Cyclic Stress at mHz Frequencies Aligns Fibroblasts in Direction of Zero Strain

Recognition of external mechanical signals is vital for mammalian cells. Cyclic stretch, e.g. around blood vessels, is one such signal that induces cell reorientation from parallel to almost perpendicular to the direction of stretch. Here, we present quantitative analyses of both, cell and cytoskeletal reorientation of umbilical cord fibroblasts. Cyclic strain of preset amplitudes was applied at mHz frequencies. Elastomeric chambers were specifically designed and characterized to distinguish between zero strain and minimal stress directions and to allow accurate theoretical modeling. Reorientation was only induced when the applied stretch exceeded a specific amplitude, suggesting a non-linear response. However, on very soft substrates no mechanoresponse occurs even for high strain. For all stretch amplitudes, the angular distributions of reoriented cells are in very good agreement with a theory modeling stretched cells as active force dipoles. Cyclic stretch increases the number of stress fibers and the coupling to adhesions. We show that changes in cell shape follow cytoskeletal reorientation with a significant temporal delay. Our data identify the importance of environmental stiffness for cell reorientation, here in direction of zero strain. These in vitro experiments on cultured cells argue for the necessity of rather stiff environmental conditions to induce cellular reorientation in mammalian tissues

Genetic deletion of Abcc6 disturbs cholesterol homeostasis in mice

Genetic studies link adenosine triphosphate-binding cassette transporter C6 (ABCC6) mutations to pseudoxanthoma elasticum (PXE). ABCC6 sequence variations are correlated with altered HDL cholesterol levels and an elevated risk of coronary artery diseases. However, the role of ABCC6 in cholesterol homeostasis is not widely known. Here, we report reduced serum cholesterol and phytosterol levels in Abcc6-deficient mice, indicating an impaired sterol absorption. Ratios of cholesterol precursors to cholesterol were increased, confirmed by upregulation of hepatic 3-hydroxy-3-methylglutaryl coenzyme A reductase (Hmgcr) expression, suggesting activation of cholesterol biosynthesis in Abcc6-/- mice. We found that cholesterol depletion was accompanied by a substantial decrease in HDL cholesterol mediated by lowered ApoA-I and ApoA-II protein levels and not by inhibited lecithin-cholesterol transferase activity. Additionally, higher proprotein convertase subtilisin/kexin type 9 (Pcsk9) serum levels in Abcc6-/- mice and PXE patients and elevated ApoB level in knockout mice were observed, suggesting a potentially altered very low-density lipoprotein synthesis. Our results underline the role of Abcc6 in cholesterol homeostasis and indicate impaired cholesterol metabolism as an important pathomechanism involved in PXE manifestation

Plasma lipid profiles discriminate bacterial from viral infection in febrile children

Fever is the most common reason that children present to Emergency Departments. Clinical signs and symptoms suggestive of bacterial infection are often non-specific, and there is no definitive test for the accurate diagnosis of infection. The 'omics' approaches to identifying biomarkers from the host-response to bacterial infection are promising. In this study, lipidomic analysis was carried out with plasma samples obtained from febrile children with confirmed bacterial infection (n = 20) and confirmed viral infection (n = 20). We show for the first time that bacterial and viral infection produces distinct profile in the host lipidome. Some species of glycerophosphoinositol, sphingomyelin, lysophosphatidylcholine and cholesterol sulfate were higher in the confirmed virus infected group, while some species of fatty acids, glycerophosphocholine, glycerophosphoserine, lactosylceramide and bilirubin were lower in the confirmed virus infected group when compared with confirmed bacterial infected group. A combination of three lipids achieved an area under the receiver operating characteristic (ROC) curve of 0.911 (95% CI 0.81 to 0.98). This pilot study demonstrates the potential of metabolic biomarkers to assist clinicians in distinguishing bacterial from viral infection in febrile children, to facilitate effective clinical management and to the limit inappropriate use of antibiotics

Plasma lipid profiles discriminate bacterial from viral infection in febrile children

Fever is the most common reason that children present to Emergency Departments. Clinical signs and symptoms suggestive of bacterial infection ar

Peptide receptor radionuclide therapy as a two-step strategy for initially unresectable liver disease from neuroendocrine tumors: a single-center experience

