25 research outputs found
Plant-derived pectin nanocoatings to prevent inflammatory cellular response of osteoblasts following Porphyromonas gingivalis infection
Background: Bioengineered plant-derived Rhamnogalacturonan-Is (RG-Is) from
pectins are potential candidates for surface nanocoating of medical devices.
It has recently been reported that RG-I nanocoatings may prevent bacterial
infection and improve the biocompatibility of implants. The aim of the study
was to evaluate in vitro impact of bioengineered RG-I nanocoatings on
osteogenic capacity and proinflammatory cytokine response of murine
osteoblasts following Porphyromonas gingivalis infection. Methods: Murine
MC3T3-E1 osteoblasts and isolated primary calvarial osteoblasts from C57BL/6J
(B6J osteoblasts) mice were infected with P. gingivalis and incubated on
tissue culture polystyrene plates with or without nanocoatings of unmodified
RG-Is isolated from potato pulps (PU) or dearabinanated RG-Is (PA). To
investigate a behavior of infected osteoblasts cultured on RG-Is cell
morphology, proliferation, metabolic activity, mineralization and osteogenic
and pro-inflammatory gene expression were examined. Results: Following P.
gingivalis infection, PA, but not PU, significantly promoted MC3T3-E1 and BJ6
osteoblasts proliferation, metabolic activity, and calcium deposition.
Moreover, Il-1b, Il-6, TNF-α, and Rankl gene expressions were downregulated in
cells cultured on PU and to a higher extent on PA as compared to the
corresponding control, whereas Runx, Alpl, Col1a1, and Bglap gene expressions
were upregulated vice versa. Conclusion: Our data clearly showed that pectin
RG-Is nanocoating with high content of galactan (PA) reduces the osteoblastic
response to P. gingivalis infection in vitro and may, therefore, reduce a risk
of inflammation especially in immunocompromised patients with rheumatoid or
periodontal disorders
study protocol for a randomized controlled trial
Background Osteoarthritis (OA) is a heterogeneous group of conditions with
disturbed integrity of articular cartilage and changes in the underlying bone.
The pathogenesis of OA is multifactorial and not just a disease of older
people. Hydroxychloroquine (HCQ) is a disease-modifying anti-rheumatic drug
(DMARD) typically used for the treatment of various rheumatic and dermatologic
diseases. Three studies of HCQ in OA, including one abstract and one letter,
are available and use a wide variety of outcome measures in small patient
populations. Despite initial evidence for good efficacy of HCQ, there has been
no randomized, double-blind, and placebo-controlled trial in a larger patient
group. In the European League Against Rheumatism (EULAR), evidence-based
recommendations for the management of hand OA, HCQ was not included as a
therapeutic option because of the current lack of randomized clinical trials.
Methods/Design OA TREAT is an investigator-initiated, multicenter, randomized,
double-blind, placebo-controlled trial. A total of 510 subjects with
inflammatory and erosive hand OA, according to the classification criteria of
the American College of Rheumatology (ACR), with recent X-ray will be
recruited across outpatient sites, hospitals and universities in Germany.
