Intrafractional 6D head movement increases with time of mask fixation during stereotactic intracranial RT-sessions.

BACKGROUND: The present study investigates the intrafractional accuracy of a frameless thermoplastic mask used for head immobilization during stereotactic radiotherapy. Non-invasive masks cannot completely prohibit head movements. Previous studies attempted to estimate the magnitude of intrafractional inaccuracy by means of pre- and postfractional measurements only. However, this might not be sufficient to accurately map also intrafractional head movements. MATERIALS AND METHODS: Intrafractional deviation of mask-fixed head positions was measured in five patients during a total of 94 fractions by means of close-meshed repeated ExacTrac measurements (every 1.4 min) conducted during the entire treatment session. A median of six (range: 4 to 11) measurements were recorded per fraction, delivering a dataset of 453 measurements. RESULTS: Random errors (SD) for the x, y and z axes were 0.27 mm, 0.29 mm and 0.29 mm, respectively. Median 3D deviation was 0.29 mm. Of all 3D intrafractional motions, 5.5 and 0.4% exceeded 1 mm and 2 mm, respectively. A moderate correlation between treatment duration and mean 3D displacement was determined (rs = 0.45). Mean 3D deviation increased from 0.21 mm (SD = 0.26 mm) in the first 2 min to a maximum of 0.53 mm (SD = 0.31 mm) after 10 min of treatment time. CONCLUSION: Pre- and post-treatment measurement is not sufficient to adequately determine the range of intrafractional head motion. Thermoplastic masks provide both reliable interfractional and intrafractional immobilization for image-guided stereotactic hypofractionated radiotherapy. Greater positioning accuracy may be obtained by reducing treatment duration (< 6 min) and applying intrafractional correction. TRIAL REGISTRATION: Clinicaltrials.gov, NCT03896555, Registered 01 April 2019 - retrospectively registered.

Occurrence of pneumonitis following radiotherapy of breast cancer - A prospective study.

AIM: of this study is to determine the temporal resolution of therapy-induced pneumonitis, and to assess promoting factors in adjuvant treated patients with unilateral mammacarcinoma. PATIENTS AND METHODS: A total of 100 post-surgery patients were recruited. The cohort was treated by 2 field radiotherapy (2FRT; breast and chest wall, N = 75), 3 field radiotherapy (3FRT; + supraclavicular lymphatic region, N = 8), or with 4 field radiotherapy (4FRT; + parasternal lymphatic region, N = 17). Ninety-one patients received various systemic treatments prior to irradiation. Following an initial screening visit post-RT, two additional visits after 12 and 25 weeks were conducted including radiographic examination. In addition, general anamnesis and the co-medication were recorded. The endpoint was reached as soon as a pneumonitis was developed or at maximum of six months post-treatment. RESULTS: A pneumonitis incidence of 13% was determined. Of 91 patients with prior systemic therapy, 11 patients developed pneumonitis. Smoking history and chronic obstructive pulmonary disease (COPD) appeared to be positive predictors, whereas past pneumonia clearly promoted pneumonitis. Further pneumonitis-promoting predictors are represented by the applied field extensions (2 field radiotherapy [2FRT] < 3 field radiotherapy [3FRT] < 4 field radiotherapy [4FRT]) and the type of combined initial systemic therapies. As a consequence, all of the three patients in the study cohort treated with 4FRT and initial chemotherapy combined with anti-hormone and antibody protocols developed pneumonitis. A combination of the hormone antagonists tamoxifen and goserelin might enhance the risk for pneumonitis. Remarkably, none of the 11 patients co-medicated with statins suffered from pneumonitis. CONCLUSIONS: The rapidly increasing use of novel systemic therapy schedules combined with radiotherapy (RT) needs more prospective studies with larger cohorts. Our results indicate that contribution to pneumonitis occurrence of various (neo)adjuvant therapy approaches followed by RT is of minor relevance, whereas mean total lung doses of >10 Gy escalate the risk of lung tissue complications. The validity of potential inhibitors of therapy-induced pneumonitis as observed for statin co-medication should further be investigated in future trials.

A domestic porcine model for studying the effects of radiation on head and neck cancers.

BACKGROUND: Radiation therapy (RT) of the head and neck region is often accompanied by serious side effects. Research in this area is needed to improve treatment outcomes and ameliorate therapy tolerance. Laboratory rodents are barely matching today's clinical standards in RT research. Yet domestic swine (Sus scrofa domestica) have previously proved suitable for various advanced tests in clinical research and training. We therefore investigated whether S. scrofa domestica is also appropriate for irradiation of the mandible. STUDY DESIGN: A common scheme for irradiation treatment of S. scrofa domestica mandibles in a split-mouth design was acquired by applying computed tomography (CT) scanning under sedation. Basing on close anatomic resemblance, a standard treatment plan comprising 2 opposed irradiation fields could be accomplished. RESULTS: RT was carried out in a clinical environment with 2 × 9 Gy. The resulting operating procedure facilitated complication-free sedation, transport, positioning, CT scanning, and effective irradiation. CONCLUSION: Based on common standards applied for RT in humans, domestic pigs can be employed to progress RT clinical research. Due to their human-like anatomy, physiology, size, and weight, the swine model is expedient for advancing experimental RT of the head and neck area.

