Subcellular localization of the low density lipoprotein receptor-related protein (alpha 2-macroglobulin receptor) in human brain

The subcellular localization of the alpha 2-macroglobulin receptor, also known as the low density lipoprotein receptor-related protein (LRP), was studied in postmortem human brain tissue by light and electron microscopic immunocytochemistry. A specific monoclonal antibody (A2MR2) against the extracellular alpha-chain of the molecule was utilized. Light microscopically, LRP was detected strongly in neurons, weakly in some glial cells and discontinuously along capillary membranes. At the electron microscopic level, positive reaction products were found to be associated with plasma membranes, ribosomes, lysosomes and lipofuscin granules of neurons, glial cells and pericytes. The results suggest that LRP may have a function, particularly in neurons, of receptor-mediated endocytosis with subsequent lysosomal uptake and degradation of ligands such as alpha 2-macroglobulin proteinase complexes and apolipoprotein E.

Untreated Graves' disease patients without clinical ophthalmopathy demonstrate a high frequency of extraocular muscle (EOM) enlargement by magnetic resonance

12 of 17, a significant frequency (71%), of untreated Graves' disease patients with no clinical ophthalmopathy showed extraocular muscle (EOM) enlargement by Magnetic Resonance Imaging (MRI). Enlargement was bilateral in 41% and unilateral in 29% in these patients. Apparent enlargements of EOM were also detected, by MRI, in all of 11 Graves' disease patients with clinical ophthalmopathy, bilateral in 73% and unilateral in 27% of patients in this group. Both group showed the inferior rectus muscle as the most frequently involved (56% and 77% respectively). In 16 patients without autoimmune thyroid disorders or ophthalmopathy who served as normal controls, only 2 of these patients (12%) demonstrated mild EOM enlargement. The severity and patterns of EOM enlargement revealed no correlation with abnormalities in serum thyroid function tests or serum thyroidal autoantibodies. In conclusion, a high frequency of Graves' disease patients without clinical eye signs or symptoms harbor EOM abnormalities, as demonstrated by MRI. This suggests that present clinical examination methods are insufficient to diagnose varying degrees of ophthalmopathy in patients with autoimmune thyroid disorders who do not initially present with clinical ophthalmopathy.

Demonstration of fibroblast growth factor receptor-I in human prostate by polymerase chain reaction and immunohistochemistry

The expression and localization of fibroblast growth factor receptor-1 were investigated in human prostatic tissues with or without benign hyperplasia. Using a polymerase chain reaction method, we were able to demonstrate that prostatic tissues with benign hyperplasia expressed a significantly higher level of fibroblast growth factor receptor-1 mRNA than normal prostatic tissues (P < 0.01 by Anova). Western blot analysis using an antiserum against the receptor gave 2 bands with molecular weights of about 140 kDa and 80 kDa; these correspond to the expected sizes of the long and secreted forms of the fibroblast growth factor receptor-1, respectively. An immunohistochemical study using the same antiserum further demonstrated that the immunoreactive staining occurred mainly in the basal cells of the glandular epithelium and occasionally in the stromal cells. These results suggest that fibroblast growth factors may influence, at least in part, the proliferation of the epithelial cells seen in benign hyperplasia of human prostate.

Clinical application of diffusion-weighted magnetic resonance imaging to intracranial disorders

Diffusion-weighted magnetic resonance imaging was performed to determine the changes in water diffusion and to investigate the detectability of diffusion anisotropy in patients with intracranial disorders. Diffusion maps of the apparent diffusion coefficient (ADC) were created of 19 patients with cerebral infarction, five with intracerebral hematoma, four with glioma, four with meningioma, four with hydrocephalus, and five with subdural hematoma. ADC was increased in chronic cerebral infarction and glioma, and decreased in acute cerebral infarction, meningioma, and the marginal area of glioma compared with the ADC of the normal gray matter. There was a significant difference in ADC between the marginal and internal areas of glioma. Increased ADC may be due to increased vasogenic edema in infarction and a lack of significant restriction of diffusion within glioma. Decreased ADC can be attributed to restricted diffusion caused by cytotoxic edema in infarction and the underlying histological pattern of densely packed tumor cells in glioma. Diffusion anisotropy of the internal capsule was less detectable in pathological than normal hemispheres. Diffusion anisotropy was less detectable in patients with hydrocephalus and subdural hematoma. Intracranial lesions were thought to have influenced the compression of the brain structures and cells, resulting in decreased diffusion. The measurement of ADC by diffusion-weighted magnetic resonance imaging has the potential for greater understanding of the biophysical changes in various intracranial disorders, including correct diagnosis of cerebral infraction, and histological diagnosis of brain tumor.

