Biomedical subjects

Hemmo A Drexhage

Publications and source records attributed to Hemmo A Drexhage.

24 records · Page 2Linked to original sources

PubMed2003

Apoptosis and apoptosis-related molecules in the submandibular gland of the nonobese diabetic mouse model for Sjögren's syndrome: limited role for apoptosis in the development of sialoadenitis.

Sjögren's syndrome is an autoimmune disease in which lymphocytic infiltrates develop in the exocrine glands. Pathogenetic aspects of the disease can be studied in the nonobese diabetic (NOD) mouse strain, a spontaneous model for Sjögren's syndrome. Apoptosis may play a role in the initation phase and in the effector phase of autoimmune diseases. Here, we have examined the role of apoptosis in the development of sialoadenitis in the NOD mouse. Apoptotic cells and the expression of apoptosis-related molecules were studied in submandibular glands (SMG) of NOD and NOD-scid mice before and after the onset of sialoadenitis. Numbers of apoptotic cells were not increased as compared with control mice, at any age. By immunohistochemistry, we demonstrated increased expression of Fas, Fas ligand (FasL), and bcl-2 on SMG epithelial cells of NOD and NOD-scid mice, as early as 3 days of age. mRNA expression of Fas and FasL was also examined in SMG by RQ-PCR. Low-level expression of Fas and FasL mRNA was observed in all mouse strains, from 1 day of age onward. We conclude that increased protein expression of Fas and FasL on SMG epithelial cells of NOD and NOD-scid mice probably indicates a genetically programmed abnormality in these cells that may form a trigger for the development of sialoadenitis in NOD mice. Because increased numbers of apoptotic cells were not observed, a role for actual apoptosis in the initiation or effector phase of sialoadenitis in the NOD mouse is unlikely.

Animals↗

PubMed2003

Proapoptosis and antiapoptosis-related molecules during postnatal pancreas development in control and nonobese diabetic mice: relationship with innervation.

The mouse pancreas, an immature organ at birth, reaches its adult size and morphology after weaning (3 weeks of age). Around this time, apoptotic phenomena and various types of macrophages are normally present. During development, Fas-Fas ligand (FasL) interactions are known to play a role in apoptotic events involved in tissue remodeling and elimination of damaged cells, and macrophages are routinely observed near apoptotic cells. Apoptosis and Fas-FasL interactions are also thought to be involved in the pathogenesis of autoimmune diseases, particularly type 1 diabetes (T1D). Therefore, we used early postnatal mouse pancreata from three control strains (C57BL/6, DBA/2, BALB/c) and from two strains with the nonobese diabetic (NOD)-related genetic background (the spontaneous T1D NOD model and the lymphocyte-deficient NODscid strain) to study apoptotic phenomena together with the molecular and immunohistochemical expression of proapoptosis (Fas, FasL) and antiapoptosis (Bcl-2) proteins. First, although no major difference in the numbers of total pancreatic apoptotic cells was noted among strains, significantly more FasL(+) expression was detected immunohistochemically in mice with the NOD genetic background than in control pancreata from birth to 1 month of age. Second, FasL(+), Fas(+), and Bcl-2(+) structures seemed to be associated with innervation, regardless of the strain and age. Third, in control and NOD strains, nerves (identified by immunohistochemical labeling of peripherin or neurofilament 200), were often observed in periductular and peri-insular areas. Finally, some peripherin-positive nerves expressed the interferon-inducible protein-10 chemokine, and various types of macrophages were found to be in close proximity. These data highlight an overlooked, innervation-related aspect of normal mouse postnatal pancreas development with possible implications in T1D pathogenesis.

Animals↗

PubMed2003

The association between autoimmune thyroiditis, autoimmune gastritis and type 1 diabetes.

Type 1 diabetes mellitus (DM1), autoimmune thyroid disease (ATD) and autoimmune gastritis often occur together forming the so-called autoimmune polyendocrine syndrome (APS) type 3. Thyroid autoimmunity is evident in up to one third and gastric autoimmunity in up to a quarter of patients with DM1. Also relatives of DM1 patients, particularly mothers, have higher frequencies of these autoimmune conditions. Vice versa, gastric autoimmunity is present in one third of ATD patients and islet autoimmunity in one out ten. The BB-DP rat, the NOD mouse, the OS chicken and the neonatal thymectomy mouse model are animal models of APS type 3. In these models the autoimmune destruction of the various target tissues has been shown to be a multi-step process in which several genetic polymorphisms need to converge to induce both local anomalies in the target gland and anomalies in the immune system. With regard to environmental factors, excess iodine is well known to elicit/aggravate thyroid autoimmunity in these animal models. Screening DM1 patients and their relatives (particularly females) for thyroid autoimmunity is recommended. If positive, excess iodine should be avoided and thyroxin treatment considered. Whether autoimmune thyroiditis and autoimmune gastritis patients should be screened for islet Ab is not clarified.

