Outcomes and Radiographic Findings of Isolated Spontaneous Superior Mesenteric Artery Dissection.

OBJECTIVES: This study aimed to investigate the features, treatments, and prognosis of patients with symptomatic and asymptomatic isolated SMA dissection. METHODS: Data from 35 consecutive patients in whom isolated SMA dissection was diagnosed on computed tomography angiography (CTA) between 2004 and 2015 at two general hospitals in Japan, were collected retrospectively. Nineteen symptomatic patients were compared, and 16 asymptomatic patients with incidentally revealed SMA dissection were also compared. In addition, the vascular remodelling and outcomes during follow-up were evaluated. RESULTS: The patient characteristics in the symptomatic and incidental groups were comparable except for age; mean ages were 55.9 ± 13.9 and 65.3 ± 10.9 years, respectively. Most of the symptomatic patients were managed conservatively (including antiplatelet therapy, anticoagulants, blood pressure control, or bowel rest). In addition, one patient was initially treated by endovascular intervention because of intestinal ischaemia, and another was switched from conservative to surgical treatment. The in-hospital outcome was good with no mortality. In the incidental group, all 16 patients were observed as outpatients without additional treatment. Complete remodelling of the false lumen was observed in 31% of patients with follow-up CTA, and was associated with the presence of symptoms and the absence of false lumen with blood flow at diagnosis. Neither recurrent or new onset abdominal pain, intervention for SMA dissection, nor SMA related death was observed in either group during the follow-up period (750 ± 779 and 1200 ± 951 days). CONCLUSIONS: The characteristics of asymptomatic patients with incidentally revealed SMA dissection were comparable with those of symptomatic patients, except for age. During follow-up, factors favouring complete remodelling of false lumens were the presence of symptoms, and the absence of false lumen blood flow at diagnosis.

Knockdown of Efp by DNA-modified small interfering RNA inhibits breast cancer cell proliferation and in vivo tumor growth.

The estrogen-responsive gene Efp promotes the growth of breast cancer cells by stimulating the degradation of a negative cell-cycle regulator, 14-3-3sigma, and is hence considered a suitable molecular target for breast cancer therapy. The use of small interfering RNA (siRNA) and its derivatives to silence cancer-related genes is being investigated with the aim of identifying clinical applications for these molecules. Recently, it has been shown that DNA-modified siRNA (chimeric siRNA) has good potential in clinical applications, because it induces fewer off-target effects or immune responses in mammalian cells. In the present study, we identified the most specific and effective siRNA (siEfp-1) for silencing Efp expression in MCF-7 breast cancer cells. For this purpose, we used an algorithm that primarily eliminates off-target effects. siEfp-1 considerably suppressed the in vitro proliferation and cell-cycle progression of MCF-7 cells, as well as the in vivo growth of MCF-7 tumors, in athymic mice. DNA-modified siEfp-1 (chimeric siEfp) significantly inhibited the expression of Efp, proliferation of cultured cells and the in vivo growth of MCF-7-derived tumors in athymic mice. In addition, the silencing of Efp expression by siEfp-1 and chimeric siEfp increased the expression of the 14-3-3sigma protein. These results suggest that siEfp-1 and chimeric siEfp could be useful in breast cancer therapy. Chimeric siEfp, in particular, has a high specificity and induces few side effects and is therefore expected to be used as a novel nucleic acid-based therapeutic agent.

[Candida mediastinitis after double closure technique for repairing ventricular septal perforation].

A 69-year-old man was referred to our hospital due to acute myocardial infarction. Systolic heart murmur was first noted on the 23rd day after the onset, but no cardiac shunt flow was detected by echocardiography at that time. Six days later, cardiac function deteriorated rapidly, followed by oliguria and shock. Re-do echocardiography showed ventricular septal perforation. Emergency operation was performed, and septal perforation was seen on the anterior portion of the septum. In addition to infarct-exclusion-technique (Komeda-David method) with the equine pericardial patch, direct closure of the septal defect was performed (double closure technique). Fibrin glue was applied between the ventricular septum and the patch. After surgery, he suffered from Candida mediastinitis and received omentum plombage. Furthermore tracheotomy was performed for pneumonia. He recovered gradually, and was discharged about 3 months after surgery. Echocardiography showed no residual shunt.

[An infant case of a rupture of chordae tendineae; report of a case].