Patients are randomized 1:1 to active treatment (HCQ 200 to 400 mg per day) or
placebo for 52 weeks. Both groups receive standard therapy (non-steroidal
anti-inflammatory drugs [NSAID], coxibs) for OA treatment, taken steadily two
weeks before enrollment and continued further afterwards. If disease activity
increases, the dose of NSAID/coxibs can be increased according to the drug
recommendation. The co-primary clinical endpoints are the changes in
Australian-Canadian OA Index (AUSCAN, German version) dimensions for pain and
hand disability at week 52. The co-primary radiographic endpoint is the
radiographic progression from baseline to week 52. A multiple endpoint test
and analysis of covariance will be used to compare changes between groups. All
analyses will be conducted on an intention-to-treat basis. Discussion The OA
TREAT trial will examine the clinical and radiological efficacy and safety of
HCQ as a treatment option for inflammatory and erosive OA over 12 months. OA
TREAT focuses on erosive hand OA in contrast to other current studies on
symptomatic hand OA, for example, HERO [Trials 14:64, 2013]
Sustained Increase of 25-Hydroxyvitamin D Levels in Healthy Young Women during Wintertime after Three Suberythemal UV IrradiationsâThe MUVY Pilot Study
Objectives Vitamin D (VitD) deficiency is a health problem prevalent not only
in the elderly but also in young adults. The primary objective of our
observational pilot study âMUVYâ (Mood, UVR, Vitamin D in Young women) was to
test both the short-term and long-term effects of a series of three
suberythemal UV radiation (UVR) exposures on the VitD status and well-being of
young healthy women during winter in a repeat measure design. Methods 20
healthy young women (Fitzpatrick skin types IâIII, aged 21â25 years) received
three full body broad band UVR exposures with an escalating erythemally
weighted dose schedule during one week in winter, and completed self-report
questionnaires monitoring symptoms of depression (Beck Depression Inventory,
BDI) and affective state/well-being (Profile of Mood States, POMS) at baseline
and three days after the last UVR exposure. 25-hydroxyvitamin D (25(OH)D) and
1,25-dihydroxyvitamin D (1,25(OH)2D) were measured in serum at baseline, and
at study days 8, 36 and 50. Results Mean baseline 25(OH)D level was 54.3
nmol/L (standard deviation (s.d.) = 24.1), with seven women having VitD
deficient status. Relevant symptoms of depression, as indicated by low BDI
total scores (0â8), were absent. After the three UVR exposures the increment
of 25(OH)D was an average of 13.9 nmol/L (95% confidence interval (CI) =
9.4â18.4) and 26.2 pmol/L (95%CI = 7.2â45.1) for 1,25(OH)2D. Î25(OH)D, and
corresponding baseline levels were significantly and inversely associated (rho
= -0.493, p = 0.027). Only 25(OH)D remained significantly increased above
baseline for at least six weeks after the last UVR exposure. A strong inverse
correlation of the POMS subscale âVigor/Activityâ and the increment in
1,25(OH)2D was found (rho = -0.739, p<0.001) at day 8. Conclusions Three
suberythemal whole body UVR exposures during one week are a simple and
suitable method for improving 25(OH)D levels during winter, for at least six
weeks, and especially in young women with VitD deficient status. Trial
Registration German Clinical Trials Register (Deutsches Register Kinischer
Studien) DRKS0000927
Prevalence of comorbidities in rheumatoid arthritis and evaluation of their monitoring: results of an international, cross-sectional study (COMORA)
Background: Patients with rheumatoid arthritis (RA) are at increased risk of developing comorbid conditions.<p></p>
Objectives: To evaluate the prevalence of comorbidities and compare their management in RA patients from different countries worldwide.<p></p>
Methods Study design: international, cross-sectional. Patients: consecutive RA patients. Data collected: demographics, disease characteristics (activity, severity, treatment), comorbidities (cardiovascular, infections, cancer, gastrointestinal, pulmonary, osteoporosis and psychiatric disorders).<p></p>
Results: Of 4586 patients recruited in 17 participating countries, 3920 were analysed (age, 56±13â
years; disease duration, 10±9â
