Ikuyo Takagi

Type 5 Adenylyl Cyclase Disruption Alters Not Only Sympathetic But Also Parasympathetic and Calcium-Mediated Cardiac Regulation

Abstract— In a genetically engineered mouse line with disruption of type 5 adenylyl cyclase (AC5−/−), a major cardiac isoform, there was no compensatory increase in other isoforms of AC in the heart. Both basal and isoproterenol (ISO)-stimulated AC activities were decreased by 30% to 40% in cardiac membranes. The reduced AC activity did not affect cardiac function (left ventricular ejection fraction [LVEF]) at baseline. However, increases in LVEF after ISO were significantly attenuated in AC5−/− (P <0.05, n=11). Paradoxically, conscious AC5−/− mice had a higher heart rate compared with wild-type (WT) mice (613±8 versus 523±11 bpm, P <0.01, n=14 to 15). Muscarinic agonists decreased AC activity, LVEF, and heart rate more in WT than in AC5−/−. In addition, baroreflex-mediated, ie, neuronally regulated, bradycardia after phenylephrine was also attenuated in AC5−/−. The carbachol-activated outward potassium current (at −40 mV) normalized to cell capacitance in AC5−/− (2.6±0.4 pA/pF, n=16) was similar to WT (2.9±0.3 pA/pF, n=27), but calcium (Ca2+)-mediated inhibition of AC activity and Ca2+ channel function were diminished in AC5−/−. Thus, AC5−/− attenuates sympathetic responsiveness and also impairs parasympathetic and Ca2+-mediated regulation of the heart, indicating that those actions are not only regulated at the level of the receptor and G-protein but also at the level of type 5 AC.

Controlled-Release Basic Fibroblast Growth Factor for Peripheral Artery Disease: Comparison with Autologous Bone Marrow-Derived Stem Cell Transfer

OBJECTIVE We examined the safety and efficacy of controlled-release basic fibroblast growth factor (b-FGF) for peripheral artery disease (PAD), compared with autologous bone marrow mononuclear cell implantation (BMCI). BACKGROUND We recently developed a b-FGF-incorporated biodegradable hydrogel that enables slow-releasing drug delivery system. METHODS PAD patients were divided into a b-FGF group (n=10) and BMCI group (n=15). Injection of gelatin hydrogel containing 600 μg b-FGF or BMCI (0.4-5.1×10(10) cell) was performed. Visual analog pain scale (VAS), (99m)technetium-tetrofosmin (Tc-TF) scintigraphy, transcutaneous oxygen tension (TcPO(2)), and ankle-brachial index (ABI) were evaluated before and 4 weeks after each treatment, and 2-year prognosis was determined. RESULTS VAS (b-FGF 67±15 to 4±5, p<0.01, BMCI 67±42 to 5±9 mm, p<0.01) and TcPO(2) (b-FGF 16±14 to 47±17, p<0.01, BMCI 13±13 to 37±21 mmHg, p<0.01) were significantly improved in both groups. Tc-TF and ABI were not changed. Prognosis was similar between the groups (b-FGF 91%, BMCI 80%, NS). CONCLUSION Controlled-release b-FGF is as safe as BMCI, and its efficacy appears to be comparable. Thus, this therapy may be an alternative to BMCI.

Therapeutic Angiogenesis by Controlled-Release Fibroblast Growth Factor in a Patient With Churg-Strauss Syndrome Complicated by an Intractable Ischemic Leg Ulcer

Churg-Strauss syndrome (CSS) causes necrotizing vasculitis affecting small- to medium-sized arteries, mainly in the lungs, gastrointestinal system, heart, kidneys, and skin. Skin lesions sometimes ulcerate because of severe ischemia and become intractable when complicated by bacterial infection. We report a rare case of CSS, characterized by a nonhealing ischemic skin ulcer of the right calf with bacterial infection resistant to antibiotics. After sterile maggot debridement therapy, 2 skin autografts failed. Subsequently, a slow-release formula of basic fibroblast growth factor incorporated in biodegradable gelatin hydrogel was administered into the calf muscles to induce vascular regeneration. The ulcer eventually healed with no recurrence. This report describes the use of controlled-release basic fibroblast growth factor for an ischemic leg ulcer in a patient with CSS, suggesting a possible therapeutic role of this novel neovascularization therapy in treating severe skin lesions complicating autoimmune vasculitis syndromes.

