Omaha VA Medical Center

OBJECTIVE: To examine the degree to which shared risk factors explain the relationship of periodontitis (PD) to rheumatoid arthritis (RA) and to determine the associations of PD and Porphyromonas gingivalis with pathologic and clinical features of RA. METHODS: Patients with RA (n = 287) and patients with osteoarthritis as disease controls (n = 330) underwent a standardized periodontal examination. The HLA-DRB1 status of all participants was imputed using single-nucleotide polymorphisms from the extended major histocompatibility complex. Circulating anti-P gingivalis antibodies were measured using an enzyme-linked immunosorbent assay, and subgingival plaque was assessed for the presence of P gingivalis using polymerase chain reaction (PCR). Associations of PD with RA were examined using multivariable regression. RESULTS: Presence of PD was more common in patients with RA and patients with anti-citrullinated protein antibody (ACPA)-positive RA (n = 240; determined using the anti-cyclic citrullinated peptide 2 [anti-CCP-2] test) than in controls (35% and 37%, respectively, versus 26%; P = 0.022 and P = 0.006, respectively). There were no differences between RA patients and controls in the levels of anti-P gingivalis or the frequency of P gingivalis positivity by PCR. The anti-P gingivalis findings showed a weak, but statistically significant, association with the findings for both anti-CCP-2 (r = 0.14, P = 0.022) and rheumatoid factor (RF) (r = 0.19, P = 0.001). Presence of PD was associated with increased swollen joint counts (P = 0.004), greater disease activity according to the 28-joint Disease Activity Score using C-reactive protein level (P = 0.045), and higher total Sharp scores of radiographic damage (P = 0.015), as well as with the presence and levels of anti-CCP-2 (P = 0.011) and RF (P < 0.001). The expression levels of select ACPAs (including antibodies to citrullinated filaggrin) were higher in patients with subgingival P gingivalis and in those with higher levels of anti-P gingivalis antibodies, irrespective of smoking status. Associations of PD with established seropositive RA were independent of all covariates examined, including evidence of P gingivalis infection. CONCLUSION: Both PD and P gingivalis appear to shape the autoreactivity of RA. In addition, these results demonstrate an independent relationship between PD and established seropositive RA.

RATIONALE: The effect of disease management for chronic obstructive pulmonary disease (COPD) is not well established. OBJECTIVES: To determine whether a simplified disease management program reduces hospital admissions and emergency department (ED) visits due to COPD. METHODS: We performed a randomized, adjudicator-blinded, controlled, 1-year trial at five Veterans Affairs medical centers of 743 patients with severe COPD and one or more of the following during the previous year: hospital admission or ED visit for COPD, chronic home oxygen use, or course of systemic corticosteroids for COPD. Control group patients received usual care. Intervention group patients received a single 1- to 1.5-hour education session, an action plan for self-treatment of exacerbations, and monthly follow-up calls from a case manager. MEASUREMENTS AND MAIN RESULTS: We determined the combined number of COPD-related hospitalizations and ED visits per patient. Secondary outcomes included hospitalizations and ED visits for all causes, respiratory medication use, mortality, and change in Saint George's Respiratory Questionnaire. After 1 year, the mean cumulative frequency of COPD-related hospitalizations and ED visits was 0.82 per patient in usual care and 0.48 per patient in disease management (difference, 0.34; 95% confidence interval, 0.15-0.52; P < 0.001). Disease management reduced hospitalizations for cardiac or pulmonary conditions other than COPD by 49%, hospitalizations for all causes by 28%, and ED visits for all causes by 27% (P < 0.05 for all). CONCLUSIONS: A relatively simple disease management program reduced hospitalizations and ED visits for COPD. Clinical trial registered with www.clinicaltrials.gov (NCT00126776).

