Martin Ploder

Vitamin D3 down-regulates monocyte TLR expression and triggers hyporesponsiveness to pathogen-associated molecular patterns.

Toll‐like receptors (TLR) represent an ancient front‐line defence system that enables the host organism to sense the presence of microbial components within minutes. As inducers of inflammation, TLR act as important triggers of distinct entities such as sepsis or autoimmune disease exacerbation. We report here that vitamin D3 [1α,25‐dihydroxycholecalciferol, 1,25(OH)2D3] suppresses the expression of TLR2 and TLR4 protein and mRNA in human monocytes in a time‐ and dose‐dependent fashion. Despite 1,25(OH)2D3‐induced up‐regulation of CD14, challenge of human monocytes with either LPS or lipoteichoic acid resulted in impaired TNF‐α and procoagulatory tissue factor (CD142) production, emphasizing the critical role of TLR in the induction of inflammation. Moreover, reduced TLR levels in 1,25(OH)2D3‐treated phagocytes were accompanied by impaired NF‐κB/RelA translocation to the nucleus and by reduced p38 and p42/44 (extracellular signal‐regulated kinase 1/2) phosphorylation upon TLR‐ligand engagement. Both TLR down‐regulation and CD14 up‐regulation were substantially inhibited by the vitamin D receptor (VDR) antagonist ZK 159222, indicating that the immunomodulatory effect of 1,25(OH)2D3 on innate immunity receptors requires VDR transcription factor activation. Our data provide strong evidence that 1,25(OH)2D3 primes monocytes to respond less effectively to bacterial cell wall components in a VDR‐dependent mechanism, most likely due to decreased levels of TLR2 and TLR4.

GREEN TEA POLYPHENOL EXTRACT ATTENUATES ZYMOSAN-INDUCED NON-SEPTIC SHOCK IN MICE

ABSTRACT Multiple-organ failure (MOF) is defined as the progressive deterioration in function which occurs in several organs or systems in patients with septic shock, multiple trauma, severe burns, or pancreatitis. In the present study, we have investigated the effects of Green Tea extract (GTE) on the development of general inflammation caused by zymosan (500 mg/kg, administered i.p. as a suspension in saline) in mice. Organ failure and systemic inflammation in mice was assessed 18 hours after administration of zymosan and/or GTE and monitored for 12 days (for loss of body weight and mortality). Treatment of mice with GTE (25 mg/kg i.p., 1 and 6 hours after zymosan) attenuated the peritoneal exudation and the migration of polymorphonuclear cells (PMNs) caused by zymosan, GTE also attenuated the lung, liver and pancreatic injury and renal dysfunction caused by zymosan as well as the increase in myeloperoxidase (MPO) activity caused by zymosan in the lung and intestine. Immunohistochemical analysis for inducible nitric oxide synthase (iNOS), nitrotyrosine and poly(ADP-ribose) (PAR) revealed positive staining in lung and intestine tissues obtained from zymosan-treated mice. The degree of staining for nitrotyrosine, iNOS and PAR were markedly reduced in tissue sections obtained from zymosan-treated mice, which received GTE. In conclusion this study provides evidence, for the first time, that GTE attenuates the degree of zymosan induced generalized inflammation in mice.

Modulation of toll-like receptor 4 expression on human monocytes by tumor necrosis factor and interleukin-6: Tumor necrosis factor evokes lipopolysaccharide hyporesponsiveness, whereas interleukin-6 enhances lipopolysaccharide activity

