Molecular defects of collagen metabolism in the Ehlers-Danlos syndrome

Dermatologic Problems in the Intensive Care Unit: Part II

Skin disorders are present in many patients hospitalized in the intensive care unit. They range in severity from being the reason for admission to being a nuisance during care. These cutaneous problems have been categorized into four groups: (1) serious skin diseases that may incur life-threatening complications; (2) subtle skin problems associated with systemic disorders that may be characterized by critical events; (3) prominent cutaneous manifestations that accompany life-threatening systemic diseases; and (4) skin disorders that develop as complications during intensive care. Diseases in the first category were discussed in Part I of this article [1]. In Part II, we discuss diseases in the second category. The remaining disorders will be covered in Parts III and IV.

Carotid-Cavernous Fistula Associated with Ehlers-Danlos Syndrome Type IV

A case of traumatic, direct, carotid cavernous fistula (CCF) associated with Ehlers — Danlos syndrome (EDS) Type IV is reported along with a review of the literature. Excluding the present case, three similar cases associated with EDS-TypeIV have already been reported by Gerard M. Debrun et Al1. Despite the risks associated with endovascular manipulation, the fistula was successfully closed by intravascular embolisation but the patient expired a few days later because of underlying disease-associated vascular and visceral complications.

The ultrastructural and histophotometric study of elastic and collagen fibers in type II Ehlers-Danlos syndrome and subclinical forms

Skin disorders in type II Ehlers-Danlos Syndrome (EDS) are characterized by signs of cutaneous hyperdistensibility, skin and vascular fragility, atrophic scars, and articular hypermobility. These features may have less important clinical presentation in the intermediate forms of type II EDS. The authors studied the ultrastructural and quantitative aspects of elastic and collagen fibers in the skin of individuals with subclinical signs of type II of Ehlers-Danlos Syndrome. A group of 27 individuals (Group I) with large atrophic scars, articular hypermobility of the hands, and cutaneous and vascular fragility were compared with 10 healthy individuals. The subjects from both groups were volunteers from Hospital das Clínicas da Universidade de São Paulo. The elastic fibers did not show alterations but collagen ultrastructural abnormalities were seen in diameter and curvature, such as torsion, collagen flower-like aspect and discrete mass enlargement by histophotometry.

Pathomorphological and biochemical alterations in Ehlers-Danlos-syndrome type IV

We are reporting the morphological and biochemical data of a patient with the characteristic features of the Ehlers-Danlos-Syndrome Type IV (Sack-Barabas Type) who died acutely after an episode of recurrent ruptures of the bowel with subsequent septic peritonitis. Morphologically, the connective tissue of the vessel walls, the dermis and the connective tissue of internal organs, particularly that of liver and lung, showed a distinct hypoplasia of the collagenous scaffold. Collagen fibers were irregularly arranged which was also corroborated by ultrastructural examination of the collagen fibrils of the dermis and of intervertebral disc material. Immunohistochemically, a loss in the staining intensity for collagen III could be observed in all locations. In contrast, the localization of collagen I, IV, V and VI appeared normal, although with some reduced staining intensity which particularly held true for collagen I in the dermis and vessel wall. The biochemical content of collagen III in lung and liver tissue was significantly reduced when compared to control tissues. Accordingly, in the pool of newly synthesized collagen from skin fibroblasts, only minute amounts of collagen III could be found which was normally secreted and had a normal electrophoretic migration.

Measurement of mechanical forces generated by skin fibroblasts embedded in a three-dimensional collagen gel

Mechanical activities developed by cells play a significant role in the embryogenesis, development, and physiopathology of pluricellular organisms. A technique is described to measure in vitro the traction force developed by cells seeded into a three-dimensional polymeric collagen lattice. It is based on the use of strain gauges generating an electrical signal upon tension that is amplified and recorded. The intensity of the signal depends on the number and type of cells, cytoskeleton integrity, concentration of collagen in the lattice support, and fetal calf serum in the culture medium. Skin fibroblasts from humans and animals produce traction forces ranging from 100 to 1000 mg per million cells. In the gel under tension, the cells are in mechanical dynamic equilibrium with their support. It is suggested that the mechanical activity of fibroblasts and the control of the tension that they operate on the lattice support participate in the structural organization of the dermis and in its physiologic tension.