We hypothesized that a high-speed all-digital video imaging system, with computerized analysis, would precisely capture and measure ciliary beat frequency (CBF) and would shorten the time from data capture to data analysis. We compared a conventional analog video system with a new high-speed digital system we developed for CBF analysis. Using ciliated primary bovine bronchial epithelial cells we made simultaneous analog and digital CBF measurements of the same region of interest (ROI) while temperature was varied. This yielded nearly identical data over a wide range of frequencies (7-15 Hz) using either system. Unlike the digital system however, the analog system did not accurately detect CBF above 15 Hz (temperatures higher than 30 degrees C). We also compared ROI analysis with a new analysis algorithm we have named whole-field analysis (WFA). WFA measurement of CBF agreed with ROI and reduced operator time required to analyse data by more than 90% compared with the analog system. We conclude that all-digital computerized CBF analysis correlates closely with standard video methods, markedly speeds up data analysis and provides new ways, including WFA, to analyse entire fields of motile cilia simultaneously. We have termed this system 'Sisson-Ammons Video Analysis' (SAVA).

The Hippo signaling pathway controls organ size and tumorigenesis through a kinase cascade that inactivates Yes-associated protein (YAP). Here, we show that YAP plays a central role in controlling the progression of cervical cancer. Our results suggest that YAP expression is associated with a poor prognosis for cervical cancer. TGF-α and amphiregulin (AREG), via EGFR, inhibit the Hippo signaling pathway and activate YAP to induce cervical cancer cell proliferation and migration. Activated YAP allows for up-regulation of TGF-α, AREG, and EGFR, forming a positive signaling loop to drive cervical cancer cell proliferation. HPV E6 protein, a major etiological molecule of cervical cancer, maintains high YAP protein levels in cervical cancer cells by preventing proteasome-dependent YAP degradation to drive cervical cancer cell proliferation. Results from human cervical cancer genomic databases and an accepted transgenic mouse model strongly support the clinical relevance of the discovered feed-forward signaling loop. Our study indicates that combined targeting of the Hippo and the ERBB signaling pathways represents a novel therapeutic strategy for prevention and treatment of cervical cancer.

OBJECTIVE: There is no consensus on which comorbidity index is optimal for rheumatic health outcomes research. We compared a new Rheumatic Disease Comorbidity Index (RDCI) with the Charlson-Deyo Index (CDI), Functional Comorbidity Index (FCI), Elixhauser Total Score (ETS), Elixhauser Point System (EPS), and a simple comorbidity count (COUNT) using a US cohort of rheumatoid arthritis (RA) patients. METHODS: Using administrative diagnostic codes and patient self-reporting, we tested predictive values of the RDCI, CDI, FCI, ETS, EPS, and COUNT for 2 outcomes: all-cause mortality and physical functioning. Indices were compared using 3 models: bare (consisting of age, sex, and race), administrative (bare plus visit frequency, body mass index, and treatments), and clinic (administrative plus erythrocyte sedimentation rate, nodules, rheumatoid factor positivity, and patient activity scale). RESULTS: The ETS and RDCI best predicted death, with FCI performing the worst. The FCI best predicted function, with ETS and RDCI performing nearly as well. CDI predicted function poorly. The order of indices remained relatively unchanged in the different models, though the magnitude of improvement in Akaike's information criterion decreased in the administrative and clinic models. CONCLUSION: The RDCI and ETS are excellent indices as a means of accounting for comorbid illness when the RA-related outcomes of death and physical functioning are studied using administrative data. The RDCI is a versatile index and appears to perform well with self-report data as well as administrative data. Further studies are warranted to compare these indices using other outcomes in diverse study populations.