We report a case of 5-month-old boy with severe mitral regurgitation due to a rupture of chordae tendinae. Cardiac echography showed a prolapse of the anterior cusp of the mitral valve. He was progressively deteriorated despite maximal medical treatment, and a surgical intervention was performed 15 hours after the onset. The operative finding was a rupture of chordae tendinae attached to the anterior cusp of the mitral valve. The infant underwent mitral valve plasty using artificial chordae together with partial annulo-plasty. A rupture of chordae tendineae is extremely rare in infants, and its cause is yet unknown. Chordal reconstruction is feasible even at this early stage of life, although the long-term follow-up is mandatory.

[Pacemaker implanted in right inguinal region following removal of infected generator; report of a case].

We treated a 62-year-old male who had previously undergone a mitral valve plasty and aorto-coronary bypass. One year after the operation, he underwent pacemaker implantation for atrial fibrillation. Two months following implantation, the pacemaker generator was exposed due to a methicillin-resistant Staphylococcus aureus (MRSA) infection. We selected a new catheter route from the right saphenous vein, and implanted a generator under the fascia of the external oblique abdominal muscle. Thereafter, the pacemaker is functioning without trouble and there is no evidence of infection.

Pathophysiological role of endothelin in ectopic ossification of human spinal ligaments induced by mechanical stress.

Ossification of the posterior longitudinal ligament (OPLL) of the spine is characterized by progressive ectopic bone formation in the spinal ligament. To identify the genes related to ossification affected by mechanical stress during OPLL, analyses using cDNA microarray were carried out using cultured human spinal ligament cells that had been subjected to uniaxial cyclic stretching. Samples were obtained from a total of 14 patients: seven cervical or thoracic OPLL patients and seven control patients. Spinal ligament cells derived from tissues of OPLL (OPLL cells) and control (non-OPLL cells) patients were subjected to uniaxial sinusoidal cyclic stretching (0.5 Hz, 20% stretch) for various time periods (0-9 hours). cDNA microarrays revealed that ranges of distribution of both up- and downregulated genes evoked by cyclic stretching were significantly wider in OPLL cells than in non-OPLL cells. Increases in the mRNA expression of endothelin-1 (ET-1) as well as various marker genes related to ossification were also observed. mRNA expression of ET-1 and alkaline phosphatase was increased by mechanical stress in a time-dependent manner, while addition of ET-1 to static cultures of OPLL cells increased mRNA expression of alkaline phosphatase in a dose-dependent manner. During 9 hours of cyclic stretching, ET-1 release increased to about sixfold the amount observed in nonstretched cells. In non-OPLL cells, neither cyclic stretching nor ET-1 induced any increase in alkaline phosphatase expression. These results suggest that mechanical stress promotes the progression of ossification in OPLL cells through autocrine and/or paracrine mechanisms of ET-1.

PMEA coating of pump circuit and oxygenator may attenuate the early systemic inflammatory response in cardiopulmonary bypass surgery.

We investigated the effects of coating a cardiopulmonary bypass (CPB) circuit and oxygenator with poly-2-methoxy-ethyl acrylate (PMEA) on the systemic inflammatory response during and after CPB. Thirty patients undergoing elective cardiac surgery were randomized into three groups (each group n = 10): noncoated (group N), heparin coated (group H), and PMEA coated circuit and oxygenator (group X). Bradykinin (BK), complement 3 activation (C3a) and interleukin-6 (IL-6) levels were measured as early phase indicators of inflammatory response, as were maximum C reactive proteins (CRP) and white blood cell (WBC) levels. The alveolar-arterial oxygen gradient (A-a DO2) was measured as a parameter of respiratory function. IL-6 levels after CPB were significantly higher in group N than in groups H and X (p < 0.05). Serum BK and C3a levels showed similar patterns in all groups. A-a DO2 was lower at the end of and 3 hours after CPB in groups H and X than in group N (p < 0.05). Maximum CRP levels were lower in group X than in groups N (p < 0.05). This prospective study suggests that PMEA coated CPB may improve respiratory function and decrease systemic inflammatory response after cardiac surgery, possibly because this circuit is as biocompatible as heparin coated CPB circuit.

Uni-axial cyclic stretch induces Cbfa1 expression in spinal ligament cells derived from patients with ossification of the posterior longitudinal ligament.

