Immunohistochemical study on tissue transglutaminase and copper-zinc superoxide dismutase in human myocardium: Its relevance to apoptosis detected by the nick end labelling method

The influence of free radicals on apoptosis was studied in the human heart; 45 autopsy cases were examined by the nick end labelling method (NELM) that detects DNA fragmentation. Immunostaining for copper-zinc superoxide dismutase (CuZn-SOD) and tissue transglutaminase (tTG) induced frequently during apoptosis were also studied. Positive immunoreaction for tTG was detected in mucinous degeneration of myocardial cells; these same cells were also positive for CuZn-SOD but negative for NELM. Myocardial cells showing basophilic alterations after haematoxylin and eosin staining were also positive for CuZn-SOD but negative for the other markers examined. Positive nuclear reaction by NELM was only observed in myocardial cells showing contraction band necrosis or irregularly shaped nuclei surrounding recent or long-standing infarcted foci. In these the other two markers were negative. Since mucinous degeneration lacks the distinguishing morphological features of apoptosis, immunoreactive tTG in this lesion may not imply that the cells are undergoing apoptosis. tTG can be induced in non-apoptotic conditions and may not be involved in apoptosis induced by infarction. Histological disassociation between CuZn-SOD expression and apoptosis suggests the possibility of a cytoprotective role played by endogenous CuZn-SOD against free radical generation in the human heart.     

Bone-specific antibodies in sera from patients with celiac disease: characterization and implications in osteoporosis

Osteopenia and osteoporosis are well-known complications detected in celiac disease patients with still obscure pathogenesis. In the present study we investigated the presence of circulating anti-bone autoantibodies in patients with celiac disease and explored their role in the associated bone disease. We evaluated serum samples from 33 patients at the time of diagnosis and from 20 of them after treatment. Sera from patients with inflammatory bowel disease (n = 9), nonceliac osteoporotic (n = 18), and healthy individuals (n = 10) were used as controls. The presence of IgA specific anti-bone antibodies was first investigated using indirect immunofluorescence on cryosections of fetal rat tibia (20-day pregnancy). Furthermore, samples were homogenized and total tissue extracts were subjected to Western blot analysis to confirm immunoreactivity. At diagnosis, sera from 51.5% (17/33) of celiac patients had antibodies that recognized antigenic structures in chondrocytes and the extracellular matrix along mature cartilage, bone interface, and perichondrium of fetal rat bone. Among controls, only two osteoporotic patients showed very low titles of anti-bone autoantibodies. The immunostaining was localized in areas where an active mineralization process occurred and was similar to the distribution of the native bone tissue transglutaminase. The frequency of patients with positive baseline titers of anti-bone antibodies diminished significantly after treatment (P = 0.048). Western blot assays confirmed the presence of autoantibodies in sera from patients with a positive immunofluorescence staining. Autoantibodies recognized a major protein band on tissue extracts with a molecular weight of 77–80 kDa, which could be displaced when sera were preadsorbed with human recombinant tissue transglutaminase. We provide original evidence that patients with celiac disease have IgA-type circulating autoantibodies against intra- and extracellular structures of fetal rat tibia. Our findings suggest that these antibodies recognize bone tissue transglutaminase as the autoantigen, and based on the localization of the immunoreactivity we speculate that they might have an active role in the pathophysiology of celiac disease-associated bone complications.     

Diagnostic immunology in celiac disease

Serum autoantibodies to transglutaminase and endomysium are found in the majority of patients with celiac disease, an autoimmune multisystem disorder affecting approximately 1% of Western and Middle-Eastern populations. Detection of these antibodies plays a crucial role in the diagnosis of celiac disease. The aim of this review is to summarize recent publications in this field, with particular focus on the applications and limitations of celiac autoantibody testing in routine clinical practice.     

Targeted delivery of a novel group of site-directed transglutaminase inhibitors to the liver using liposomes: a new approach for the potential treatment of liver fibrosis

Liver fibrosis and its end-stage disease cirrhosis are a main cause of mortality and morbidity worldwide. Thus far, there is no efficient pharmaceutical intervention for the treatment of liver fibrosis. Liver fibrosis is characterized by excessive accumulation of the extracellular matrix (ECM) proteins. Transglutaminase (TG)-mediated covalent cross-linking has been implicated in the stabilization and accumulation of ECM in a number of fibrotic diseases. Thus, the use of tissue TG2 inhibitors has potential in the treatment of liver fibrosis. Recently, we introduced a novel group of site-directed irreversible specific inhibitors of TGs. Here, we describe the development of a liposome-based drug-delivery system for the site-specific delivery of these TG inhibitors into the liver. By using anionic or neutral-based DSPC liposomes, the TG inhibitor can be successfully incorporated into these liposomes and delivered specifically to the liver. Liposomes can therefore be used as a potential carrier system for site-specific delivery of the TG2 inhibitors into the liver, opening up a potential new avenue for the treatment of liver fibrosis and its end-stage disease cirrhosis.     

