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Biomedical subjects

G Millonig

Publications and source records attributed to G Millonig.

13 recordsLinked to original sources

Direct interaction of the extracellular matrix protein DANCE with apolipoprotein(a) mediated by the kringle IV-type 2 domain.

Lipoprotein(a) [Lp(a)] consists of LDL and apolipoprotein(a), and has been shown to be a major, independent, risk factor for arteriosclerosis and thrombosis in humans. To further elucidate the (patho)physiological function(s) of Lp(a)/apo(a), we searched for new protein ligands, using the yeast two-hybrid system and employing the highly repetitive kringle IV type 2 (KIV-2) sequence from apo(a) as bait. The extracellular matrix protein DANCE [developmental arteries and neural crest epidermal growth factor (EGF)-like] recently implicated in atherogenesis was identified as an interactor. A direct physical interaction between DANCE and apo(a) was confirmed by co-purification of both recombinant proteins derived from culture supernatants of transiently transfected COS-1 cells. Furthermore, binding of human plasma-derived Lp(a) to recombinant DANCE was also observed. Finally, when monoclonal anti-apo(a) and polyclonal anti-DANCE antibodies were applied to tissue slices of atherosclerotic carotid artery, the two proteins were found to be co-localized in endothelial and smooth muscle cells, suggesting that they occur together in the arterial wall. However, as yet, the in vivo relevance and the possible functional role of this newly identified DANCE:Lp(a)/apo(a) interaction remains speculative.

Animals↗

Atherosclerosis as an autoimmune disease: an update.

Immunoinflammatory processes are discussed increasingly as possible pathogenic factors for the development of atherosclerosis. Here, we summarize the data on which we have built our immunological hypothesis of atherogenesis. This concept is based on the observation that almost all humans have cellular and humoral immune reactions against microbial heat-shock protein 60 (HSP60). Because a high degree of antigenic homology exists between microbial (bacterial and parasitic) and human HSP60, the 'cost' of immunity to microbes might be the danger of cross-reactivity with human HSP60 expressed by the endothelial cells of stressed arteries. Genuine autoimmunity against altered autologous HSP60 might trigger this process also.

Amino Acid Sequence↗

The vascular-associated lymphoid tissue: a new site of local immunity.

Recent data suggest that atherosclerosis might be a systemic (auto)immune reaction against heat shock protein 60, first occurring at notorious local predilection sites, i.e. the intima at arterial branching points. The local infiltration of mononuclear cells, mainly macrophage-derived foam cells, T cells and smooth-muscle cells in atheromatous plaques, have long been described. During the past few years, research has been concentrated on the early stages in the development of atherosclerosis, and on healthy arteries from young individuals unaffected by arterial disease. In this review, we summarize data characterizing pre-existing mononuclear cell infiltrations in healthy arteries from children and teenagers. These arterial accumulations at regions known to be predilection sites for the later development of atherosclerosis consist mostly of activated T cells, macrophages and dendritic cells, with only a few mast cells and virtually no B or natural killer cells. In analogy to the mucosa-associated lymphoid tissue, we termed these accumulations 'vascular-associated lymphoid tissue', and assumed a similar function as a local immunosurveillance system, monitoring the bloodstream for potentially harmful endogenous or exogenous antigens. In addition to the remarkable accumulation of mononuclear cells, the vascular-associated lymphoid tissue regions are characterized by a typical distribution of extracellular matrix proteins: collagen type I, collagen type III, fibronectin and tenascin are expressed preferentially in the vascular-associated lymphoid tissue region, whereas collagen type IV, collagen type V, collagen type VI and laminin show a homogenous distribution throughout all regions of the intima. Vascular adhesion molecules type 1, intercellular adhesion molecules type 1 and P-selectin are already present on the healthy endothelial cells of young children. Interactions between adhesion molecules, extracellular matrix components and cellular elements of the vascular-associated lymphoid tissue may provide the basis for the cellular accumulations in the vascular-associated lymphoid tissue regions and the possible development of atherosclerotic lesions later in life.

Animals↗

Network of vascular-associated dendritic cells in intima of healthy young individuals.

In earlier studies, our group has established a new "immunological" hypothesis for atherogenesis supported by experimental and clinical studies showing that inflammatory immunological reactions against heat shock protein 60 initiate the development of atherosclerosis. In the present study, we describe the discovery of a so-far-unknown network of dendritic cells in the innermost layer of arteries, the intima, but not veins of healthy humans and rabbits. The number of these dendritic cells is comparable to that of Langerhans cells in the skin, and dendritic cells show a similar phenotype (CD1a(+) S-100(+) lag(+) CD31(-) CD83(-) CD86(-) and no staining for von Willebrand factor or smooth muscle cell myosin). These vascular-associated dendritic cells accumulate most densely in those arterial regions that are subjected to major hemodynamic stress by turbulent flow conditions and are known to be predisposed for the later development of atherosclerosis. These results open new perspectives for the activation of the immune system within the arterial wall.

Adolescent↗

Ultrastructural study of gonads in the complete and incomplete feminization syndrome.

The gonads of two individuals with complete and one with incomplete testicular feminization were examined by light and electron microscopy. In the seminiferous tubules of the complete forms, clear, intermediate, and dark-type Sertoli cells could be distinguished. These are immature elements which had assumed, under the influence of hormones, different morphology. Leydig cells were also immature, at varying stages of differentiation. In the complete form Sertoli and Leydig cells had an almost normal fine structure; the lamina basalis of the tubules, however, was considerably thickened.

Adolescent↗