BACKGROUND: Similarities exist in the epidemiology and immunopathogenesis of periodontitis and rheumatoid arthritis (RA), but the associations between their respective disease activities and severities are less well documented. We evaluated the prevalence and severity of periodontitis in United States (U.S.) veterans with RA and their relationship to RA disease activity and severity. METHODS: Patients with RA from an outpatient rheumatology clinic were eligible, and patients with osteoarthritis (OA) served as controls. Dentists, masked to the rheumatologic diagnoses, performed periodontal probing and examined dental panoramic radiographs to assess the presence and severity of periodontitis. Associations of periodontitis with RA were examined using multivariate regression, whereas the association of periodontitis with disease-severity measures in RA was examined using the chi(2) test. RESULTS: Sixty-nine patients with RA (57 males and 12 females) and 35 patients with OA (30 males and five females) were studied. Moderate to severe periodontitis was more prevalent in patients with RA (51%) than controls (26%) (P = 0.03), an association independent of age, race, smoking, diabetes mellitus, and gender. Patients with RA who were seropositive for rheumatoid factor (RF) were more likely to have moderate to severe periodontitis (59%) than patients who were RF negative (15%) (P = 0.02). Likewise, patients with RA who were positive for the anti-cyclic citrullinated peptide (CCP) antibodies were more likely to have moderate to severe periodontitis (56%) than patients who were anti-CCP negative (22%) (P = 0.01). There were no associations of periodontitis status with other measures of RA disease activity or severity. CONCLUSIONS: In a cohort of U.S. veterans, periodontitis was more common and severe in patients with RA compared to patients with OA. Although unrelated to disease activity, the presence of periodontitis in patients with RA was associated with seropositivity for RF and the anti-CCP antibody, which was highly relevant given the associations of these autoantibodies with poor outcomes and disease pathogenesis in RA.

Peripheral blood granulocytes from normal healthy donors were found to reproducibly inhibit the cytolytic effector function of specifically sensitized cytotoxic T lymphocytes in vitro when co-incubated with these effector cells and target cells in 8 hr 51Cr release assays. Inhibition required intact granulocytes, was proportional to the number of granulocytes present, and was independent of granulocyte adherence, phagocytic function, and viability. Equivalent numbers of enriched normal or leukemic peripheral T lymphocytes did not cause inhibition of 51Cr release, and preincubation of granulocytes with effectors did not significantly alter viability or cytotoxic function. Because granulocytes can inhibit natural killer cell function in vitro, these data indicate that granulocytes can regulate diverse antigen-specific and spontaneous cytotoxic functions in vitro, suggesting that circulating granulocytes may have the potential for in vivo regulation of these cytotoxic effectors.

The impact of demographic, psychosocial, and medical regimen-related variables on adherence of 123 human immunodeficiency virus (HIV)-infected patients to antiretroviral therapy was assessed by means of refill methodology. Satisfaction with social support (P = .029), problem-focused coping (P = .027), and active-behavioral coping (P = .011) correlated significantly with adherence, whereas loss of motivation (P = .006), hopelessness (P = .16), and avoidant coping (p = .015) correlated with nonadherence. At the 6-month follow-up, the mean CD4 cell count differed significantly among adherent versus nonadherent patients (a mean increase of 78/mm3 vs. a mean decrease of 5/mm3; P = .018). Adherence did not correlate with the number of antiretroviral medications consumed per day (mean, 3.0 vs. 2.5). Non-Caucasian patients were more likely to be nonadherent than Caucasian patients (relative risk, 2.5; 95% confidence interval, 1.2-5.3; P = .013); this difference was not explained by age, education, employment, income, history of intravenous drug use, or medical regimen. Non-Caucasian patients, however, were less satisfied with their social support (P = .04) and informational support (P = .016) and were more likely to utilize emotion-focused coping (P = .01). Thus, satisfaction with social support and coping style significantly impacted adherence and likely accounted for the observed racial difference in adherence among HIV-infected patients.