Toll-like receptors (TLR) play a pivotal role in the innate immune response, and the expression levels of these receptors may reflect the sensitivity of immune cells to infections. The binding of lipopolysaccharide (LPS) to TLR-4 triggers human monocytes to produce cytokines, which play a dominant role in the inflammatory response, as can be observed during sepsis and after polytrauma. Here, we evaluated TLR-4 expression of isolated monocytes in the presence of tumor necrosis factor (TNF)-&agr;, interleukin (IL) 6, IL-8, and IL-10, and we investigated cellular activation of this treatment. TNF-&agr; significantly down-regulated TLR-4 mRNA expression after 6 h (100% vs. 38.5% ± 4%; P < 0.05). This down-regulation was followed by a dose- and time-dependent diminished expression of TLR-4 surface protein (100% vs. 8.0% ± 5%; P < 0.01). Forty-eight hours after TNF-&agr; treatment, a reduced nuclear factor (NF)-&kgr;B translocation and a diminished IL-6 secretion after LPS stimulation were found (100% vs. 42.0% ± 23%; P < 0.05). In contrast, IL-6 incubation upregulated TLR-4 cell surface protein (100% vs. 165.8% ± 24%; P < 0.05) and increased the ability to activate NF-&kgr;B and AP-1 after LPS stimulation. Stimulation with IL-8 or IL-10 had no significant effects. We conclude that not only LPS but also TNF-&agr; and IL-6 have the potency to regulate the immune response via TLR-4. Down-regulation of TLR-4 by TNF-&agr; is associated with LPS hyporeactivity for NF-&kgr;B formation, whereas upregulation of TLR-4 via IL-6 can increase the responsiveness of mononuclear phagocytes.

Elevated serum levels of epithelial cell apoptosis-specific cytokeratin 18 neoepitope m30 in critically ill patients.

Apoptosis of the epithelium is deemed to play a pivotal role in the pathogenesis of sepsis. A neoepitope in cytokeratin 18 (CK18), termed M30 neoantigen, becomes available at an early caspase cleavage event during apoptosis of epithelium-derived cells and is not detectable in vital or necrotic epithelial cells. A monoclonal antibody, M30, specifically recognizes a fragment of CK18 cleaved at Asp396 (M30 neoantigen). We used an enzyme-linked immunosorbent assay (ELISA) to measure M30 antigen levels in the sera of 15 septic patients. Healthy humans and critical ill patients suffering from severe trauma served as controls. Mann-Whitney U test was used to calculate significance, and a P value of <0.01 was considered to be statistically significant. Serum levels of the CK18 neoepitope M30 were significantly increased in septic patients (236.88 ± 47.4 U/L) versus trauma (97.2 ± 17.1 U/L) and healthy controls (66.9 ± 9.2 U/L) (P < 0.01 and P < 0.008, respectively). The increased serum level of the CK18 neoepitope in septic patients indicates a heightened apoptotic turnover in epithelial cells as compared with trauma patients and healthy controls. Interestingly, nonsurviving trauma patients exhibited a significant increase in the M30 neoantigen as compared with survivors and healthy controls (P < 0.003 and P < 0.002, respectively). The detection of CK18 neoepitope M30 in the serum might be a useful marker in tracing apoptotic epithelium in septic patients.

Serum phenylalanine in patients post trauma and with sepsis correlate to neopterin concentrations

Summary.Increased blood concentrations of phenylalanine in patients with trauma and sepsis are common but unexplained. We examined the potential relationship between serum concentrations of phenylalanine and the immune activation marker neopterin in 84 specimens of 18 patients (14 males and 4 females) post-trauma during 12–14 days of follow up. Compared to healthy controls, average phenylalanine and neopterin concentrations were elevated in patients, and there existed a positive correlation between concentrations of the two analytes (rs = 0.375, p < 0.001). No such association existed between neopterin and tyrosine concentrations (rs = −0.018), but neopterin concentrations correlated to the phenylalanine to tyrosine ratio (rs = 0.328, p = 0.001).Increased phenylalanine implies insufficient conversion by phenylalanine (4)-hydroxylase (PAH). Oxidative stress due to immune activation and inflammation may destroy cofactor 5,6,7,8-tetrahydrobiopterin and impair PAH activity. This assumption is further supported by the correlation found between higher neopterin concentrations and higher phenylalanine to tyrosine ratio, which estimates efficacy of PAH.

