Molecular pathogenesis of plasminogen Hakodate: the second Japanese family case of severe type I plasminogen deficiency manifested late-onset multi-organic chronic pseudomembranous mucositis.

A 64-year-old man first developed ligneous conjunctivitis at the age of 58 years after right pulmonary resection because of suspected cancer; otherwise, he had been healthy. Since then, he began to suffer from various forms of chronic pseudomembranous mucositis. Laboratory tests demonstrated that he had 7.8 % of plasminogen activity and 5.9 % of the normal antigen level. Thus, he was diagnosed as having severe type I plasminogen deficiency, making him the third case in Japan. DNA sequencing and PCR-restriction fragment length polymorphism analyses revealed that this patient was a compound heterozygote of a G-to-A missense mutation (G266E) in exon VIII and a g-to-a mutation at the obligatory splicing acceptor site in intron 12 (IVS12-1g>a). These two mutations were confirmed to be novel. Molecular modeling and splice site strength calculation predicted conformational disorder(s) for the Glu266 mutant and a drastic decrease in splicing efficiency for intron 12, respectively. Western blot analysis demonstrated that the patient contained a small amount of the normal-sized plasminogen protein. Mass spectrometric analysis of the patient's plasminogen revealed a peptide containing the wild-type Gly266 residue and no peptides with mutations at Glu266. However, he had never suffered from thrombosis. Low levels of fibrinogen/fibrin degradation products (FDP), D-dimer, and plasmin-α2-plasmin inhibitor complex clearly indicated a hypo-fibrinolytic condition. However, his plasma concentration of elastase-digested crosslinked FDPs was 4.8 U/mL, suggesting the presence of an on-going plasmin(ogen)-independent "alternative" fibrinolytic system, which may protect the patient from thrombosis. The patient has been free from recurrence of ligneous conjunctivitis for approximately 2.5 years.

Tranexamic acid-induced ligneous conjunctivitis with renal failure showed reversible hypoplasminogenaemia.

Ligneous conjunctivitis is a rare severe conjunctivitis characterised by fibrin-rich, 'woody', pseudomembranes on the tarsal conjunctiva complicated by congenital hypoplasminogenaemia. A previous report suggested that ligneous conjunctivitis may result from tranexamic acid (TA)-induced 'secondary' hypoplasminogenaemia. However, the serum plasminogen level has not been confirmed in that scenario. We report for the first time a case of TA-induced ligneous conjunctivitis with reversible hypoplasminogenaemia. A 70-year-old woman developed a gastric ulcer that was treated with oral TA. After 5 weeks of treatment, the patient presented with bilateral pale yellow pseudomembranes on the palpebral conjunctivae. Haematological analysis showed hypoplasminogenaemia. We diagnosed ligneous conjunctivitis. TA was discontinued after 14 weeks after the gastric ulcer symptoms resolved. Six weeks after discontinuation of therapy, the pseudomembranes regressed and the serum plasminogen level returned to the normal range. TA should be considered a possible aetiology in the setting of unresolving ligneous conjunctivitis.

Acute hyperglycemia-induced endothelial dysfunction in retinal arterioles in cats.

PURPOSE: To investigate the effects of acute hyperglycemia on retinal microcirculation and endothelial function in cats and removal of superoxide to prevent retinal endothelial dysfunction from hyperglycemia. METHODS: Hyperglycemia was induced by intravenous injection of 25% glucose to maintain the plasma glucose concentration at 30 mM. Laser Doppler velocimetry was used to measure the vessel diameter (D) and blood velocity (V) simultaneously and calculated retinal blood flow (RBF) in second-order retinal arterioles in cats. Intravitreous, endothelial-dependent vasodilator bradykinin (BK) and endothelium-independent vasodilator sodium nitroprusside (SNP) were administered into the vitreous cavity to evaluate endothelial function in the retinal arterioles. To control osmolality, 25% mannitol was administered the same way. Systemic hyperoxia was induced to noninvasively examine endothelial function during hyperglycemia. To determine the effect of the superoxide on the hyperglycemia-induced changes in the retinal circulation, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPOL) was administered in drinking water for 14 days before the experiment. RESULTS: The D, V, and RBF increased with acute hyperglycemia and mannitol compared with baseline. BK-induced increases in D, V, and RBF significantly declined, whereas SNP-induced increases were unattenuated during acute hyperglycemia. Return of the decreased RBF to baseline after cessation of systemic hyperoxia was significantly (P < 0.05) inhibited by acute hyperglycemia. TEMPOL significantly (P < 0.05) prevented a decrease in the BK-induced increase in RBF during hyperglycemia. CONCLUSIONS: The results suggest that acute hyperglycemia increases RBF via increased osmolality and may cause retinal endothelial dysfunction partially via increased oxidative stress. Systemic hyperoxia can be used to noninvasively evaluate retinal endothelial function during hyperglycemia.

Short-term effects of topical tafluprost on retinal blood flow in cats.

