Ryota Kikuchi

Hypercapnia Accelerates Adipogenesis: A Novel Role of High CO2 in Exacerbating Obesity

Abstract Obesity is a major risk factor for the development of obstructive sleep apnea (OSA) and obesity hypoventilation syndrome (OHS), which manifest as intermittent hypercapnia and sustained plus intermittent hypercapnia, respectively. In this study, we investigated whether CO2 affects adipocyte differentiation (adipogenesis) and maturation (hypertrophy). Human visceral or subcutaneous preadipocytes were grown to confluence and then induced to differentiate to adipocytes under hypocapnia, normocapnia, and hypercapnia with or without hypoxia. Adipogenesis was also induced under intermittent or sustained hypercapnia. Differentiated adipocytes were maintained to maturity under normocapnia or hypercapnia. Our main findings are as follows: (1) hypercapnia accelerated adipogenesis in visceral and subcutaneous preadipocytes, whereas hypocapnia inhibited adipogenesis; (2) hypercapnia did not affect adipocyte hypertrophy; (3) hypercapnia‐accelerated adipogenesis was independent of extracellular acidosis, oxygen concentration, or either intermittent or sustained exposure to high CO2; and (4) the mechanisms underlying hypercapnia‐accelerated adipogenesis involved increased production of cyclic adenosine monophosphate (cAMP) via soluble adenylyl cyclase, leading to the activation of protein kinase A and exchanger protein directly activated by cAMP, which, in turn, activated proadipogenic transcription factors, such as cAMP response element binding protein, CCAAT/enhancer binding protein &bgr;, and peroxisome proliferator‐activated receptor &ggr;. This study reveals a novel role of high CO2 in promoting adipogenesis, which provides mechanistic clues to a pathoetiological interaction between OSA/OHS and obesity. Our data suggest a vicious cycle of disease progression via the following mechanism: OSA/OHS → hypoventilation → hypercapnia → increased adipogenesis → increased fat mass → exacerbated OSA/OHS.

Clinical factors associated with negative urinary antigen tests implemented for the diagnosis of community-acquired pneumococcal pneumonia in adult patients.

Objective: This study investigated clinical factors associated with negative urinary antigen tests (UAT) implemented for the diagnosis of pneumococcal community-acquired pneumonia (CAP) in adult patients. Subjects and Methods: We reviewed the medical records of 755 adult patients who completed the UAT in our hospital between 2009 and 2012. Of these, we evaluated 63 patients with bacteriologically confirmed definite pneumococcal CAP (33 were UAT-positive, and 30 were UAT-negative). Results: There was no significant difference between the UAT-positive and the UAT-negative patients regarding age, dehydration, respiratory failure, orientation, blood pressure (ADROP) score (the CAP severity score proposed by the Japanese Respiratory Society), gender, white blood cell counts, liver/kidney function tests, or urinalysis. However, serum C-reactive protein (CRP) concentrations were 31% lower in the UAT-negative patients than in the UAT-positive patients (p = 0.02). Furthermore, the prothrombin time-international normalized ratio was 50% higher in the UAT-negative patients than in the UAT-positive patients, although the difference did not reach statistical significance (p = 0.06). The prevalence of comorbidities was similar in both UAT-positive and UAT-negative patients. However, warfarin had been prescribed in 8 (27%) of the UAT-negative patients compared to only 1 (3%) of the UAT-positive patients (odds ratio = 11.6; p = 0.01). Conclusions: These results suggested that low serum CRP concentrations and the use of warfarin increased the possibility with which false-negative UAT results occurred in these patients with pneumococcal CAP.

Promotion of adipogenesis by an EP2 receptor agonist via stimulation of angiogenesis in pulmonary emphysema