years (mean±SD); female gender, 82%; DAS28 (Disease Activity Score using 28 joints)âerythrocyte sedimentation rate, 3.7±1.6 (mean±SD); Health Assessment Questionnaire, 1.0±0.7 (mean±SD); past or current methotrexate use, 89%; past or current use of biological agents, 39%. The most frequently associated diseases (past or current) were: depression, 15%; asthma, 6.6%; cardiovascular events (myocardial infarction, stroke), 6%; solid malignancies (excluding basal cell carcinoma), 4.5%; chronic obstructive pulmonary disease, 3.5%. High intercountry variability was observed for both the prevalence of comorbidities and the proportion of subjects complying with recommendations for preventing and managing comorbidities. The systematic evaluation of comorbidities in this study detected abnormalities in vital signs, such as elevated blood pressure in 11.2%, and identified conditions that manifest as laboratory test abnormalities, such as hyperglycaemia in 3.3% and hyperlipidaemia in 8.3%.<p></p>
Conclusions: Among RA patients, there is a high prevalence of comorbidities and their risk factors. In this multinational sample, variability among countries was wide, not only in prevalence but also in compliance with recommendations for preventing and managing these comorbidities. Systematic measurement of vital signs and laboratory testing detects otherwise unrecognised comorbid conditions.<p></p>
The association between rheumatoid arthritis and periodontal disease
Chronic, plaque-associated inflammation of the gingiva and the periodontium are among the most common oral diseases. Periodontitis (PD) is characterized by the inflammatory destruction of the periodontal attachment and alveolar bone, and its clinical appearance can be influenced by congenital as well as acquired factors. The existence of a rheumatic or other inflammatory systemic disease may promote PD in both its emergence and progress. However, there is evidence that PD maintains systemic diseases. Nevertheless, many mechanisms in the pathogenesis have not yet been examined sufficiently, so that a final explanatory model is still under discussion, and we hereby present arguments in favor of this. In this review, we also discuss in detail the fact that oral bacterial infections and inflammation seem to be linked directly to the etiopathogenesis of rheumatoid arthritis (RA). There are findings that support the hypothesis that oral infections play a role in RA pathogenesis. Of special importance are the impact of periodontal pathogens, such as Porphyromonas gingivalis on citrullination, and the association of PD in RA patients with seropositivity toward rheumatoid factor and the anti-cyclic citrullinated peptide antibody
Rheumatoid arthritis - clinical aspects: 134. Predictors of Joint Damage in South Africans with Rheumatoid Arthritis
Background: Rheumatoid arthritis (RA) causes progressive joint damage and functional disability. Studies on factors affecting joint damage as clinical outcome are lacking in Africa. The aim of the present study was to identify predictors of joint damage in adult South Africans with established RA. Methods: A cross-sectional study of 100 black patients with RA of >5 years were assessed for joint damage using a validated clinical method, the RA articular damage (RAAD) score. Potential predictors of joint damage that were documented included socio-demographics, smoking, body mass index (BMI), disease duration, delay in disease modifying antirheumatic drug (DMARD) initiation, global disease activity as measured by the disease activity score (DAS28), erythrocyte sedimentation rate (ESR), C reactive protein (CRP), and autoantibody status. The predictive value of variables was assessed by univariate and stepwise multivariate regression analyses. A p value <0.05 was considered significant. Results: The mean (SD) age was 56 (9.8) years, disease duration 17.5 (8.5) years, educational level 7.5 (3.5) years and DMARD lag was 9 (8.8) years. Female to male ratio was 10:1. The mean (SD) DAS28 was 4.9 (1.5) and total RAAD score was 28.3 (12.8). The mean (SD) BMI was 27.2âkg/m2 (6.2) and 93% of patients were rheumatoid factor (RF) positive. More than 90% of patients received between 2 to 3 DMARDs. Significant univariate predictors of a poor RAAD score were increasing age (pâ=â0.001), lower education level (pâ=â0.019), longer disease duration (pâ<â0.001), longer DMARD lag (pâ=â0.014), lower BMI (pâ=â0.025), high RF titre (pâ<â0.001) and high ESR (pâ=â0.008). The multivariate regression analysis showed that the only independent significant predictors of a higher mean RAAD score were older age at disease onset (pâ=â0.04), disease duration (pâ<â0.001) and RF titre (pâ<â0.001). There was also a negative association between BMI and the mean total RAAD score (pâ=â0.049). Conclusions: Patients with longstanding established RA have more severe irreversible joint damage as measured by the clinical RAAD score, contrary to