PURPOSE: The aim of this study was to determine the short-term effects of topical tafluprost, a novel prostaglandin F(2) derivative, on feline retinal circulation. METHODS: Seventeen (17) adult cats were anesthetized with enflurane and mechanically ventilated. One (1) drop of tafluprost (0.0015%; n = 8), latanoprost (0.005%; n = 5), or control vehicle (n = 4) was instilled in 1 eye and the fellow eye was untreated. We measured the intraocular pressure (IOP), vessel diameter, and blood velocity simultaneously for 120 min in the large retinal arterioles and calculated the retinal blood flow (RBF) with a laser Doppler velocimetry system. RESULTS: Tafluprost 0.0015% significantly increased RBF (maximum change, 42.8 +/- 4.2% [mean +/- standard error of the mean; P < 0.01) and blood velocity (maximum change, 24.1 +/- 3.3%; P < 0.01) for 120 min after instillation; there was no significant change in vessel diameter. Latanoprost 0.005% significantly increased RBF (maximum change, 31.7 +/- 3.4%; P < 0.05); there was no significant change in vessel diameter and blood velocity. There were no significant differences in the IOP reduction among the three groups. CONCLUSIONS: We observed, for the first time, that topical tafluprost significantly increased RBF in cats, suggesting that dual-action tafluprost may be a beneficial antiglaucomatous agent for reducing IOP and increasing RBF.

Role of nitric oxide in regulation of retinal blood flow in response to hyperoxia in cats.

PURPOSE: To investigate whether nitric oxide (NO) regulates retinal circulation during and after induction of hyperoxia in cats. METHODS: Hyperoxia was induced for 10 minutes with 100% oxygen. The vessel diameter and blood velocity were measured simultaneously in second-order retinal arterioles by laser Doppler velocimetry; the retinal blood flow (RBF) and wall shear rate (WSR) were calculated during and after hyperoxia. PBS, L-NAME, D-NAME, BQ-123, BQ-788, and 7-nitroindazole (7-NI) were administered before induction of hyperoxia. RESULTS: In the PBS group, vessel diameter, blood velocity, and RBF decreased during hyperoxia and returned to baseline within 10 minutes after hyperoxia ended. WSR decreased transiently and then returned to baseline by the delayed constriction of retinal arterioles during hyperoxia. In the l-NAME and BQ-788 groups, the decreases in RBF during hyperoxia did not differ from those in the PBS group. However, the recovery of RBF after hyperoxia ended was attenuated significantly until 20 minutes after hyperoxia ended in both groups compared with the PBS group (P < 0.05). In the BQ-123 group, the intravitreous injection of BQ-123 caused less reduction of blood velocity and RBF during hyperoxia compared with that in the PBS group, whereas the RBF immediately returned to baseline after hyperoxia. D-NAME and 7-NI did not affect RBF in response to hyperoxia. CONCLUSIONS: The current results indicate that NO contributes to RBF recovery after hyperoxia, probably through the action of endothelial NOS via the ETB receptor in the vascular endothelium of the retinal arterioles, suggesting that the RBF response to hyperoxia may be used to evaluate the endothelial function of the retinal arterioles.

Relation between plasma nitric oxide levels and diabetic retinopathy.

PURPOSE: Nitric oxide (NO) plays an important role in homeostatic vasodilation and the regulation of blood flow. On the other hand, excess release of NO causes various vascular complications. There are only a few reports on the relationship between plasma NO levels and microvascular complications, especially diabetic retinopathy (DR) in patients with type 2 diabetes. The purpose of this study was to determine the relationship between plasma NO levels and DR. METHODS: In a prospective study, blood samples were obtained from 36 patients with diabetes and no diabetic retinopathy (NDR), 43 patients with nonproliferative diabetic retinopathy (NPDR), 18 patients with proliferative diabetic retinopathy (PDR), and 40 subjects without diabetes mellitus, who served as controls. The levels of plasma NOx (nitrite and nitrate), the stable metabolites of NO, were measured by high-performance liquid chromatography with the Griess method. RESULTS: The plasma NOx levels were 92.8 +/- 16.0, 70.2 +/- 6.8, 90.3 +/- 9.1, and 53.8 +/- 6.1 micromol/l in patients with NDR, NPDR, or PDR, and in the controls, respectively. The plasma NOx levels in the three diabetic groups were significantly higher than those in the control group (P < 0.05 in each case). CONCLUSION: The increased plasma NO levels in patients with type 2 diabetes indicate that NO may be associated with the pathogenesis of DR.

Effect of systemic administration of simvastatin on retinal circulation.

OBJECTIVE: To investigate the effect of systemic administration of simvastatin on the retinal circulation. METHODS: The effects of systemic administration of simvastatin on the retinal circulation after 90 minutes and after 7 days were studied in a placebo-controlled, double-masked, clinical trial among 12 healthy men. We used laser Doppler velocimetry to measure vessel diameter and blood velocity and calculated the blood flow in retinal arteries and veins. We also measured the intraocular pressure and the plasma nitrite/nitrate levels, the stable end products of nitric oxide metabolism. RESULTS: There were no significant changes in any retinal circulatory parameters at 90 minutes after administration of simvastatin. Daily administration of simvastatin for 7 days significantly increased blood velocity and blood flow in retinal arteries and veins but did not significantly change vessel diameter. The intraocular pressure significantly decreased at 90 minutes and at 7 days after administration of simvastatin. Simvastatin also significantly increased the plasma nitrite/nitrate levels. CONCLUSION: Simvastatin induced an increase in blood velocity and blood flow in retinal arteries and veins, increased the plasma nitrite/nitrate levels, and decreased the intraocular pressure, probably through the increase in nitric oxide.