Case Report: Durable therapy response to Osimertinib in rare EGFR Exon 18 mutated NSCLC.

Up to 20% of all non-small cell lung cancer patients harbor tumor specific driver mutations that are effectively treated with tyrosine kinase inhibitors. However, for the rare EGFR deletion-insertion mutation of exon 18, there is very little evidence regarding the effectiveness of tyrosine kinase inhibitors. A particular challenge for clinicians in applying tyrosine kinase inhibitors is not only diagnosing a mutation but also interpreting rare mutations with unclear therapeutic significance. Thus, we present the case of a 65-year-old Caucasian male lung adenocarcinoma patient with an EGFR Exon 18 p.Glu709_Thr710delinsAsp mutation of uncertain therapeutic relevance. This patient initially received two cycles of standard platinum-based chemotherapy without any therapeutic response. After administration of Osimertinib as second line therapy, the patient showed a lasting partial remission for 12 months. Therapy related toxicities were limited to mild thrombocytopenia, which ceased after dose reduction of Osimertinib. To our knowledge, this is the first report of effective treatment of this particular mutation with Osimertinib. Hence, we would like to discuss Osimertinib as a viable treatment option in EGFR Exon 18 p.Glu709_Thr710delinsAsp mutated lung adenocarcinoma.

Outpatient palliative care during the COVID-19 pandemic: a retrospective single centre analysis in Germany.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic has challenged health care systems worldwide. In Germany, patients in a palliative care setting have the opportunity to receive treatment by a specialised mobile outpatient palliative care team (OPC). The given retrospective single centre analysis describes the use of OPC structures for terminally ill COVID-19 patients during the height of the pandemic in Germany and aims to characterise this exceptional OPC patient collective. METHODS: First, death certificates were analysed in order to collect data about the place of death of all deceased COVID-19 patients (n = 471) within our local governance district. Second, we investigated whether advance care planning structures were established in local nursing homes (n = 30) during the height of the COVID-19 pandemic in 2020. Third, we examined patient characteristics of COVID-19 negative (n = 1579) and COVID-19 positive (n = 28) patients treated by our tertiary care centre guided OPC service. RESULTS: The analysis of death certificates in our local district revealed that only 2.1% of all deceased COVID-19 patients had succumbed at their home address (n = 10/471). In contrast, 34.0% of COVID-19 patients died in nursing homes (n = 160/471), whereas 63.5% died in an inpatient hospital setting (n = 299/471). A large proportion of these hospitalised patients died on non-intensive care unit wards (38.8%). Approximately 33.0% of surveyed nursing homes had a palliative care council service and 40.0% of them offered advance care planning (ACP) structures for their nursing home residents. In our two OPC collectives we observed significant differences concerning clinical characteristics such as the Index of Eastern Cooperative Oncology Group [ECOG] (p = 0.014), oncologic comorbidity (p = 0.004), as well as referrer and primary patient location (p = 0.001, p = 0.033). CONCLUSIONS: Most COVID-19 patients in our governance district died in an inpatient setting. However, the highest number of COVID-19 patients in our governance district who died in an outpatient setting passed away in nursing homes where palliative care structures should be further expanded. COVID-19 patients who died under the care of our OPC service had considerably fewer oncologic comorbidities. Finally, to relieve conventional health care structures, we propose the expansion of established OPC structures for treating terminally ill COVID-19 patients.

Palliative care of older glioblastoma patients in neurosurgery.

PURPOSE: The care of older neurosurgical patients at the end life is a particularly demanding challenge. Especially, the specific needs of very old patients with glioblastoma at the end of life are at risk of being deprived of adequate care. METHODS: Based on a narrative literature review, this article aims to explore key issues of the thematic intersection of geriatric glioblastoma patients, palliative care and neurosurgery. RESULTS AND DISCUSSION: Four key issues were identified: patient-centeredness (need orientation and decision making), early palliative care, advance care planning, and multi-professionalism. Possible benefits and barriers are highlighted with regard to integrating these concepts into neurosurgery. CONCLUSIONS: Palliative care complements neurosurgical care of geriatric glioblastoma multiforme patients to optimise care for this highly vulnerable category of patients.

