AB0099 METHOTREXATE REDUCES THE INVASIVE ACTIVITIES OF PRIMARY RA SYNOVIAL FIBROBLASTS

Background:

Rheumatoid Arthritis synovial fibroblasts (RASFs) are key player in tissue destruction via the production of a wide range of chemical reactions in the joint with high growth rate and resistance to mortality [1]. Methotrexate (MTX) is a dihydrofolate reductase inhibitor that attenuates inflammation within joints resulting in reduced cartilage and bone damage and is the anchor therapy for RA. Its mechanisms of action are thought to differ from its anti-proliferative effects and are known to include increased adenosine release (2), but may also involve alterations in intracellular methyl donor status resulting in alteration in DNA methylation and gene expression.

Objectives:

To investigate the effects of MTX on RASFs auto-aggressive activities, including invasion, migration, proliferation and apoptosis.

Methods:

RASF were derived from knee biopsies of RA patients taken at arthroscopy (n=9). Matrigel chambers were used to measure invasive activities. The cells were incubated with DMSO (control), 1μM or 10μM MTX for 96 hours. Wound healing (scratch assays) were used to measure migration. Proliferation and apoptosis was determined using BrdU and caspase-3/7 assays respectively. Significance was determined via repeated measures ANOVA using SPSS software.

Results:

Incubation with MTX resulted in significantly reduced invasive activity compared with DMSO control; 1μM (35%, p=0.006) and 10μM (58%, p=0.002) in paired samples. However MTX did not have significant effects on RASF migration, apoptosis or proliferation at either concentration.

Conclusion:

Our data reveals that MTX reduces the invasive potential of RASFs in vitro, this effect may contribute to the clinical efficacy of this agent. Further investigation will involve epigenome-wide methylation to determine if the DNA methylome of RASFs is altered by MTX.

References:

[1]Huber LC, et al. (2006) Rheumatol. 45(6):669-675.

[2]Chan ES & Cronstein BN (2010) Nat Rev Rheumatol 6(3):175-178.

Acknowledgments:

This abstract arose from work funded by the National Children’s Research Centre, Our Lady’s Children’s Hospital, Crumlin

Disclosure of Interests:

None declared

Identical and Nonidentical Twins: Risk and Factors Involved in Development of Islet Autoimmunity and Type 1 Diabetes

OBJECTIVE

There are variable reports of risk of concordance for progression to islet autoantibodies and type 1 diabetes in identical twins after one twin is diagnosed. We examined development of positive autoantibodies and type 1 diabetes and the effects of genetic factors and common environment on autoantibody positivity in identical twins, nonidentical twins, and full siblings.

RESEARCH DESIGN AND METHODS

Subjects from the TrialNet Pathway to Prevention Study (N = 48,026) were screened from 2004 to 2015 for islet autoantibodies (GAD antibody [GADA], insulinoma-associated antigen 2 [IA-2A], and autoantibodies against insulin [IAA]). Of these subjects, 17,226 (157 identical twins, 283 nonidentical twins, and 16,786 full siblings) were followed for autoantibody positivity or type 1 diabetes for a median of 2.1 years.

RESULTS

At screening, identical twins were more likely to have positive GADA, IA-2A, and IAA than nonidentical twins or full siblings (all P < 0.0001). Younger age, male sex, and genetic factors were significant factors for expression of IA-2A, IAA, one or more positive autoantibodies, and two or more positive autoantibodies (all P ≤ 0.03). Initially autoantibody-positive identical twins had a 69% risk of diabetes by 3 years compared with 1.5% for initially autoantibody-negative identical twins. In nonidentical twins, type 1 diabetes risk by 3 years was 72% for initially multiple autoantibody-positive, 13% for single autoantibody-positive, and 0% for initially autoantibody-negative nonidentical twins. Full siblings had a 3-year type 1 diabetes risk of 47% for multiple autoantibody-positive, 12% for single autoantibody-positive, and 0.5% for initially autoantibody-negative subjects.