other studies in Africa. This is largely reflected by a delay in the initiation of early effective treatment. Independent of disease duration, older age at disease onset and a higher RF titre are strongly associated with more joint damage. The inverse association between BMI and articular damage in RA has been observed in several studies using radiographic damage scores. The mechanisms underlying this paradoxical association are still widely unknown but adipokines have recently been suggested to play a role. Disclosure statement: C.I. has received a research grant from the Connective Tissue Diseases Research Fund, University of the Witwatersrand. All other authors have declared no conflicts of interes
Strategies for prognostic improvement in patients with rheumatoid arthritis
Das Management der Rheumatoiden Arthritis (RA) zeigt inzwischen gerade auf
medikamentösem Gebiet gute Erfolge fĂŒr den Patienten, so dass die
KrankheitsaktivitÀt, die Funktion und die LebensqualitÀt der Patienten mit
Hilfe zahlreicher Therapiestrategien deutlich verbessert werden konnten. Das
Treat-to target-Konzept (T2T) fasst die Erkenntnisse der vergangenen Jahre,
die weltweit publiziert wurden, in einer Empfehlung zu einem
interdisziplinÀren RA-Management unter direktem Einbezug des Patienten
zusammen. Inzwischen sind Behandlungserfolge in allen RA-Erkrankungsstadien
erreichbar. Zunehmend geht es um die Verbesserung der Versorgung durch eine
bessere FrĂŒherkennung und eine optimale Behandlungsstrategie, wie
beispielsweise die frĂŒhe Induktionstherapie in der FrĂŒhphase der Erkrankung
bzw. inzwischen sogar noch vor Manifestation des vollstÀndigen
Erkrankungsbildes. DarĂŒber hinaus wurde erkannt, dass zahlreiche
KomorbiditĂ€ten bei RA-Patienten im Hinblick auf die MortalitĂ€t eine groĂe
Rolle spielen und deren Erkennung als auch Ăberwachung beim RA-Patienten noch
deutlichen Versorgungsdefiziten unterworfen ist. So können zahlreiche
MaĂnahmen, um KomorbiditĂ€ten zu kontrollieren und zu reduzieren, sowohl von
anderen chronischen Erkrankungen ĂŒbernommen werden, andere Strategien mĂŒssen
unter dem Blickwinkel der entzĂŒndlichen Autoimmunerkrankung festgelegt werden
bzw. in ihren Assoziationen der Erkrankungen weiter erforscht werden. Die
Habilitationsschrift vermittelt einen Ăberblick zu ausgewĂ€hlten T2T-
Schwerpunkten, wie 1. das Konzept des âwindow of opportunityâ mit der
Darstellung der Ergebnisse der Therapieinduktion in der FrĂŒhphase der RA in
der durch das Bundesministerium fĂŒr Bildung und Forschung geförderten HIT
HARD-Studie (ISRCTN36745608; EudraCT-Number: 2006-003146-41.), 2\. Ergebnisse
zu PrÀvalenzuntersuchungen von KomorbiditÀten bei RA und ersten
Schlussfolgerungen im inter- und transdisziplinÀren Management der
KomorbiditÀten, 3\. Studienergebnisse zu beispielhaft ausgewÀhlten
KomorbiditÀten der RA mit dem Ziel, Wege der verbesserten Diagnostik und
Versorgung der KomorbiditÀten zu finden. Folgende Schlussfolgerungen können
aus der Auswahl der in dieser Habilitationsschrift zugrunde gelegten
Forschungsergebnisse zusammenfassend dargelegt werden: 1\. Die frĂŒhe
Identifizierung der RA-Patienten und daran gebundenen frĂŒhen intensiven
Therapieeinleitung fĂŒhrt bei einem groĂen Anteil von Patienten zu einem
schnellen Therapieansprechen mit positiven Auswirkungen auf die LebensqualitÀt
ermittelt am SF-36-Score und auf den HAQ-DI ermittelten Funktionsstatus. Eine
Kombination der MTX-Basistherapie mit einem Biologikum ermöglicht bei der
Mehrzahl der Patienten das Erreichen einer Remission bzw. einer
niedrigmöglichen KrankheitsaktivitÀt (low disease activity, LDA), sowie eine
prognostische Verbesserung im radiologischen Verlauf. 2\. Die RA-Erkrankung
wird in ihrem Verlauf nicht nur von der Erkrankung selbst, sondern auch von
der Diagnostik und adÀquaten Behandlung der KomorbiditÀten bestimmt. 3\. Die
Diagnostik und Behandlung der KomorbiditÀten erfordert ein inter- und
transdisziplinÀres Management zwischen den einzelnen FachdisziplinÀren und
Akteuren der rheumatologischen Versorgung. 4\. Fatigue wird hÀufig mit
Schlafstörungen verbunden, die sich möglicherweise in einzelnen Schlafphasen
nachweisen lassen. Weitere Studien dazu sind kĂŒnftig erforderlich. Therapien,
so auch antirheumatische Basis- und Biologikatherapien können die
Schlafeffizienz der RA-Patienten verbessern und wirken sich im Zusammenspiel
der pro- und inflammatorischen Zytokinwirkungen auf den EntzĂŒndungs- und
Schmerzprozess aus, die in weiteren Studien spezifiziert werden mĂŒssen. 5\.
Die Parodontitis hat als EntzĂŒndungsfokus Auswirkungen auf die RA-Erkrankung.
