PubMed Health⌕ Search

Biomedical subjects

Detlef Schuppan

Publications and source records attributed to Detlef Schuppan.

At least 19 recordsLinked to original sources

Identification of food-grade subtilisins as gluten-degrading enzymes to treat celiac disease.

Gluten are proline- and glutamine-rich proteins present in wheat, barley, and rye and contain the immunogenic sequences that drive celiac disease (CD). Rothia mucilaginosa, an oral microbial colonizer, can cleave these gluten epitopes. The aim was to isolate and identify the enzymes and evaluate their potential as novel enzyme therapeutics for CD. The membrane-associated R. mucilaginosa proteins were extracted and separated by DEAE chromatography. Enzyme activities were monitored with paranitroanilide-derivatized and fluorescence resonance energy transfer (FRET) peptide substrates, and by gliadin zymography. Epitope elimination was determined in R5 and G12 ELISAs. The gliadin-degrading Rothia enzymes were identified by LC-ESI-MS/MS as hypothetical proteins ROTMU0001_0241 (C6R5V9_9MICC), ROTMU0001_0243 (C6R5W1_9MICC), and ROTMU0001_240 (C6R5V8_9MICC). A search with the Basic Local Alignment Search Tool revealed that these are subtilisin-like serine proteases belonging to the peptidase S8 family. Alignment of the major Rothia subtilisins indicated that all contain the catalytic triad with Asp (D), His (H), and Ser (S) in the D-H-S order. They cleaved succinyl-Ala-Ala-Pro-Phe-paranitroanilide, a substrate for subtilisin with Pro in the P2 position, as in Tyr-Pro-Gln and Leu-Pro-Tyr in gluten, which are also cleaved. Consistently, FRET substrates of gliadin immunogenic epitopes comprising Xaa-Pro-Xaa motives were rapidly hydrolyzed. The Rothia subtilisins and two subtilisins from Bacillus licheniformis, subtilisin A and the food-grade Nattokinase, efficiently degraded the immunogenic gliadin-derived 33-mer peptide and the immunodominant epitopes recognized by the R5 and G12 antibodies. This study identified Rothia and food-grade Bacillus subtilisins as promising new candidates for enzyme therapeutics in CD.

Bacteria↗

Laser-induced thermotherapy (LITT) elevates mRNA expression of connective tissue growth factor (CTGF) associated with reduced tumor growth of liver metastases compared to hepatic resection.

BACKGROUND AND OBJECTIVES: Proliferation and synthesis of hepatocellular tissue after tissue damage are promoted by specific growth factors such as hepatic tissue growth factor (HGF) and connective growth factor (CTGF). Laser-induced thermotherapy (LITT) for the treatment of liver metastases is deemed to be a parenchyma-saving procedure compared to hepatic resection. The aim of this study was to compare the impact of LITT and hepatic resection on intrahepatic residual tumor tissue and expression levels of mRNA HGF/CTGF within liver and tumor tissue. STUDY DESIGN/MATERIALS AND METHODS: Two independent adenocarcinomas (CC531) were implanted into 75 WAG rats, one in the right (untreated tumor) and one in the left liver lobe (treated tumor). The left lobe tumor was treated either by LITT or partial hepatectomy. The control tumor was submitted to in-situ hybridization of HGF and CTGF 24-96 hours and 14 days after intervention. RESULTS: Volumes of the untreated tumors prior to intervention were 38+/-8 mm(3) in group I (laser), 39 +/- 7 mm(3) in group II (resection), and 42 +/- 12 mm(3) in group III (control) and did not differ significantly (P > 0.05). Fourteen days after the intervention the mean tumor+/-SEM volume of untreated tumor in group I (laser) [223 +/- 36] was smaller than in group II (resection) [1233.28 +/- 181.52; P < 0.001], and in group III (control) [978.92 +/- 87.57; P < 0.003]. Forty-eight hours after the intervention intrahepatic mRNA expression level of HGF in group II (resection) was almost twofold higher than in group I (laser) [7.2 +/- 1.0 c/mf vs. 3.9 +/- 0.4 c/mf; P<0.01]. Fourteen days after the intervention intrahepatic mRNA expression level of CTGF in group I (laser) was higher than in group II (resection) [13.89 +/- 0.77 c/mf vs. 9.09 +/- 0.78 c/mf; P < 0.003]. CONCLUSIONS: LITT leads to a decrease of residual tumor growth in comparison to hepatic resection. Accelerated tumor growth after hepatic resection is associated with higher mRNA level of HGF and reduced tumor growth after LITT with higher mRNA level of CTGF. The increased CTGF-mediated regulation of ECM may cause reduced residual tumor growth after LITT.

