counting measured truncal fat, appendicular skeletal muscle mass (ASM) and body cell mass (BCM), respectively. TNF-alpha, IL-6 and the relative truncal fat mass were higher in elderly compared with young controls. ASM was lower in diabetic men than in young controls and BCM was lower in elderly men compared with young men. TNF-alpha and IL-6 were correlated with the absolute as well as the relative truncal fat mass in univariate regression analyses. Similar results were found in multivariate linear regression analyses after adjusting for the effect of age and gender. TNF-alpha was related to lower ASM and BCM in elderly men both in a univariate regression analysis and a multivariate regression analysis. In conclusion, high plasma levels of TNF-alpha and IL-6 in elderly healthy people and in patients with type 2 diabetes are associated with increased truncal fat mass, suggesting that cytokines are partly derived from this adipose tissue bed. Furthermore, TNF-alpha was related to lower ASM and BCM, suggesting that TNF-alpha contributes to sarcopenia in ageing.     

Synthesis and regulation of accessory/proinflammatory cytokines by intestinal epithelial cells.

Intestinal epithelial cells (IEC) have been shown to act as antigen-presenting cells (APC) in vitro and may have this capacity in vivo. In order to determine whether IEC, like other APC, are able to produce accessory cytokines which may play a role in T cell activation, we assessed the accessory cytokine profile of IEC constitutively or after stimulation. We measured expression, production and regulation of accessory cytokines (IL-1 beta, IL-6, tumour necrosis factor-alpha (TNF-alpha), transforming growth factor-beta (TGF-beta) by the presence of mRNA as well as secreted protein. Freshly isolated IEC from surgical specimens were cultured in the presence or absence of lipopolysaccharide (LPS), interferon-gamma (IFN-gamma), IL-1 beta or TNF-alpha. mRNA was assessed by a specific RNAse protection assay which controlled for contaminating cell populations while protein secretion was measured by ELISA (IL-1) or bioassay (TNF and IL-6). Neither IL-1 beta nor TNF-alpha were detectable in cultured IEC supernatants, supporting the lack of macrophage contamination. All IEC spontaneously secreted IL-6 at levels comparable to those of macrophages. IEC IL-6 mRNA also increased approximately 200-fold during the first 24 h of culture. LPS, IFN-gamma or TNF-alpha had no effect on spontaneous IL-6 production, and neither resulted in the secretion of IL-1 beta or TNF-alpha. However, IL-1 beta up-regulated IL-6 synthesis by 6-7-fold. IEC express a profile of cytokine mRNAs distinct from conventional APC (low level constitutive IL-6 expression but no detectable IL-1 beta, TGF-beta or TNF-alpha), adding to their uniqueness as APC.     

Mycobacterium avium infection in HIV-1-infected subjects increases monokine secretion and is associated with enhanced viral load and diminished immune response to viral antigens.

The complex interaction between HIV-1 infection and Mycobacterium avium was studied. Viral burden was assessed, as well as immune response to HIV-1 in the context of Myco. avium infections. We also examined serum cytokine levels and cytokine release by blood mononuclear cells in HIV-1-infected subjects, infected or not with Myco. avium. Undetectable serum levels of IL-1, tumour necrosis factor-alpha (TNF-alpha) and IL-6 were found in normal controls and in groups I, II and III of HIV-1-infected subjects. Moderate levels of TNF-alpha, IL-1 and IL-6 were found in the sera of group IV patients. When group IV was subdivided into subjects with and without Myco. avium infections, subjects with Myco, avium infections were shown to have higher serum levels of TNF-alpha, IL-1 beta and IL-6 than those with other infections. Blood mononuclear cells from controls and HIV subjects were stimulated with bacterial lipopolysaccharide, and cytokine levels assessed. Cells from group II patients were shown to secrete normal levels of TNF-alpha and IL-6, and lower levels of IL-1 beta; group III subjects released higher levels of IL-6. Patients in group IV had blood cells that released elevated levels of IL-6 and TNF-alpha, and lower levels of IL-1 beta. Group IV subjects with Myco. avium infections had blood cells that released higher levels of TNF-alpha, IL-6 and IL-1 than group IV subjects with other infections. Assessment of viral burden in cells of HIV-1-infected subjects revealed that Myco. avium-infected subjects had a higher level of virus burden and a lower level of lymphoproliferative response to an inactivated gp120-depleted HIV-1 antigen than AIDS subjects with other infections. These data suggest that Myco. avium infections in HIV-1-infected subjects hasten the progression of viral disease, enhance cytokine release and contribute to the anergy to viral antigens.