Purification and characterization of secretory-type GDP-L-fucose: beta-D-galactoside 2-alpha-L-fucosyltransferase from human gastric mucosa

alpha-(1,2)-Fucosyltransferase (GDP-L-fucose:beta-D-galactoside 2-alpha-L-fucosyltransferase) from human gastric mucosa was purified to homogeneity by column chromatographies on Ultrogel AcA34, phenyl-Sepharose, hydroxylapatite, SP-Sephadex, and GDP-hexanol-amine Sepharose. The molecular weight of the purified enzyme was estimated to be 65,000 by SDS-PAGE. The Km value of this enzyme for a type 1 sugar acceptor was a little smaller than that for a type 2 one, indicating this enzyme is a secretor-type alpha-(1,2)-fucosyltransferase. However, the difference between the Km value for a type 1 precursor and that for a type 2 one was very small, suggesting that this enzyme can use both types of precursors as sugar acceptors approximately equally, unlike the purified alpha-(1,2)-fucosyltransferase from human serum as the secretor-type reported previously. The characteristics of the purified enzyme were compared with those of H-type alpha-(1,2)-fucosyltransferase from human plasma. The activities of both enzymes were inhibited by salt and N-ethylmaleimide, but they showed a significant difference in their divalent cation requirements.

A new model of subretinal neovascularization in the rabbit

PURPOSE

To establish a new model of subretinal neovascularization (SRN) in the rabbit by implanting basic fibroblast growth factor (bFGF)-impregnated gelatin microspheres beneath the retina.

METHODS

Basic fibroblast growth factor-impregnated gelatin microspheres were prepared by forming a polyion complex between gelatin and bFGF. The microspheres, containing 2.5 micrograms of bFGF, were injected into the subretinal space of rabbit eyes (n = 29). Control eyes (n = 10) received bFGF-free gelatin microspheres. Eyes were followed up for 3 days to 8 weeks by ophthalmoscopy, photography, fluorescein angiography, light microscopy, and transmission electron microscopy.

RESULTS

Twenty of 24 experimental eyes (83%) showed fluorescein leakage from SRN 2 weeks after implantation of the bFGF-impregnated microspheres. This leakage continued for 2 to 6 more weeks. In striking contrast, control eyes showed no fluorescein leakage. Histologic examination revealed SRN in all the experimental eyes but in none of the control eyes.

CONCLUSIONS

Subretinal implantation of bFGF-impregnated gelatin microspheres induces reproducible SRN in the rabbit.

New magnetic resonance imaging techniques for the evaluation of traumatic brain injury

Although current computerized tomography (CT) and magnetic resonance imaging (MRI) techniques have shown great utility in diagnosing various aspects traumatic brain injury, damage resulting from mild diffuse brain injury often goes undetected with these procedures. Newly developed MRI techniques, including magnetization transfer imaging (MTI) and diffusion-weighted imaging (DWI), have been proposed to have enhanced sensitivities for identifying damage induced by both diffuse and focal brain injury. Results from recent initial studies with experimental models of brain injury suggest that MTI may be useful for evaluating diffuse white matter damage, while DWI may demonstrate regions of focal contusion more acutely and with greater accuracy than conventional MRI procedures.