CONCLUSIONS

Risk of type 1 diabetes at 3 years is high for initially multiple and single autoantibody-positive identical twins and multiple autoantibody-positive nonidentical twins. Genetic predisposition, age, and male sex are significant risk factors for development of positive autoantibodies in twins.

Surgical site infections following pediatric liver transplantation: risks and costs

PURPOSE

Infectious complications following orthotopic liver transplantation (OLT) represent a significant cause of morbidity and mortality in both adults and children. In adults, surgical site infections complicating OLT have been shown to significantly increase resource utilization, but their impact in children has not been studied. In this study we identify risk factors for surgical site infections in children undergoing primary OLT for end-stage liver disease and estimate their impact on patient survival, graft survival, length of stay, and charges.

METHODS

All pediatric liver transplants (n = 77) less than 16 years of age from the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) Liver Transplantation Database were included in the analysis. Surgical site infections (n = 25) were defined as wound infections, abdominal abscesses, and bacterial or fungal infections of the liver, intestine, or peritoneum during the initial transplant admission. Risk of infection was estimated using logistic regression, survival rates were estimated using the Kaplan-Meier method, and length of stay and charges were compared using Student's t-test. Multivariate analysis of charges was performed using linear regression.

RESULTS

Of the 77 patients, 25 (32.5%) developed a surgical site infection. Several factors were associated with increased risk of infections, including a leak at the biliary anastomosis (odds ratio [OR] 115, P = 0.003), preoperative white blood cell count (OR = 1.28, P = 0.009), surgery > 7 h (OR = 15.0, P = 0.011), HLA mismatches (OR = 6.0, P = 0.03), and female gender (OR = 8.0, P = 0.038). Surgical site infections did not significantly decrease either patient survival or graft survival, and increased hospital stay by an average of 21 days (P = 0.14). After controlling for other factors, patients who developed surgical site infections incurred on average $132,507 (P = 0.03) more in charges than patients who did not develop infections.

CONCLUSIONS

Surgical site infections in pediatric patients following liver transplantation are significantly influenced by surgical technique and endogenous patient characteristics. Though survival outcomes are not different, the development of such infections has significant implications for resource utilization in the care of these patients.

Impaired system A amino acid transport mimics the catabolic effects of acid in L6 cells

BACKGROUND

Metabolic acidaemia stimulates protein catabolism in skeletal muscle cells, leading to muscle wasting. As this occurs without decreasing cytosolic pH, the initial signal is unclear. A possible explanation is that extracellular pH acts on solute transporters at the cell surface, inhibiting nutrient influx.

DESIGN

Influx through glucose and Pi transporters and System A amino acid transporters into L6 skeletal muscle cells was assessed using 3H-2-deoxyglucose (2-DG), 33Pi and 14C-methylaminoisobutyrate (MeAIB), respectively. Protein degradation (PD) was assessed from 14C efflux from cells prelabelled with 14C-Phe. Branched-chain amino acids and Phe were assayed by selective fluorimetric assays.

RESULTS

While acid (pH 7.1) had little immediate effect on 2-DG or 33Pi influx, exposure to pH 7.1 rapidly inhibited MeAIB influx. To determine whether System A inhibition was sufficient to trigger PD, it was blocked at pH 7.5 by a saturating dose (10 mmol L(-1)) of nonmetabolisable substrate (MeAIB). Like acid, this increased PD and decreased total protein. It also mimicked the decreases in protein synthesis, DNA synthesis, glucose transport and glycolysis, and depletion of branched-chain amino acids and Phe, which are induced in L6 by acid. The onset of inhibition of PD by an extracellular Gln load was retarded at pH 7.1, and stimulation of PD by acid was negligible if PD had already been stimulated by Gln depletion. The stimulatory effect of MeAIB on PD was selectively blunted by an excess of Gln, whereas the inhibitory effect of Gln on PD was blocked by excess MeAIB.