Body weight loss is a common manifestation in patients with chronic obstructive pulmonary disease (COPD), particularly those with severe emphysema. Adipose angiogenesis is a key mediator of adipogenesis and use of pro-angiogenic agents may serve as a therapeutic option for lean COPD patients. Since angiogenesis is stimulated by PGE2, we examined whether ONO-AE1-259, a selective E-prostanoid (EP) 2 receptor agonist, might promote adipose angiogenesis and adipogenesis in a murine model of elastase-induced pulmonary emphysema (EIE mice). Mice were intratracheally instilled with elastase or saline, followed after 4 weeks by intraperitoneal administration of ONO-AE1-259 for 4 weeks. The subcutaneous adipose tissue (SAT) weight decreased in the EIE mice, whereas in the EIE mice treated with ONO-AE1-259, the SAT weight was largely restored, which was associated with significant increases in SAT adipogenesis, angiogenesis, and VEGF protein production. In contrast, ONO-AE1-259 administration induced no alteration in the weight of the visceral adipose tissue. These results suggest that in EIE mice, ONO-AE1-259 stimulated adipose angiogenesis possibly via VEGF production, and thence, adipogenesis. Our data pave the way for the development of therapeutic interventions for weight loss in emphysema patients, e.g., use of pro-angiogenic agents targeting the adipose tissue vascular component.

Little evidence for epithelial-mesenchymal transition in a murine model of airway fibrosis induced by repeated naphthalene exposure.

Recent evidence suggests that epithelial-mesenchymal transition (EMT) is involved in the pathogenesis of airway obstructive diseases, such as chronic obstructive pulmonary disease, asthma and bronchiolitis obliterans syndrome after lung transplantation. However, whether EMT occurs in an experimental model of airway fibrosis is not well known. We explored evidence of EMT in a murine model of airway fibrosis induced by repeated exposure to naphthalene. Mice were administered intraperitoneal injections of naphthalene or corn oil vehicle once weekly for 14 consecutive weeks. The animals were sacrificed 5days after the final injection of naphthalene or corn oil vehicle. EMT was evaluated in lung tissue sections using immunohistochemistry and immunofluorescence. Repeated naphthalene exposure induced loss of club cells, hyperplasia of epithelial cells and peribronchial fibrosis. However, we did not find any loss of E-cadherin expression or any acquisition of vimentin, S100A4 or αSMA in epithelial cells in control or naphthalene-exposed mice. These results suggest that EMT does not contribute significantly to naphthalene-induced airway fibrosis in mice.

Hypertrophic Osteoarthropathy Secondary to Lung Cancer: Beneficial Effect of Anti-vascular Endothelial Growth Factor Antibody

FIGURE 1. Clinical features of the case. A, Clubbing of the fingers. Chest X-ray (B) and CT scan (C) showing a mass in the right upper lobe of the lung (arrow) and enlarged mediastinal and hilar lymph nodes (arrowheads), which compressed the superior vena cava (asterisk) and resulted in obstructive atelectasis of the right upper lobe (dashed arrows). D, Plain radiography of the left tibia showing a periosteal reaction (arrowheads). E, Bone scintigraphy showing symmetric, diffuse cortical uptake in the bilateral radius and ulna and the left tibia (arrowheads). F, Bone scintigraphy after treatment showing improvements of the abnormal cortical uptake. Color online figure A available at www.jclinrheum. H ypertrophic osteoarthropathy (HOA) is a syndrome characterized by digital clubbing, periostosis, and arthritis. Although primary cases of HOA are rare, this syndrome is frequently associated with a variety of hypoxic and malignant conditions, and lung cancer is one of the most common malignancies leading to HOA. A previous study reported that 115 (1.9%) of 6,151 patients with lung cancer had HOA. HOA symptoms have been shown to improve in 91% of patients after surgical resection of lung cancer. However, in inoperable cases, painful osteoarthropathy becomes a significant clinical problem because it is often refractory to nonsteroidal anti-inflammatory drugs (NSAIDs) and narcotic analgesics. We report a case of lung-cancer-associated HOA that exhibited local and systemic elevation of vascular endothelial growth factor (VEGF) and was successfully managed with radiotherapy and chemotherapy, including the neutralizing anti-VEGFantibody bevacizumab. The presented case highlights a beneficial effect of VEGF inhibition in the management of HOA. A 46-year-old Japanese man was admitted to our hospital because of cough, dyspnea, and pain in his bilateral upper and lower extremities, including the bilateral elbow and knee joints, lasting for 2 months. He had a 24 pack/year smoking history, but no medical or allergy history, or family history of HOA. On physical examination, he had facial edema, painless enlargement of the cervical and supraclavicular lymph nodes, decreased breath sound in the right upper lobe of the lung, clubbed fingers (Fig. 1A), tenderness along the bilateral upper and lower limb bones, and painful swelling and redness of the bilateral elbow and knee joints. The range of motion of the upper and lower limbs was limited due to severe bone pain with arthralgia. Blood tests revealed leukocytosis (8,700 cells/μL) with high levels of C-reactive protein (5.77 mg/dL; reference range: <0.3 mg/dL), alkaline phosphatase (376 IU/L; reference range: <325 IU/L), and VEGF (317 pg/mL; reference range: <38.3 pg/mL). Blood tests for cyclic citrullinated peptide antibody and