Changes in Pain Medication Profile among Patients Admitted to Specialized Home Palliative Care in Relation to Referral Source: An Exploratory Study.

Pain is a common symptom leading to referrals to specialized home palliative care (SHPC) services and is known to affect patients' quality of life. To date, little is known about the impact of referral source on its management. To assess changes to pain medication profile in the course of SHPC and to identify potential differences in relation to referral source. This exploratory study is a retrospective analysis of 501 electronic medical records of a SHPC team in Germany. This included the assessment of baseline pain medication profiles according to the WHO analgesic ladder and changes to analgesic treatment in the course of SHPC with respect to referral source. At the time of admission, 77.4% of patients referred by a hospital and 78.8% of patients referred by the outpatient sector received a fixed analgesic regimen. In all, 61.9% of the inpatient group versus 62.9% of the outpatient group were treated with opioids, and 79.0% received modifications to pain medication at one point in time following admission. Thereby, patients referred by the outpatient sector received significantly earlier modifications and more supplementations of pain medication. Our study suggests positive development in the prescription of opioid analgesics compared to earlier studies in Germany. On the one hand, it highlights the relevance of thorough assessment and responsive evaluation of pain in SHPC, and on the other hand it reveals possible training needs of referring physicians, particularly those working in the outpatient sector. Our results inspired further research examining more closely the links between referral source and pain management.

Poor sleep quality is associated with exercise limitation in precapillary pulmonary hypertension.

BACKGROUND: Patients with precapillary pulmonary hypertension (PH) have been reported to suffer from poor sleep quality, however, if this is related to physical exercise performance has not yet been thoroughly investigated. METHODS: Clinically stable out-patients with idiopathic pulmonary arterial hypertension (IPAH, n = 52) and chronic thromboembolic PH (CTEPH, n = 64) in NYHA classes II and III were prospectively enrolled. 54 healthy volunteers matched for anthropometric variables served as a control group. The Pittsburgh Sleep Quality Index (PSQI) was used to rate subjective sleep quality. In the PH patients, six-minute walk tests (6MWT) were performed to assess exercise capacity. RESULTS: Poor sleep quality (i.e. a PSQI score > 5) occurred more frequently in PH (IPAH: n = 25 [48.1%], CTEPH: n = 39 [60.9%], controls: n = 10 [18.5%]; p < 0.01 when compared to controls). In addition, poor vs. good sleepers had significantly higher average NYHA class (IPAH: 2.6 ± 0.1 vs. 2.3 ± 0.1, CTEPH: 2.8 ± 0.1 vs. 2.3 ± 0.2; p < 0.01) and shorter 6MWT distances (IPAH: 338 ± 23 vs. 441 ± 29 m, CTEPH: 355 ± 15 vs. 413 ± 26 m; p < 0.05). CONCLUSIONS: Self-reported poor sleep quality is more common in PH than in healthy controls. Furthermore, it is related to reduced physical exercise capacity.

Arterial hypertension in a murine model of sleep apnea: role of NADPH oxidase 2.

OBJECTIVES: To investigate whether NADPH oxidase 2 (NOX2), a major source of reactive oxygen species (ROS), contributes to the emergence of arterial hypertension in a murine model of sleep apnea. BACKGROUND: Obstructive sleep apnea (OSA) is a risk factor for arterial hypertension and it is linked to oxidative stress. METHODS: C57BL/6J mice were exposed to chronic intermittent hypoxia (CIH) for 6 weeks (5 days/week, 8 h/day, alternating cycles of hypoxia and normoxia, each lasting 120 s, nadir FiO2: 7%). Blood pressure was monitored by telemetric catheters implanted into the abdominal aorta. Pharmacological inhibition of NOX by apocynin and NOX2-deficient mice were used to assess the role of NOX in CIH-induced arterial hypertension. NOX2 gene expression was measured by real-time PCR in different cardiovascular tissues. RESULTS: When compared with room air conditions, wild-type mice showed significant blood pressure elevations after exposure to CIH. This response was attenuated after treating animals with apocynin and in NOX2 (=gp91) knockout mice, whereas NOX2 was not upregulated in the heart, aorta, and femoral/carotid arteries of CIH mice. CONCLUSION: We suggest that the CIH-induced arterial hypertension is mediated by ROS derived from an activation of NOX2 within cells located outside the cardiovascular system.

