Molecular abnormalities of collagen: a review

Facial nerve regeneration with bioabsorbable collagen conduits filled with collagen filaments: An experimental study

Introduction

A bioabsorbable collagen conduit (Renerve™) filled with collagen filaments is currently approved as an artificial nerve conduit in Japan and is mainly used for connecting and repairing peripheral nerves after traumatic nerve injury. However, there are few reports on its applications for reconstructing and repairing the facial nerve. The present study evaluated the efficacy of the conduit on promoting nerve regeneration in a murine model with a nerve defect at the buccal branch of the facial nerve.

Methods

Under inhalational anesthesia and microscopic guidance, the buccal branch of the left facial nerve in an 8-week-old Lewis rat was exposed, and a 7 mm gap was created in the nerve. The gap was then connected with either the nerve conduits (NC group) or an autologous nerve graft (the autograft group). At 13 weeks after the procedure, we compared the histological and physiological regenerations in the both groups.

Results

We found compound muscle action potential amplitude is significantly larger in the autograft group (2.8 ± 1.4 mV) than in NC group (1.3 ± 0.5 mV) (p < 0.05). The number of myelinated fibers of the autograft group was higher (3634 ± 1645) than that of NC group (1112 ± 490) (p < 0.01). The fiber diameter of the autograft group (4.8 ± 1.9 μm) was larger than that of NC group (3.8 ± 1.4 μm) (p < 0.05). The myelin thickness of the autograft group was thicker than that of NC group (0.6 ± 0.3 μm vs. 0.4 ± 0.1 μm) (p < 0.05). G-ratio of the autograft group (0.74 ± 0.19) was lower than that of NC group (0.79 ± 0.10) (p < 0.05).

Conclusion

This study demonstrated the efficacy of collagen nerve conduit for facial nerve reconstruction following nerve injury. However, the effectiveness of the conduit on the promotion of nerve regeneration was inferior to that of the autograft.

Demystifying the nature of hard tissues in odontogenic tumors using Modified Gallego's stain: A preliminary study

Introduction

Histological stains are dyes that bind to a variety of tissues. Modified Gallego's (MG) stain is a modification of Lille's stain that can be used as a differential stain for identification of hard tissues in oral pathological lesions.

Objectives

The objective of this study was to identify the presence of hard tissues such as enamel, dentin and cementum in normal extracted teeth and odontogenic tumors using MG stain and to compare the efficacy of MG stain with hematoxylin and eosin (H&E) stain.

Methods

A total of fifty samples, twenty decalcified sections of teeth and thirty cases of odontogenic tumors, were included in the present study. Two sections were cut from the above cases and stained with H&E stain and MG stain, respectively, and assessed for the nature of hard tissue.

Results

In H&E staining, enamel, dentine, cementum and bone stained pink. Whereas, in MG stain, enamel stained pink, dentin and bone stained green, while cementum stained red. The shade of color differs with the degree of mineralization of the hard tissues in MG stain.

Conclusion

MG stain can be used as a differential stain for different hard-tissue structures when compared to routine H and E staining.

Fulminant myocardial bleeding: another clinical course of vascular Ehlers-Danlos Syndrome

Vascular Ehlers-Danlos Syndrome (vEDS) is a dominantly inherited connective tissue disorder characterised by colon rupture and arterial aneurysm, dissection and rupture. A patient was diagnosed with vEDS after a spontaneous colon rupture when he was brought to our institute because of sudden chest pain. An ECG revealed wide regional ST elevation, which was initially suggestive of acute myocarditis. On the second day, haemodynamics suddenly deteriorated because of a rapid accumulation of bloody pericardial effusion, and the patient died. Autopsy revealed an excessive spontaneous myocardial haemorrhage owing to fragility, which suggested an underlying disease—vEDS.

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.