Ossification of the posterior longitudinal ligament of the spine (OPLL) is characterized by ectopic bone formation in the spinal ligaments. Mechanical stress, which acts on the posterior ligaments, is thought to be an important factor in the progression of OPLL. To clarify this mechanism, we investigated the effects of in vitro cyclic stretch (120% peak to peak, at 0.5 Hz) on cultured spinal ligament cells derived from OPLL (OPLL cells) and non-OPLL (non-OPLL cells) patients. The mRNA expressions of Cbfa1 (an osteoblast-specific transcription factor), type I collagen, alkaline phosphatase (ALP), osteocalcin and integrin beta1 (a mechanotransducer) were increased by cyclic stretch in OPLL cells, whereas no change was observed in non-OPLL cells. The effects of cyclic stretch on the spinal ligament tissues derived from OPLL and non-OPLL patients were also analyzed by immunohistochemistry using an antibody against Cbfa1. The expression of Cbfa1 was increased by cyclic stretch at the center of the spinal ligament tissues of OPLL patients, whereas no change was observed in the tissues of non-OPLL patients. Furthermore, U0126, a specific inhibitor of MAPK kinase (MEK), suppressed the stretch-induced mRNA expressions of Cbfa1, ALP and type I collagen in OPLL cells. These results suggest that in OPLL cells, mechanical stress is converted by integrin beta1 into intracellular signaling and that Cbfa1 is activated through the MAP kinase pathway. Therefore, we propose that mechanical stress plays a key role in the progression of OPLL through an increase in Cbfa1 expression.

Uniaxial cyclic stretch induces osteogenic differentiation and synthesis of bone morphogenetic proteins of spinal ligament cells derived from patients with ossification of the posterior longitudinal ligaments.

Ossification of the posterior longitudinal ligament of the spine (OPLL) is characterized by ectopic bone formation in the spinal ligaments. Mechanical stress, which acts on the posterior ligaments, is thought to be an important factor in the progression of OPLL. To elucidate this mechanism, we investigated the effects of in vitro sinusoidal cyclic stretch (120% peak to peak, at 1 Hz) on cultured spinal ligament cells derived from OPLL and non-OPLL patients. The mRNA expressions of alkaline phosphatase (ALP), osteopontin, bone morphogenetic protein (BMP)-2, BMP-4, and BMP receptors as well as ALP activity in cell layers and production of BMPs into the conditioned medium were significantly increased by cyclic stretch in OPLL cells, whereas no change was observed in non-OPLL cells. A stretch-activated Ca(2+) channel blocker, Gd(3+), the voltage-dependent L-type Ca(2+) channel blockers diltiazem and nifedipine, and Ca(2+)-free medium suppressed stretch-induced ALP activity, which suggests a role of Ca(2+) influx in the signal transduction of mechanical stress to the osteogenic response of OPLL cells. Our study provides first evidences that mechanical stress plays a key role in the progression of OPLL through the induction of osteogenic differentiation in spinal ligament cells and the promotion of the autocrine/paracrine mechanism of BMPs in this lesion.

[The method of skeletonized right gastroepiploic artery is useful for following upper abdominal cancer operations].

We reported 5 cases of upper abdominal malignant tumors in patients with previously underwent coronary artery bypass grafting (CABG) using in situ gastroepiploic artery (GEA) graft. In our cases, we found that the GEA grafts were easily identified during abdominal operation when the GEA were collected by the skeletonize method.

[Total aortic arch replacement with a right femur neck fracture on chronic renal dialysis; report of a successful case].

Although recent operative outcome for aortic arch aneurysm has been improved by various newly-devised assistant measures, satisfactory results have not been obtained in cases with serious preoperative complications, such as chronic renal failure. We present here an operative case of a 67-year-old woman on chronic hemodialysis with a calcified aortic arch aneurysm and a right femur neck fracture. First, we performed femur head replacement under careful hemodynamic control. After her mobilization was achieved, total aortic arch replacement was performed in "arch-first technique" using deep hypothermia plus retrograde cerebral perfusion in consideration of her calcified vessels. Her postoperative course was uneventful. We believe that early mobilization was a key for her recovery, because it was useful to prevent postoperative complications such as pulmonary infection and atelectasis. Our experience suggested that meticulous management throughout the whole perioperative course is very important for total aortic arch replacement in such complicated cases.