The neuropeptide catestatin acts as a novel angiogenic cytokine via a basic fibroblast growth factor-dependent mechanism.

RATIONALE: The neuropeptide catestatin is an endogenous nicotinic cholinergic antagonist that acts as a pleiotropic hormone. OBJECTIVE: Catestatin shares several functions with angiogenic factors. We therefore reasoned that catestatin induces growth of new blood vessels. METHODS AND RESULTS: Catestatin induced migration, proliferation, and antiapoptosis in endothelial cells and exerted capillary tube formation in vitro in a Matrigel assay, and such effects were mediated via G protein, mitogen-activated protein kinase, and Akt. Catestatin-induced endothelial cell functions are further mediated by basic fibroblast growth factor, as shown by blockade of effects by a neutralizing fibroblast growth factor antibody. Furthermore, catestatin released basic fibroblast growth factor from endothelial cells and stimulated fibroblast growth factor signaling. In addition to its function on endothelial cells, catestatin also exerted effects on endothelial progenitor cells and vascular smooth muscle cells. In vivo, catestatin induced angiogenesis in the mouse cornea neovascularization assay and increased blood perfusion and number of capillaries in the hindlimb ischemia model. In addition to angiogenesis, catestatin increased density of arterioles/arteries and incorporation of endothelial progenitor cells in the hindlimb ischemia model, indicating induction of arteriogenesis and postnatal vasculogenesis. CONCLUSION: We conclude that catestatin acts as a novel angiogenic cytokine via a basic fibroblast growth factor-dependent mechanism.

Gene therapy with the angiogenic cytokine secretoneurin induces therapeutic angiogenesis by a nitric oxide-dependent mechanism.

RATIONALE: The neuropeptide secretoneurin induces angiogenesis and postnatal vasculogenesis and is upregulated by hypoxia in skeletal muscle cells. OBJECTIVE: We sought to investigate the effects of secretoneurin on therapeutic angiogenesis. METHODS AND RESULTS: We generated a secretoneurin gene therapy vector. In the mouse hindlimb ischemia model secretoneurin gene therapy by intramuscular plasmid injection significantly increased secretoneurin content of injected muscles, improved functional parameters, reduced tissue necrosis, and restored blood perfusion. Increased muscular density of capillaries and arterioles/arteries demonstrates the capability of secretoneurin gene therapy to induce therapeutic angiogenesis and arteriogenesis. Furthermore, recruitment of endothelial progenitor cells was enhanced by secretoneurin gene therapy consistent with induction of postnatal vasculogenesis. Additionally, secretoneurin was able to activate nitric oxide synthase in endothelial cells and inhibition of nitric oxide inhibited secretoneurin-induced effects on chemotaxis and capillary tube formation in vitro. In vivo, secretoneurin induced nitric oxide production and inhibition of nitric oxide attenuated secretoneurin-induced effects on blood perfusion, angiogenesis, arteriogenesis, and vasculogenesis. Secretoneurin also induced upregulation of basic fibroblast growth factor and platelet-derived growth factor-B in endothelial cells. CONCLUSIONS: In summary, our data indicate that gene therapy with secretoneurin induces therapeutic angiogenesis, arteriogenesis, and vasculogenesis in the hindlimb ischemia model by a nitric oxide-dependent mechanism.

Monocyte migration: a novel effect and signaling pathways of catestatin.

Several members of the neuropeptide family exert chemotactic actions on blood monocytes consistent with neurogenic inflammation. Furthermore, chromogranin A (CgA) containing Alzheimer plaques are characterized by extensive microglia activation and such activation induces neuronal damage. We therefore hypothesized that the catecholamine release inhibitory peptide catestatin (hCgA(352-372)) would induce directed monocyte migration. We demonstrate that catestatin dose-dependently stimulates chemotaxis of human peripheral blood monocytes, exhibiting its maximal effect at a concentration of 1 nM comparable to the established chemoattractant formylated peptide Met-Leu-Phe (fMLP). The naturally occurring catestatin variants differed in their chemotactic property insofar as that the Pro370Leu variant was even more potent than wild type, whereas the Gly364Ser variant was less effective. Specificity of this effect was shown by inhibition of catestatin-induced chemotaxis by a specific neutralizing antibody. In addition, catestatin mediated effect was blocked by dimethylsphingosine and treatment with endothelial differentiation gene (Edg)-1 and Edg-3 antisense RNA as well as by incubation with pertussis toxin and genistein indicating involvement of tyrosine kinase receptor-, G-protein- and sphingosine-1-phosphate signaling. Catestatin also stimulated Akt- and extracellular signal related kinase (ERK)-phosphorylation and catestatin-induced chemotaxis was blocked by blockers of phosphoinositide-3 (PI-3) kinase and nitric oxide as well as by inhibition of the mitogen-activated protein kinases (MAPK) system indicating involvement of these signal transduction pathways. In summary, our data indicate that catestatin induces monocyte chemotaxis by activation of a variety of signal transduction pathways suggesting a role of this peptide as an inflammatory cytokine.