OBJECTIVE: The co-occurrence of rheumatoid factor (RF) and anti-citrullinated protein antibody (ACPA) positivity in rheumatoid arthritis (RA) is well described. However, the mechanisms underlying the potential interaction between these 2 distinct autoantibodies have not been well defined. The aim of this study was to evaluate the epidemiologic and molecular interaction of ACPAs and RF and its association with both disease activity and measures of RA-associated inflammation. METHODS: In a cohort of 1,488 US veterans with RA, measures of disease activity and serum levels of cytokines and multiplex ACPAs were compared between the following groups of patients: double-negative (anti-cyclic citrullinated peptide [anti-CCP]-/RF-), anti-CCP+/RF-, anti-CCP-/RF+, or double-positive (anti-CCP+/RF+). Additional studies were performed using an in vitro immune complex (IC) stimulation assay in which macrophages were incubated with ACPA ICs in the presence or absence of monoclonal IgM-RF, and tumor necrosis factor α production measured as a readout of macrophage activation. RESULTS: Compared with the double-negative subgroup (as well as each single-positive subgroup), the double-positive subgroup exhibited higher disease activity as well as higher levels of C-reactive protein and inflammatory cytokines (all P < 0.001). In vitro stimulation of macrophages by ACPA ICs increased cytokine production, and the addition of monoclonal IgM-RF significantly increased macrophage tumor necrosis factor α production (P = 0.003 versus ACPA ICs alone). CONCLUSION: The combined presence of ACPAs and IgM-RF mediates increased proinflammatory cytokine production in vitro and is associated with increased systemic inflammation and disease activity in RA. Our data suggest that IgM-RF enhances the capacity of ACPA ICs to stimulate macrophage cytokine production, thereby providing a mechanistic link by which RF enhances the pathogenicity of ACPA ICs in RA.

Sleep quality is often poor in patients with chronic obstructive pulmonary disease (COPD), but these night-time symptoms are frequently unnoticed by physicians and/or not reported by patients themselves. Therefore, the prevalence and clinical impact of sleep disturbances and night-time symptoms in COPD is not well understood and has not been a clinical focus to date. To address this gap, an expert panel meeting was convened in Barcelona, Spain, in March 2011 to discuss the aetiology, evolution, burden, long-term clinical consequences and optimal management of night-time symptoms in COPD. The term "night-time symptoms" in COPD has not been distinctly defined in an objective sense but epidemiological data suggests that the prevalence of nocturnal symptoms and symptomatic sleep disturbance may exceed 75% in patients with COPD. The panel concluded that night-time symptoms in COPD are prevalent and bothersome; that their cause(s) are multiple and include demographic factors, such as age and obesity, pharmacotherapy, disease-specific symptoms and the presence of comorbid sleep disorders, and other medical conditions; and that potential long-term consequences can include lung function changes, increased exacerbation frequency, emergence or worsening of cardiovascular disease, cognitive effects, depression, impaired quality of life and increased mortality. To date, few interventional studies have investigated them, but emerging data suggest that bronchodilator therapy can improve them if deployed appropriately. In summary, night-time symptoms in COPD warrant further clinical investigation with validated tools.

OBJECTIVE: To examine the relationship of Porphyromonas gingivalis to the presence of autoantibodies in individuals at risk of rheumatoid arthritis (RA). METHODS: Study participants included the following: 1) a cohort enriched in subjects with HLA-DR4 and 2) subjects at risk of RA by virtue of having a first-degree relative with RA. None of the study subjects satisfied the American College of Rheumatology 1987 classification criteria for RA. Autoantibodies measured included anti-citrullinated protein antibody (ACPA; by second-generation anti-cyclic citrullinated peptide antibody enzyme-linked immunosorbent assay [ELISA]) and rheumatoid factor (RF; by nephelometry or ELISA for IgA, IgM, or IgG isotype). Individuals were considered autoantibody positive (n = 113) if they had ≥1 RA-related autoantibody; individuals were further categorized as high risk (n = 38) if they had ACPA or positive findings ≥2 assays for RF. Autoantibody-negative individuals (n = 171) served as a comparator group. Antibody to P gingivalis, P intermedia, and F nucleatum were measured. Associations of bacterial antibodies with group status were examined using logistic regression. RESULTS: Anti-P gingivalis concentrations were higher in high-risk (P = 0.011) and autoantibody positive group (P = 0.010) than in the autoantibody negative group. There were no group differences in anti-P intermedia or anti-F nucleatum concentrations. After multivariable adjustment, anti-P gingivalis concentrations (but not anti-P intermedia or anti-F nucleatum) were significantly associated with autoantibody-positive and high-risk status (P < 0.05). CONCLUSION: Immunity to P gingivalis, but not P intermedia or F nucleatum, is significantly associated with the presence of RA-related autoantibodies in individuals at risk of RA. These results support the hypothesis that infection with P gingivalis may play a central role in the early loss of tolerance to self antigens that occurs in the pathogenesis of RA.