A new technique for endoscopic carpal tunnel decompression

A new one-portal technique for endoscopic carpal tunnel release (ECTR) is introduced with its clinical results. The incision is made at the palmar aspect of the hand. A custom-made glass tube with a groove is inserted, and under endoscope observation, a meniscus knife is pushed forward along the groove to release the flexor retinaculum. This new technique has been studied in ten fresh cadaver hands and used in 123 patients' hands. Results of the cadaver study showed that the flexor retinaculum was released completely in all ten hands. No injuries to tendons, nerves, or arteries were noted. In one case the cotton tip was lost from the stick. All clinical releases were performed uneventfully except for three cases of neuropraxia of the digital nerve of the radial side of the ring finger, one laceration of the motor branch of the median nerve, one mild infection, one loss of cotton tip from the cotton swab stick, and one case of chipping of the glass tube. The case with the laceration of the motor branch of the median nerve occurred early in the series and required the conventional open incision to repair the nerve. The cases with loss of cotton from the stick and chipping of the tube also required a conventional incision to remove the cotton and glass chip. Advantages of this one-portal technique with the glass tube include less scar tenderness than with two-portal techniques, decreased risk of injury to the superficial palmar arch and ulnar nerve because of the distal approach, a view of pathology in the carpal tunnel through the glass tube, and confirmation of release of the flexor retinaculum.

Esophageal stricture secondary to candidiasis without underlying disease

Candidiasis of the esophagus progressing to stricture formation in a 74-year-old male is reported. Esophageal candidiasis develops in the presence of various predisposing conditions such as long-standing administration of antibiotics or corticosteroids, and malignancy. The first endoscopic examination of this patient revealed unusual multiple black plaques in the esophagus. Despite intensive exploration, no predisposing factors were found. The stricture was progressive, despite the administration of adequate antifungal therapy, and its presence necessitated several attempts at dilatation. Case reports of esophageal candidiasis without underlying disease are very rare.

Intact antigen presentation for Epstein-Barr virus (EBV)-specific CTL by a lymphoblastoid cell line established from a patient with severe chronic active EBV infection

Severe chronic active Epstein-Barr virus (EBV) infection is a lymphoproliferative disease characterized by extremely high antibody titers to EBV, fever, lymphadenopathy, hepatosplenomegaly, and pancytopenia, without any prior immunological abnormality. A spontaneous lymphoblastoid cell line was established from a 4-year-old boy with severe chronic active EBV infection. Immunofluorescence and Western blotting analyses showed that the cell line was of B cell origin and expressed Epstein-Barr nuclear antigens 1, 2 3a, 3b and 3c, and latent membrane protein 1, which are reported to be targets for EBV-specific cytotoxic T lymphocytes (CTL). The cytotoxicity of peripheral blood mononuclear cells derived from the patient and his HLA-identical sister was assayed against the cell line. The cell line was recognized and killed by anti-EBV CTL derived from the HLA-identical sister, but the patient's peripheral blood mononuclear cells had no cytotoxicity. We conclude that antigen presentation in the EBV-infected cells from the patient is intact and sufficient for generation of an EBV-specific CTL response. These observations suggest that severe chronic active EBV infection may not be caused by impaired EBV-antigen presentation of the infected cells but by impaired cellular immune responses to the virus. Our results also suggest the therapeutic possibility that this disease may be treated by adoptive transfer of EBV-specific CTL or bone marrow transplantation from an HLA-matched donor whose immune response to EBV is intact.

Adjuvant immunotherapy with interleukin 2 and lymphokine-activated killer cells after noncurative resection of primary lung cancer

A randomized controlled study of immunotherapy with interleukin 2 (IL-2) and lymphokine-activated killer (LAK) cells was conducted in 105 patients after noncurative resection of primary lung cancer. Half the patients received only the standard postoperative radiation therapy or chemotherapy (control group). The other half received immunotherapy with IL-2 and LAK cells in addition to the standard therapy (immunotherapy group). The primary endpoint was survival. The 7-year survival rate was greater in the immunotherapy group than in the control group (39.1% vs. 12.7%, P < 0.01). Among patients with squamous cell carcinoma, there was no statistical difference in outcome. In contrast, the 7-year survival rate among patients with adenocarcinoma in the control group was only 5.2% but for those in the immunotherapy group it was 38.9% (P < 0.05). If resection was noncurative because of pulmonary metastasis, residual cancer or incomplete resection of lymph nodes, then immunotherapy was effective. If resection was noncurative because of residual cancer in the chest wall or diaphragm, or because of carcinomatous pleuritis or pleural dissemination, then there was no statistical difference in survival between the control group and the immunotherapy group.