Functional recovery after peripheral nerve injury and implantation of a collagen guide

Although surgery techniques improved over the years, the clinical results of peripheral nerve repair remain unsatisfactory. In the present study, we compare the results of a collagen nerve guide conduit to the standard clinical procedure of nerve autografting to promote repair of transected peripheral nerves. We assessed behavioral and functional sensori-motor recovery in a rat model of peroneal nerve transection. A 1cm segment of the peroneal nerve innervating the Tibialis anterior muscle was removed and immediately replaced by a new biodegradable nerve guide fabricated from highly purified type I+III collagens derived from porcine skin. Four groups of animals were included: control animals (C, n=12), transected animals grafted with either an autologous nerve graft (Gold Standard; GS, n=12) or a collagen tube filled with an acellular skeletal muscle matrix (Tube-Muscle; TM, n=12) or an empty collagen tube (Collagen-Tube; CT, n=12). We observed that 1) the locomotor recovery pattern, analyzed with kinetic parameters and peroneal functional index, was superior in the GS and CT groups; 2) a muscle contraction was obtained in all groups after stimulation of the proximal nerve but the mechanical muscle properties (twitch and tetanus threshold) parameters indicated a fast to slow fiber transition in all operated groups; 3) the muscular atrophy was greater in animals from TM group; 4) the metabosensitive afferent responses to electrically induced fatigue and to two chemical agents (KCl and lactic acid) was altered in GS, CT and TM groups; 5) the empty collagen tube supported motor axonal regeneration. Altogether, these data indicate that motor axonal regeneration and locomotor recovery can be obtained with the insertion of the collagen tube RevolNerv. Future studies may include engineered conduits that mimic as closely as possible the internal organization of uninjured nerve.

Ehlers-Danlos syndrome type IV: unusual congenital anomalies in a mother and son with a COL3A1 mutation and a normal collagen III protein profile

A mother and son with Ehlers-Danlos syndrome (EDS) type IV and unusual congenital anomalies are described. The congenital anomalies include, in the mother, amniotic band-like constrictions on one hand, a unilateral clubfoot, and macrocephaly owing to normal-pressure hydrocephaly and, in the son, an esophageal atresia and hydrocephaly. Protein analysis of collagen III in cultured fibroblasts of the mother showed no abnormalities. However, DNA analysis of the COL3A1 gene revealed a pathogenic mutation (388G-->T) in both the mother and the son. The possible relationship between the observed congenital anomalies and EDS IV are discussed. We stress that DNA analysis of COL3A1 should be performed in all patients when there is a strong suspicion of EDS IV, despite negative findings in a collagen protein analysis.

Ehlers-Danlos syndrome type IV with a unique point mutation in COL3A1 and familial phenotype of myocardial infarction without organic coronary stenosis

We report on a 43-year-old male patient with Ehlers-Danlos syndrome (EDS) type IV with acute myocardial infarction (MI) without organic coronary stenosis. The disease was complicated with pneumothorax, subcutaneous and mediastinal emphysema, and splenic artery rupture. Three of the patient's family members suffered sudden cardiac death or MI. A diagnosis of EDS type IV was confirmed by decreased production of type III collagen by 86%. Mutation analysis revealed a point mutation in the COL3A1 gene that substituted glycine for aspartate at amino acid position 877. This mutation had not been reported as pathogenic for EDS type IV. These findings suggest close linkage between the mutation and the phenotype with familial MI.

Pathophysiology of delayed healing

Delayed union represents an ongoing failure of initial fracture management. It still occurs partly because the precise reason why a patient's fracture does not heal frequently is unknown. This article aims to outline the limited material available on the pathophysiology of delayed healing. The systemic status of the patient, local limb status before injury, the nature of the traumatic injury, local host response to the injury, potential negative impact of orthopaedic fracture care, and pharmacologic variables are considered.

The mechanical properties of elastic arteries in Ehlers-Danlos syndrome

OBJECTIVE

To study whether measurements of wall mechanics can be used as an indicator of disturbed vessel wall integrity and predictor of vessel fragility in Ehlers-Danlos Syndrome (EDS).