Accelerated reendothelialization with suppressed thrombogenic property and neointimal hyperplasia of rabbit jugular vein grafts by adenovirus-mediated gene transfer of C-type natriuretic peptide.

BACKGROUND: Vein graft disease limits the late results of coronary revascularization. C-type natriuretic peptide (CNP) inhibits the growth of vascular smooth muscle cells. Given the effects of CNP on cGMP cascade, we hypothesized that transfected CNP genes modulate endothelial repair and thrombogenicity in the vein graft. METHODS AND RESULTS: Autologous rabbit jugular vein grafts were incubated ex vivo in a solution of adenovirus vectors containing CNP gene (Ad.CNP) or Escherichia coli lac Z gene (Ad.LacZ) and then interposed in the carotid artery. Reendothelialization, mural thrombi formation, and intima/media ratio were evaluated on the 14th and 28th postoperative days. More reendothelialization was seen in Ad.CNP-infected grafts than in Ad.LacZ-infected grafts both at 14 days (0.81+/-0.05 versus 0.30+/-0.14, P<0.01) and at 28 days (0.96+/-0.01 versus 0.45+/-0.08, P<0.001). The mural thrombus area was smaller in Ad.CNP-infected grafts than in Ad.LacZ-infected grafts. Neointimal thickening was significantly suppressed in the Ad.CNP group. The in vitro wound assay with human coronary artery endothelial cells revealed significant potentiation of the wound repair process by CNP and atrial natriuretic peptide administration. CONCLUSIONS: Infected Ad.CNP accelerated reendothelialization and suppressed thrombosis and neointimal hyperplasia. The method may potentially prevent vein graft disease in patients undergoing coronary artery revascularization.

Interobserver and intraobserver reliability of the japanese orthopaedic association scoring system for evaluation of cervical compression myelopathy.

STUDY DESIGN: The inter- and intraobserver reliabilities of an assessment scale for cervical compression myelopathy were examined statistically. This scoring system consists of seven categories: motor function of fingers, shoulder and elbow, and lower extremity; sensory function of upper extremity, trunk and lower extremity; and function of the bladder. It evaluates the severity of myelopathy by allocating points based on degree of dysfunction in each category. OBJECTIVES: To determine the inter- and intraobserver reliabilities of the revised scoring system (17 - 2 points) for cervical compression myelopathy proposed by the Japanese Orthopedic Association. SUMMARY OF BACKGROUND DATA: Several scales to assess clinical outcome from treatment of cervical compression myelopathy have been proposed. Most of these scales include items evaluated by observers. However, no system, including the Japanese Orthopedic Association scoring system, has yet been validated in terms of interobserver reliability. METHODS: From five different university hospitals, 10 spine surgery specialists, 10 orthopedic surgeons who had just passed the board examination of the Japanese Orthopedic Association, and 13 residents in the first or second year of orthopedic residency programs were chosen. The participants in this study were 29 patients with myelopathy secondary to ossification of the posterior longitudinal ligament selected from five participating university hospitals. Several surgeons interviewed each patient twice at intervals of 1 to 6 weeks. Inter- and intraobserver reliabilities of the total score for all categories were evaluated by the intraclass correlation coefficient. The extension of the kappa coefficient of Kraemer also was calculated for each category to assess reliability of multivariate categorical data. RESULTS: The interobserver reliability of the total score for the first interview (intraclass correlation coefficient = 0.813) and the intra- and interobserver reliabilities of the total score (intraclass correlation coefficient = 0.826) were high. The level of experience and the hospital slightly affected the reliability of the Japanese Orthopedic Association scoring system. The kappa values for intraobserver data generally were high in each category, whereas the kappa values for interobserver data were relatively low for the categories of shoulder-elbow motor function and lower extremity sensory function. CONCLUSIONS: The inter- and intraobserver reliabilities of the Japanese Orthopedic Association scoring system for cervical myelopathy were high, suggesting that this system is useful for assessment of cervical myelopathy in comparative studies of treatment.

Effect of tranexamic acid on blood loss reduction after cardiopulmonary bypass.