Animals↗

Liver-homing of purified glucose oxidase: a novel in vivo model of physiological hepatic oxidative stress (H2O2).

BACKGROUND/AIMS: Reactive oxygen species (ROS), such as H2O2, are implicated in normal and pathological liver function. However, due to the lack of suitable in vivo models of ROS generation the (patho) physiological relevance of H2O2 remains controversial. METHODS: We established a novel model of sustained hepatic H2O2 release using intravenous administration of purified Aspergillus niger glucose oxidase (GOX) in rats. RESULTS: GOX is rapidly cleared from the blood stream and almost exclusively localizes to Kupffer cells. GOX maintained its ability to generate H2O2 over 24h. While sublethal GOX doses induced hepatocellular necrosis, our morphological and functional studies show that lower levels of GOX which generate H2O2 comparable to release by inflammatory cells are non-toxic and do not induce histological inflammation. However, these non-toxic H2O2 levels increased oxidized glutathione and induced heme oxygenase 1 in the liver. In addition, several hepatocyte transporters were downregulated, while no decrease of bile formation, a sensitive marker of liver function, was observed. CONCLUSIONS: Our in vivo model allows to study the effects of extracellular H2O2 in the liver as is released by inflammatory cells. Thus analysis of the role of this major ROS in the absence of confounding inflammatory cofactors will be possible.

Animals↗

Endothelin-1 enhances fibrogenic gene expression, but does not promote DNA synthesis or apoptosis in hepatic stellate cells.

BACKGROUND: In liver injury, the pool of hepatic stellate cell (HSC) increases and produces extracellular matrix proteins, decreasing during the resolution of fibrosis. The profibrogenic role of endothelin-1 (ET-1) in liver fibrosis remains disputed. We therefore studied the effect of ET-1 on proliferation, apoptosis and profibrogenic gene expression of HSCs. RESULTS: First passage HSC predominantly expressed endothelin A receptor (ETAR) mRNA and 4th passage HSC predominantly expressed the endothelin B receptor (ETBR) mRNA. ET-1 had no effect on DNA synthesis in 1st passage HSC, but reduced DNA synthesis in 4th passage HSC by more than 50%. Inhibition of proliferation by endothelin-1 was abrogated by ETBR specific antagonist BQ788, indicating a prominent role of ETBR in growth inhibition. ET-1 did not prevent apoptosis induced by serum deprivation or Fas ligand in 1st or 4th passage HSC. However, ET-1 increased procollagen alpha1(I), transforming growth factor beta-1 and matrix metalloproteinase (MMP)-2 mRNA transcripts in a concentration-dependent manner in 1st, but not in 4th passage HSC. Profibrogenic gene expression was abrogated by ETAR antagonist BQ123. Both BQ123 and BQ788 attenuated the increase of MMP-2 expression by ET-1. CONCLUSION: We show that ET-1 stimulates fibrogenic gene expression for 1st passage HSC and it inhibits HSC proliferation for 4th passage HSC. These data indicate the profibrogenic and antifibrogenic action of ET-1 for HSC are involved in the process of liver fibrosis.

Journal Article↗

Synthesis of collagen I in collagenous sprue.