METHODS

The wall mechanics of the abdominal aorta (AO) and common carotid artery (CCA) were estimated from the indices Ep (pressure strain elastic modulus) and stiffness (beta) in twelve individuals with EDS of different subtypes and compared with the results of a healthy reference population. Ep and beta were calculated from diameter and pulsatile diameter change determined non-invasively with the aid of an ultrasonic echo-tracking system and blood pressure obtained by the auscultatory method.

RESULTS

Compared with normal individuals and their confidence intervals, subjects with EDS had unaltered diameter, Ep and beta in the AO, as well as in the CCA. Analysis of covariance (ANCOVA) also showed unaltered results. AO: diameter (males p = 0.66, females p = 0.27), Ep (males p = 0.81, females p = 0.27) and beta (males p = 0.95, females p = 0.12). CCA: diameter (males p = 0.36, females p = 0.46), Ep (males p = 0.93, females p = 0.48) and beta (males p = 0.86, females p = 0.47).

CONCLUSIONS

This investigation could not demonstrate any alteration in wall mechanics as a sign of disturbed vessel wall integrity of elastic arteries in EDS. This might indicate that the structural defect in the arterial wall collagen, and thus the tendency to vessel fragility, cannot be revealed under normal physiological pressure conditions.

Balloon occlusion of a spontaneous carotid-cavernous fistula in Ehlers-Danlos syndrome type IV

A case of spontaneous carotid-cavernous fistula associated with Ehlers-Danlos syndrome Type IV was treated successfully by transarterial balloon embolization. To minimize the stress to the arterial wall, we detached three silastic balloons with low-attachment force in the cavernous sinus with the aid of a proximal balloon to control the high flow of the fistula. To achieve complete obliteration, we had to inflate the third balloon to dimensions that occluded the cavernous portion of the internal carotid artery. Patients with Ehlers-Danlos syndrome Type IV carry a high risk when undergoing any diagnostic or therapeutic endovascular procedure due to the fragility of their blood vessels. Recognition of this entity is important and special attention should be paid to its pathophysiology for a successful treatment.

Electron microscopic observations and electrophoresis of the glycosaminoglycans in the epiphyseal cartilage of the congenital osteochondrodysplasia rat (ocd/ocd)

The osteochondrodysplasia rat, inherited by a single autosomal recessive lethal gene ocd, shows a typical dwarfing syndrome with systemic subcutaneous edema. The skeletal system is most severely affected. The affected newborn also demonstrates abnormal kidney position and respiratory system anomalies and central nervous malfunction. Previous light microscopic observations show that the chondrocytes are expanded and destroyed, and the amounts of extracellular matrix (ECM) and glycosaminoglycans (GAGs) are decreased. The present studies describe ultrastructural appearances, and measurement and electrophoretic analysis of the major components of the cartilaginous GAGs. Decrease in amounts of ECM and swollen chondrocytes with the expanded organelles were reconfirmed in the ocd/ocd by electron microscopic observation. The large expanded vesicles contained unevenly distributed granular materials and large ruthenium red (RR) granules. The RR granules in the ECM were small and most parts of the collagen fibers did not associate with the granule in the ocd/ocd, while the RR granules attached to all the collagen fibers in the phenotypically normal (+/?). There were large collagen bundles in the region where the chondrocytes were committed to self-destruction. The biochemical analysis of the cartilage showed that noncollagenous proteins were increased and the GAGs were decreased in amount in the ocd/ocd, although the hydroxyproline content was comparable to that of the +/?. The hyaluronic acid was close to the limit of detection by electrophoresis of the cartilaginous GAGs in the ocd/ocd. These results suggest that the ocd gene affects GAG metabolism. The decrease in amounts of GAGs, especially hyaluronic acid, may be responsible for the anomalies of the cartilage in the ocd/ocd.