[Sarcoidosis with hypercalcemia and increased 1 alpha, 25-dihydroxyvitamin D in lung tissue]

A 60-year-old woman was admitted to our hospital complaining of nausea, thirst, and dyspnea on exertion. She had skin eruptions on her back and right knee. Her serum calcium level was 12.6 mg/dl. The chest roentgenogram showed diffuse nodular shadows in both lung fields. The level of angiotensin-converting enzyme in serum was markedly high, and epithelioid cell granulomas were found in the specimens obtained by skin biopsy and by transbronchial lung biopsy. Sarcoidosis was diagnosed. After administration of prednisolone, the serum calcium level decreased to within the normal range and the shadows on the chest roentgenogram resolved. Hypercalcemia complicated with sarcoidosis is caused by overproduction of 1 alpha,25-dihydroxyvitamin D in granulomas. The content of 1 alpha, 25-dihydroxyvitamin D in the transbronchial lung biopsy specimen from this patient was higher than that from a sarcoidosis patient whose serum calcium level was normal. A few case reports of sarcoidosis with hypercalcemia have been published in Japan. The association with HLA type and the possibility of overintake of dietary vitamin D are discussed in reference to hypercalcemia in this patient.

Circulation of red blood cells having high levels of 2,3-bisphosphoglycerate protects rat brain from ischemic metabolic changes during hemodilution

BACKGROUND AND PURPOSE

We designed the present study to examine the effects of red blood cell oxygen-delivering capacity on ischemic brain metabolism during hemodilution with respect to red blood cell 2,3-bisphosphoglycerate content.

METHODS

A modification of red blood cell 2,3-bisphosphoglycerate content was achieved by an exchange transfusion of blood in which red blood cells were treated with either phospho(enol)pyruvate or inorganic phosphate in spontaneously hypertensive rats. Hematocrit values of circulating blood were varied from 30% to 20% during transfusion. Brain ischemia was produced in rats by bilateral carotid artery occlusion lasting 60 minutes. The concentrations of ATP and 2,3-bisphosphoglycerate in the blood and the ATP, phosphocreatine, and lactate concentrations in the brain were estimated by an enzymatic method.

RESULTS

Red blood cell 2,3-bisphosphoglycerate concentration increased to 200% of the pretransfusion level after the transfusion in which red blood cells were treated with phospho(enol)pyruvate, whereas the concentration decreased to 80% after the transfusion in which red blood cells were treated with phosphate. Red blood cell ATP content did not differ significantly between the phospho(enol)pyruvate- and phosphate-treated groups after transfusion. When hematocrit was approximately 30%, the ischemic brain ATP and lactate contents did not differ between the nonischemic and ischemic groups. However, as hematocrit was reduced to less than 25% the ischemic brain ATP content remarkably decreased and the lactate content substantially increased in the 2,3-bisphosphoglycerate-subnormal red blood cell group. In contrast, the ischemic brain ATP and phosphocreatine contents in the 2,3-bisphosphoglycerate-enriched red blood cell group were preserved and as high as those in the nonischemic group under the same conditions.

CONCLUSIONS

Cerebral ischemia was compensated with the increment of cerebral blood flow as a result of the reduction of hematocrit to optimal levels, but the extreme hemodilution induced insufficient oxygen supply to the brain tissue, resulting in a more marked impairment of brain metabolism despite an increase in cerebral blood flow. However, even in extreme hemodilution conditions the 2,3-bisphosphoglycerate-enriched red blood cells in circulating blood protected the brain from ischemic metabolic changes. These results suggest that the 2,3-bisphosphoglycerate-enriched red blood cells in the circulating blood may thus compensate for the insufficient oxygen supply in extremely anemic conditions by providing a sufficient supply of oxygen in the face of ischemic insult.

