Association between colorectal cancer testing and insurance type: Evidence from the Swiss Health Interview Survey 2012.

Both colonoscopy and fecal occult blood test (FOBT) are commonly used for colorectal cancer (CRC) screening, but colonoscopy costs much more than FOBT. Swiss insurance offers high or low deductibles and choice of basic or private insurance. We hypothesized that high deductibles and basic insurance discourage colonoscopy, but do not change FOBT rates. We determined the proportion of patients tested for CRC in Switzerland (colonoscopy within 10 years, FOBT within 2 years), and determined associations with health insurance type. We extracted data on 50-75-year-olds from the Swiss Health Interview Surveys of 2012 to determine colonoscopy and FOBT testing rates (n = 7335). Multivariate logistic regression models estimated prevalence ratios (PRs) of CRC testing associated with health insurance type (deductible and private insurance), adjusted for socio-demographic factors (age, gender, education, income) and self-rated health. The weighted proportion of individuals tested for CRC within recommended intervals was 39.5%. Testing with colonoscopy was significantly associated with private insurance (PR 1.85, 95% CI: 1.46-2.35) and low deductible (PR 2.00, 95% CI: 1.56-2.57). Testing with FOBT was significantly associated with deductible (PR 1.71, 95%CI:1.09-2.68) but not with private insurance. About 60% of the Swiss population was not current with CRC testing. After adjusting for covariates, private insurance and low deductible was significantly associated with higher prevalence of CRC testing, indicating that waiving the deductible could increase CRC screening uptake and reduce health inequality.

Trends in the use of mammography for early breast cancer detection in Switzerland: Swiss Health Surveys 2007 and 2012.

AIMS: Breast cancer is the most common cancer in women worldwide. We assessed changes in the use of breast cancer screening 2007-2012 in Switzerland, and associations with socioeconomic and health-related determinants. METHODS: We used the nationwide and representative data from the Swiss Health Surveys 2007 and 2012. We analysed the self-reported use of mammography in the last 12 months (proportion of population) among women aged 40-79 years, and opportunistic (without clinical symptoms, initiated by the woman or a physician) and programmatic screening mammography (as part of a systematic screening programme). We performed multivariate logistic regression analyses (presented as adjusted odds ratios, aORs). RESULTS: The use of any mammography in the last 12 months declined from 19.1% (95% confidence interval [CI] 17.7-20.5%) in 2007 to 11.7% (95% CI 10.7-12.6%) in 2012. This decline was more pronounced in regions with a long-standing or no cantonal breast cancer screening programme (aOR 0.5, 95% CI 0.4-0.6, and aOR 0.5, 95% CI 0.4-0.6, respectively), but remained relatively stable in regions with a recently introduced programme (aOR 0.9, 95% CI 0.6-1.3, p-value from test for interaction 0.01). Opportunistic screening dropped from 12.0% (95% CI 10.9-13.2%) in 2007 to 6.2% (95% CI 5.5-6.9%; p <0.001) in 2012, whereas the use of programmatic mammography remained stable at 3.1% (95% CI 2.6-3.7%). Use of any mammography was higher in women aged 50-69 years, residing in a region with a systematic screening programme in place, and women having a private hospital stay insurance, but was not associated with education level and non-Swiss citizenship. CONCLUSIONS: Overall attendance of breast cancer screening is low in Switzerland and decreased between 2007 and 2012, despite expanding cantonal mammography screening programmes. Many factors may have contributed to this decline, including the ongoing scientific and public debates on the value of breast cancer screening.

Molecular structure and interaction of recombinant human type XVI collagen.

Collagen XVI is a minor component of at least two different extracellular fibrillar networks of specialized regions of skin and cartilage. In skin, collagen XVI is integrated into particular fibrillin-rich microfibrils lacking an amorphous elastin core. In cartilage, collagen XVI is a component of small heterotypic D-banded fibrils, mainly occurring in the territorial matrix of chondrocytes. Here, we present the first direct evidence for the molecular structure and functional properties of these fibril-associated collagens with interrupted triple helices (FACIT). We have expressed recombinantly the full-length alpha1 chain of human collagen XVI in HEK 293 EBNA cells in large quantities using an episomal expression system. Secreted full-length recombinant collagen XVI forms stable disulfide-bonded homotrimers and is rapidly proteolytically processed to distinct fragments at specific protease sequence motifs, one resembling an aggrecanase recognition site. Limited trypsin digestion assays and thermal transition curves imply sequential thermal denaturation of individual triple helical domains of this recombinant collagen, similar to authentic collagen XVI. Molecular images of collagen XVI reveal rod-like molecules which harbor multiple sharp kinks attributing a highly flexible structure presumably introduced by non-collagenous (NC) regions. Terminally located cloverleaf-shaped nodules correspond to the large NC NC11 domain of trimeric collagen XVI. The total length of individual trimeric recombinant collagen XVI molecules constitutes about 240 nm as calculated by atomic force and negative staining electron microscopy. Recombinant collagen XVI interacts with fibrillin-1 and with fibronectin indicating multiple molecular interactions in which this ubiquitously expressed and versatile FACIT-collagen can participate. In vitro generated collagen XVI provides an indispensable tool for future determination of its function during supramolecular assembly of matrix aggregates and its role in maintenance, organization and interaction of fibrillar structures.

Discrete integration of collagen XVI into tissue-specific collagen fibrils or beaded microfibrils.