BACKGROUND: Rheumatoid arthritis (RA) is characterised by autoimmunity to citrullinated proteins, and there is increasing epidemiologic evidence linking Porphyromonas gingivalis to RA. P gingivalis is apparently unique among periodontal pathogens in possessing a citrullinating enzyme, peptidylarginine deiminase (PPAD) with the potential to generate antigens driving the autoimmune response. OBJECTIVES: To examine the immune response to PPAD in patients with RA, individuals with periodontitis (PD) and controls (without arthritis), confirm PPAD autocitrullination and identify the modified arginine residues. METHODS: PPAD and an inactivated mutant (C351A) were cloned and expressed and autocitrullination of both examined by immunoblotting and mass spectrometry. ELISAs using PPAD, C351A and another P gingivalis protein arginine gingipain (RgpB) were developed and antibody reactivities examined in patients with RA (n=80), individuals with PD (n=44) and controls (n=82). RESULTS: Recombinant PPAD was a potent citrullinating enzyme. Antibodies to PPAD, but not to Rgp, were elevated in the RA sera (median 122 U/ml) compared with controls (median 70 U/ml; p<0.05) and PD (median 60 U/ml; p<0.01). Specificity of the anti-peptidyl citrullinated PPAD response was confirmed by the reaction of RA sera with multiple epitopes tested with synthetic citrullinated peptides spanning the PPAD molecule. The elevated antibody response to PPAD was abolished in RA sera if the C351A mutant was used on ELISA. CONCLUSIONS: The peptidyl citrulline-specific immune response to PPAD supports the hypothesis that, as a bacterial protein, it might break tolerance in RA, and could be a target for therapy.

UNLABELLED: Aldehyde dehydrogenase 2 (ALDH2) is the major enzyme that metabolizes acetaldehyde produced from alcohol metabolism. Approximately 40-50% of East Asians carry an inactive ALDH2 gene and exhibit acetaldehyde accumulation after alcohol consumption. However, the role of ALDH2 deficiency in the pathogenesis of alcoholic liver injury remains obscure. In the present study, wild-type and ALDH2(-/-) mice were subjected to ethanol feeding and/or carbon tetrachloride (CCl4 ) treatment, and liver injury was assessed. Compared with wild-type mice, ethanol-fed ALDH2(-/-) mice had higher levels of malondialdehyde-acetaldehyde (MAA) adduct and greater hepatic inflammation, with higher hepatic interleukin (IL)-6 expression but surprisingly lower levels of steatosis and serum alanine aminotransferase (ALT). Higher IL-6 levels were also detected in ethanol-treated precision-cut liver slices from ALDH2(-/-) mice and in Kupffer cells isolated from ethanol-fed ALDH2(-/-) mice than those levels in wild-type mice. In vitro incubation with MAA enhanced the lipopolysaccharide (LPS)-mediated stimulation of IL-6 production in Kupffer cells. In agreement with these findings, hepatic activation of the major IL-6 downstream signaling molecule signal transducer and activator of transcription 3 (STAT3) was higher in ethanol-fed ALDH2(-/-) mice than in wild-type mice. An additional deletion of hepatic STAT3 increased steatosis and hepatocellular damage in ALDH2(-/-) mice. Finally, ethanol-fed ALDH2(-/-) mice were more prone to CCl4 -induced liver inflammation and fibrosis than ethanol-fed wild-type mice. CONCLUSION: ALDH2(-/-) mice are resistant to ethanol-induced steatosis but prone to inflammation and fibrosis by way of MAA-mediated paracrine activation of IL-6 in Kupffer cells. These findings suggest that alcohol, by way of acetaldehyde and its associated adducts, stimulates hepatic inflammation and fibrosis independent from causing hepatocyte death, and that ALDH2-deficient individuals may be resistant to steatosis and blood ALT elevation, but are prone to liver inflammation and fibrosis following alcohol consumption.