Genetic detection of lymph node micrometastases : A selection criterion for liver transplantation in patients with liver metastases after colorectal cancer

Background. Liver transplantation for nonresectable liver metastases from colorectal cancer was abandoned in 1994 on account of high recurrence rates. The aim of this study was to investigate whether the genetic detection of micrometastases in histologically negative lymph nodes of the primary colon cancer could be applied to select patients for liver transplantation. Methods. We analyzed 21 patients with colorectal cancer who had undergone liver transplantation between 1983 and 1994 for liver metastases. Eleven patients were histologically lymph node negative at the time of surgery; ten patients with lymph node metastases served as control group. DNA sequencing was used to screen tumor material for p53 and K-ras mutations. Mutant allele-specific amplification (MASA) was then used to search for micrometastases in DNA from regional lymph nodes of the primary colorectal cancer. Results. p53 and K-ras mutations were detected in 12 (57%) and 3 (14%) of 21 patients in the colorectal cancer, respectively. The mutations were confirmed in the corresponding liver metastases. Of 11 patients with histologically negative lymph nodes, nine were eligible for MASA due to presence of p53 or K-ras mutation. MASA revealed six of nine patients to be genetically positive for micrometastases. Three patients were both genetically and histologically negative. These three patients showed a significantly longer overall survival (P=0.011) of 4, 5, and 20 years, respectively. Conclusions. We conclude that the genetic detection of micrometastases by MASA could be a powerful prognostic indicator for selecting patients with colorectal liver metastases who could benefit from liver transplantation.

Age, microbiology and prognostic scores help to differentiate between secondary and tertiary peritonitis

Background and aimsTertiary peritonitis is a severe persisting intra-abdominal infection and associated with high mortality. The aim was to find significant risk factors for mortality and tertiary peritonitis including the Mannheim Peritonitis Index (MPI), the Acute Physiology and Chronic Health Evaluation (APACHE) II score, and a sumscore of both.Materials and methodsIn this retrospective single-center cohort study, 122 patients were treated at the Surgical Department of a University Hospital.ResultsSixty-nine patients (56.6%) developed tertiary peritonitis. Nineteen patients (27.5%), who suffered from tertiary peritonitis, died in contrast to eight patients (15.1%) with secondary peritonitis (P = 0.101). Patients with tertiary peritonitis had significantly higher APACHE II (P < 0.001), MPI (P = 0.035), and combined APACHE II and MPI scores (P < 0.001) than patients with secondary peritonitis. Age (P = 0.035), fungal infections (P = 0.025), and infections with more than one microbial organism (P = 0.047) were predictive for tertiary peritonitis. Combined APACHE II and MPI scores detected tertiary peritonitis better than the MPI (P = 0.014). Detection of mortality was comparable in all evaluated prognostic scores.ConclusionPrognostic scores besides age and fungal infections are risk factors for mortality and help to differentiate between secondary and tertiary peritonitis. The combination of prognostic scores is comparable to the APACHE II and superior compared to the MPI in regard to detection of tertiary peritonitis.

Early Increase of Plasma Homocysteine in Sepsis Patients with Poor Outcome

Moderate hyperhomocysteinemia is a well-established coronary risk factor that develops when dietary supply with folate and/or vitamin B12 is inadequate. Recently, stimulated peripheral blood mononuclear cells were shown to produce homocysteine. Thus, the stimulated immune system may contribute to moderate hyperhomocysteinemia during certain diseases. Because multiple trauma and sepsis are accompanied by often strong inflammatory responses, we investigated whether hyperhomo-cysteinemia may develop in patients. Total homocysteine and cysteine concentrations were measured in 83 plasma specimens from 18 patients (14 men, 4 women; 15 posttrauma with sepsis and 3 with sepsis alone) every third day of follow-up. Finally results were compared with concentrations of cytokines tumor necrosis factor (TNF)-α and interleukin (IL)-6, the immune activation marker neopterin and the extent of tryptophan degradation as indicated by the kynurenine-to-tryptophan ratio (kyn/trp). Compared with baseline, average total homocysteine (P < 0.05, d 4-d 10) and cysteine (P < 0.05, d 7-d 13) concentrations increased during follow-up of patients. However, only the increase of homocysteine was related to the survival status: total homocysteine was significantly higher in nonsurvivors (P < 0.05, d 4 and d 10) than in survivors, whereas cysteine concentrations increased in both subgroups. Homocysteine correlated with kyn/trp but not with neopterin concentrations. Increase of total homocysteine is common in patients after trauma with unfavorable outcome. Because all patients received standardized enteral nutrition after the end of hypodynamic shock, inconsistent vitamin supply is unlikely to be the reason for hyperhomocysteinemia in some of the patients; rather, it is associated with a stronger proinflammatory response. Certainly, the number of patients in our study is still small and results can only be regarded as preliminary.