CONCLUSIONS

The similarity of changes in response to MeAIB and acid implies that these share a common intracellular signalling pathway triggered by inhibition of System A. Even though System A is only a minor contributor to total Gln influx in L6 cells, it is suggested that blockade of System A with acid or MeAIB induces a catabolic state by denying Gln access to a key intracellular regulatory site.

Cadaveric allograft discards as a result of positive skin cultures

INTRODUCTION

The availability of cadaveric allograft is often limited by potentially pathogenic microbial organisms. Little data exists on cadaveric allograft discard rates related to positive microbiology. The purpose of this retrospective review was to determine the cadaveric allograft discard rates related positive microbiology and the subsequent breakdown of those organisms involved.

METHODS

From January 1995 to June 1997, 1112 donors were screened and procured after informed consent had been obtained. The procedures used were in accordance with American Association of Tissue Banks (AATB) standards and guidelines. The number of discards due to positive skin cultures was reviewed and analyzed for type of microbial organism.

RESULTS

Fifty-four donors (4.9%) were discarded due to positive skin cultures. Methicillin resistant Staphylococcus epidermidis, (MRSE), was the most predominant organism (22.2%), followed by gram negative rods as a group (18.5%), with Aspergillus species being the least predominant isolate.

CONCLUSION

Despite the strict adherence to AATB protocol, microbial contamination of cadaveric allograft skin does not reach zero. It is not surprising that S. epidermidis was the predominant isolate, since skin is one of its common habitats. Continued vigilance in microbial testing remains paramount to ensure the quality of the allograft.

Cadaver donor discards secondary to serology

The use of cadaveric skin has made a major impact in the survival of patients experiencing major thermal injury. However, the availability of cadaveric skin is often limited by potentially pathogenic organisms. Very little data exists as to why cadaveric skin from donors who have been previously screened was discarded. From March 1994 to March 1996, 813 donors were referred to our tissue bank. All donors were reviewed for the cause of death, history and physical, and social history. One hundred fifty-three donors screened were discarded. Sixty-one donors of this group were discarded because of positive serologies. The following are the percentages of the specific positive serologies: hepatitis B core antibody, 52.3%; hepatitis B surface antigen, 18.1%; hepatitis C virus antibody, 14.3%; human immunodeficiency virus antibody, 4.9%; human T lymphocyte virus antibody, 4.9% and syphilis, 5.5%. Retrospectively, all donor screening questionnaires were reviewed for possible indicators in relation to positive serologic testing. Current screening methods, although excellent in social screening, still fail to identify a significant number of donors who may have positive serologies because of hepatitis, human immunodeficiency virus, human T lymphocyte virus, or syphilis. As the field of tissue banking continues to evolve, the focus will need to be directed toward better screening mechanisms in order to decrease our current discard rates after donors have been approved through the screening process.

Measuring and modeling facial affect

In recent years, researchers in computer science and human-computer interaction have become increasingly interested in characterizing perception of facial affect. Ironically, this applied interest comes at a time when the classic findings on perception of human facial affect are being challenged in the psychological research literature, largely on methodological grounds. This paper first describes two experiments that empirically address Russell's methodological criticisms of the classic work on measuring "basic emotions," as well as his alternative approach toward modeling "facial affect space." Finally, a user study on affect in a prototype model of a robot face is reported; these results are compared with the human findings from Experiment 1. This work provides new data on measuring facial affect, while also demonstrating how basic and more applied research can mutually inform one another.

Expression and use of human immunodeficiency virus type 1 coreceptors by human alveolar macrophages