Cerebrovascular disease in Ehlers-Danlos syndrome type IV

We describe two patients with cerebrovascular complications of Ehlers-Danlos syndrome type IV. A 16-year-old girl with spontaneous internal carotid artery dissection and a 46-year-old woman with aneurysmal subarachnoid hemorrhage and multiple aortic dissections were both deficient in collagen type III, analyzed in cultured skin fibroblasts. To our knowledge, spontaneous carotid artery dissection associated with collagen type III deficiency has not been reported previously. Early clinical recognition of this syndrome is of great importance in view of the hazards of angiography and surgery. Collagen type III deficiency plays a role in the pathogenesis of intracranial saccular aneurysms and may also be involved in the pathogenesis of carotid cavernous fistulas and dissections of the cervical arteries.

Obstetrical problems in patients with Ehlers-Danlos syndrome type IV; a case report

The Ehlers-Danlos syndrome type IV is a heritable connective-tissue disorder characterized by thin translucent skin, pronounced bruising and scarring, and extreme tissue fragility. Obstetrical complications include premature rupture of membranes, rupture of blood vessels and gravid uterus, tearing of perineum, vagina, urethra and bladder, requesting specific prophylactic and therapeutic measurements. Hereditary transmission is usually autosomal dominant with variable expression. Histological examination of skin biopsy and biochemical analysis of collagen proteins from skin fibroblast cultures confirm the clinical diagnosis. DNA studies offer the possibility of prenatal diagnosis in suitable families. The consecutive severe obstetrical complications of a woman with Ehlers-Danlos syndrome type IV are reported here. The patient died at age 33 years from renal artery rupture.

Dysmorphic syndromes with demonstrable biochemical abnormalities

Many inborn errors of metabolism are associated with dysmorphic manifestations. In this review, we have attempted to correlate the dysmorphic features with the underlying metabolic defect or its consequences. Most of the defects which we have discussed affect the synthesis or degradation of macromolecules (for example, collagen, elastin, bone mineral, proteoglycans, glycoproteins, and triglycerides). Such defects may affect either a single enzyme or multiple enzymes in specific organelles, such as lysosomes or peroxisomes, or they may affect hormonal control of synthesis and degradation. Examples are also included of defects affecting the catabolism of simple molecules when accumulating metabolites have a secondary effect on macromolecules, as in homocystinuria. In a number of instances, however, the correlation between the biochemical abnormality and the dysmorphic features are not understood. Ultimately, all dysmorphic syndromes will be attributable to a biochemical defect or its effects. The aim of this overview is to provide an insight into the relationship between the two at the present time.

The effects of mechanical stability on the macromolecules of the connective tissue matrices produced during fracture healing. I. The collagens

The distribution of types I, II, III, V and IX collagens in healing fractures of the rabbit tibia has been demonstrated by immunofluorescent techniques. It has also been shown that the mechanical stability of the healing fracture affects both the distribution and types of the collagens present. The initial fibrous matrix contains types III and V collagens; type I collagen was only located in this matrix if unfixed tissue was used. In mechanically stable fractures, cancellous bone forms over the entire periosteal surface by 5-7 days; type I collagen is laid down within the previous fibrous matrix. The trabeculae are heterogeneous in their collagen content. The cavities contain a matrix of types III and V collagens. Small nodules of cartilage may be present between 7 and 14 days; these contain types II and IX collagens. In mechanically unstable fractures, cancellous bone is initially formed away from the fracture gap. The fibrous tissue over the gap is replaced by cartilage; types II and IX collagens are laid down on the pre-existing fibrous matrix. The cartilage is replaced by endochondral ossification. At the ossification front, type I collagen is found around the chondrocyte lacunae of the spicules of cartilage. The new trabeculae contain a core of cartilage which is surrounded by a bone matrix of types I and V collagens. The fracture gaps are invaded by fibrous tissue, which contain types III and V collagens. this is later replaced by cancellous bone.