The Ehlers-Danlos syndrome: recognition, characterization, and importance of a milder variant of the classic form. A preliminary study

The diagnosis of Ehlers-Danlos syndrome is based on the clinical criteria of joint hypermobility, increased skin extensibility, abnormal scarring, and easy bruisibility. The literature reports this syndrome as rare, yet our experience dictated to the contrary. The present study of the prevalence of Ehlers-Danlos syndrome in a general dermatology population revealed (1) a milder variant of the classic mitis form of Ehlers-Danlos syndrome was common and present in 9% of the population studied, (2) these patients could be easily identified by the use of a defined clinical scoring system, and (3) a statistically significant association existed between clinical findings in Ehlers-Danlos syndrome and electron microscopic collagen abnormalities. The identification of this syndrome may be important prognostically in patients with diseases or conditions in which collagen plays a major role, such as joint disease (dislocations), bruising disease (pigmented purpura), and potentially scarring diseases (acne, patients undergoing cutaneous surgery).

Collagen biosynthesis and isomorphism in a case of Ehlers-Danlos syndrome type VI

Collagen metabolism was studied in fibroblasts grown from a skin biopsy specimen of a patient who presented the striking clinical features of Ehlers-Danlos syndrome and, in particular, hyperextensibility of the skin, hypermobility of the joints, and kyphoscoliosis. A reduction in lysine hydroxylation, characteristic of Ehlers-Danlos Type VI, was observed after labelling of the collagen with 14C-proline and 3H-lysine. Other modifications in the collagen metabolism of fibroblast cultures were noted, including an increase in collagen and total protein synthesis, and an increase in both the Type I and Type III collagen. The percentage of Type III collagen was, however, lower than in the control fibroblasts. The results point out the complexity of collagen disturbances in Ehlers-Danlos Type VI.

Contraction of collagen lattices by fibroblasts from patients and animals with heritable disorders of connective tissue

Fibroblasts derived from patients and animals presenting various heritable connective tissue disorders were investigated for the ability to retract a reconstituted collagen matrix. When seeded into gels, dermatosparactic calf and sheep fibroblasts did not exhibit the elongated shape of normal fibroblasts and did not contract the collagen lattice to the same extent as control fibroblasts. In contrast, several cell strains obtained from patients with Ehlers-Danlos syndrome type VII displayed contractile properties for collagen gels similar to controls. Delayed contraction was noted by two strains of fibroblasts from patients with Ehlers-Danlos syndrome type IV, whereas fibroblasts from patients with osteogenesis imperfecta, Marfan syndrome and cutis laxa had normal retraction properties.

Ehlers-Danlos syndrome type VI: collagen type specificity of defective lysyl hydroxylation in various tissues

The Ehlers-Danlos syndrome type VI is an inherited disorder of collagen metabolism characterized by a defective lysyl hydroxylase. The resulting lack of hydroxylysine has been found in several connective tissues, all of which show varying degrees of clinical symptoms. In the present study, collagen was isolated from different connective tissues and the degree of hydroxylation of lysyl residues was determined. Subsequently, collagen types I, II, III, IV, and V have been prepared from a number of tissues. Insufficient hydroxylation of lysyl residues was found in type I and type III collagen, whereas types II, IV, and V showed normal amounts of hydroxylysine. The expression of the defect, even for type I and type III collagen, varied widely from one tissue to another. A complete lack of hydroxylysine was observed in skin, while it was less pronounced in tissues such as bone, tendon, lung, or kidney. The data suggest the presence of several isoenzymes having varying affinities to the different collagen types.

Dermal changes in Ehlers-Danlos syndrome

Skin biopsies from thirteen patients suffering from Ehlers-Danlos syndrome, including 6 of the mitis type, 4 of the benign hypermobile type, one of the X-linked type, one of the ocular type and one of the periodontitis type, were studied by electron microscopy after routine preparation. Collagen fibrils showed a distorted arrangement of bent, curled or twisted fibrils and thread-like material. Similar changes may be seen in the skin of other hereditary disorders of connective tissue. However, abnormal collagen fibrils in normal skin suggests one of eight types of Ehlers-Danlos syndrome. Clinical variants cannot be differentiated on the basis of ultrastructural findings. Elastic fibres were normal without degenerative changes. Perineurium was lacking in dermal nerves of most patients. Fibroblast-like cells showed no cystic cisterna of endoplasmic reticula.

Histopathological aid at the diagnosis of the Ehlers-Danlos syndrome, gravis and mitis types

The Ehlers-Danlos syndrome is commonly divided into at least 8 types according to clinical, genetic, and biochemical aspects. We propose histological criteria that would permit a more precise diagnosis of the gravis and mitis types. In the gravis type, collagen bundles are thin and rare in the dermis and hypodermal septae; in polarized light, they are less refringent than in normal skin. This is associated with an increase in the relative proportion of elastic fibers. In the mitis type, the looseness of the collagen network is much less evident; elastic fibers are not in excess but irregular in size, shape, distribution, and orientation.