A Double-blind, Placebo-controlled, Multicenter, Prospective, Randomized Study of Beraprost Sodium Treatment for Cats with Chronic Kidney Disease.

BACKGROUND: Chronic kidney disease (CKD) is a common progressive and irreversible disease in cats. The efficacy and safety of beraprost sodium (BPS) in cats with CKD have not been evaluated. HYPOTHESIS/OBJECTIVES: To evaluate the efficacy and safety of BPS in the treatment of cats with CKD, as compared to placebo. ANIMALS: Seventy-four client-owned cats with naturally occurring CKD. METHODS: Double-blind, placebo-controlled, multicenter, prospective, randomized trial. The cats received BPS (55 µg/cat) or a placebo PO q12 h for 180 days. The primary endpoint was prospectively defined as a change in the serum creatinine (sCr), serum phosphorus-to-calcium ratio or urine specific gravity (USG). RESULTS: The sCr increased significantly (P = 0.0030) in the placebo group (mean ± SD: 2.8 ± 0.7 to 3.2 ± 1.3 mg/dL) but not in the BPS group (2.4 ± 0.7 to 2.5 ± 0.7 mg/dL). The difference between the groups at day 180 was significant (0.8 mg/dL, 95% CI: 0.2 to 1.3 mg/dL, P = 0.0071). The serum phosphorus-to-calcium ratio was significantly (P = 0.0037) increased in the placebo group (0.46 ± 0.10 to 0.52 ± 0.21 mg/dL) but not in the BPS group (0.50 ± 0.08 to 0.51 ± 0.11 mg/dL). There was no significant change in the USG in either group. An adverse event judged as being treatment-related included vomiting that occurred in 1 case in the placebo group. No clinically relevant change was observed in the CBC and other blood chemistry tests. CONCLUSIONS AND CLINICAL IMPORTANCE: Beraprost sodium treatment was well tolerated and safe in cats with CKD. BPS inhibited the reduction in renal filtration function as measured by sCr increase.

Role of sympathetic activity in blood pressure reduction with low calorie regimen.

To investigate the effects of a low calorie regimen on sympathetic function and its relation to blood pressure response, 22 untreated obese essential hypertensive patients (50 +/- 2 years, body mass index 29 +/- 1 kg/m2) were hospitalized and a diet was prescribed of 2,000 kcal/day for 5 days (control period) followed by 800 kcal/day for 21 days without changing salt intake (8-10 g/day). The dose of intravenous phenylephrine infusion needed to elevate systolic blood pressure 20 mm Hg (CD20) and the 24-hour urinary excretion of norepinephrine (UNE) were measured. During the low calorie period, blood pressure normalized in 14 patients (responder group, 124 +/- 3/79 +/- 4 mm Hg) and eight remained hypertensive (poor responder group, 158 +/- 6/103 +/- 3 mm Hg). At the control period, blood pressure and body mass index were similar, but the responder group had higher UNE (134 +/- 15 micrograms/day) and CD20 (127 +/- 11 micrograms) than the poor responder group (89 +/- 6 micrograms/day and 79 +/- 13 micrograms, respectively). During the low calorie period, both UNE (87 +/- 15 micrograms/day) and CD20 (74 +/- 10 micrograms) decreased in the responder group; no change was seen in the poor responder group. Changes in UNE and systolic blood pressure were correlated (r = 0.6, p less than 0.05). In conclusion, suppression of sympathetic activity plays a role in blood pressure reduction during moderate caloric restriction.

Blood pressure response to hyperinsulinemia in salt-sensitive and salt-resistant rats.