Alcohol breakdown in the liver results in the generation of the reactive molecule acetaldehyde and, as a byproduct, highly reactive oxygen-containing molecules known as oxygen radicals. Both acetaldehyde and oxygen radicals can interact with proteins and other complex molecules in the cell, forming hybrid compounds called adducts. Other adducts are formed with aldehyde molecules, which are produced through the interaction of oxygen radicals with lipids in the cells. Adduct formation impedes the function of the original proteins participating in the reaction. Moreover, the adducts may induce harmful immune responses. Both of these effects may account for some of the damage observed in alcoholic liver disease. Adduct formation has been shown to occur in the livers of humans and animals consuming alcohol and to start and predominate in those liver regions that show the first signs of liver damage.

Alcohol-induced fatty liver (steatosis) was believed to result from excessive generation of reducing equivalents from ethanol metabolism, thereby enhancing fat accumulation. Recent findings have revealed a more complex picture in which ethanol oxidation is still required, but specific transcription as well as humoral factors also have important roles. Transcription factors involved include the sterol regulatory element binding protein 1 (SREBP-1) which is activated to induce genes that regulate lipid biosynthesis. Conversely, ethanol consumption causes a general down-regulation of lipid (fatty acid) oxidation, a reflection of inactivation of the peroxisome proliferator-activated receptor-alpha (PPAR-alpha) that regulates genes involved in fatty acid oxidation. A third transcription factor is the early growth response-1 (Egr-1), which is strongly induced prior to the onset of steatosis. The activities of all these factors are governed by that of the principal regulatory enzyme, AMP kinase. Important humoral factors, including adiponectin, and tumor necrosis factor-alpha (TNF-alpha), also regulate alcohol-induced steatosis. Their levels are affected by alcohol consumption and by each other. This review will summarize the actions of these proteins in ethanol-elicited fatty liver. Because steatosis is now regarded as a significant risk factor for advanced liver pathology, an understanding of the molecular mechanisms in its etiology is essential for development of effective therapies.

OBJECTIVE: To determine if minocycline is an effective therapy for seropositive rheumatoid arthritis (RA) when used within the first year of disease. METHODS: The Rheumatoid Arthritis Investigational Network enrolled 46 patients with RA of <1 year duration into a 6-month study of minocycline (100 mg twice daily) versus placebo. All patients were rheumatoid factor positive. The primary end point of the study was successful completion of 6 months of treatment with no drug toxicity while maintaining 50% improvement in composite symptoms of arthritis. RESULTS: Eighteen of the 46 patients who were enrolled met 50% improvement criteria at 3 months, and maintained at least a 50% improvement for 6 months with no significant drug toxicity. Among them were 15 of the 23 patients (65%) treated with minocycline and 3 of 23 patients (13%) treated with placebo (P < 0.001). CONCLUSION: In patients with early seropositive RA, therapy with minocycline is superior to placebo.