Modified one-layer microsurgical vasovasostomy in vasectomized patients

Bilateral vasovasostomies were performed in 7 previously vasectomized patients. The method employed was a modification of a one-layer anastomotic technique. There was no correlation between the presence of absence of sperm in the vas fluid, presence or absence of sperm granuloma, and site of vasectomy. No correlation was revealed between the presence or absence of sperm in the vas fluid and the duration of obstructive period. After vasovasostomy, sperm was observed in the ejaculate in 86% of the patients. Only one patient's partner became pregnant. However, the partner of one patient with short postoperative period and good seminal finding after vasovasostomy was expected to become pregnant. This modified method of one-layer microsurgical vasovasostomy can be performed more easily and quickly, but requires further clinical experience and evaluation of usefulness.

Effects of 2-deoxyglucose, a metabolic inhibitor, on spontaneous contraction and adrenoceptor responsiveness in cultured rat ventricular myocytes

Although it is well known that myocardial ischemia induces the depletion of myocardial ATP and sustained myocardial dysfunction, the mechanisms causing impaired myocardial function have not been elucidated completely. To clarify the relationship between ATP depletion and myocardial contractility, we investigated the influence of myocardial ATP depletion on spontaneous beating in cultured rat ventricular myocytes. Furthermore, because catecholamines have been used to improve myocardial contraction in the ischemic heart, we attempted to determine whether the ATP depletion per se alters the contractile responses to alpha 1- and beta-adrenoceptor stimulation. After 24 hr of culture in the presence of a metabolic inhibitor, 2-deoxyglucose (2DG, 5mM), myocardial contractility decreased to 19% of the vehicle level, and returned to normal after the removal of 2DG. The beating rate did not show any alterations in the vehicle, in the presence of 2DG (2DG [+/+]) or after the removal of 2DG (2DG [+/-]). Norepinephrine (NE) caused significant decreases in beating rate and increases in contractility in all groups. Isoproterenol (ISP) caused significant increases in beating rate and contractility in all groups. In the 2DG (+/+) group, the contractility was significantly lower as compared to other groups during NE or ISP stimulation. However, the percent change of contractility was similar to those of other groups after NE or ISP stimulation in the 2DG (+/+) group. These results suggest that decreased myocardial ATP causes the decreased contractility and does not affect the alpha 1- or beta-adrenoceptor-mediated responses.

Detection and quantification of virus DNA in plasma of patients with Epstein-Barr virus-associated diseases

Epstein-Barr virus (EBV) causes various diseases, such as infectious mononucleosis (IM), fatal IM, EBV-associated hemophagocytic syndrome (EBVAHS), and chronic active EBV infection (CAEBV). In the present study, cell-free EBV DNA was detected in the plasma of patients with EBV-associated diseases by PCR assay. The patients included 20 patients with IM, 2 patients with fatal IM, 4 patients with EBVAHS, 4 patients with CAEBV, and 38 healthy children (20 EBV seropositive and 18 EBV seronegative). In patients with IM, plasma samples were positive for EBV DNA in all patients (100%) in the acute phase and in 44% of the patients in the convalescent phase, but plasma samples from the 38 healthy control children were negative (0%) for EBV DNA. Quantitative PCR assay revealed that plasma from patients with IM contained the highest amount of virus DNA within 7 days following the onset of disease (mean, 6 x 10(4) copies per ml). The EBV DNA concentration decreased thereafter as the patients recovered. Plasma from patients with fatal IM contained more than 100 times more copies of EBV DNA (3 x 10(7) copies per ml) than plasma from patients with IM. Plasma from patients with the acute phase of EBVAHS contained 10 times more copies of EBV DNA (5 x 10(5) copies per ml) than plasma from IM, and then patients with the number of copies decreased similarly in both groups of patients in the convalescent phase (2 x 10(4) copies per ml). The amount of virus DNA in patients with CAEBV (6 x 10(4) copies per ml) was similar to that noted in patients with IM; however, it became higher (1 x 10(6) copies per ml) when the patients' clinical status deteriorated. These data suggest that the presence of cell-free EBV DNA in plasma is a common phenomenon in patients with EBV-associated diseases. The concentration of EBV DNA in plasma seems to be higher in patients with the more severe clinical categories of EBV diseases.