Tryptophan degradation in multiple trauma patients: survivors compared with non-survivors.

Immune dysfunction in trauma patients is associated with immune system activation and inflammation. The cytokine-inducible enzyme IDO (indoleamine 2,3-dioxygenase) initiates the degradation of the essential aromatic amino acid tryptophan via the kynurenine pathway and could contribute to deficient immune responsiveness. Activated IDO is indicated by an increased kyn/trp (kynurenine/tryptophan) ratio. The aim of the present study was to investigate whether tryptophan degradation is associated with outcome in patients post-trauma. Tryptophan and kynurenine concentrations were measured by HPLC in serum specimens of 15 patients post-trauma during 12-14 days of follow-up. Up to five samples within this observation period from each patient were included in this analysis, and a total a 69 samples were available. For further comparisons, concentrations of the immune activation marker neopterin were measured. Compared with healthy controls, the average kyn/trp ratio and kynurenine concentrations were increased in patients, whereas tryptophan concentrations were decreased. During follow-up, increased kyn/trp ratio and kynurenine concentrations (all P<0.001) were observed, whereas the changes in tryptophan concentrations were not significant. Non-survivors had higher kyn/trp ratios and kynurenine concentrations compared with survivors. The kyn/trp ratio correlated with neopterin concentrations (r(s)=0.590, P<0.001). In conclusion, these results imply that increased tryptophan degradation in patients is due to activated IDO, which most probably is a consequence of a host defence response. These findings support a possible role for IDO in the development of immunodeficiency and death in patients.

Serum concentrations of insulin-like growth factor-1, members of the TGF-beta superfamily and follistatin do not reflect different stages of dynapenia and sarcopenia in elderly women

There is a high need for blood-based biomarkers detecting age-related changes in muscular performance at an early stage. Therefore, we investigated whether serum levels of growth and differentiation factor-15 (GDF-15), activin A, myostatin, follistatin, and insulin-like growth factor-1 (IGF-1) would reflect age- and physical performance-related differences between young (22-28 years) and elderly (65-92 years) females. Isokinetic peak torque of knee extension (PTE) was measured in young females to obtain reference values for the discrimination of different stages of age-associated muscle weakness. Additionally, elderly women were screened for sarcopenia using the algorithm of the European Working Group on Sarcopenia in Older People (low muscle mass in addition to low PTE and/or low walking speed). IGF-1 levels were higher and GDF-15 levels were lower in young females in comparison to the elderly (p < 0.01), whereas members of the activin A/myostatin/follistatin axis showed similar levels across age groups. In older women, IGF-1 correlated negatively with age (ρ = -0.359, p < 0.01) and positively with muscle mass (ρ = 0.365, p < 0.01). In contrast, GDF-15 correlated positively with age (ρ = 0.388, p < 0.001) and negatively with muscle mass (ρ = -0.320, p < 0.01). However, none of the serum markers differed between women classified as non-, mildly and severely dynapenic/sarcopenic. Multiple linear regression analyses revealed that a combination of all blood-based biomarkers obtained in addition to age and fat mass moderately predicted muscle mass (+2.9%). Neither a single nor a combined set of tested biomarkers reflected the presence of dynapenia or sarcopenia in elderly women. However, due to the associations of IGF-1 and GDF-15 with correlates of muscle mass and function, these parameters remain promising candidates in a potential set of blood-based biomarkers to diagnose sarcopenia and/or dynapenia.