BACKGROUND & AIMS: Collagenous sprue (CS) is a rare severe malabsorption syndrome of unknown etiology, characterized by villus atrophy and a broad subepithelial collagen band. We studied the expression patterns of genes involved in fibrogenesis and fibrolysis and analyzed the composition of the subepithelial collagen band in CS compared with untreated celiac diseases (CDs). METHODS: Duodenal biopsies from 2 patients with CS were hybridized with (35)S-labeled RNA probes for procollagen alpha1(I), matrix metalloproteinases (MMPs)-1 and -3, and tissue inhibitor of MMP-1 (TIMP-1). Numbers of positive subepithelial and lamina propria cells and grain density per cell were determined microscopically. Immunohistochemistry for collagens I, III, IV, XIV, and tenascin was performed by the immunoalkaline phosphatase method. Findings were compared with earlier data from patients with untreated CD. RESULTS: Numbers of cells expressing procollagen I, MMP-1, and MMP-3 mRNA were similar, but subepithelial procollagen I transcripts per cell were significantly increased (42 and 38 vs 18 [13-23]; P < .05) in CS compared with CD, whereas cellular transcript densities for MMP-1 and MMP-3 mRNA were similar. In addition, the number of TIMP-1 mRNA-positive cells was higher in CS compared with CD (32 and 25 vs 16.5 [4-25]; P < .05). The subepithelial collagenous bands stained for collagen I, collagen III, and tenascin. CONCLUSIONS: The prominent subepithelial matrix deposition in CS is due to increased expression of the main fibrogenic genes (procollagen I and TIMP-1) by myofibroblastic cells, whereas expression of fibrolytic MMPs remains unaltered.

Adult↗

Signaling pathways involved in the inhibition of epidermal growth factor receptor by erlotinib in hepatocellular cancer.

AIM: To examine the underlying mechanisms of erlotinib-induced growth inhibition in hepatocellular carcinoma (HCC). METHODS: Erlotinib-induced alterations in gene expression were evaluated using cDNA array technology; changes in protein expression and/or protein activation due to erlotinib treatment as well as IGF-1-induced EGFR transactivation were investigated using Western blotting. RESULTS: Erlotinib treatment inhibited the mitogen activated protein (MAP)-kinase pathway and signal transducer of activation and transcription (STAT)-mediated signaling which led to an altered expression of apoptosis and cell cycle regulating genes as demonstrated by cDNA array technology. Overexpression of proapoptotic factors like caspases and gadds associated with a down-regulation of antiapoptotic factors like Bcl-2, Bcl-X(L) or jun D accounted for erlotinib's potency to induce apoptosis. Downregulation of cell cycle regulators promoting the G1/S-transition and overexpression of cyclin-dependent kinase inhibitors and gadds contributed to the induction of a G1/G0-arrest in response to erlotinib. Furthermore, we displayed the transactivation of EGFR-mediated signaling by the IGF-1-receptor and showed erlotinib's inhibitory effects on the receptor-receptor cross talk. CONCLUSION: Our study sheds light on the under-standing of the mechanisms of action of EGFR-TK-inhibition in HCC-cells and thus might facilitate the design of combination therapies that act additively or synergistically. Moreover, our data on the pathways responding to erlotinib treatment could be helpful in predicting the responsiveness of tumors to EGFR-TKIs in the future.

Antineoplastic Agents↗

Activation and dramatically increased cytolytic activity of tumor specific T lymphocytes after radio-frequency ablation in patients with hepatocellular carcinoma and colorectal liver metastases.