We investigated the role of insulin in salt-sensitive hypertension in Dahl salt-sensitive and salt-resistant rats. The rats were kept in metabolic cages, and sodium intake and urinary sodium excretion were measured. In salt-sensitive rats receiving a 0.3% NaCl diet, sodium retention was significantly greater at weeks 1 and 2 in rats that received an insulin infusion than in those receiving a saline infusion. Mean arterial blood pressure and plasma norepinephrine levels were significantly higher at week 3 in insulin-treated rats than in saline-treated rats (mean arterial pressure, 137 +/- 3 mm Hg versus 119 +/- 3 mm Hg, p < 0.05; plasma norepinephrine, 0.40 +/- 0.02 ng/ml versus 0.27 +/- 0.01 ng/ml, p < 0.05). Insulin did not influence sodium retention, mean arterial pressure, or plasma norepinephrine in salt-resistant rats. Coadministration of an alpha-blocker (bunazosin, 10 mg/kg per day for 3 weeks) in salt-sensitive rats abolished the insulin-induced elevations in mean arterial pressure and sodium retention. When salt-sensitive rats were fed a low salt diet (0.03% NaCl), insulin did not raise mean arterial pressure. Thus, insulin elevated blood pressure only in the salt-sensitive model. The sympathetic nervous system and sodium retention in the early phase of insulin overload may contribute to elevation of mean arterial pressure in this model.

Comparative effects of beraprost, a stable analogue of prostacyclin, with PGE(1), nitroglycerin and nifedipine on canine model of vasoconstrictive pulmonary hypertension.

Acute hemodynamic effects of beraprost sodium were tested in a canine vasoconstrictive pulmonary hypertension model induced by the continuous infusion of U-46619, a thromboxane A(2)mimetic. The effects of beraprost were compared with those of prostaglandin E(1), nitroglycerin and nifedipine. Beraprost and nitroglycerin decreased pulmonary arterial pressure. On the other hand, prostaglandin E(1)and nifedipine increased pulmonary arterial pressure. All drugs except nitroglycerin increased cardiac output and decreased pulmonary vascular resistance. Beraprost was selective to pulmonary circulation, while nitroglycerin, prostaglandin E(1), and nifedipine showed poor selectivity for the pulmonary vasculature. These results suggest that the vasodilative effect of beraprost is the most selective for the pulmonary circulation among these four vasodilators.

Small diameter vascular prostheses with incorporated bioabsorbable matrices. A preliminary study.

The authors have designed small diameter vascular prostheses with incorporated matrices that can be absorbed into a growing anastomotic neointima. First, a gelatin-heparin complex was coated on the inner surface of tubular ultrafine polyester fabrics presealed with heat denatured albumin. Second, to control the bioabsorption rate, the prepared grafts were cross-linked with polyepoxy compounds for 3 days (Group I; n = 14) or 5 days (Group II; n = 4). These grafts, 3 mm in diameter and 4 cm long, replaced the carotid arteries of nine mongrel dogs weighing 9.5-14 kg. Six of eight (75%) grafts in Group I were patent when the animals were killed 4 weeks after surgery. Doppler sound examination revealed that the remaining six were patent for 16 weeks. In Group II, three of four (75%) grafts were patent when the animals were killed 8 weeks after surgery. In both groups, scanning electron microscopic study showed neither platelet aggregation nor fibrin formation on the midportion. However, these two groups significantly differed in histology. In Group I, thin anastomotic neointima advanced over the mostly absorbed gelatin-heparin complex layer. Connective tissue was well formed around the polyester scaffold. In contrast, thick neointima advanced over the gelatin-heparin complex layer that still remained on the luminal surface in Group II. These results suggest that the gelatin-heparin complex, when cross-linked adequately, could simultaneously function as a temporary antithrombogenic surface and as an excellent substructure of an anastomotic neointima.

[Pharmacological and clinical properties of beraprost sodium, orally active prostacyclin analogue].