Human immunodeficiency virus type 1 (HIV-1) requires, in addition to CD4, coreceptors of the CC or CXC chemokine families for productive infection of T cells and cells of the monocyte-macrophage lineage. Based on the hypothesis that coreceptor expression on alveolar macrophages (AM) may influence HIV-1 infection of AM in the lung, this study analyzes the expression and utilization of HIV-1 coreceptors on AM of healthy individuals. AM were productively infected with five different primary isolates of HIV-1. Levels of surface expression of CCR5, CXCR4, and CD4 were low compared to those of blood monocytes, but CCR3 was not detectable. mRNA for CCR5, CXCR4, CCR2, and CCR3 were all detectable, but to varying degrees and with variability among donors. Expression of CCR5, CXCR4, and CCR2 mRNA was downregulated following stimulation with lipopolysaccharide (LPS). In contrast, secretion of the chemokines RANTES, MIP-1alpha, and MIP-1beta was upregulated with LPS stimulation. Interestingly, HIV-1 replication was diminished following LPS stimulation. Infection of AM with HIV-1 in the presence of the CC chemokines demonstrated blocking of infection. Together, these studies demonstrate that AM can be infected by a variety of primary HIV-1 isolates, AM express a variety of chemokine receptors, the dominant coreceptor used for HIV entry into AM is CCR5, the expression of these receptors is dependent on the state of activation of AM, and the ability of HIV-1 to infect AM may be modulated by expression of the chemokine receptors and by chemokines per se.

Hand preference, immune system disorder and cognitive function among gay/bisexual men: the Multicenter AIDS Cohort Study (MACS)

This study evaluated the self-reported patterns of handedness among a large subsample (n = 1612) of the gay/bisexual men comprising the Multicenter AIDS Cohort Study (MACS). There was a small but significant elevation in left-handedness among gay/bisexual men compared to available normative data. However, there were no differences within the cohort in measures of immune function, self-reported autoimmune disorders, asthma, or hay fever, although there was an association between handedness and allergy. Performance on neuropsychological tests also did not differ as a function of handedness.

Phorbol ester-induced differentiation of U937 cells enhances attachment to fibronectin and distinctly modulates the alpha 5 beta 1 and alpha 4 beta 1 fibronectin receptors

Monocyte interaction with fibronectin (Fn) involves specific cell surface receptors and results in cell attachment and differentiation. We have studied the regulation of these receptors using the promonocytic cell line U937 and its PMA-induced differentiation as a model. We recently reported that U937 cells interact with two sites in Fn, RGD and CS-1, via two independent receptors (O. C. Ferreira, A. Garcia-Pardo, and C. Bianco (1990) J. Exp. Med. 171, 351). In this study we have determined the effects of PMA on the interaction of U937 cells with both sites in Fn. PMA-U937 cells showed an enhanced attachment to Fn and to an RGD-containing 80-kDa Fn fragment. This enhancement paralleled a two- to threefold increase in the surface expression of the RGD-dependent receptor alpha 5 beta 1. An anti-alpha 5 beta 1 mAb completely inhibited cell adhesion to Fn and to the 80-kDa fragment. alpha 5 beta 1 receptors from untreated and PMA-treated U937 cells were isolated on 80-kDa-Sepharose columns and shown to contain a similar complex of 152/125-kDa proteins, although proteins from PMA-treated cells had slightly faster mobility on SDS-gels. In contrast, the total number of PMA-U937 cells adhering to a 38-kDa Fn fragment (containing the CS-1 site) was lower when compared to that of untreated cells. This decrease was accompanied by a 50% loss of cell surface alpha 4 beta 1, the specific receptor for CS-1. Our results indicate that differentiation of U937 cells enhances adhesion to Fn primarily by up-regulating the alpha 5 beta 1 Fn receptor. PMA also induces a down-regulation of alpha 4 beta 1, suggesting that these two integrins play different roles during monocyte differentiation.

Behavioral, health and psychosocial factors and risk for HIV infection among sexually active homosexual men: the Multicenter AIDS Cohort Study

We examined whether 644 homosexual men who engaged in receptive anal intercourse were at particularly elevated risk for seroconversion if they also possessed specific behavioral, health or psychosocial vulnerability characteristics. Of 11 potential factors examined, heavy drinking, moderate to heavy drug use, and younger age were significantly related to seroconversion. These variables were also associated with an increased number of sexual partners, anonymous sex, and failure to use condoms.