Previous studies have shown that ethanol feeding to rats alters methionine metabolism by decreasing the activity of methionine synthetase. This is the enzyme that converts homocysteine in the presence of vitamin B12 and N5-methyltetrahydrofolate to methionine. The action of the ethanol results in an increase in the hepatic level of the substrate N5-methyltetrahydrofolate but as an adaptive mechanism, betaine homocysteine methyltransferase, is induced in order to maintain hepatic S-adenosylmethionine at normal levels. Continued ethanol feeding, beyond 2 months, however, produces depressed levels of hepatic S-adenosylmethionine. Because betaine homocysteine methyltransferase is induced in the livers of ethanol-fed rats, this study was conducted to determine what effect the feeding of betaine, a substrate of betaine homocysteine methyltransferase, has on methionine metabolism in control and ethanol-fed animals. Control and ethanol-fed rats were given both betaine-lacking and betaine-containing liquid diets for 4 weeks, and parameters of methionine metabolism were measured. These measurements demonstrated that betaine administration doubled the hepatic levels of S-adenosylmethionine in control animals and increased by 4-fold the levels of hepatic S-adenosylmethionine in the ethanol-fed rats. The ethanol-induced infiltration of triglycerides in the liver was also reduced by the feeding of betaine to the ethanol-fed animals. These results indicate that betaine administration has the capacity to elevate hepatic S-adenosylmethionine and to prevent the ethanol-induced fatty liver.

The fibroblast-populated collagen matrix (FPCM) has been utilized as an in vitro model of wound healing for more than 2 decades. It offers a reasonable approximation of the healing wound during the phases of established granulation tissue and early scar. The gross and microscopic morphology of the FPCM and the healing wound are similar at analogous phases. The processes of proliferation, survival/apoptosis, protein synthesis, and contraction act in similar directions in these two models, and the response to exogenous agents also is consistent between them. If its limitations are respected, then the FPCM can be used as a model of the healing wound.

Cirrhosis is a major risk factor for severe pneumococcal infection, and patients evaluated for liver transplantation routinely receive pneumococcal vaccine. This study followed serologic antibody levels of 45 adults evaluated for transplantation and 13 age-matched control subjects. All received 23-valent pneumococcal polysaccharide vaccine (PPS). Serum anti-PPS levels and antibodies specific for capsular types 3 and 23 were measured by ELISA before and 1 and 6 months after vaccination. Antibody levels for the 25 patients who received transplants also were measured immediately before and 3 months after transplantation. Control subjects had higher IgG responses to the whole vaccine, whereas patients appeared to produce more IgM and IgA. IgA, and possibly IgM levels, also declined faster in patients than in control subjects. All anti-PPS levels were at or below prevaccination baselines by 3 months after transplantation. These data suggest that vaccination with PPS may not be effective for patients during and after liver transplantation.

A pathological feature of Type 2 diabetes is deposits in the pancreatic islets primarily composed of amylin (islet amyloid polypeptide). Although much attention has been paid to the expression and secretion of amylin, little is known about the enzymes involved in amylin turnover. Recent reports suggest that insulin-degrading enzyme (IDE) may have specificity for amyloidogenic proteins, and therefore we sought to determine whether amylin is an IDE substrate. Amylin-degrading activity co-purified with IDE from rat muscle through several chromatographic steps. Metalloproteinase inhibitors inactivated amylin-degrading activity with a pattern consistent with the enzymatic properties of IDE, whereas inhibitors of acid and serine proteases, calpains, and the proteasome were ineffective. Amylin degradation was inhibited by insulin in a dose-dependent manner, whereas insulin degradation was inhibited by amylin. Other substrates of IDE such as atrial natriuretic peptide and glucagon also competitively inhibited amylin degradation. Radiolabeled amylin and insulin were both covalently cross-linked to a protein of 110 kDa, and the binding was competitively inhibited by either unlabeled insulin or amylin. Finally, a monoclonal anti-IDE antibody immunoprecipitated both insulin- and amylin-degrading activities. The data strongly suggest that IDE is an amylin-degrading enzyme and plays an important role in the clearance of amylin and the prevention of islet amyloid formation.