Prostacyclin is an endogeneous eicosanoid synthesized by vascular endothelial cells, and has potent inhibitory effects on platelet adhesion/aggregation and vasoconstriction. However, its therapeutic use is restricted by its extremely short half-life. Beraprost sodium (beraprost) is the first orally active prostacyclin analogue developed by TORAY Industries, Inc. Beraprost possesses a phenol moiety instead of the exo-enol ether moiety, which is the cause of the instability of prostacyclin, and has a modified omega-side chain that contributes to dissociating antiplatelet action from adverse reactions. In 1992, beraprost was approved as a drug for chronic arterial occlusion. Beraprost is now widely used clinically as "Dorner" or "Procylin". The indication for "primary pulmonary hypertension" was also approved in 1999. Recently in Europe, a placebo controlled trial named "Beraprost et Claudication Intermittent-2 (BERCI-2)" was performed, and it was reported that beraprost improved the walking distances of the patients. Beraprost has a variety of biological activities such as antiplatelet effects, vasodilation effects, antiproliferative effects on vascular smooth muscle cells, cytoprotective effects on endothelial cells and inhibitory effects on the production of inflammatory cytokines. On the basis of basic and clinical research, it has been suggested that beraprost is also effective for many intractable diseases. We expect that the relationship between reduced prostacyclin level and these diseases would be clarified and the beneficial effects of beraprost would be demonstrated by controlled clinical trials in the future.

Surface induced in vitro angiogenesis: surface property is a determinant of angiogenesis.

The control of cellular responses on substrate surfaces is essential for logical surface design aiming at endothelialized, vital implant devices. In this paper, the surface property that alters cell adhesion, spreading, migration, and proliferation processes is shown to be a determinant of endothelial cell assembly or angiogenesis in vitro. This was clearly demonstrated on slightly hydrophobic cellulosic surfaces, which induced organized three-dimensional cellular assemblies of bovine thoracic endothelial cells. The results indicated that this was driven by enhanced migratory response and/or retraction or involution of two-dimensional adherent cells, in which cell-cell interaction was enforced in a time dependent fashion. The present study strongly suggests that the mechanism leading to in vitro angiogenesis is primarily due to a weak cell-substrate interaction relative to cell-cell interaction.

[Effects of intracerebroventricular (I.C.V.) administration of 5-hydroxytryptamine (5-HT) on hemodynamics in conscious spontaneously hypertensive rats (SHR): relation to sympathetic nervous system].

UNLABELLED: Recently, the serotonergic nervous system has been receiving attention as part of the blood pressure regulating mechanism of the central nervous system, and it has been postulated that the system may participate in the pathogenesis of hypertension. The purpose of this experiment is to investigate the mechanism of hemodynamic change after i.c.v. administration of 5-HT in SHR and in normotensive Wistar Rats (WR). MATERIALS AND METHODS: Twenty-week-old male SHR (n = 11) and age-matched WR (n = 14) were used. On the day before the experiments, the unilateral carotid artery and jugular vein were cannulated. Also, a cannula was inserted stereotaxically into the anterior horn of the lateral cerebral ventricle. Experiments were performed under the conscious and minimum restrained state. Experiment I: After observation of resting mean arterial pressure (MAP) and heart rate (HR) for 20 minutes, 5-HT (5 micrograms/5 microliter saline) was administrated i.c.v., and MAP and HR were observed for 90 minutes. Then, 200 micrograms of phenoxybenzamine (POB) was given from the jugular cannula. Thirty minutes after the POB administration when MAP was stabilized, 5 micrograms of 5-HT was again given i.c.v., and MAP and HR were recorded for 30 minutes. Experiment II: Plasma norepinephrine (PNE) was measured before and 2 minutes after 5-HT i.c.v. administration. The control sample (1.5 ml) was withdrawn at least 30 minutes before the 5-HT injection, and immediately after the blood sampling, the same amount of blood which was obtained from the age-matched donor rat of the same strain was transfused. RESULTS: Experiment I: Resting MAP was 136.4 +/- 5.1 mmHg in SHR and 99.1 +/- 3.0 mmHg in WR. I.c.v. administration of 5-HT elicited consistent pressor response in SHR and in WR.(ABSTRACT TRUNCATED AT 250 WORDS)

[Role of the serotonergic nervous system in hemodynamic and vasopressin responses to centrally administrated angiotensin-II in spontaneously hypertensive rats].