Aber auch die RA-Erkrankung beeinflusst die Parodontitis. Es liegt
insbesondere bei RA-Patienten als auch bei Patienten mit einer ankylosierenden
Spondyloarthritis und Patienten mit einer Systemischen Sklerose ein erhöhtes
Risiko fĂŒr die Entwicklung einer Parodontitis mit der Folge eines erhöhten
Attachementverlustes vor. PrĂ€ventionsmaĂnahmen, aber auch effiziente
Diagnostik und Behandlung der Parodontitis sollten im inter- und
transdisziplinĂ€ren Management der rheumatischen Erkrankungen berĂŒcksichtigt
werden. 6\. Der Vitamin D-Mangel ist im Auftreten sowohl national als auch
weltweit in der Bevölkerung sehr hÀufig mit Auswirkungen auf den
Knochenstoffwechsel, psychischen StimmungsverÀnderungen und zahlreichen
anderen metabolisch verursachten Störungen als Folge. Neben der
Supplementation ist die Induktion des natĂŒrlichen Vitamin D-Syntheseprozesses
ĂŒber die Haut eine effiziente Methode, um den 25-Hydroxy-Vitamin D3-Spiegel zu
erhöhen und zu stabilisieren. Eine dreimalige UV-Applikationen unterhalb der
individuell definierten und vom jeweiligen Hauttyp abhÀngigen Erythemschwelle
zeigen bei gesunden, jungen Probandinnen einen signifikanten Effekt auf die
Steigerung des 25-Hydroxy-Vitamin D3- Spiegels ĂŒber mehrere Tage anhaltend.
DarĂŒber hinaus zeigten sich tendenzielle Effekte auf die Stimmung der
Probandinnen. Weitere Studien an Patienten sind nachfolgend zur Untersuchung,
ob sich diese Ergebnisse auf die verschiedenen Erkrankungsbilder ĂŒbertragen
lassen, erforderlich. 7\. Klinisch orientierte Versorgungsstudien sind
wichtiger Bestandteil funktionierender Gesundheitssysteme und Basis der
universitÀren Forschung, um relevante Fragestellungen des diagnostischen und
therapeutischen Alltags und der Patientenperspektive zu beantworten und in
Form von evidencebasierten Handlungsempfehlungen konkret umzusetzen als auch
stetig im Erfolg zu ĂŒberprĂŒfen.The management of rheumatoid arthritis (RA) has now shown good results for the
patient, especially in the area of medication, so that the patient's disease
activity, function and quality of life are significantly improved by means of
numerous therapies could become. The published worldwide treat-to-target-
concept (T2T) summarizes the findings of the past years in a recommendation to
an interdisciplinary RA management with direct involvement of the patient. In
the meantime, treatment success is achievable at all RA disease stages.
Increasingly, care is being improved by means of better early detection and an
optimal treatment strategy, such as early induction therapy in the early phase
of the disease or even before the manifestation of the complete picture of the
disease. In addition, it was recognized that numerous comorbidities in RA
patients with regard to mortality play a major role and their detection and
monitoring are still subject to significant deficits in the RA patient. Thus,
numerous measures to control and reduce comorbidities can be taken over by
other chronic diseases; other strategies must be defined under the angle of
inflammatory autoimmune disease, or further investigated in their associations
of diseases. This work provide an overview of selected T2T centers such as 1\.