Reappraisal of safety of endoscopic sphincterotomy for common bile duct stones in the elderly

BACKGROUND

Endoscopic sphincterotomy is the method of choice for elderly patients with common bile duct stones, even though these patients are poor operative risks. We undertook this study to analyze the operative risk factors for this age group.

METHODS

We compared specific problems of 182 patients aged 80 years or older and 921 younger patients who underwent endoscopic sphincterotomy for common bile duct stones.

RESULTS

Despite a higher frequency of periampullary diverticula in the elderly than in the younger patients (54% versus 36%, P < 0.001), the success rates of sphincterotomy were not different. The elderly patients required lithotripsy more often than did the younger ones (15% versus 4%, P < 0.001), and the necessity of stenting or nasobiliary drainage was greater in this group (9%) than in the younger group (5%, P < 0.05). This difference in the tactics between the older and younger groups was due to the greater number and size of stones, longer period of time for complete clearance of the common bile duct (13.5 versus 6.0 days, P < 0.01), and a greater percentage of patients with operative risks (55% versus 36%, P < 0.001). The elderly also had significantly greater overall morbidity compared with the younger patients (13% versus 7%, P < 0.005), frequency of acute cholangitis (8% versus 2%, P < 0.001), and mortality (1% versus 0%).

CONCLUSION

These results suggest that frequent stenting or nasobiliary drainage to prevent cholangitis or prompt stone removal by lithotripsy would be necessary in this group of patients.

Molecular cloning of cDNA encoding mouse Cdc21 and CDC46 homologs and characterization of the products: physical interaction between P1(MCM3) and CDC46 proteins

Two new mouse genes encoding proteins that belong to the yeast minichromosome maintenance (MCM) protein family, which is involved in the initiation of DNA replication, were isolated and their nucleotide sequence was determined. They were a putative CDC46/MCM5 homolog and a putative cdc21 homolog. About 30% amino acid identity was obtained between members in the family, and > 40% between the putative mouse and yeast homologs. The expression of these genes was cell-cycle specific at the late G1 to S phase. Immunochemical analyses showed the physical interaction between mouse P1MCM3 and CDC46 protein. These results suggest that MCM proteins function in co-ordination for DNA replication.

Detection of T to G mutation at position 59 in the Lewis gene by mismatch polymerase chain reaction

Recently, we discovered the missense mutations of T to G at position 59 and of G to A at position 508 in one of the Lewis-negative (le) genes (Koda et al. 1993). In the present study, we report a method to detect the mutation at position 59 using mismatch PCR amplification and endonuclease MspI digestion. For this mutation, we found that 7 out of 12 Lewis-negative, and none of 15 Lewis-positive individuals were homozygous, while 4 out of 12 Lewis-negative, and 4 out of 15 Lewis-positive individuals were heterozygous. These results indicate that the mutation at position 59 is a common mutation in the le genes.

Spatial heterogeneity of mucosal blood flow during ischemia-reperfusion injury of rat stomach investigated by laser Doppler perfusion imaging

Spatial alterations in blood flow during the development of mucosal injury induced by ischemia-reperfusion in rats were determined with a two-dimensional laser Doppler tissue perfusion imager. The rats were anesthetized with pentobarbital, and the stomach was exteriorized on a stage; the mucosa was then sequentially scanned. The mucosa was constantly superfused with 0.1 N HCl in physiological saline. Systemic arterial pressure was continuously monitored and blood was stepwisely withdrawn from the femoral artery by 20-mmHg stage and then maintained at 20 mmHg for 20 min. The shed blood was reinfused and the stomach was removed 30 min later. Under control conditions, the average perfusion of the forestomach was usually greater than that in the glandular stomach. When systemic blood pressure was stepwisely decreased, the extent of decrease in the mucosal blood perfusion unit was always greater than that in systemic blood pressure, but mucosal perfusion appeared to be uniformly decreased throughout the stomach. Ten min after reperfusion, a hypoperfused area began to appear in the corpus near the greater curvature, and this area subsequently increased. The area of ulcer formation corresponded with the hypoperfused area in the gastric mucosa 30 min after reperfusion. Pretreatment with CV-6209, a platelet-activating factor antagonist, significantly attenuated the hypoperfusion induced by reperfusion and also prevented gastric mucosal damage. Our results suggest that hypoperfusion in the mucosal microcirculation is indeed an important factor contributing to the localized occurrence of gastric mucosal lesions and that the laser Doppler perfusion imager is useful for the detection of local hypoperfused areas in the gastric mucosa.