OBJECTIVE: We evaluated the effect of tranexamic acid on blood loss in patients undergoing elective cardiopulmonary bypass for coronary artery bypass surgery. METHODS: We randomly assigned 7 of 14 patients to a group receiving 50 mg/kg tranexamic acid before skin incision and after the start of cardiopulmonary bypass and the other 7 as controls. RESULTS: Intraoperative and postoperative blood loss was significantly (p = 0.025) reduced in the tranexamic acid group. A similar decrease in platelet count was observed during cardiopulmonary bypass in both groups. Antithrombin III was significantly (p = 0.013) decreased in both groups during cardiopulmonary bypass. Antithrombin III and thrombin-antithrombin III complexes were significantly (p = 0.001) increased after protamine administration. A significant (p = 0.010) decrease in alpha 2-plasmin inhibitor was noted at 5 and 60 minutes after the start of cardiopulmonary bypass in the tranexamic acid group. alpha 2-plasmin inhibitor-plasmin complexes were significantly (p = 0.001) increased after the start of cardiopulmonary bypass in both groups and were significantly (p = 0.012) decreased after protamine administration. alpha 2-plasmin inhibitor-plasmin complexes in the tranexamic acid group were significantly (p = 0.030) lower than in controls 60 minutes after the start of cardiopulmonary bypass, just prior to the end of cardiopulmonary bypass, and after protamine administration. CONCLUSIONS: These findings showed that tranexamic acid administration effectively prevented perioperative blood loss without thromboembolic complications and that tranexamic acid during cardiopulmonary bypass coordinates the anticoagulative effect of heparin and the antifibrinolytic effect of tranexamic acid.

C-type natriuretic peptide induces redifferentiation of vascular smooth muscle cells with accelerated reendothelialization.

We recently reported that C-type natriuretic peptide (CNP) occurs in vascular endothelial cells and acts as a vascular-type natriuretic peptide. In the present study, we stimulated the cGMP cascade in proliferating smooth muscle cells (SMCs), in which particulate guanylate cyclase-B, the specific receptor for CNP, is predominantly expressed, by use of an adenovirus encoding rat CNP cDNA (Ad.CNP). In the Ad.CNP-treated cultured SMCs, CNP caused the growth inhibition of SMCs at G(1) phase with an early increase of p21(CIP1/WAF1) expression and subsequent upregulation of p16(INK4a). The expression of smooth muscle myosin heavy chain-2, which is the molecular marker of highly differentiated SMCs, was reinduced in the Ad.CNP-treated SMCs. The Ad.CNP-treated SMCs also reexpressed particulate guanylate cyclase-A, which shows high affinity to atrial and brain natriuretic peptide and is exclusively expressed in well-differentiated SMCs. CNP, which was overexpressed in rabbit femoral arteries in vivo at the time of balloon injury, significantly suppressed neointimal formation. Furthermore, an enhancement of the expression of smooth muscle myosin heavy chain-2 occurred in the residual neointima. In addition, early regeneration of endothelial cells was observed in the Ad.CNP-infected group. Thus, stimulation of cGMP cascade in proliferating dedifferentiated SMCs can induce growth inhibition and redifferentiation of SMCs with accelerated reendothelialization.

Ultrasound vasography evaluation of radial arterial grafts used for coronary arterial bypass surgery.

OBJECTIVES: For coronary bypass surgery, radial arteries are often used as bypass grafts. Some of these arteries however, have arteriosclerotic lesions. We attempted to evaluate the relationship between arteriosclerosis and vasodilation. METHODS: Prior to bypass surgery, 20 patients underwent ultrasound vasography to determine the condition of their radial and brachial arteries. Flow-mediated dilation, which is the same as endothelium-dependent vasodilation, was measured in the brachial artery of the nondominant arm by reactive hyperemia after 5-minute forearm ischemia. Vasodilation after application of a sublingual glyceryl trinitrate spray was also measured. RESULTS: During surgery, 4 of 20 radial arteries demonstrated calcification, and 3 of the 4 could be used by removing the calcified part. However, the other artery, which had extensive calcification that could not be detected by ultrasound vasography, was discarded. The amount of vasodilation seen after the administration of sublingual glyceryl trinitrate had no correlation with calcified grafts. Calcified radial arteries demonstrated significantly poor brachial artery vasodilation by an endothelial-dependent vasodilation test. CONCLUSIONS: Calcification in radial arteries can thus only be evaluated by flow-mediated dilation.

[A case of surgical treatment for cardiac tamponade caused by a ruptured coronary aneurysm accompanied by a coronary artery-pulmonary artery fistula].