Neuropsychological performance in HIV-1-infected homosexual men: The Multicenter AIDS Cohort Study (MACS)

We administered a battery of standardized neuropsychological measures to assess cognitive functions in a group of 769 HIV-1 seronegative, 727 asymptomatic HIV-1 seropositive (CDC Groups 2 and 3), and 84 symptomatic HIV-1 seropositive (CDC Group 4) homosexual/bisexual men enrolled in the Multicenter AIDS Cohort Study (MACS). Measures included tests of attention, memory, and psychomotor speed. Comparison of group means revealed significant differences in performance between HIV-1 seronegative and symptomatic HIV-1 seropositive subjects on measures of memory and on measures with strong motor and psychomotor timed components. These findings support the sensitivity of these neuropsychological instruments for detecting cognitive changes that may be related to HIV-1, and are consistent with other reports of neuropsychological abnormalities in symptomatic HIV-1-infected individuals. Asymptomatic seropositive men, on the other hand, did not differ significantly from seronegative subjects on any of the neuropsychological measures. Only 5.5% of the asymptomatic HIV-1 seropositive men showed abnormal performance on individual tests. This proportion did not differ significantly from that of seronegative controls. Further, among asymptomatic seropositive subjects, we found no statistically significant differences as a function of duration of HIV infection or level of immune system functioning. Thus, results from this study support the hypothesis that the frequency of neuropsychological abnormalities in asymptomatic HIV-1-infected homosexual men is low, and not statistically different from that of seronegative controls.

HIV-1 infection: no evidence of cognitive decline during the asymptomatic stages. The Multicenter AIDS Cohort Study

Cross-sectional studies have not adequately resolved the question of whether subjects infected with HIV-1 may suffer cognitive decline during the early, asymptomatic stages of the infection. We studied longitudinally 238 asymptomatic healthy HIV-1-infected homosexual/bisexual men (CDC groups 2 and 3) and 170 uninfected controls in the Multicenter AIDS Cohort Study with neuropsychological testing at semiannual intervals. A comparison of change in scores between visits 1 and 4 as well as a multivariate autoregressive analysis revealed no evidence of decline in test performance over time in the HIV-1-infected group compared with the seronegative controls. These findings suggest that a gradual cognitive decline does not occur during the early, asymptomatic stages of HIV infection.

Motor slowing in asymptomatic HIV infection

To examine neuropsychological deficits associated with the human immunodeficiency virus (HIV), 25 asymptomatic homosexual men and sexual partners of intravenous drug users and 25 seronegative homosexual men and nonhigh-risk heterosexuals were assessed on measures of fine motor control, visual scanning, attention, depression, and global psychological functioning. Analysis suggested that HIV infection is associated with reduced fine motor control. Seropositivity is associated with elevated depression and global psychological maladjustment. When depression and global adjustment were analyzed as covariates, motor slowing was evident in the seropositive group. These findings suggest an association between motor slowing and HIV infection in asymptomatic subjects and point to the necessity of measuring affect at least as a control variable. Further study is needed to determine whether the fine motor deficit evident in this sample is limited to distinct subgrouping of the over-all sample.

Hormonal specificity and activation of social behavior in male red-winged blackbirds

Five groups of male red-winged blackbirds were observed 12 times over 14 days in an aviary setting. An estradiol-treated female was present during the last two observations of each group. Each group of males consisted of a castrated (CA) and an intact (IN) control and six castrated males given one of the following hormone treatments: the aromatizable androgens, testosterone (T) and androstenedione (AE); the nonaromatizable androgens, 5 alpha-dihydrotestosterone (DHT), and androsterone (AN); the estrogen, estradiol (E); or a combination of E + DHT. Castration significantly reduced the frequency of singing and three common vocalizations, chucks, checks, and ips, below the levels shown by IN males. Only hormone treatments which provided both androgenic and estrogenic metabolites (A + E = T, AE, E + DHT) restored normal levels of these behaviors in castrated males. Endocrine status also modulated epaulet display. IN and A + E males were more likely than other males to keep their epaulets constantly exposed. The frequency of sidling and supplanting also varied significantly across hormone-treatment groups, with A + E males showing higher frequencies of these behaviors than other males. T was clearly the most effective hormone treatment in activating hormone-sensitive behaviors in this species. Hormone treatment was more important than size or plumage pattern in determining the outcome of aggressive interactions. In some groups, the dominant male clearly inhibited the performance of hormone-sensitive behaviors by other males. Among A + E males, the frequency of higher intensity song spread displays was highly correlated with the frequency of high-intensity aggressive behaviors and negatively correlated with the tendency to withdraw from other males. Patterns of correlations among behaviors suggest that some calls are more hormone dependent than others, and thus may serve different signal functions.