Human type III collagen gene expression is coordinately modulated with the type I collagen genes during fibroblast growth

Type III collagen is one of the major interstitial collagens and, as such, plays an important role in modulating the structure and function of most tissues. To compare the expression of the type III collagen gene to that of the type I collagen alpha 1(I) and alpha 2(I) genes, cDNAs encoding the 3' one-third of the human alpha 1(III) collagen mRNA were obtained by screening a human fetal lung fibroblast cDNA library with a cloned segment of the chicken alpha 1(III) gene. Northern blot analysis of human fetal lung fibroblast RNA demonstrated two alpha 1(III)-specific mRNAs of sizes 6.6 and 5.8 kilobases, sizes clearly different from those of the type I collagen mRNAs. Analyses of populations of dividing and nondividing human lung fibroblasts revealed that, on a per cell basis, the nondividing population contained twice as much alpha 1(III) mRNA than did the dividing population. The same was true for the type I collagen alpha 1(I) and alpha 2(I) mRNA transcripts. Similar results were obtained when alpha 1(III), alpha 1(I), and alpha 2(I) mRNA transcripts were quantified by using dot blot evaluation of total RNA, Northern analysis of total RNA, and dot blot evaluation of cytoplasmic RNA. Thus, despite the fact that the alpha 1(III) collagen gene is located on a chromosome different from the alpha 1(I) and alpha 2(I) genes, the expression of these three collagen chains appears to be coordinately controlled during periods of rapid and slow fibroblast growth.

Usefulness of a registry of congenital malformations for genetic counseling and prenatal diagnosis

During three years, 39,924 infants born consecutively in the area covered by our registry of congenital malformations were surveyed; 775 had major congenital malformations. Recurrence risks for the major malformation was estimated and classified as high (greater than 10%, 5.3% of the cases), low (1 to 10%, 85.3% of the cases) or occasional (less than 1%, 9.4% of the malformed). Feasibility of prenatal diagnosis was considered. On the basis of the recurrence risk of 1% or higher and the feasibility of prenatal diagnosis, such a procedure should be considered in future pregnancies in 64.1% of the mothers. Genetic counseling has to be given to couples at risk of having a malformed child. For this purpose, as is shown in our study, the best way is the possibility of using a registry of congenital malformations.

Amniotic bands in connective tissue disorders

Amniotic bands are described in two children with Ehlers-Danlos syndrome type IV and in one with severe osteogenesis imperfecta. Since the basic defect in both of these disorders rests in collagen, which constitutes the main component of the load bearing amnion, it is proposed that these cases provide further insight into the pathogenesis of amniotic bands.

Mitral valve prolapse, aortic compliance, and skin collagen in joint hypermobility syndrome

Mitral valve prolapse was sought clinically and with phonocardiography and M mode and sector echocardiography in 15 women aged 22-57 years with joint hypermobility syndrome. The type III:III + I collagen ratio was measured in skin biopsy specimens and was found to be raised in seven of 10 patients sampled. Thirteen patients had increased aortic wall compliance measured by the continuous wave Doppler ultrasound technique. Ten (67%) patients had mitral valve prolapse shown by auscultatory signs or echocardiography or both--a prevalence at least three times greater than that in the general adult population. It is concluded that if the abnormality of collagen biosynthesis found in skin biopsy samples in these patients is also present in their mitral valve tissue this may predispose them to prolapse of the valve.

Fatal splenic rupture in Ehlers-Danlos syndrome

A fatal case of Ehlers-Danlos syndrome (Type IV) is described. Autopsy revealed splenic rupture that had resulted from spontaneous haemorrhage into the splenic parenchyma. This is a previously unrecorded complication of Ehlers-Danlos syndrome and should be considered in the differential diagnosis of chest and abdominal pain in patients with this condition.