Obstructive sleep apnea, oxidative stress and cardiovascular disease: lessons from animal studies.

Obstructive sleep apnea (OSA) is an independent risk factor for cardiovascular (CV) diseases such as arterial hypertension, heart failure, and stroke. Based on human research, sympathetic activation, inflammation, and oxidative stress are thought to play major roles in the pathophysiology of OSA-related CV diseases. Animal models of OSA have shown that endothelial dysfunction, vascular remodelling, and systemic and pulmonary arterial hypertension as well as heart failure can develop in response to chronic intermittent hypoxia (CIH). The available animal data are clearly in favour of oxidative stress playing a key role in the development of all of these CV manifestations of OSA. Presumably, the oxidative stress is due to an activation of NADPH oxidase and other free oxygen radicals producing enzymes within the CV system as evidenced by data from knockout mice and pharmacological interventions. It is hoped that animal models of OSA-related CV disease will continue to contribute to a deeper understanding of their underlying pathophysiology and will foster the way for the development of cardioprotective treatment options other than conventional CPAP therapy.

Sleep apnea in precapillary pulmonary hypertension.

OBJECTIVES: Pilot studies have described the occurrence of sleep apnea in patients with precapillary pulmonary hypertension (PH). However, there are no data on the prevalence of sleep-related breathing disorders in larger patient cohorts with PH. METHODS: 169 patients with a diagnosis of PH confirmed by right heart catheterisation and clinically stable in NYHA classes II or III were prospectively investigated by polygraphy (n = 105 females, mean age: 61.3 years, mean body mass index: 27.2 kg/m(2)). Recruitment was independent of sleep-related symptoms and the use of vasodilator drugs or nasal oxygen. RESULTS: 45 patients (i.e. 26.6%) had an apnea-hypopnea-index (AHI) >10/h. Of these, 27 patients (i.e. 16%) had obstructive sleep apnea (OSA) and 18 patients (i.e. 10.6%) had central sleep apnea (CSA). The mean AHI was 20/hour. As a polygraphy had been performed with nasal oxygen in half of the patients without evidence for sleep apnea, the frequency of CSA was probably underestimated. Patients with OSA were characterized by male gender and higher body mass index whereas, those with CSA were older and hypocapnic. CONCLUSIONS: At least every fourth patient with PH suffers from mild-to-moderate sleep apnea. Considering the anthropometric characteristics of the patients studied, the prevalence of both OSA and CSA seem to be higher in PH than in the general population.

Quality of life in clinically stable adult cystic fibrosis out-patients: associations with daytime sleepiness and sleep quality.

BACKGROUND: Patients with cystic fibrosis (CF) may suffer from sleep disturbances and reduced health-related quality of life (HRQoL). However, the relationships of daytime sleepiness and sleep quality to HRQoL in CF have not yet been investigated. PATIENTS AND METHODS: 55 adult CF out-patients free from a pulmonary exacerbation were prospectively enrolled in this study. Questionnaires were used to assess disease-specific HRQoL (German version of the revised Cystic Fibrosis Questionnaire for adults, CFQ18 + R), daytime sleepiness (Epworth Sleepiness Scale, ESS) and sleep quality (Pittsburgh Sleep Quality Index, PSQI). 30 age- and sex-matched healthy volunteers served as a control group. RESULTS: The prevalence of daytime sleepiness was higher in the CF than in the control group (ESS > 10; n = 11 [20%] vs. n = 2 [6.7%]; p < 0.01) as was reduced sleep quality (PSQI > 5; n = 21 [38.2%] vs. n = 1 [3.3%]; p < 0.01). Multiple regression analysis including age, gender, body mass index, lung function and pseudomonas status showed that higher PSQI scores significantly correlated with lower CFQ18 + R scores for vitality, emotional functioning, social, role, eating disturbances and digestive symptoms. CONCLUSION: In clinically stable adult CF out-patients self-reported daytime sleepiness and poor sleep quality are more common than in age and sex-matched healthy controls. In addition, impaired sleep quality is related to reduced disease-specific HRQoL in CF.