Therapeutic vascular angiogenesis for intractable macroangiopathy-related digital ulcer in patients with systemic sclerosis: a pilot study

OBJECTIVE SSc causes intractable ischaemic ulcers. To avoid major amputation, we examined the safety and efficacy of therapeutic vascular angiogenesis for digital ulcers due to SSc. METHODS A single-centre, open-label pilot study was conducted in patients with an ischaemic digital ulcer [n = 40, mean age 65 years (s.d. 8), Rutherford class III-5 or III-6) due to lcSSc (n = 11) or arteriosclerosis obliterans (ASO; n = 29). Bone marrow mononuclear cells (0.4-5.1 × 10(10) cells in total) were administered into the ischaemic limbs. We evaluated short-term safety and efficacy by means of a pain scale, (99m)Tc-tetrofosmin scintigraphy and transcutaneous oxygen tension (TcPO2) before and 4 weeks after treatment. Also, the 2-year outcome was compared. RESULTS There was a case of amputation in each group within 4 weeks after therapy. The pain scale significantly decreased in both groups [lcSSc 93 mm (s.d. 9) to 11 (s.d. 16), P < 0.01; ASO 77 mm (s.d. 22) to 16 (s.d. 13), P < 0.01] and TcPO2 significantly improved [lcSSc 9.0 mmHg (s.d. 9) to 35 (s.d. 14), P < 0.01; ASO 18 mmHg (s.d. 10) to 29 (s.d. 21), P < 0.05). At the 2-year follow-up, the limb amputation rate was 9.1% in lcSSc and 20.7% in ASO (P = 0.36), while the recurrence rate was 18.2% in lcSSc and 17.2% in ASO (P = 0.95). All-cause mortality was 27.3% in lcSSc and 17.2% in ASO (P = 0.65). CONCLUSION In patients with lcSSc, bone marrow mononuclear cell implantation provides clinical benefit and is safe, without major adverse reactions, and may become an effective strategy. TRIAL REGISTRATION UMIN-CTR, http://www.umin.ac.jp/ctr/index-j.htm, no. UMIN000004112.

The incidence of deep vein thrombosis in Japanese patients undergoing endoscopic submucosal dissection

BACKGROUND Endoscopic submucosal dissection (ESD) is more invasive than other common endoscopic procedures and may increase the risk for deep vein thrombosis (DVT)/pulmonary embolism. The incidence of DVT/pulmonary embolism after ESD has not been adequately studied. OBJECTIVE To evaluate DVT incidence and disease-specific features of D-dimer levels in ESD patients. DESIGN Prospective cohort study. SETTING Single academic center. PATIENTS This study involved 60 patients with superficial gastric neoplasms indicated for ESD. INTERVENTION For all patients who underwent ESD, ultrasonography of the lower limbs was performed to detect DVT the day after ESD. D-dimer levels were measured 3 times: before ESD, immediately after ESD, and the day after ESD. MAIN OUTCOME MEASUREMENTS DVT incidence after ESD. RESULTS The DVT incidence was 10.0% (6/60). At all 3 time points, D-dimer measurements were higher in patients with DVT than in patients without DVT. According to receiver operating characteristic curve analysis, the resulting cut-off value of the D-dimer level the day after ESD was 1.9 μg/mL (sensitivity 83.3%; specificity 79.6%) for ESD patients, with superior association to pre-ESD or immediately after ESD. In univariate analyses, high D-dimer levels the day after ESD and the presence of comorbidities were significantly associated with DVT development. LIMITATIONS Single center and small number of patients. CONCLUSION ESD procedures have a moderate risk for venous thromboembolism. In patients undergoing ESD, D-dimer levels, especially on the day after ESD, may have specific features associated with DVT development.

Prediction of Limb Salvage after Therapeutic Angiogenesis by Autologous Bone Marrow Cell Implantation in Patients with Critical Limb Ischemia

PURPOSE Despite advances in therapeutic angiogenesis by bone marrow cell implantation (BMCI), limb amputation remains a major unfavorable outcome in patients with critical limb ischemia (CLI). We sought to identify predictor(s) of limb salvage in CLI patients who received BMCI. MATERIALS AND METHODS Nineteen patients with CLI who treated by BMCI were divided into two groups; four patients with above-the-ankle amputation by 12 weeks after BMCI (amputation group) and the remaining 15 patients without (salvage group). We performed several blood-flow examinations before BMCI. Ankle-brachial index (ABI) was measured with the standard method. Transcutaneous oxygen tension (TcPO2) was measured at the dorsum of the foot, in the absence (baseline) and presence (maximum TcPO2) of oxygen inhalation. (99m)technetium-tetrofosmin ((99m)Tc-TF) perfusion index was determined at the foot and lower leg as the ratio of brain. RESULTS Maximum TcPO2 (p = 0.031) and (99m)Tc-TF perfusion index in the foot (p = 0.0068) was significantly higher in the salvage group than in the amputation group. Receiver operating characteristic (ROC) curve analysis identified maximum TcPO2 and (99m)Tc-TF perfusion index in the foot as having high predictive accuracy for limb salvage. CONCLUSION Maximum TcPO2 and (99m)Tc-TF perfusion index in the foot are promising predictors of limb salvage after BMCI in CLI.