A 67-year-old woman experienced a sudden severe pain in the area of her left shoulder and back. Three days later the pain recurred, after which she fell into shock and was taken to another hospital by ambulance. A plain chest CT scan showed a cardiac tamponade, while an enhanced chest CT scan demonstrated a coronary aneurysm in the left anterior descending branch draining to the pulmonary artery. Coronary arteriography revealed a saccular type aneurysm, 5 cm in diameter, with a coronary artery-pulmonary artery fistula. After pericardiocentesis, she recovered from her state of shock. The patient was then transferred to our hospital, where she underwent emergency surgery. Under a cardiopulmonary bypass, the stem of the aneurysm and the fistula were ligated and resected. She recovered smoothly and was discharged on the 24th postoperative day.

Compact, reliable ventricular assist device as a bridge to recovery or for semipermanent use.

OBJECTIVES: The magnetically suspended centrifugal pump has gained attention as an implantable ventricular assist device for long-term use. We report recovery-oriented pump operation and results of a chronic animal experiment. METHODS: In an acute experiment in 8 sheep having microspheres injected to induce heart failure, left ventricular assist was implemented by 2 inflow cannulas, 1 each in the left atrium and left ventricle. The pressure-volume loop of the left ventricle and myocardial oxygen consumption were measured varying the assist rate. The chronic animal experiment used 10 sheep whose native heart was kept intact. Continuous hemodynamic monitoring and periodic blood sampling were conducted. RESULTS: In the acute study, myocardial oxygen consumption decreased proportionally with increasing assist rate in left atrial drainage, but was significantly less at a 100% assist rate in left ventricular drainage. External work in left ventricular drainage did not decrease until a 75% assist rate, suggesting that the left ventricle shape and size were maintained despite decreased myocardial oxygen consumption. In the chronic experiment, the pumping duration was 14 to 248 days. No thrombi or emboli in the pump or any major organ were found in sacrificed sheep after living more than 100 days. Hepatic and renal function were within an almost normal range throughout the experiment. CONCLUSION: Left ventricular blood drainage effectively reduced oxygen consumption, maintaining the shape of the left ventricle. The magnetically suspended centrifugal pump is suitable for recovery of a failing heart or semipermanent use.

[Two successful cases of coronary artery bypass grafting followed by transluminal carotid angioplasty with stenting].

In coronary artery bypass grafting (CABG), carotid artery disease is an important factor that affects the incidence of perioperative stroke. The incidence of stroke following cardiac surgery is about 5 times higher in patients with carotid lesions than in patients without them. However, therapeutic strategies for those cases have not established in recent years. We report 2 successful cases of CABG following transluminal carotid angioplasty with stenting (TCAS) for concomitant coronary and carotid artery disease. The first case was a 71-year-old male who had left main trunk (LMT) and three-vessel coronary artery disease (CAD) and a 90% stenosis of the right internal carotid artery (ICA). One month after TCAS, triple CABG with cardiopulmonary bypass (CPB) was performed. The second case was a 75-year-old male who had LMT and single vessel CAD and a 99.9% stenosis of the lt. ICA. Considering his poor general conditions, combined strategy of off-pump CABG and PTCA was performed following TCAS. During and after cardiac surgery, they had no cerebral complications. Postoperative myocardial scintigraphy showed improved imaging in both cases. Preoperative TCAS is a safe and minimally invasive procedure for the patients with carotid artery stenosis who need CABG.

Structural varieties of small proteoglycans in human spinal ligament.

Three types of small proteoglycan were purified from human spinal ligaments by ultracentrifugation, ion-exchange chromatography, gel-chromatography, and hydrophobic chromatography. Two of them were identified as decorin and biglycan, and the other was thought to be a decorin-subtype. Molecular sizes of decorin and decorin-subtype were both 85 kDa, and that of biglycan was 200 kDa. N-Terminal amino acid sequence of decorin-subtype corresponded with that of decorin, although it was different from decorin in terms of composition of amino acids and glycosaminoglycan chains, and reactivity with anti-human decorin antibody. The ratios of chondroitin sulfate to dermatan sulfate contained in the three proteoglycans were different, and the location of that in glycosaminoglycan chains was also thought to be different. It was demonstrated that three types of proteoglycan which are structurally different are present in extracellular matrix.