Sleep-disordered breathing in deep vein thrombosis and acute pulmonary embolism.

Sleep-disordered breathing (SDB) may trigger thromboembolic events by enhancing intravascular clot formation. The primary objective of the present nested case-control study was to investigate whether the prevalence of SDB is increased in patients with deep vein thrombosis (DVT) and/or acute pulmonary embolism (PE). 82 consecutive patients with DVT and/or PE (cases) were prospectively enrolled irrespective of SDB-related symptoms and formed matched pairs with patients without DVT and/or PE (controls) according to sex and pre-defined categories of age and body mass index. The prevalence of SDB (respiratory disturbance index assessed by polygraphy ≥ 15 events·h(-1)) was significantly greater in the cases with DVT and/or PE than in controls (40 versus 26%, p=0.046) and was predominantly obstructive in nature. Multiple regression analysis revealed that SDB was significantly associated with DVT and/or PE (OR 2.28, 95% CI 1.08-4.85; p=0.032) independent of established risk factors for thrombosis. In the sex-specific analyses this association was significant in females (OR 4.14, 95% CI 1.05-16.36; p=0.042), but not in males (OR 1.55, 95% CI 0.57-4.21; p=0.391). SDB occurs more frequently in females with DVT and/or PE than in controls matched for anthropometric variables, and is independently associated with the occurrence of these thromboembolic events.

Inducible NOS inhibition reverses tobacco-smoke-induced emphysema and pulmonary hypertension in mice.

Chronic obstructive pulmonary disease (COPD) is one of the most common causes of death worldwide. We report in an emphysema model of mice chronically exposed to tobacco smoke that pulmonary vascular dysfunction, vascular remodeling, and pulmonary hypertension (PH) precede development of alveolar destruction. We provide evidence for a causative role of inducible nitric oxide synthase (iNOS) and peroxynitrite in this context. Mice lacking iNOS were protected against emphysema and PH. Treatment of wild-type mice with the iNOS inhibitor N(6)-(1-iminoethyl)-L-lysine (L-NIL) prevented structural and functional alterations of both the lung vasculature and alveoli and also reversed established disease. In chimeric mice lacking iNOS in bone marrow (BM)-derived cells, PH was dependent on iNOS from BM-derived cells, whereas emphysema development was dependent on iNOS from non-BM-derived cells. Similar regulatory and structural alterations as seen in mouse lungs were found in lung tissue from humans with end-stage COPD.

The role of dimethylarginine dimethylaminohydrolase in idiopathic pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a progressive, dysregulated response to alveolar injury that culminates in compromised lung function from excess extracellular matrix production. Associated with high morbidity and mortality, IPF is generally refractory to current pharmacological therapies. We examined fibrotic lungs from mice and from patients with IPF and detected increased expression of dimethylarginine dimethylaminohydrolases (DDAHs)--key enzymes that metabolize asymmetric dimethylarginine (ADMA), which is an endogenous inhibitor of nitric oxide synthase, to form l-citrulline and dimethylamine. DDAHs are up-regulated in primary alveolar epithelial type II cells from these mice and patients where they are colocalized with inducible nitric oxide synthase. In cultured alveolar epithelial type II cells from bleomycin-induced fibrotic mouse lungs, inhibition of DDAH suppressed proliferation and induced apoptosis in an ADMA-dependent manner. In addition, DDAH inhibition reduced collagen production by fibroblasts in an ADMA-independent but transforming growth factor/SMAD-dependent manner. In mice with bleomycin-induced pulmonary fibrosis, the DDAH inhibitor L-291 reduced collagen deposition and normalized lung function. In bleomycin-induced fibrosis, inducible nitric oxide synthase inhibition decreased fibrosis, but an even stronger reduction was observed after inhibition of DDAH. Thus, DDAH inhibition reduces fibroblast-induced collagen deposition in an ADMA-independent manner and reduces abnormal epithelial proliferation in an ADMA-dependent manner, offering a possible therapeutic avenue for attenuation of pulmonary fibrosis.