Novel approach to ischemic skin ulcer in systemic lupus erythematosus: therapeutic angiogenesis by controlled-release basic fibroblast growth factor.

Systemic lupus erythematosus (SLE) frequently involves the vascular system, and the acquired inflammatory process is known to accelerate atherosclerosis. We report a 65-year-old woman with SLE complicated by an ischemic skin ulcer of the superior portion of the right lateral malleolus which was untreatable by local therapy. The ankle–brachial index was reduced to 0.72 in the right leg, and transcutaneous oxygen tension (TcPO2) at the dorsum of the right foot was 1.0 mmHg (normal limit: >30 mmHg) with no increase after pure oxygen inhalation. Angiography revealed total occlusions of all the below-the-knee arteries with poor distal collateral circulation, indicating an Inter-Society Consensus type D lesion. Because the patient’s SLE disease activity index was 11 points under the administration of prednisolone and methotrexate, invasive therapy by percutaneous or surgical revascularization was not preferable. Thus, we decided to perform therapeutic angiogenesis by administration of controlled-release basic fibroblast growth factor (bFGF)-incorporated biodegradable gelatin hydrogel. Four weeks after the therapy, there was no significant improvement in ankle–brachial index (ABI) and angiographic findings. Instead, basal TcPO2 was increased to 10 mmHg with an additional increase up to 39 mmHg by oxygen inhalation. Furthermore, the ulcer healed completely without any complications. This result suggests that bFGF protein therapy using the drug delivery system can be a promising approach to intractable skin ulcers complicating SLE. Systemic lupus erythematosus is manifested by an interaction between susceptible genes and environmental risk factors, which leads to autoimmune reactions. As the next step, generated autoantibodies and immune complexes deposited in tissue activate complement, induce inflammation and lead to irreversible organ damage. SLE frequently involves the vascular system, and the occurring inflammation accelerates atherosclerosis. Roman et al. reported that the prevalence of atherosclerosis was significantly higher in patients with SLE, and the accelerated atherosclerosis was not attributable to traditional cardiovascular risk factors. Furthermore, progressive ischemic skin ulcers, requiring limb amputation, occasionally complicate SLE. Previously, we demonstrated that i.m. administration of controlled-release bFGF-incorporated biodegradable gelatin hydrogel successfully improved leg ischemia and cured a skin ulcer in a patient with Churg–Strauss syndrome. In the present case, we applied this novel treatment approach to a patient with SLE complicated by an unhealed skin ulcer, and achieved successful improvement of the local skin blood perfusion and healing of the skin ulcer 4 weeks after the therapy. A 65-year-old woman, diagnosed with SLE at 42 years old, was referred to our hospital with resting pain of her right foot complicated by a skin ulcer of the superior portion of her right lateral malleolus (Fig. 1a), which was not improved by topical and systemic medication for 1 month. As a conventional therapy for peripheral arterial disease, cilostazol and prostaglandin agents were used before admission, and Geriatr Gerontol Int 2011; 11: 527–530

Chronic direct stimulation of adenylyl cyclase induces cardiac desensitization to catecholamine and beta-adrenergic receptor downregulation in rabbits.

Chronic stimulation of beta-adrenergic receptors (βARs) induces βAR downregulation. However, it is not known whether continuous activation of adenylyl cyclase without direct stimulation of βARs leads to receptor downregulation. This study investigated the effects of chronic stimulation of adenylyl cyclase with colforsin, on hemodynamic variables, and on myocardial βAR density. In all, 55 rabbits received intravenous colforsin (1.6 μg/kg/min, n = 20), isoproterenol (ISO; 0.4 μg/kg/min, n = 16), or saline (n = 19) for two weeks. After chronic drug administration, responses of systolic (Δ% peak LV +dP/dt) and diastolic function (Δ% peak LV −dP/dt), and heart rate (Δ% heart rate), to acute administration of ISO (0.05 to 0.2 μg/kg/min) or colforsin (5 to 20 nmol/kg/min) were decreased compared to those before chronic administration. βAR density in the colforsin group (69.8 ± 13.8 fmol/ml protein) was less than that in the saline group (79.8 ± 15.0 fmol/ml protein, P < 0.05), but was greater than that in the ISO group (56.3 ± 8.4 fmol/ml protein, P < 0.05). Thus, chronic direct stimulation of adenylyl cyclase elicited systolic and diastolic functional desensitization to βAR stimulation or adenylyl cyclase stimulation, and myocardial βAR downregulation.