Improvement of hypothyroidism after glucocorticoid replacement in isolated adrenocorticotropin deficiency

We report a 50-year-old female who suffered from reversible hypothyroidism accompanied by isolated ACTH deficiency. There were no findings indicating a complication of autoimmune thyroiditis. Replacement of maintenance dose of glucocorticoid not only led to improvement of thyroid function, but also caused a transient decrease in T3 and an increase in reverse T3, suggesting that chronic cortisol deficiency may impair thyroid function, and that the maintenance dose, as well as pharmacological doses of glucocorticoids may influence T4 deiodination. The findings of this case suggest that thyroid function should be re-evaluated to avoid unnecessary replacement of thyroid hormone, a few months after glucocorticoid replacement.

Effect of tecogalan sodium on angiogenesis in vitro by choroidal endothelial cells

PURPOSE

To examine the possible inhibitory effect of tecogalan sodium, derived from bacteria, on three important components of in vitro angiogenesis (endothelial proliferation, migration, and tube formation in a collagen gel) using bovine choroidal endothelial cells (CECs).

METHODS

The effects of tecogalan sodium (1, 5, 25, 125, and 250 micrograms/ml) on cultured CECs were examined when basic fibroblast growth factor (bFGF, 10 ng/ml), vascular endothelial growth factor (VEGF, 50 ng/ml), a combination of bFGF (10 ng/ml) and VEGF (50 ng/ml) (bFGF/VEGF) and 10% fetal calf serum (FCS) were used as angiogenic stimulants. For the proliferation assay, CECs were cultured and the cell numbers counted on days 1, 3, and 5. For migration assay, CECs were seeded in the upper half of a Boyden chamber while an angiogenic growth factor was loaded in the lower half. After 6 hours of incubation, cell migration was evaluated by counting the numbers of migrated cells per microscopic field on the lower side of the filter. For the tube-forming assay, CECs were seeded in a type I collagen gel, and the length of the tube-like structures (an indicator of angiogenesis) formed by CECs per microscopic field was quantified by image analysis. The effect of neutralizing antibody for bFGF also was tested in these three assays.

RESULTS

All tested angiogenic stimulants induced CEC proliferation. The stimulatory effect of bFGF and bFGF/VEGF was reduced by tecogalan sodium (IC50 for bFGF effect, 26.1 micrograms/ml). However, the effect of VEGF and of 10% FCS was not altered by low doses of tecogalan sodium (< 25 micrograms/ml). Chemotaxis of CECs was stimulated by bFGF alone and by bFGF/VEGF, and this effect was inhibited by tecogalan sodium (IC50 for bFGF, 3.2 micrograms/ml). Stimulation of chemotaxis by VEGF alone and by 10% FCS was not affected by tecogalan sodium in low doses but was inhibited by high doses. Tube formation was stimulated by administration of each of the factors. Stimulation of tube formation by bFGF and by bFGF/VEGF was inhibited by tecogalan sodium (IC50 for bFGF, 18.2 micrograms/ml). High doses of tecogalan sodium (125 and 250 micrograms/ml) also inhibited 10% FCS-induced proliferation, migration, and tube formation.

CONCLUSION

bFGF, VEGF, and a combination of bFGF and VEGF stimulated proliferation, migration, and tube formation by CECs in vitro. These stimulatory effects, but especially those of bFGF, were inhibited by tecogalan sodium. If tecogalan sodium can be shown to have a similar effect in vivo, it might have the potential for pharmacologic control of subretinal neovascularization.