Zinc oxide nanoparticles (ZnO-NP) are widely spread in consumer products. Data about the toxicological characteristics of ZnO-NP is still under controversial discussion. The human skin is the most important organ concerning ZnO-NP exposure. Intact skin was demonstrated to be a sufficient barrier against NPs; however, defect skin may allow NP contact to proliferating cells. Within these cells, stem cells are the most important toxicological target for NPs. The aim of this study was to evaluate the genotoxic and cytotoxic effects of ZnO-NP at low-dose concentrations after long-term and repetitive exposure to human mesenchymal stem cells (hMSC). Cytotoxic effects of ZnO-NP were measured by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Furthermore, genotoxicity was evaluated by the comet assay. For long-term observation over 6 weeks, transmission electron microscopy (TEM) was applied. The results of the study indicated cytotoxic effects of ZnO-NP beginning at high concentrations of 50 μg/mL and genotoxic effects in hMSC exposed to 1 and 10 μg/mL ZnO-NP. Repetitive exposure enhanced cyto- but not genotoxicity. Intracellular NP accumulation was observed up to 6 weeks. The results suggest cytotoxic and genotoxic potential of ZnO-NP. Even low doses of ZnO-NP may induce toxic effects as a result of repetitive exposure and long-term cellular accumulation. This data should be considered before using ZnO-NP on damaged skin.

Background: There is an ongoing discussion concerning the potential origins of chronic rhinosinusitis with nasal polyposis (CRSwNP). Objective: The aim of this study was to quantify subpopulations of T cells in peripheral blood and nasal polyps in CRSwNP to examine their influence on the etiology of this disease. Methods: Tissue and blood samples were collected from 11 patients who underwent nasal sinus surgery, and these samples were analyzed by multicolor flow cytometry. Results: There was a significantly lower frequency of CD4 ⁺ T-helper (Th) cells and a significantly higher frequency of CD8 ⁺ T cells among lymphocytes isolated from nasal polyps compared with peripheral blood mononuclear cells (PBMC). In both T-cell subpopulations, a shift mainly from naive T cells among peripheral blood lymphocytes toward an effector memory and terminally differentiated subtype predominance in nasal polyps was observed. Among CD4 ⁺ T cells, the frequencies of cluster of differentiation (CD) 45RA- Forkhead-Box-Protein P3high (FoxP3 ^high ) cytotoxic T-lymphocyte-associated Protein 4 ^high (CTLA-4 ^high ) activated regulatory T (T _reg ) cells, and CD45RA- Forkhead-Box-Protein P3low (FoxP3 ^low ) memory T cells were significantly increased in nasal polyps compared with PBMC. Conclusion: In this study, we presented a detailed characterization of CD4 ⁺ and CD8 ⁺ T-cell subpopulations in patients with CRSwNP. CD8 ⁺ T cells were more prominent in nasal polyps than in CD4 ⁺ T cells. Both nasal CD8 ⁺ T cells and CD4 ⁺ T cells predominantly had an effector memory phenotype. Among CD4 ⁺ T cells, activated T _reg cells were increased in nasal polyps compared with PBMC. The data point toward a local regulation of T-cell composition within the microenvironment of nasal polyps, which might be further exploited in the future to develop novel immunotherapeutic strategies.

When compared with standard multiport laparoscopy, the larger fascial incision in single-port surgery (SPS) may imply a potentially increased risk of surgical-site complications, such as herniation. The long-term risk of access-site complications in SPS is still unpredictable. Between July 2009 and May 2011, n=78 patients (n=54 females), with a median age of 42 years (range: 18-85 years), underwent single-port cholecystectomy. The median body mass index was 25.4 kg/m(2) (range: 17-39 kg/m(2)). All surgeries were performed by a single surgeon (K.K.) using a completely reusable single-port access device (X-Cone™; KARL STORZ GmbH, Tuttlingen, Germany), and fascial closure technique was comparable in all patients. The first 50 patients (n=32 females) attended a structured follow-up examination including a meticulous clinical examination and ultrasonography of the access site at a median follow-up time of 17 months (range: 9-23 months). We recorded postoperative complications in 5 of the 50 patients (10%) after single-port cholecystectomy. Four occurred in the early postoperative course and presented as mild wound complications. One of the 50 patients (2%) experienced a symptomatic trocar-site hernia (TSH) 4 months after surgery. No biliary complications (bile leakage, retained stones, etc.) were recorded. Although potentially biased by a relatively small number of patients, our study provides evidence that TSH after single-port cholecystectomy is (i) not less frequent when compared with standard laparoscopy, (ii) not as infrequent as suggested by the current literature, and (iii) not only associated with technical failure or patients' comorbidity.