Activation of the WNT/ß-catenin pathway attenuates experimental emphysema.

RATIONALE: Chronic obstructive pulmonary disease (COPD) is a devastating disease, for which no causal therapy is available. OBJECTIVES: To characterize WNT/ß-catenin signaling in COPD in humans and elucidate its potential role as a preventive and therapeutic target in experimental emphysema in mice. METHODS: The expression, localization, and activity of WNT/ß-catenin signaling was assessed in 12 COPD and 12 transplant donor samples using quantitative reverse transcriptase polymerase chain reaction, immunohistochemistry, and Western blotting. The role of WNT/ß-catenin signaling was assessed in elastase- and cigarette smoke-induced emphysema and therapeutic modulation thereof in elastase-induced emphysema in TOPGAL reporter and wild-type mice in vivo. MEASUREMENTS AND MAIN RESULTS: No differences in the mRNA expression profile of the main WNT/ß-catenin signaling components were observed comparing COPD and donor lung homogenates. Immunohistochemical analysis revealed reduced numbers of nuclear ß-catenin-positive alveolar epithelial cells in COPD. Similarly, WNT/ß-catenin signaling was down-regulated in both experimental emphysema models. Preventive and therapeutic, WNT/ß-catenin activation by lithium chloride attenuated experimental emphysema, as assessed by decreased airspace enlargement, improved lung function, reduced collagen content, and elevated expression of alveolar epithelial cell markers. CONCLUSIONS: Decreased WNT/ß-catenin signaling is involved in parenchymal tissue destruction and impaired repair capacity in emphysema. These data indicate a crucial role of WNT/ß-catenin signaling in lung repair mechanisms in vivo, and highlight WNT/ß-catenin activation as a future therapeutic approach for emphysema.

Increased expression of 5-hydroxytryptamine2A/B receptors in idiopathic pulmonary fibrosis: a rationale for therapeutic intervention.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) has a poor prognosis and limited responsiveness to available treatments. It is characterised by epithelial cell injury, fibroblast activation and proliferation and extracellular matrix deposition. Serotonin (5-hydroxytryptamine; 5-HT) induces fibroblast proliferation via the 5-HTR(2A) and 5-HTR(2B) receptors, but its pathophysiological role in IPF remains unclear. A study was undertaken to determine the expression of 5-HT receptors in IPF and experimental lung fibrosis and to investigate the effects of therapeutic inhibition of 5-HTR(2A/B) signalling on lung fibrosis in vivo and in vitro. METHODS AND RESULTS: Quantitative RT-PCR showed that the expression of 5-HTR(1A/B) and 5-HTR(2B) was significantly increased in the lungs of patients with IPF (n=12) and in those with non-specific interstitial pneumonia (NSIP, n=6) compared with transplant donors (n=12). The expression of 5-HTR(2A) was increased specifically in IPF lungs but not in NSIP lungs. While 5-HTR(2A) protein largely localised to fibroblasts, 5-HTR(2B) localised to the epithelium. To assess the effects of 5HTR(2A/B) inhibition on fibrogenesis in vivo, mice were subjected to bleomycin-induced lung fibrosis and treated with the 5-HTR(2A/B) antagonist terguride (or vehicle) in a therapeutic approach (days 14-28 after bleomycin). Terguride-treated mice had significantly improved lung function and histology and decreased collagen content compared with vehicle-treated mice. Functional in vitro studies showed that terguride is a potent inhibitor of transforming growth factor ß(1)- or WNT3a-induced collagen production. CONCLUSION: The studies revealed an increased expression of 5-HTR(2A) specifically in IPF. Blockade of 5-HTR(2A/B) signalling by terguride reversed lung fibrosis and is thus a promising therapeutic approach for IPF.