the concept of the "window of opportunity" with the presentation of the
results of the therapy induction in the early phase of the RA in the HIT HARD
study funded by the German Federal Ministry of Education and Research
(ISRCTN36745608, EudraCT-Number: 2006-003146-41), 2\. results on prevalence
studies of comorbidities in RA and first conclusions in inter- and
transdisciplinary management of comorbidities, 3\. study results on exemplary
comorbidities of RA with the aim of finding ways of improved diagnosis and
care for comorbidities. The following conclusions can be summarized from the
selection of the research results used in this work: 1\. The early
identification of RA patients and the early intensive initiation of therapy,
which is linked to this, leads to a rapid response to therapy with a positive
effect on the quality of life determined by the SF-36 score in a large
proportion of patients and the function status determined on the HAQ-DI. A
combination of MTX therapy with a biologic enables the majority of patients to
achieve a response or a low disease activity (LDA) as well as a prognostic
improvement in the radiological outcome. 2\. RA disease is determined not only
by the disease itself, but also by the diagnosis and adequate treatment of the
comorbidities. 3\. The diagnosis and treatment of comorbidities requires an
interdisciplinary and transdisciplinary management between the various
specialist disciplines and rheumatologic care providers. 3\. The diagnosis and
treatment of comorbidities requires an interdisciplinary and transdisciplinary
management between the various specialist disciplines and rheumatologic care
providers. 4\. Fatigue is often associated with sleep disturbances that may be
detected in individual sleep phases. Further studies will be necessary in the
future. Therapies, including conventional synthetic and biologic disease
modifying therapies, can improve the sleep efficacy of RA patients and
interfere with the pro-inflammatory and cytokine effects on the inflammation
and pain process, which must be specified in further studies. 5\. Periodontal
disease has as an inflammatory focus effects on RA disease. But the RA disease
also affects periodontal disease. In RA patients as well as in patients with
ankylosing spondyloarthritis and patients with systemic sclerosis, there is an
increased risk of the development of periodontal disease with the consequence
of increased attachment loss. Prevention measures as well as efficient
diagnostics and treatment of periodontal disease should be taken into account
in the interdisciplinary and transdisciplinary management of rheumatic
diseases. 6\. The vitamin D deficiency is occurring both nationally and
globally in the population very frequently with effects on bone metabolism,
mental mood changes and numerous other metabolically caused disorders as a
result. In addition to supplementation, the induction of the natural vitamin D
synthesis process via the skin is an efficient method to increase and
stabilize the 25-hydroxy vitamin D3 level. A three-fold UV application below
the individually defined erythema threshold, which is dependent on the
particular type of skin, shows a significant effect on the increase in the
25-hydroxy vitamin D3 level in healthy young subjects. A three-fold UV
application below the individually defined erythema threshold, which is
dependent on the particular type of skin, shows a significant effect on the
increase in the 25-hydroxy vitamin D3 level over several days in healthy young
subjects. In addition, approximate effects on the mood of the subjects were
shown. Further studies in patients are subsequently required to determine
whether these results can be transferred to the various disease images. 7\.
Clinically oriented care studies are an important part of functioning health
systems and the basis of university research in order to answer relevant
questions of everyday diagnostic and therapeutic practice and the patient's
perspective, and to implement them in the form of evidence-based
recommendations for action
Plant-derived pectin nanocoatings to prevent inflammatory cellular response of osteoblasts following <em>Porphyromonas gingivalis</em> infection
Induction maintenance with tumour necrosis factor-inhibitor combination therapy with discontinuation versus methotrexate monotherapy in early rheumatoid arthritis: a systematic review and meta-analysis of efficacy in randomised controlled trials
To determine whether an induction-maintenance strategy of combined therapy (methotrexate (MTX)+tumour necrosis factor (TNF) inhibitor (TNFi)) followed by withdrawal of TNFi could yield better long-term results than a strategy with MTX monotherapy, since it is unclear if the benefits from an induction phase with combined therapy are sustained if TNFi is withdrawn. We performed a meta-analysis of trials using the initial combination of MTX+TNFi in conventional synthetic disease-modifying antirheumatic drug-naĂŻve patients with early rheumatoid arthritis (RA). A systematic literature search was performed for induction-maintenance randomised controlled trials (RCTs) where initial combination therapy was compared with MTX monotherapy in patients with clinically active early RA. Our primary outcome was the proportion of patients who achieved low disease activity (LDA; Disease Activity Score (DAS)28 <3.2) and/or remission (DAS28 <2.6) at 12-76â
weeks of follow-up. A random-effects model was used to pool the risk ratio (RR) for LDA and remission and heterogeneity was explored by subgroup analyses. We identified 6 published RCTs, 4 of them where MTX+adalimumab was given as initial therapy and where adalimumab was withdrawn in a subset of patients after LDA/remission had been achieved. 2 additional trials used MTX+infliximab as combination therapy. The pooled RRs for achieving LDA and clinical remission at follow-up after withdrawal of TNFi were 1.41 (95% CI 1.05 to 1.89) and 1.34 (95% CI 0.95 to 1.89), respectively. There was significant heterogeneity between trials due to different treatment strategies, which was a limitation to this study. Initial therapy with MTX+TNFi is associated with a higher chance of retaining LDA and/or remission even after discontinuation of TNF