Celiac Disease and Metabolic Bone Disease

Celiac disease is a common autoimmune gastrointestinal disorder affecting multiple organs, precipitated in genetically vulnerable persons by the ingestion of gluten. Gluten is poorly digested and is presented to the intestinal mucosa as a large polypeptide. Binding to human leukocyte antigen-DQ2 and human leukocyte antigen-DQ8 molecules on antigen-presenting cells stimulates cellular and humeral immune reactions. Although common serological tests are available to diagnose celiac disease, the diagnosis of celiac disease is often delayed or missed because of lack of recognition as the disease presentation in adults is highly variable and may be asymptomatic. Celiac disease is a common secondary cause of metabolic bone disease and delayed treatment with gluten-free diet affects bone mineral density and fracture risk, so it is crucial to diagnose and treat celiac disease promptly. In this article, we will review recent studies of celiac disease in adults and provide practical, easily accessible information for busy clinicians.     

Two Japanese cases of dermatitis herpetiformis associated each with lung cancer and autoimmune pancreatitis but showing no intestinal symptom or circulating immunoglobulin A antibodies to any known antigens

Dermatitis herpetiformis (DH) is common in some Caucasian populations but extremely rare in Japanese, probably because of different immunogenetic backgrounds. We report two Japanese DH cases with typical clinical, histological and direct immunofluorescence features. However, no symptom of gluten‐sensitive enteropathy was shown. The diagnosis was confirmed by eliminating other autoimmune blistering diseases by indirect immunofluorescence, enzyme‐linked immunosorbent assays and immunoblotting. However, circulating immunoglobulin (Ig)A anti‐endomysium, reticulin and gliadin antibodies were not detected. IgA antibodies to tissue and epidermal transglutaminases were also negative. One case was associated with lung cancer and the other one with autoimmune pancreatitis. On review of 17 cases of DH reported in Japan over the previous 10 years, including our cases, one case was associated with gluten‐sensitive enteropathy, four with malignant neoplasms, two with autoimmune systemic disorders and one with psoriasis. Although our cases were typical of DH in clinical, histopathological and IgA deposit features, they showed different human leukocyte antigen haplotypes, no gluten‐sensitive enteropathy and no DH‐specific IgA antibodies, including those to epidermal and tissue transglutaminases. These results suggest that studies of unique characteristics in Japanese DH patients should facilitate further understanding of pathogenesis in DH.     

Clinical,histological and immunpathological findings in 32 patients with dermatitis herpetiformis Duhring

Background: Dermatitis herpetiformis is a chronic severely pruritic dermatosis. It is a cutaneous manifestation of celiac disease. The aim of our study was to collect clinical, histological and immunopathological data on patients who were treated in the University Departments of Dermatology in Würzburg and Lübeck from 1996 to 2008. Patients and Methods: We retrospectively analyzed 32 patients. Only patients with positive findings on direct immunofluorescence microscopy were included in this study. Results: All patients demonstrated skin lesions in the predilection areas of knees, elbows, gluteal region and scalp. The male to female ratio was 1.5 : 1 and the average age was 43 years. The interval between the first symptoms and diagnosis ranged from 6 weeks to 20 years. Direct immunofluorescence microscopy showed that granular IgA deposits were more often found continuously along the dermal‐epidermal junction rather than focally in the tips of the dermal papillae. Results of small intestinal biopsies were available from 29 patients and confirmed the presence of celiac disease in all cases. None of the patients reported gastrointestinal symptoms. IgA antibodies against tissue transglutaminase and epidermal transglutaminase were found in 88% and 94% of patient sera, respectively. Conclusions: The detection of IgA autoantibodies against epidermal transglut‐aminase is the most sensitive serological test in the diagnosis of dermatitis herpetiformis. Our observations confirm that patients with dermatitis herpetiformis usually do not demonstrate apparent gastrointestinal symptoms.