Effects of phosphodiesterase 4 inhibition on bleomycin-induced pulmonary fibrosis in mice.

BACKGROUND: Pulmonary fibrosis (PF) is a group of devastating and largely irreversible diseases. Phosphodiesterase (PDE) 4 is involved in the processes of remodeling and inflammation, which play key role in tissue fibrosis. The aim of the study was, therefore, to investigate the effect of PDE4 inhibition in experimental model of PF. METHODS: PF was induced in C57BL/6N mice by instillation of bleomycin. Pharmacological inhibition of PDE4 was achieved by using cilomilast, a selective PDE4 inhibitor. Changes in either lung inflammation or remodeling were evaluated at different stages of experimental PF. Lung inflammation was assessed by bronchoalveolar lavage fluid (BALF) differential cell count and reverse transcription quantitative polymerase chain reaction (RT-qPCR) for inflammatory cytokines. Changes in tissue remodeling were evaluated by pulmonary compliance measurement, quantified pathological examination, measurement of collagen deposition and RT-qPCR for late remodeling markers. Survival in all groups was analyzed as well. RESULTS: PDE4 inhibition significantly reduced the total number of alveolar inflammatory cells in BALF of mice with bleomycin-induced PF at early fibrosis stage (days 4 and 7). Number of macrophages and lymphocytes, but not neutrophils, was significantly reduced as well. Treatment decreased lung tumor necrosis factor (TNF)-alpha mRNA level and increased mRNA level of interleukin (IL)-6 but did not influence IL-1 beta. At later stage (days 14 and 24) cilomilast improved lung function, which was shown by increase in lung compliance. It also lowered fibrosis degree, as was shown by quantified pathological examination of Hematoxilin-Eosin stained lung sections. Cilomilast had no significant effect on the expression of late remodeling markers such as transforming growth factor (TGF)-beta1 and collagen type Ia1 (COL(I)alpha1). However, it tended to restore the level of lung collagen, assessed by SIRCOL assay and Masson's trichrome staining, and to improve the overall survival. CONCLUSIONS: Selective PDE4 inhibition suppresses early inflammatory stage and attenuates the late stage of experimental pulmonary fibrosis.

Inactivation of sestrin 2 induces TGF-beta signaling and partially rescues pulmonary emphysema in a mouse model of COPD.

Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality worldwide. Cigarette smoking has been identified as one of the major risk factors and several predisposing genetic factors have been implicated in the pathogenesis of COPD, including a single nucleotide polymorphism (SNP) in the latent transforming growth factor (TGF)-beta binding protein 4 (Ltbp4)-encoding gene. Consistent with this finding, mice with a null mutation of the short splice variant of Ltbp4 (Ltbp4S) develop pulmonary emphysema that is reminiscent of COPD. Here, we report that the mutational inactivation of the antioxidant protein sestrin 2 (sesn2) partially rescues the emphysema phenotype of Ltbp4S mice and is associated with activation of the TGF-beta and mammalian target of rapamycin (mTOR) signal transduction pathways. The results suggest that sesn2 could be clinically relevant to patients with COPD who might benefit from antagonists of sestrin function.

Role of epidermal growth factor inhibition in experimental pulmonary hypertension.