AIM: To assess if a specific cytotoxic T cell response can be induced in patients with malignant liver tumors treated with radio-frequency ablation (RFA). METHODS: Six Patients with liver metastases of colorectal cancer and 6 with hepatocellular carcinoma (HCC) underwent RFA. Blood was sampled before, 4 and 8 wk after RFA. Test antigens were autologous liver and tumor lysate obtained from each patient by biopsy. Peripheral T cell activation was assessed by an interferon gamma (IFNgamma) secretion assay and flow cytometry. T cells were double-stained for CD4/CD8 and IFNgamma to detect cytotoxic T cells. The ratio of IFNgamma positive and IFNgamma negative T cells was determined as the stimulation index (SI). To assess cytolytic activity, T cells were co-incubated with human CaCo colorectal cancer and HepG2 HCC cells and release of cytosolic adenylate kinase was measured by a luciferase assay. RESULTS: Before RFA SI was 0.021 (+/- 0.006) for CD4(+) and 0.022 (+/- 0.004) for CD8(+) T cells against nonmalignant liver tissue and 0.018 (+/- 0.005) for CD4(+) and 0.021 (+/- 0.004) for CD8(+) cells against autologous tumor tissue. Four weeks after RFA SI against tumor tissue increased to 0.109 (+/- 0.005) for CD4(+) and 0.11 (+/- 0.012) for CD8(+) T cells against HCC, and to 0.115 (+/- 0.031) for CD4(+) and 0.15 (+/- 0.02) for CD8(+) cells for colorectal metastases (P < 0.0001). No increased SI was observed with nonmalignant tumor tissue at all time points. Before RFA cytolytic activity against the respective cancer cells was low with 2.62 (+/- 0.37) relative luminescence units (RLU), but rose more than 100 fold 4 and 8 wk after RFA. Spontaneous release was < 2% of maximum release in all experiments. CONCLUSION: Patients with primary and secondary tumors of the liver show a significant tumor-specific cytotoxic T-cell stimulation with a dramatically increased tumor specific cytolytic activity of CD8(+) T cells after RFA.

Adenylate Kinase↗

Matrix-derived serum markers in monitoring liver fibrosis in children with chronic hepatitis B treated with interferon alpha.

AIM: To evaluate prospectively 4 selected serum fibrosis markers (tenascin, hyaluronan, collagen VI, TIMP-1) before, during and 12 mo after IFN treatment of children with chronic hepatitis B. METHODS: Forty-seven consecutive patients with chronic hepatitis B (range 4-16 years, mean 8 years) underwent IFN treatment (3 MU tiw for 20 wk). Fibrosis stage and inflammation grade were assessed in a blinded fashion before and 12 mo after end of treatment. Serum fibrosis markers were determined using automated assays. RESULTS: IFN treatment improved histological inflammation but did not change fibrosis in the whole group or in subgroups. Only hyaluronan correlated significantly with histological fibrosis(r = 0.3383, P = 0.021). Basal fibrosis markers did not differ between responders (42.5%) and nonresponders(57.5%). During IFN treatment only serum tenascin decreased significantly in the whole group and in nonresponders. When pretreatment values were compared to values 12 mo after therapy, TIMP-1 increased in all patients and in nonresponders, and hyaluronan decreased in all patients and in responders. CONCLUSION: Tenascin reflects hepatic fibrogenesis and inflammation which decreases during IFN treatment of children with chronic hepatitis B. TIMP-1 correlates with nonresponse and hyaluronan with histological fibrosis.

Adolescent↗

Mortality excess in individuals with elevated IgA anti-transglutaminase antibodies: the KORA/MONICA Augsburg cohort study 1989-1998.

OBJECTIVES: Immunoglobulin A (IgA) autoantibodies to tissue transglutaminase (tTG) are commonly used for screening and diagnosing of celiac disease. We examined the hypothesis that elevated IgA anti-tTG antibodies were associated with higher all-cause mortality risk. METHODS: The cohort, 2333 men and 2300 women, was based on the follow-up of participants of a representative population-based survey in Southern Germany (KORA/MONICA Augsburg project) conducted in 1989-1990. The endpoint for the vital status with cause of death was the year 1998. The sera drawn at baseline and stored at -80 degrees C, were recently screened with an IgA enzyme-linked immunosorbent assay (ELISA) using human recombinant tTG. Age-standardized mortality rates and age-adjusted hazard ratios were calculated. RESULTS: From the 4633 sera analyzed, 63 had an IgA anti-tTG concentration>or=7 AU/ml. Of these 63 individuals, 15 died between 1989 and 1998. The age-adjusted hazard ratio (HRa) of all-cause mortality was 1.86 (95% CI: 1.01-3.41) and 3.92 (95% CI: 1.44-10.71) for men and women, respectively. The excess of cancer mortality was even higher with an HR(a) of 2.47 (95% CI: 0.89-6.83) in men and of 6.65 (95% CI: 2.04-21.63) in women. CONCLUSIONS: Individuals with elevated IgA anti-tTG antibodies had a highly increased mortality risk, particularly due to cancer. New studies are necessary to clarify if this increased risk is due to undiagnosed celiac disease or/and if this elevated IgA anti-tTG antibodies level is a marker of serious diseases like cancer, chronic liver disease or end-stage heart failure.