Animals↗

PubMed2002

High rate of autoimmune thyroiditis in bipolar disorder: lack of association with lithium exposure.

BACKGROUND: We assessed the prevalence of thyroperoxidase antibodies (TPO-Abs) and thyroid failure in outpatients with bipolar disorder compared with two control groups. METHODS: The TPO-Abs of outpatients with DSM-IV bipolar disorder (n = 226), a population control group (n = 252), and psychiatric inpatients of any diagnosis (n = 3190) were measured. Thyroid failure was defined as a raised thyroid stimulating hormone level, previously diagnosed hypothyroidism, or both. Subjects were compared with attention to age, gender, and exposure to lithium. RESULTS: The TPO-Abs were more prevalent in bipolar patients (28%) than population and psychiatric controls (3-18%). The presence of TPO-Abs in bipolar patients was associated with thyroid failure, but not with age, gender, mood state, rapid cycling, or lithium exposure. Thyroid failure was present in 17% of bipolar patients and more prevalent in women. It was associated with lithium exposure, especially in the presence of TPO-Abs, but not with current rapid cycling, although an association may have been masked by thyroid hormone replacement. CONCLUSIONS: Thyroid autoimmunity was highly prevalent in this sample of outpatients with bipolar disorder and not associated with lithium treatment. These variables appear to be independent risk factors for the development of hypothyroidism, especially in women with bipolar disorder.

Adult↗

PubMed2002

Islet abnormalities in the pathogenesis of autoimmune diabetes.

Type 1 diabetes mellitus is a T-cell-mediated autoimmune disease that results in the destruction of the insulin-producing beta cells in the pancreatic islets of Langerhans. In spite of extensive genetic and immunological studies, mainly performed in the non-obese diabetic (NOD) spontaneous mouse model, the etiology of the autoimmune attack remains unknown. Several autoantigens have been identified and numerous studies have suggested a role for defective regulation of immune function. However, this account does not explain why the autoimmune process specifically affects the insulin-producing beta cells. Thus, abnormal immune regulation might explain the predisposition to autoimmunity in general, but additional factors should then determine the target of the autoimmune attack. Here, we review the evidence that abnormalities in islet cell differentiation and function exist that might trigger the immune system towards beta-cell autoimmunity in humans and NOD mice.

Animals↗

PubMed2002

Accessory cells with a veiled morphology and movement pattern generated from monocytes after avoidance of plastic adherence and of NADPH oxidase activation. A comparison with GM-CSF/IL-4-induced monocyte-derived dendritic cells.

Veiled cells (VC) present in afferent lymph transport antigen from the periphery to the draining lymph nodes. Although VC in lymph form a heterogeneous population, some of the cells clearly belong on morphological grounds to the Langerhans cell (LC)/ dendritic cell (DC) series. Here we show that culturing monocytes for 24 hrs while avoiding plastic adherence (polypropylene tubes) and avoiding the activation of NADPH oxidase (blocking agents) results in the generation of a population of veiled accessory cells. The generated VC were actively moving cells like lymph-borne VC in vivo. The monocyte (mo)-derived VC population existed of CD14(dim/-) and CD14(brighT) cells. Of these the CD14(dim/-) VC were as good in stimulating allogeneic T cell proliferation as immature DC (iDC) obtained after one week of adherent culture of monocytes in granulocyte-macrophage-colony stimulating factor (GM-CSF)/interleukin (IL)-4. This underscores the accessory cell function of the mo-derived CD14(dim/-) VC. Although the CD14(dim/-)VC had a modest expression of the DC-specific marker CD83 and were positive for S100, expression of the DC-specific markers CD1a, Langerin, DC-SIGN, and DC-LAMP were absent. This indicates that the here generated CD14(dim/-) VC can not be considered as classical LC/DC. It was also impossible to turn the CD14(dim/-) mo-derived VC population into typical DC by culture for one week in GM-CSF/IL-4 or LPS. In fact the cells died tinder such circumstances, gaining some macrophage characteristics before dying. The IL-12 production from mo-derived CD14(dim/-) VC was lower, whereas the production of IL-10 was higher as compared to iDC. Consequently the T cells that were stimulated by these mo-derived VC produced less IFN-gamma as compared with T cells stimulated by iDC. Our data indicate that it is possible to rapidly generate a population of CD14(dim/-) veiled accessory cells from monocytes. The marker pattern and cytokine production of these VC indicate that this population is not a classical DC population. The cells might earlier be related to the veiled macrophage-like cells also earlier described in afferent lymph.

Antigen-Presenting Cells↗