Remission of ALK-negative primary pulmonary inflammatory myofibroblastic tumor on treatment with clarithromycin: A case report and review of the literature

Inflammatory myofibroblastic tumors (IMTs) belong to an intermediate group of soft-tissue tumors, they are relatively rare but exhibit a wide range of pathologies, from benign to malignant. At present, no standard treatment has been established, however, it is known to be important to determine the grade of malignancy of the tumor, prior to treatment. The present study reports a 73-year-old female patient with no clinical manifestations, who, when examined radiographically at a health check exhibited bilateral thoracic infiltrative shadows and nodular shadows by chest CT. A metastatic tumor or an organizing pneumonia were suspected. Blood examination showed no abnormal findings, and a pathological diagnosis of IMT was given from the histological findings of the tissue extracted by video-assisted thoracic surgery. Histological analysis established the lack of expression of anaplastic lymphoma kinase (ALK1) and immunoglobulin subtype G4 (IgG4). Alteration of the radiological shadows was observed over several weeks, and after concluding that chronic inflammation was worsening the patients condition, clarithromycin was administered as a long-term macrolide therapy. The IMT decreased in size, and eight months later it had almost resolved. The patient was last reported to be maintaining a stable condition with no relapse. Some IMT cases have malignant pathology, and should be carefully followed-up. However, in the present case, where the IMT is both ALK1-negative and IgG4-negative, its biological immune responsiveness appears to differ from positive cases, and an inflammatory response was predominant. Clarithromycin, has immunomodulatory and anti-inflammatory effects and appeared to be effective in treating the IMT of the patient in the present study.

Diffuse alveolar hemorrhage after use of a fluoropolymer -based waterproofing spray

A 30-year-old man developed chills, cough and dyspnea a few minutes after using a fluoropolymer-based waterproofing spray in a small closed room. He visited our hospital 1xa0h later. Examination revealed that the patient had incessant cough, tachypnea, fever and decreased peripheral arterial oxygen saturation. Blood tests revealed leukocytosis with elevated serum C-reactive protein levels. Chest radiographs and computed tomography (CT) scan showed bilateral ground glass opacities, mainly in the upper lobes. Bronchoalveolar lavage (BAL) fluid obtained from the right middle lobe showed a bloody appearance. Microscopic examination of a BAL cytospin specimen revealed the presence of numerous red blood cells associated with extreme neutrophilia. Microbiological studies of the BAL fluid were negative. The patient was observed without corticosteroid therapy, and his symptoms and abnormal shadows on the chest radiographs and CT improved. On day 7 after admission, the patient was discharged from the hospital. Accidental inhalation of waterproofing spray may cause diffuse alveolar hemorrhage, a rare manifestation of acute lung injury. Supportive treatment may be effective and sufficient.

Repeated exposure to 5-bromo-2'-deoxyuridine causes decreased proliferation and low-grade inflammation in the lungs of mice.

Incorporation of 5-bromo-2-deoxyuridine (BrdU) into proliferating cells has been used to label dividing cells in many tissues. Although BrdU has been shown to be genotoxic, teratogenic and mutagenic, such adverse effects have largely been ignored by researchers. We determined whether long-term BrdU exposure causes any histopathological changes in the lungs of mice. Eight-week-old male C57/BL6J mice were administered BrdU by intraperitoneal injection on 3 consecutive days of each week for 14 weeks. While no obvious structural changes such as tissue damage, fibrosis, emphysema, airway remodeling, vascular thickening or tumorigenesis were noted, a moderate degree of macrophage infiltration was observed in the airways and lung parenchyma in the lungs of the mice exposed repeatedly to BrdU (BrdU-exposed mice). The proliferative activities of the airway and alveolar epithelial and mesenchymal cells were reduced in the BrdU-exposed mice, although the numbers of these cells in the lungs were maintained. Double immunofluorescence study of the lungs of the BrdU-exposed mice showed overexpression of IL-6 in the airway epithelial and alveolar wall cells, some of which were also double-positive for BrdU. These results indicate that long-term exposure to BrdU inhibits cell proliferation and induces low-grade inflammation in the lungs of mice. Our findings underscore the need for caution in the interpretation of studies that involve long-term exposure to BrdU.