Adult↗

Alcohol dehydrogenase 1C*1 allele is a genetic marker for alcohol-associated cancer in heavy drinkers.

Chronic alcohol consumption is associated with an increased risk for upper aerodigestive tract cancer and hepatocellular carcinoma. Increased acetaldehyde production via alcohol dehydrogenase (ADH) has been implicated in the pathogenesis. The allele ADH1C*1 of ADH1C encodes for an enzyme with a high capacity to generate acetaldehyde. So far, the association between the ADH1C*1 allele and alcohol-related cancers among heavy drinkers is controversial. ADH1C genotypes were determined by polymerase chain reaction and restriction fragment length polymorphism in a total of 818 patients with alcohol-associated esophageal (n=123), head and neck (n=84) and hepatocellular cancer (n=86) as well as in patients with alcoholic pancreatitis (n=117), alcoholic liver cirrhosis (n=217), combined liver cirrhosis and pancreatitis (n=17) and in alcoholics without gastrointestinal organ damage (n=174). The ADH1C*1 allele and genotype ADH1C*1/1 were significantly more frequent in patients with alcohol-related cancers than that in individuals with nonmalignant alcohol-related organ damage. Using multivariate analysis, ADH1C*1 allele frequency and rate of homozygosity were significantly associated with an increased risk for alcohol-related cancers (p<0.001 in all instances). The odds ratio for genotype ADH1C*1/1 regarding the development of esophageal, hepatocellular and head and neck cancer were 2.93 (CI, 1.84-4.67), 3.56 (CI, 1.33-9.53) and 2.2 (CI, 1.11-4.36), respectively. The data identify genotype ADH1C*1/1 as an independent risk factor for the development of alcohol-associated tumors among heavy drinkers, indicating a genetic predisposition of individuals carrying this genotype.

Adult↗

Blockade of IGF-1 receptor tyrosine kinase has antineoplastic effects in hepatocellular carcinoma cells.

UNLABELLED: Hepatocellular carcinoma (HCC) is one of the most common cancer-related causes of death worldwide. Due to very poor 5-year-survival new therapeutic approaches are mandatory. Most HCCs express insulin-like growth factors and their receptors (IGF-R). As IGF-1R-mediated signaling promotes survival, oncogenic transformation and tumor growth and spread, it represents a potential target for innovative treatment strategies of HCC. Here we studied the antineoplastic effects of inhibiting IGF-1R signaling in HCC cells by the novel IGF-1R tyrosine kinase inhibitor NVP-AEW541. METHODS AND RESULTS: NVP-AEW541 induced a time- and dose-dependent growth inhibition in the human hepatoblastoma and hepatocellular carcinoma cell lines SK-Hep-1, Hep-3B, Hep-G2 and Huh-7. Measurement of LDH-release showed that the antineoplastic effect of NVP-AEW541 was not due to cytotoxicity. Instead NVP-AEW541 induced apoptosis as evidenced by both caspase-3 and -8 activation as well as by apoptosis-specific morphological and mitochondrial changes. In addition, nuclear degradation was monitored by DNA-laddering. NVP-AEW541-treatment suppressed the expression of the antiapoptotic proteins Bcl-2 and survivin, while the expression of the proapoptotic protein BAX was stimulated in a dose-dependent manner. Moreover, NVP-AEW541 arrested the cell cycle at the G1/S checkpoint. When NVP-AEW541 was combined with cytotoxic chemotherapy or with a specific epidermal growth factor receptor antibody additive antiproliferative effects were observed. INTERPRETATION: Inhibition of IGF-1R tyrosine kinase (IGF-1R-TK) by NVP-AEW541 induces growth inhibition, apoptosis and cell cycle arrest in human HCC cell lines without accompanying cytotoxicity. Thus, IGF-1R-TK inhibition may be a promising novel treatment approach in HCC.