Purpose In this study, we describe our experience with peptide receptor radionuclide therapy (PRRT) for initially unresectable liver disease as a two-steps therapeutic strategy, first in neoadjuvant intention before surgery and then later on in case of disease relapse. Methods We performed a retrospective evaluation of four cases of unresectable liver metastases of NET of different origins treated with neoadjuvant Lu-177-DotaTATE for conversion into resectability first and as rechallenging treatment after disease relapse. Results After treatment with Lu-177-DotaTAE, resectability was reached in three of four cases. In one case, SIRT was additionally performed preoperatively. Relapse occurred in three of four cases after 32, 34, and 37 months, respectively, and was managed with Re-PRRT-treatment. Conclusion Although more data are needed, our retrospective study suggests that treatment with Lu-177-DotaTATE is an important adjunct to surgery not only in neoadjuvant intention but also for treating disease relapse. A register study might deliver more evidence for supporting this strategy

Outcomes and complications of cataract surgery in patients with chronic ocular graft-versus-host-disease-a multicenter, retrospective analysis

Purpose To evaluate the outcome of phacoemulsification in patients with chronic ocular Graft-versus-host disease (oGVHD) after allogeneic hematopoietic stem cell transplantation (aHSCT). Methods Retrospective, observational multicenter study from 1507 oGVHD patients. From the patient files, data were collected including best-corrected visual acuity (BCVA), intraocular pressure (IOP), Schirmer's test I, tear film break-up time (TFBUT), corneal fluorescein staining score, postoperative complications, and pre- and post-operative topical therapy. Results Seventy-three patients underwent cataract surgery in 104 eyes. In n = 84 eyes, the oGVHD NIH grade was documented; 12% (n= 12) of analyzed eyes were staged oGVHD NIH grade 1, 31% (n= 32) NIH 2 and 39% (n = 41) NIH 3. The mean BCVA improved in 82% of the eyes (n = 86 eyes). BCVA significantly increased from 0.7 +/- 0.5 to 0.4 +/- 0.4 LogMAR after surgery independent from oGVHD severity. The mean IOP decreased from 14 +/- 4 to 13 +/- 4 mmHg after surgery. Visual acuity was moderately correlated to the pre-operative degree of corneal staining (Pearson p = 0.26, p = 0.002, Cohen's effect size f= 0.29). The visual acuity decreased by 0.078 LogMar units (95% CI =0.027-0.141) with each increase of corneal staining by one grade (p = 0.05). After surgery, corneal epitheliopathy increased significantly in 42% (n = 44) of the eyes. Postoperative complications included corneal perforation (n = 6, 6%), cystoid macular edema (n = 4, 4%), and endophthalmitis (n =1 , 1%) . Conclusion Phacoemulsification in patients with chronic oGVHD significantly improves visual acuity, but is associated with an increased risk of complications in particular corneal epitheliopathy and corneal perforations

Genetic deletion of Abcc6 disturbs cholesterol homeostasis in mice

Genetic studies link adenosine triphosphate-binding cassette transporter C6 ($\it {ABCC6}$) mutations to pseudoxanthoma elasticum (PXE). $\it {ABCC6}$ sequence variations are correlated with altered HDL cholesterol levels and an elevated risk of coronary artery diseases. However, the role of ABCC6 in cholesterol homeostasis is not widely known. Here, we report reduced serum cholesterol and phytosterol levels in Abcc6-deficient mice, indicating an impaired sterol absorption. Ratios of cholesterol precursors to cholesterol were increased, confirmed by upregulation of hepatic 3-hydroxy-3-methylglutaryl coenzyme A reductase ($\it {Hmgcr}$) expression, suggesting activation of cholesterol biosynthesis in $\it {Abcc6}^{−/−}$ mice. We found that cholesterol depletion was accompanied by a substantial decrease in HDL cholesterol mediated by lowered ApoA-I and ApoA-II protein levels and not by inhibited lecithin-cholesterol transferase activity. Additionally, higher proprotein convertase subtilisin/kexin type 9 (Pcsk9) serum levels in $\it {Abcc6}^{−/−}$ mice and PXE patients and elevated ApoB level in knockout mice were observed, suggesting a potentially altered very low-density lipoprotein synthesis. Our results underline the role of Abcc6 in cholesterol homeostasis and indicate impaired cholesterol metabolism as an important pathomechanism involved in PXE manifestation