Acute lethal graft-versus-host disease stimulates cellular proliferation in Peyer's Patches and follicle associated ileal epithelium of adult rats

In this study cell proliferation in Peyer's Patches (PP) and the crypts of Lieberkuhn of the follicle-associated ileal epithelium was analyzed during the development of acute lethal graft-versus-host disease (GVHD) in adult rats. In addition, the effect of thymectomy on GVHD-induced lymphoproliferation was determined by analyzing the 3H-thymidine labeling index in neonatally thymectomized-control and thymectomized-GVHD rats. A significant increase in the 3H-thymidine-labeling index was found in interfollicular (days 2-7), dome (days 5-10), and follicular (days 5-12) regions of PP as well as in associated ileal crypts (days 5-12) of GVHD rats as compared with controls. Thymectomy altered the proliferative response in PP of GVHD rats in that incorporation of 3H-thymidine by follicular and interfollicular cells was significantly lower than in sham-thymectomized GVHD controls during the later stages of the disease. The results suggest a possible role for host thymus-dependent cells in stimulation of or participation in cell proliferation within follicular and interfollicular areas of PP.

Hormonal specificity and activation of sexual behavior in male zebra finches

Castrated zebra finches receiving one of six hormone treatments were given three weekly tests with different females and their sexual behavior was contrasted with that of two control groups consisting of intact or castrated males given implants of cholesterol. The six hormone treatments were: two aromatizable androgens, testosterone (T) and androstenedione (AE); two nonaromatizable androgens, androsterone (AN) and dihydrotestosterone (DHT); an estrogen, estradiol (E); or a combination of E + DHT. Half the males receiving DHT received the 5 alpha-isomer, half received the 5 beta-isomer. Castration significantly reduced the proportion of males which courted females, total courtship displays, high-intensity courtship displays, beak wiping activity, and significantly increased the latencies to show these behaviors compared to intact males. Castrated males never attempted to mount a female. All of these measures of courtship and copulatory behavior were restored to normal levels only by treatments providing both estrogenic and alpha-androgenic metabolites (i.e., T, AE, E + alpha DHT). AE was clearly the most effective of these, raising behavior significantly above normal on several measures. AN treatment was more effective than alpha DHT on all measures and not significantly different from intact birds on some. Treatment with E, alpha DHT, beta DHT, or E + beta DHT was totally ineffective. Surprisingly, females only solicited males whose hormone treatments provided estrogenic metabolites. Not only did they solicit males given aromatizable androgens, which showed high rates of courtship activity, they also solicited males given E or E + beta DHT, some of which never even courted. Castration and hormone treatment also affected body and syringeal weight, but in opposite directions. Castration increased body weight while decreasing syringeal weight. Hormone treatments providing alpha-androgenic metabolites decreased body weight and increased syrinx weight. Treatments supplying estrogen as well were slightly more effective.

Hyperactivity with tactile defensiveness as a phobia

Conceptualizing some cases of hyperkinesis (those with tactile defensiveness) as tactile phobias provides the rationale for two unconventional management approaches modeled on the two most popular behavioral treatments of phobia: systematic desensitization and implosion. Both methods are adapted to a nonverbal level, befitting the age of the afflicted children and the nature of the problem. The first method uses the sensory integration techniques developed by Ayres to desensitize the child to touch systematically and gradually. The other method, developed by Henderson and Dahlin, uses restraint and intense tactile stimulation implosively to break through the fear and hyperactive resistance.