The structural and functional diversity of extracellular matrices is determined, not only by individual macromolecules, but even more decisively, by the alloyed aggregates they form. Although quantitatively major matrix molecules can occur ubiquitously, their organization varies from one tissue to another due to their amalgamation with specific sets of minor components. Here, we show that the fibril-associated collagen with interrupted triple helices collagen XVI is unique in that, depending on the tissue context, it can be incorporated into distinct suprastructural aggregates. In papillary dermis, the protein unexpectedly does not occur in banded collagen fibrils, but rather, is a component of specialized fibrillin-1-containing microfibrils. In territorial cartilage matrix, however, collagen XVI is not a component of aggregates containing fibrillin-1. Instead, the protein resides in a discrete population of thin, weakly banded collagen fibrils also containing collagens II and XI. Collagen IX also occurs in this population of fibrils, but at longitudinal locations discrete from those of collagen XVI. This suprastructural versatility of a collagen is without precedent and highlights pivotal differences in the tissue-specific organization of matrix aggregate structures.

A secreted collagen- and fibronectin-binding streptococcal protein modulates cell-mediated collagen gel contraction and interstitial fluid pressure.

Fibroblast-mediated collagen gel contraction depends on collagen-binding beta1 integrins. Perturbation of these integrins reveals an alternative contraction process that is integrin alphaVbeta3-dependent and platelet-derived growth factor (PDGF) BB-stimulated. Connective tissue cells actively control interstitial fluid pressure (IFP), and inflammation-induced lowering of IFP provides a driving force for edema formation. PDGF-BB normalizes a lowered IFP by an alphaVbeta3-dependent process. A potential modulation of IFP by extracellular matrix-binding bacterial proteins has previously not been addressed. The fibronectin (FN)-binding protein FNE is specifically secreted by the highly virulent Streptococcus equi subspecies equi. FNE bound FN and native collagen type I with K(d) values of approximately 20 and approximately 50 nm determined by solid-phase binding assays. Rotary shadowing revealed a single FNE binding site located at on average 122 nm from the C terminus of procollagen type I. FNE induced alphaVbeta3-mediated contraction by C2C12 cells in a concentration-dependent manner having a maximal effect at approximately 100 nm. This activity of FNE required cellular FN, and FNE acted synergistically to added plasma FN or PDGF-BB. FNE enhanced binding of soluble FN to immobilized collagen, and conversely the binding of collagen to immobilized FN. Marked bell-shaped concentration dependences for these interactions suggest that FNE forms a bridge between FN and collagen. Finally, FNE normalized dermal IFP lowered by anaphylaxis. Our data suggest that secreted FNE normalized lowering of IFP by stimulating connective tissue cell contraction.

COMP acts as a catalyst in collagen fibrillogenesis.

We have previously reported that COMP (cartilage oligomeric matrix protein) is prominent in cartilage but is also present in tendon and binds to collagens I and II with high affinity. Here we show that COMP influences the fibril formation of these collagens. Fibril formation in the presence of pentameric COMP was much faster, and the amount of collagen in fibrillar form was markedly increased. Monomeric COMP, lacking the N-terminal coiled-coil linker domain, decelerated fibrillogenesis. The data show that stimulation of collagen fibrillogenesis depends on the pentameric nature of COMP and not only on collagen binding. COMP interacts primarily with free collagen I and II molecules, bringing several molecules to close proximity, apparently promoting further assembly. These assemblies further join in discrete steps to a narrow distribution of completed fibril diameters of 149 +/- 16 nm with a banding pattern of 67 nm. COMP is not found associated with the mature fibril and dissociates from the collagen molecules or their early assemblies. However, a few COMP molecules are found bound to more loosely associated molecules at the tip/end of the growing fibril. Thus, COMP appears to catalyze the fibril formation by promoting early association of collagen molecules leading to increased rate of fibrillogenesis and more distinct organization of the fibrils.

Collagen XVI harbors an integrin alpha1 beta1 recognition site in its C-terminal domains.

Collagen XVI is integrated tissue-dependently into distinct fibrillar aggregates, such as D-banded cartilage fibrils and fibrillin-1-containing microfibrils. In skin, the distribution of collagen XVI overlaps that of the collagen-binding integrins alpha1 beta1 and alpha2 beta1. Basal layer keratinocytes express integrin alpha2 beta1, whereas integrin alpha1 beta1 occurs in smooth muscle cells surrounding blood vessels, in hair follicles, and on adipocytes. Cells bearing the integrins alpha1 beta1 and alpha2 beta1 attach and spread on recombinant collagen XVI. Furthermore, collagen XVI induces the recruitment of these integrins into focal adhesion plaques, a principal step in integrin signaling. Of potential physiological relevance, these integrin-collagen XVI interactions may connect cells with specialized fibrils, thus contributing to the organization of fibrillar and cellular components within connective tissues. In cell-free binding assays, collagen XVI is more avidly bound by alpha1 beta1 integrin than by alpha2 beta1 integrin. Both integrins interact with collagen XVI via the A domain of their alpha subunits. A tryptic collagen XVI fragment comprising the collagenous domains 1-3 is recognized by alpha1 beta1 integrin. Electron microscopy of complexes of alpha1 beta1 integrin with this tryptic collagen XVI fragment or with full-length collagen XVI revealed a unique alpha1 beta1 integrin-binding site within collagen XVI located close to its C-terminal end.