Antineoplastic Agents↗

Halofuginone induces matrix metalloproteinases in rat hepatic stellate cells via activation of p38 and NFkappaB.

The semisynthetic plant alkaloid halofuginone (HAL) was reported to prevent and partly reverse experimental liver fibrosis. However, its mechanisms of action are poorly understood. We therefore aimed to determine the antifibrotic potential of HAL and to characterize involved signal transduction pathways in hepatic stellate cells (HSCs). Results were compared with its in vivo effects in a rat model of reversal of established liver fibrosis induced by thioacetamide. In vitro HAL inhibited HSC proliferation and migration dose dependently at submicromolar concentrations. HAL (200 nm) up-regulated matrix metalloproteinase (MMP)-3 and MMP-13 expression between 10- and 50-fold, resulting in a 2- to 3-fold increase of interstitial collagenase activity. Procollagen alpha1(I) and MMP-2 transcript levels were suppressed 2- to 3-fold, whereas expression of other profibrogenic mRNAs remained unaffected. p38 mitogen-activated protein kinase (p38 MAPK) and nuclear factor kappaB(NFkappaB) pathways were activated by HAL, and specific inhibitors of p38 MAPK and NFkappaB dose dependently inhibited MMP-13 induction. Treatment with HAL did not affect HSC viability, and observed effects were reversible after its removal. In vivo HAL up-regulated MMP-3 and -13 mRNA expression 1.5- and 2-fold, respectively, in cirrhotic rats, whereas tissue inhibitor of metalloproteinase-1 was suppressed by 50%. In conclusion, submicromolar concentrations of HAL inhibit HSC proliferation and migration and up-regulate their expression of fibrolytic MMP-3 and -13 via activation of p38 MAPK and NFkappaB. The remarkable induction of MMP-3 and -13 makes HAL a promising agent for antifibrotic combination therapies.

Animals↗

Keratin variants associate with progression of fibrosis during chronic hepatitis C infection.

Keratins 8 and 18 (K8/K18) protect the liver from various forms of injury. Studies of liver explants from a large cohort of U.S. patients showed that K8/K18 mutations confer a risk to developing end-stage liver diseases, though which diseases are preferentially involved is unknown. We tested the hypothesis that K8/K18 variants are associated with chronic hepatitis C (CHC) and that their presence correlates with progression of fibrosis. Genomic DNA was isolated from peripheral blood of a well-characterized German cohort of 329 patients with CHC infection. Exonic regions were PCR-amplified and analyzed using denaturing high-performance liquid chromatography and DNA sequencing. Our findings showed: (1) amino acid altering keratin heterozygous variants in 24 of 329 CHC patients (7.3%) and non-coding heterozygous variants in 26 patients (7.8%), and (2) 3 new exonic K8 variants (T26R/G55A/A359T); 6 novel non-coding variants and one K18 coding variant (K18 S230T; 2 patients). The most common variants were K8 R341H (10 patients), K8 G62C (6 patients) and K8 I63V (4 patients). A novel and exclusive association of an intronic KRT8 IVS7+10delC deletion in all 10 patients with K8 R341H was observed. Notably, there was a significant association of exonic, but not of intronic K8 variants with increased fibrosis. In conclusion, previously described and novel K8 variants are present in a German population and collectively associate with progression of fibrosis in CHC infection. The unique 100% segregation of the most common K8 variant, R341H, with an intronic deletion suggests that one of these two genetic changes might lead to the other.

Adult↗

EUS-guided alcohol ablation of an insulinoma.