The purpose of the study is to investigate the role of the serotonergic nervous system in centrally administrated angiotensin II (A-II) mediated hemodynamic as well as vasopressin (AVP) responses. Eight-week-old male SHR and age-matched Wistar Kyoto rats (WKY) were used and the experiment was performed in the conscious state. In protocol 1, after resting observation of 30 minutes 10ng of A-II was given intracerebroventricularly (i.c.v.). This was followed by i.c.v. injection of 1 microgram of 5-HT2 receptor antagonist, xylamidine, 50 minutes later; then 10ng of i.c.v. A-II was repeated after 10 minutes (SHR: n = 7, WKY: n = 10). In protocol 2, plasma vasopressin (AVP) was measured in the following groups. In one group, 1.3ml of blood was sampled from the carotid cannula after resting observation, and the same amount of blood from an age-matched donor rat of the same strain was transfused immediately. Two hours later, 10ng of A-II was given i.c.v., and blood was sampled again after 1 minute (SHR: n = 7, WKY: n = 12). In another group, 1 microgram of xylamidine was given i.c.v. and was followed by 10ng of A-II 10 minutes later; then blood was collected after 1 minute (SHR: n = 8, WKY: n = 13). In protocol 1, resting MAP were 144 +/- 6mmHg in SHR and 99 +/- 2mmHg in WKY. I.c.v. A-II elicited a consistent pressor response in both SHR and WKY, but the response was significantly larger in SHR than that in WKY, +45 +/- 3 and +37 +/- 1mmHg, respectively. Xylamidine had no effect on MAP, and repeated A-II produced significant pressor responses. However, the responses were significantly smaller in both SHR (+36 +/- 3mmHg) and WKY (+25 +/- 1mmHg) as compared with those to initial A-II injection. In protocol 2, resting AVP were similar in SHR (1.5 +/- 0.2pg/ml) and in WKY (1.6 +/- 0.1pg/ml). However, after i.c.v. A-II injection, AVP became higher in SHR (131 +/- 14pg/ml) than in WKY (64 +/- 6pg/ml). AVP after A-II injection with xylamidine pretreatment were similar in SHR (48 +/- 6pg/ml) and in WKY (45 +/- 4pg/ml). Since the responses of both MAP and AVP to i.c.v. A-II were larger in SHR, and the responses were effectively suppressed by S2 receptor antagonists, the central serotonergic nervous system may play an important role in the hemodynamic as well as AVP responses to i.c.v. A-II administration.

An autologous connective tissue tube with high healing ability as a small diameter vascular substitute with temporary antithrombogenicity.

Although autologous connective tissue grafts (ACTG) are an ideal vascular substitute, they have not yet been used as small diameter vascular grafts because of thrombogenicity. We reported on ACTGs in which mesh tubes were fabricated from ultra-fine polyester fibers (UFPF) and used as a framework. Antithrombogenicity was established using an original heparinization method, with a 50% patency 1 month postimplantation. Early failure of these grafts was caused mainly by loss of antithrombogenicity before development of endothelialization on the inner surface. In this study, higher concentrations of heparin were used for in situ heparinization of the grafts before implantation in combination with antiplatelet therapy (cilostazol, OPC-13013 for the first month after substitution for canine carotid arteries. As a result, more complete healing of the grafts was attained, with a patency rate of 63% at 1 month, when small doses of antiplatelet agents were used. More intensive antiplatelet therapy resulted in impairment of graft healing, causing hematomas around the grafts. Thus, optimal doses of antiplatelet agents remain uncertain.

Development of ultrafine polyester fiber vascular grafts with high endothelialization capability. Angiogenesis by ultrafine polyester fibers.