A case of eosinophilic pneumonia simultaneously diagnosed in a patient and a tame cat: a case report

IntroductionChronic eosinophilic pneumonia is an idiopathic disorder of unknown etiology. Corticosteroid treatment provides a good response but recurrence frequently occurs after tapering of corticosteroid. Chronic eosinophilic pneumonia occurs predominantly in middle-aged women and non-cigarette smokers, which leads to the speculation that environmental antigens, particularly in the home, contribute to the etiology.Case presentationA 66-year-old Japanese woman was given a diagnosis of chronic eosinophilic pneumonia for 8 years and was treated with prednisone. She developed respiratory symptoms again with tapering of prednisone (10mg/day). A chest radiograph revealed patchy shadows in her bilateral upper lung fields, and bronchoalveolar lavage fluid revealed marked eosinophilia. Based on negative findings for other causes of eosinophilia, the diagnosis of the recurrence of chronic eosinophilic pneumonia was established. She was treated with prednisone (20mg/day), which demonstrated rapid improvement. Around the same time, her tame cat developed oral breathing, tachypnea and peripheral eosinophilia. Chest radiography of the cat revealed ground-glass opacity in its bilateral upper lung fields. Eosinophilic pneumonia was also diagnosed in the cat that was treated by prednisone (3mg/day). Since eosinophilic pneumonia was diagnosed simultaneously in the patient and her tame cat, it can be suggested that inhaled environmental antigens in the home caused the eosinophilic pneumonia. After moving out of her home, she and the cat had no recurrence of eosinophilic pneumonia.ConclusionsAlthough chronic eosinophilic pneumonia is an idiopathic disorder of unknown etiology, our case suggests that inhaled environmental antigens in the home may be associated with the causes of chronic eosinophilic pneumonia. A pet’s disease may give us an important clue for the therapeutic approach of the owner’s disease.

Sitagliptin-induced diffuse alveolar hemorrhage mimicking pulmonary edema

Dear Editor, We read with great interest the article entitled “Noncardiac pulmonary edema induced by sitagliptin treatment” by Belice et al.[1] published in this journal, and also a commentary on this article by Sureka et al.,[2] who discussed the pulmonary edema of unknown etiology in this patient. Through our recent clinical experience, we would like to point out diffuse alveolar hemorrhage (DAH) as another potential cause of “pulmonary edema” in the patient reported by Belice et al. Our patient, a 50‐year‐old Japanese male with diabetes mellitus who had been started on treatment with sitagliptin at the dose of 50 mg once a day 3 months earlier, was admitted to our hospital because of bloody sputum and worsening of dyspnea. He had previously been diagnosed as having interstitial pneumonia, but his respiratory symptoms had been stable before he started to receive sitagliptin. On admission, he had tachypnea and hypoxemia (SpO2 75%), and chest examination revealed fine and coarse crackles in the lower lung regions on both sides. His chest X‐ray [Figure 1a] and computed tomography (CT) [Figure 1b] revealed new‐onset bilateral diffuse infiltrative and ground‐glass opacities, in addition to the preexisting bibasilar reticular shadows due to interstitial pneumonia; the new opacities suggested the complication of pulmonary edema. However, there were no clinical signs suggestive of cardiogenic edema, for example, no pretibial edema, normal plasma brain natriuretic peptide levels, a normal 12‐lead electrocardiograph, and normal cardiac function on echocardiography. In contrast, bronchoalveolar lavage fluid obtained by fiberoptic bronchoscopy showed a bloody appearance [Figure 1c], confirming the diagnosis of DAH as the cause of the acute respiratory insufficiency with the CT opacities suggestive of pulmonary edema. A positive result of the drug‐induced lymphocyte stimulation test with sitagliptin strongly suggested that this drug was the cause of the DAH in our patient. Thereafter, sitagliptin was discontinued, and the patient was started on intravenous methylprednisolone pulse therapy (1 g/day), his symptoms improved, and the bilateral diffuse infiltrative and ground glass opacities on the chest CT almost disappeared.