BACKGROUND: Surgical resection is currently considered to be the criterion standard for treatment of insulinomas. Alternative treatments, despite medication with diazoxide, are lacking. EUS-guided ethanol ablation of endocrine tumors has not been reported before. INTERVENTION: A 78-year-old woman was referred with typical symptoms of an insulinoma. Diagnosis was confirmed by laboratory findings, EUS, and EUS-guided FNA. Because of severe complications during several hypoglycemic episodes, a poor general condition, and strict refusal of surgical resection, the decision was made to ablate the insulinoma by EUS-guided alcohol injection. A total of 8 mL 95% ethanol was injected into the tumor. RESULTS: The patient was discharged and exhibited no further hypoglycemic episodes, and her general condition improved rapidly. Based on clinical, morphologic, and biochemical criteria, we achieved a durable complete remission of the tumor. CONCLUSIONS: EUS-guided ablation may become a minimally invasive alternative for patients with insulinomas in whom surgery is not feasible.

Aged↗

Monitoring nonresponsive patients who have celiac disease.

Because of the wide variations in the clinical presentation of celiac disease and because treatment exists that is effective in most cases, screening of the general population for celiac disease has been considered. There is still no evidence that patients who have symptom-free celiac disease are at increased risk of small intestinal lymphoma or other complications. Prevention of osteoporosis seems to be the strongest indicator for widespread screening today [22]. The major cause of failure to respond to a gluten-free diet is continuing ingestion of gluten, but other underlying diseases must be considered. Many different drugs (eg, anti-tumor necrosis factor [TNF]-alpha) have been used in patients who have RCD [23]. Steroid treatment has been reported to be effective even in patients who have underlying early EATL. Histologic recovery in patients who have celiac disease usually takes several months but can take up to 1 year, even if the patient remains on a strict gluten-free diet. Some patients report celiac-related symptoms for months after a single gluten intake. The definitions for RCD in literature vary. The authors consider the definition give by Daum and colleagues [24] suitable. They defined true RCD as villous atrophy with crypt hyperplasia and increased IELs persisting for more than 12 months in spite of a strict gluten-free diet. If a patient is not responding well to a gluten-free diet, three considerations are necessary: (1) the initial diagnosis of celiac disease must be reassessed;(2) the patient should be sent to a dietician to check for errors in diet or compliance problems, because problems with the gluten-free diet are the most important cause for persisting symptoms; (3) other reasons for persisting symptoms (eg, pancreatic insufficiency, irritable bowel syndrome, bacterial overgrowth, lymphocytic colitis, collagenous colitis, ulcerative jejunitis, protein-losing enteropathy,T-cell lymphoma, fructose intolerance, cavitating lymphadenopathy, and tropical sprue) should be considered. Other causes for villous atrophy are Crohn's disease, collagenous sprue, and autoimmune enteropathy. Abdulkarim and colleagues [25] examined 55 patients who had a diagnosis of nonresponsive celiac disease. He found that 6 did not have celiac disease, and25 still had some gluten ingestion.Tursi and colleagues [26] reported 15 patients who had celiac disease with persisting symptoms. Because histology improved in all patients after several months, RCD was excluded. Of the 15 patients, 10 had small intestinal bacterial overgrowth, 2 showed lactose malabsorption causing the described symptoms, 1 had mistakenly taken an antibiotic containing gluten, and 1 patient each had Giardia lamblia and Ascaris lumbricoides. Thus, other entities must be considered in patients who have celiac disease and ongoing symptoms. In a follow-up clinical trial, 158 patients who had celiac disease underwent follow-up small intestine biopsies within 2 years after starting a gluten-free diet. Eleven patients (7.0%) with persisting (partial) villous atrophy were considered to have RCD; 5 of them developed EATL [27].RCD type I is characterized by normal expression of T-cell antigens and polyclonal TCR gene rearrangement.RCD type II is characterized by an abnormal IEL phenotype with the expression of intracytoplasmic CD3e, surface CD103, and the lack of classic surface T-cell markers such as CD8, CD4, and TCR-alpha/beta. This clonal IEL population can be considered crypt IEL [24]. RCD II has a poor prognosis, which is a problem for therapy. Clonal TCR gene rearrangements and loss of T-cell antigens such as CD8 and TCR-beta in IELs may indicate the development of an EATL in patients who have RCD. The markers for an overt EATL are a positive stool blood test, increased lactate dehydrogenase, or beta2-microglobulin [24]. If an overt lymphoma is suspected, upper and lower endoscopy, an ear, nose, and throat work-up, CT scan, capsule endoscopy, and possibly double-balloon enteroscopy should be performed. Most reports of the difficulties in treating patients who have true RCE are casereports. Turner and colleagues [28] reported on an induction of remission by useof the anti-TNF-alpha antibody infliximab and maintenance with prednisoloneand azathioprine. Olaussen and colleagues [29] and Mandal and colleagues [30]tried a nonimmunogenic elemental diet. Gillet and colleagues [31] reported successful treatment of a patient who hadRCD using anti-TNF-alpha antibodies (infliximab) for induction and azathioprinefor maintenance. Maurino and colleagues [32] studied seven consecutive patients diagnosed ashaving refractory sprue and no response to oral or parenteral steroids. Aftertreatment with azathioprine (2 mg/kg/d) and oral prednisone (1 mg/kg/d), fivepatients had a complete clinical remission. Two patients who did not respond totreatment at any time died. Goerres and colleagues [33] described 18 patients who had RCD, 10 of whomhad type I RCD, and 8 of whom had type II RCD. Treatment consisted ofazathioprine combined with prednisone for 1 year. Consistent with reports byother investigators, the response rates in the two groups differed. Eight of the10 patients who had type I RCD had a histologic response. Seven of the eightpatients who had type II RCD died, and six of the eight developed a lymphoma. At present there is no effective treatment for type II RCD.Fig. 3 presents a proposed algorithm for monitoring patients who have ce-liac disease.