The authors previously showed that a vascular prosthesis made of ultrafine polyester fibers (UFPF) had high healing ability even when of low porosity. In this study, new highly porous vascular grafts fabricated from UFPF (water porosity: 3,600 ml/min/cm2, 8 mm in inner diameter and 5 cm in length), were developed and implanted in the thoracic descending aorta of dogs to evaluate their endothelialization capability. Two weeks after implantation, many colonies of endothelial cells with openings of capillary blood vessels were noted, even in the middle portion of the grafts. Numerous fibroblasts and capillary blood vessels were also observed in the synthetic walls. These results suggest that UFPF vascular grafts provide a suitable microenvironment for infiltration and proliferation of fibroblasts, which are accompanied by the capillary formation as nutrient supply; these capillaries provide multiple sources of endothelial coverage on the luminal surface. It is expected that the new, highly porous vascular grafts may have rich endothelialization capability and stable healing properties in humans.

Real time measurement of nitric oxide released from cultured endothelial cells.

Direct detection of nitric oxide (NO) is essential for understanding the precise mechanism of its production from endothelial cells. Previously, we developed an NO detection system based on the chemiluminescence reaction between NO and luminol-H2O2. Here, we have applied this system to cultured endothelial cells for the direct and on-time measurement of NO. The perfusate from cultured endothelial cells was continuously mixed with luminol-H2O2. N(G)-monomethyl-L-arginine (L-NMMA) (10(-4) M) decreased the chemiluminescence signal of NO, suggesting the existence of basal NO release. Bradykinin (10(-8) M-10(-6) M) increased the NO signal (10(-6) M; 5.1+/-0.4 fmol/min, corresponding to 1.7 pM in the perfusate), and this was inhibited by 10(-4) M L-NMMA (1.8+/-0.3 fmol/min). These results corresponded to the changes in cGMP levels in RFL-6 cells, which provide an NO bioassay system. We conclude that the luminol-H2O2 system is useful for the direct and continuous measurement of NO from cultured endothelial cells.

Development of a new scrim cardiac wall substitute.

A cardiac wall substitute made of non-woven ultrafine fibers was developed. It consists of a basal knitted scrim with strongly entangled ultrafine polyester fibers, lined with a fine velour of entangled ultrafine fibers that provide high ravel and tear resistance, a perfect matrix for preclotting, and an anchor for cell adhesion. Six of the new patches and all control patches (a polytetrafluorethylene patch, woven Dacron patch, and glutaraldehyde-treated equine pericardium) were implanted in the right ventricular outflow tracts in 24 dogs. Animal experiments showed that the new patch was easy to handle and suture without fraying or tearing through the edge.

Role of central serotonergic (5-HT2) receptor in blood pressure regulation in rats.

To investigate the role of the serotonergic nervous system in blood pressure regulation, 5 micrograms of 5-hydroxytryptamine (5-HT) was given i.c.v. before and after 1 microgram of i.c.v. xylamidine or 200 micrograms of i.c.v. ketanserin or 200 micrograms of i.v. ketanserin in conscious Wistar Kyoto rats. Also i.v. (0.5, 1, 2 micrograms) or i.c.v. (1 microgram) phenylephrine (PHE) were given before and after 1 microgram of i.c.v. xylamidine. I.c.v. 5-HT elicited a consistent pressor response of approximately 27mmHg and slight decrease in heart rate. MAP and heart rate did not change after xylamidine or ketanserin. Whereas pressor response to i.c.v. 5-HT after i.c.v. ketanserin or i.c.v. xylamidine was suppressed, it did not change after i.v. ketanserin. Neither i.c.v. nor i.v. PHE-induced pressor response was influenced by i.c.v. xylamidine pretreatment. These data suggest that the central 5-HT2 receptor may subserve pressor function in rats.

Transesophageal echocardiographically detected atherosclerotic aortic debris in a patient with systemic embolism following coronary angiography.

Transesophageal echocardiography (TEE) has enabled detection of the cardiac source of systemic emboli. We report the case of a patient who manifested systemic, multiple embolization in the kidney, skin, and upper gastrointestinal tract following coronary angiography. TEE allowed visualization of the atherosclerotic debris in the thoracic aorta. The clinical picture of the patient was consistent with that of cholesterol embolism. We recommend that patients with extensive atherosclerotic disease should undergo TEE before cardiac catheterization or other invasive procedures involving the aorta are carried out.