RATIONALE: Epidermal growth factor (EGF) and its receptors play a role in cell proliferation and survival and are implicated in the pathobiology of pulmonary arterial hypertension (PAH). OBJECTIVES: To study the role of EGF inhibition on experimental pulmonary hypertension. METHODS: We investigated (1) the effects of three clinically approved EGF receptor (EGFR) antagonists in vitro on rat pulmonary arterial smooth muscle cell proliferation and in vivo on experimental pulmonary hypertension (PH) induced by monocrotaline injection in rats and by chronic hypoxia in mice, and (2) the expression of EGFR in the lung tissues from experimental and clinical PH. MEASUREMENTS AND MAIN RESULTS: The EGFR inhibitors gefitinib, erlotinib, and lapatinib inhibited the EGF-induced proliferation of pulmonary arterial smooth muscle cells. In rats with established PH, gefitinib and erlotinib significantly reduced right ventricular systolic pressure and right ventricular hypertrophy. In addition, the medial wall thickness and muscularization of pulmonary arteries were improved. In contrast, lapatinib did not provide therapeutic benefit. These EGFR antagonists at their highest tolerable dose did not yield significant improvement in right ventricular systolic pressure, right ventricular hypertrophy, and pulmonary vascular remodeling in mice with chronic hypoxic PH. Moreover, no significant alteration in the EGFR expression was detected in the lung tissues from patients with idiopathic PAH. CONCLUSIONS: The partial therapeutic efficacy of the EGFR antagonists in animal models of pulmonary hypertension and the absence of significant alteration in EGFR expression in the lungs from patients with idiopathic PAH suggest that EGFRs do not represent a promising target for the treatment of pulmonary hypertension.

The soluble guanylate cyclase activator HMR1766 reverses hypoxia-induced experimental pulmonary hypertension in mice.

Severe pulmonary hypertension (PH) is a disabling disease with high mortality, characterized by pulmonary vascular remodeling and right heart hypertrophy. In mice with PH induced by chronic hypoxia, we examined the acute and chronic effects of the soluble guanylate cyclase (sGC) activator HMR1766 on hemodynamics and pulmonary vascular remodeling. In isolated perfused mouse lungs from control animals, HMR1766 dose-dependently inhibited the pressor response of acute hypoxia. This dose-response curve was shifted leftward when the effects of HMR1766 were investigated in isolated lungs from chronic hypoxic animals for 21 days at 10% oxygen. Mice exposed for 21 or 35 days to chronic hypoxia developed PH, right heart hypertrophy, and pulmonary vascular remodeling. Treatment with HMR1766 (10 mg x kg(-1) x day(-1)), after full establishment of PH from day 21 to day 35, significantly reduced PH, as measured continuously by telemetry. In addition, right ventricular (RV) hypertrophy and structural remodeling of the lung vasculature were reduced. Pharmacological activation of oxidized sGC partially reverses hemodynamic and structural changes in chronic hypoxia-induced experimental PH.

Evaluation of angiogenesis using micro-computed tomography in a xenograft mouse model of lung cancer.

Quantitative evaluation of lung tumor angiogenesis using immunohistochemical techniques has been limited by difficulties in generating reproducible data. To analyze intrapulmonary tumor angiogenesis, we used high-resolution micro-computed tomography (micro-CT) of lung tumors of mice inoculated with mouse Lewis lung carcinoma (LLC1) or human adenocarcinoma (A549) cell lines. The lung vasculature was filled with the radiopaque silicone rubber, Microfil, through the jugular vein (in vivo application) or pulmonary artery (ex vivo application). In addition, human adenocarcinoma lung tumor-bearing mice treated site-specifically with humanized monoclonal antibody (bevacizumab) against vascular endothelial growth factor. Quantitative analysis of lung tumor microvessels imaged with micro-CT showed that more vessels (mainly small, <0.02 mm(2)) were filled using the in vivo (5.4%) compared with the ex vivo (2.1%) method. Furthermore, bevacizumab-treated lung tumor-bearing mice showed significantly reduced lung tumor volume and lung tumor angiogenesis compared with untreated mice as assessed by micro-CT. Interestingly, microvascularization of mainly the smaller vessels (<0.02 mm(2)) was reduced after bevacizumab treatment. This observation with micro-CT was nicely correlated with immunohistochemical measurement of microvessels. Therefore, micro-CT is a novel method for investigating lung tumor angiogenesis, and this might be considered as an additional complementary tool for precise quantification of angiogenesis.