Algorithms↗

Monitoring non-responsive patients with celiac disease.

Current data clearly suggest that VCE has an important role in the diagnostic workup of complicated Cd, especially in those cases with suspected RCd or EATL. This is supported by the high yield of relevant pathological findings in distal parts of the small intestine, such as severe ulceration and mucosal infiltration, by VCE compared to conventional upper GI endoscopy. In this setting, VCE allows for an assessment of the extent of small bowel involvement, detection of overt though often small neoplasms and assists in planning further diagnostic procedures, especially push or double-balloon enteroscopy which are necessary to obtain specimens either to rule out or to confirm aberrant monoclonal T cell proliferation. Currently, those patients in whom RCd type II or EATL are excluded profit most from a thorough diagnostic workup, since most of them can be treated or cured pharmacologically. At present the prognosis of RCd type II or EATL is poor due to lack of effective therapies. However, treatments that effectively target the aberrant lymphocytes can be anticipated.

Algorithms↗

The receptor for advanced glycation end products is highly expressed in the skin and upregulated by advanced glycation end products and tumor necrosis factor-alpha.

Advanced glycation end products (AGEs) form non-enzymatically from reactions of proteins with reducing sugars. In the skin, AGEs were reported to accumulate in dermal elastin and collagens and to interact nonspecifically with the cell membrane of dermal fibroblasts. Therefore, AGEs may influence the process of skin aging. We investigated the presence of the AGE receptor RAGE in skin and the influence of AGEs on receptor expression and the formation of extracellular matrix (ECM). Sections of sun-protected and sun-exposed skin were analyzed with monoclonal antibodies against (RAGE), heat-shock protein 47, factor XIIIa, CD31, and CD45. RAGE was mainly expressed in fibroblasts, dendrocytes, and keratinocytes and to a minor extent in endothelial and mononuclear cells. Human foreskin fibroblasts (HFFs) highly expressed RAGE on the protein and mRNA level when analyzed by quantitative Western blotting and real-time PCR. Incubation of HFFs with the specific RAGE ligand Nepsilon-(carboxymethyl)lysine-modified BSA (CML-BSA) and tumor necrosis factor-alpha resulted in significant upregulation of RAGE expression. CML-BSA induced a mildly profibrogenic pattern, increasing connective tissue growth factor, transforming growth factor-beta (TGF-beta) 1, and procollagen-alpha1(I) mRNA, whereas expression of matrix metalloproteinase (MMP)-1, -2, -3, and -12 was unaffected. We conclude that in HFFs, AGE-RAGE interactions may influence the process of skin aging through mild stimulation of ECM gene expression.

Adult↗