T cell subpopulations in nasal polyps differ from peripheral lymphocytes in patients with chronic rhinosinusitis with nasal polyps (CRSwNP). However, little is known about the modulatory influence of the inflamed nasal polyp epithelial cells on the phenotype of the T cells. The aim of the present study was to assess this interaction. Tissue and blood samples were collected from 16 patients undergoing paranasal sinus surgery. Polypoid tissue was cultured under air‑liquid interface conditions. Subsequently, cluster of differentiation (CD)3/CD28 activated peripheral lymphocytes from the same patients were added. After 3 days lymphocytes were separated from co‑culture and analyzed by multicolor flow cytometry. Additionally, cytokine expression of the polyp tissue was measured using a human T helper cell (TH)1/TH2/TH17 antibody array. Viability staining of CD3+ lymphocytes detected fewer apoptotic cells under co‑culture conditions compared with in mono‑culture. There was a significantly higher frequency of CD4+ and CD8+ T cells in the co‑culture system than in PBMC culture alone. Human leukocyte antigen (HLA)‑DR isotype was significantly downregulated on co‑cultured CD3+ lymphocytes and CD3+CD4+ T cells compared with the mono‑cultured counterparts. Conventional Forkhead box P3‑ memory CD4+ T cells and activated regulatory T cells increased in frequency, and resting regulatory T cells decreased in the co‑culture. Cytokine analysis identified expression of interleukin (IL)‑6, IL‑6 receptor, granulocyte‑macrophage colony‑stimulating factor, transforming growth factor‑β and macrophage inflammatory protein‑3 in the polyp tissue. In summary, the present study performed a comparison between peripheral lymphocytes cultured with and without nasal polyp tissue cells was performed. The downregulation of HLA and the differentiation of Treg and Tconv by nasal polypoid tissue on PBMCs was demonstrated. Interestingly, the in vivo downregulation of HLA‑DR on CD3+ lymphocytes, as reported previously, was confirmed in vitro. The inhibitory effect of polypoid tissue on the activation of lymphocytes is a possible pathogenic mechanism underlying CRSwNP.

In patients with chronic rhinosinusitis with nasal polyps (CRSwNP), a relative accumulation of cluster of differentiation (CD)8+ T cells over CD4+ T cells occurs in nasal polyps compared with the peripheral blood. Nasal CD8+ T cells and CD4+ T cells predominantly present an effector memory phenotype. Immunological studies have reported that memory T cells recirculate from the tissues to the peripheral blood and a high percentage of these T cells persist within the tissue. The aim of the present study was to characterize CD69+ sphingosine‑1‑phosphate receptor 1 (S1PR1)‑ tissue resident memory T cells (Trm) in the polyps of patients with CRSwNP. Tissue and blood samples were collected from 10 patients undergoing nasal sinus surgery. Expression of specific extra‑ and intracellular molecules were analyzed using multicolor flow cytometry. A significantly higher level of CD8+ T cells than CD4+ T cells was present in nasal polyps, while significantly more CD4+ T cells than CD8+ T cells were detected in the peripheral blood of patients with CRSwNP. The frequency of CD69+ T cells was significantly higher in CD8+ and CD4+ T cells in nasal polyps compared with the peripheral blood. The frequency of CD69+ S1PR1‑ Trm was also significantly higher in CD4+ and CD8+ T cells from nasal polyps compared with the peripheral blood. Within polyps, the frequency of CD69+ S1PR1‑ Trm was again significantly higher in CD8+ compared with CD4+ T cells. In summary, a significantly higher frequency of CD69+ S1PR1‑ T cells was observed in the nasal polyps compared with the peripheral blood in patients with CRSwNP. The results of the present study suggest that local regulation of the immune response occurs within nasal polyps. As such, Trm should be considered a potential stimulus in the pathogenesis of nasal polyps. However, the role of Trm in nasal polyps as a pathogenic trigger of the local inflammatory reaction requires further investigation.

Zinc oxide nanoparticles (ZnO-NP) are commonly used for a variety of applications in everyday life. In addition, due to its versatility, nanotechnology supports promising approaches in the medical sector. NP can act as drug-carriers in the context of targeted chemo- or immunotherapy, and might also exhibit autonomous immune-modulatory characteristics. Knowledge of potential immunosuppressive or stimulating effects of NP is indispensable for the safety of consumers as well as patients. In this study, primary human peripheral blood lymphocytes of 9 donors were treated with different sub-cytotoxic concentrations of ZnO-NP for the duration of 1, 2, or 3 days. Flow cytometry was performed to investigate changes in the activation profile and the proportion of T cell subpopulations. ZnO-NP applied in this study did not induce any significant alterations in the examined markers, indicating their lack of impairment in terms of immune modulation. However, physicochemical characteristics exert a major influence on NP-associated bioactivity. To allow a precise simulation of the complex molecular processes of immune modulation, a physiological model including the different components of an immune response is needed.