Integrin alpha2beta1 plays a critical role in osteoblast response to micron-scale surface structure and surface energy of titanium substrates

Efforts to improve bone response to biomaterials have focused on ligands that bind α5β1 integrins. However, antibodies to α5β1 reduce osteoblast proliferation but do not affect differentiation when cells are grown on titanium (Ti). β1-silencing blocks the differentiation stimulus of Ti microtopography, suggesting that other β1 partners are important. Stably α2-silenced MG63 human osteoblast-like cells were used to test whether α2β1 specifically mediates osteoblast response to Ti surface micron-scale structure and energy. WT and α2-silenced MG63 cells were cultured on tissue culture polystyrene (TCPS) and Ti disks with different surface microtopographies: machined pretreatment (PT) surfaces [mean peak to valley roughness (R_a) < 0.02 μm], PT surfaces that were grit-blasted and acid-etched (SLA; R_a = 4 μm), and SLA with high surface energy (modSLA). Alkaline phosphatase (ALP), α2 and β1 mRNA, but not α5, αv, β3, type-I collagen, or osteocalcin, increased on SLA and modSLA at 6 days. α2 increased at 8 days on TCPS and PT, but remained unchanged on SLA and modSLA. α2-protein was reduced 70% in α2-siRNA cells, whereas α5-mRNA and protein were unaffected. α2-knockdown blocked surface-dependent increases in β1 and osteocalcin and decreases in cell number and increases in ALP and local factors typical of MG63 cells grown on SLA and modSLA [e.g., prostaglandin E₂, osteoprotegerin, latent and active TGF-β1, and stimulatory effects of 1α,25(OH)₂D₃ on these parameters]. This finding indicates that α2β1 signaling is required for osteoblastic differentiation caused by Ti microstructure and surface energy, suggesting that conclusions based on cell behavior on TCPS are not predictive of behavior on other substrates or the mechanisms involved.     

Cytokine and chemokine secretion by human peripheral blood cells in response to viable Echinococcus multilocularis metacestode vesicles

In human alveolar echinococcosis, asexually proliferating metacestodes of Echinococcus multilocularis progressively infiltrate host tissues and cause serious pathology to the affected organs. This study employed an in vitro culture of E. multilocularis and examined the production of cytokines and chemokines by peripheral blood cells from echinococcosis patients in response to viable proliferating E. multilocularis metacestode vesicles (Em-vesicles). A significant interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) production was elicited in echinococcosis patients when their cells were cocultured with viable Em-vesicles and autologous immune sera. Furthermore, in echinococcosis patients, substantial amounts of cytokines were detected; and the levels of IL-12 and IL-13 found in patients correlated with the actual state of clinical disease. These observations suggest that viable E. multilocularis vesicles will induce significant cellular production of cytokines and chemokines in patients, and that such immune mediators may activate and enhance antibody-dependent cellular effector mechanism against proliferating metacestodes of E. multilocularis.     

Biochemical changes and their relationship with morphological and functional findings in pig heart subjected to lasting volume overload: a possible role of acylphosphatase in the regulation of sarcoplasmic reticulum calcium pump

We evaluated the changes in sarcoplasmic reticulum (SR) function and the parallel hemodynamic and morphological modifications in a heart subjected to volume overload. We also determined the levels of acylphosphatase, a cytosolic enzyme, that could play a regulatory effect on SR Ca²⁺ pump by hydrolyzing the phosphorylated intermediate of this transport system. For this, swine hearts were subjected to volume overload by aorta-cava shunt for 1, 2, or 3 months. Changes in heart contractility reflected modifications of SR function, whose reduction after 1 month of overload was followed by a gradual recovery. A decrease in SERCA2a protein and mRNA content was shown from 1 month and remained for the following 2 months. Phospholamban content and its phosphorylation status were not modified. Acylphosphatase was unchanged at 1 month, but at 2 months this enzyme exhibited an increased activity, protein and mRNA expression. Morphological alterations consisting of the cytoskeletal architectures, intermyofibrillar oedema, swollen mithochondria and abnormality of the membrane system (T-tubule and SR cisternae) were particularly evident after 1 month but almost disappeared after 3 months. These results suggest that our overloaded hearts underwent a substantial recovery of their structural and biochemical properties at 3 months after surgery. A possible involvement of acylphosphatase in the modification of SR function is discussed. Received: 6 November 2001, Returned for revision: 4 December 2001, Revision received: 14 January 2002, Accepted: 12 February 2002 Correspondence to: Prof. P. Nassi     

Relationship of progressively increasing albuminuria to apoprotein(a) and blood pressure in Type 2 (non-insulin-dependent) and Type 1 (insulin-dependent) diabetic patients

Summary This study has explored the temporal relationship between apoprotein(a), blood pressure and albuminuria over a mean interval of 11 years in a cohort of 107 diabetic patients of whom 26 (14 Type 2 (non-insulin-dependent), 12 Type 1 (insulin-dependent) had progressively increasing albuminuria (‘progressors’). In Type 2 diabetic patients, no significant differences were noted for HbA₁, blood pressure, creatinine clearance or serum lipids between progressors and non-progressors. In Type 1 diabetic patients, final systolic and diastolic blood pressures were higher in progressors compared with non-progressors and progressors showed impairment of renal function in association with a rise in blood pressure at the macroalbuminuric stage. Initial apoprotein(a) levels were similar in progressors and non-progressors of either diabetes type. Apoprotein(a) levels increased exponentially with time in 12 of 14 Type 2 progressors but only in 5 of 12 Type 1 progressors (p<0.01). In Type 2 diabetic patients, the annual increase in apoprotein(a) levels was 9.1±2.4%, which was significantly greater than in non-progressors, 2.0±1.2% (p<0.01) and also exceeded the rates of increase of apoprotein(a) in progressors with Type 1 diabetes, 4.0±1.4%, (p<0.05). Apoprotein(a) levels correlated significantly with albuminuria in 8 of 14 Type 2 progressors but only in 3 of 12 Type 1 progressors (p<0.05). The rate of increase of apoprotein(a) levels was not related to mean HbA₁, creatinine or creatinine clearance levels, or to albuminuria. The rate of rise of apoprotein(a) was not influenced by initial apoprotein(a) levels, suggesting that specific apoprotein(a) isoforms do not influence albuminuria-related increases in apoprotein(a). The data are consistent with the hypothesis that apoprotein(a) levels increase in response to albuminuria and may be part of a self-perpetuating process. This study also suggests that increases in apoprotein(a) levels commence during the microalbuminuria stage in diabetic patients, which is earlier than has been documented in non-diabetic proteinuria.     

Four weeks of near‐normalization of blood glucose has no effect on postprandial GLP‐1 and GIP secretion,but augments pancreatic B‐cell responsiveness to a meal in patients with Type 2 diabetes

Objective The aim of the present study was to investigate whether 4 weeks of near‐normalization of blood glucose (BG) improves incretin hormone secretion and pancreatic B‐cell function during a mixed meal. Research design and methods Nine patients with Type 2 diabetes in poor glycaemic control [glycated haemoglobin (HbA_1c) 8.0 ± 0.4%] were investigated before and after 4 weeks of near‐normalization of BG (mean BG 6.4 ± 0.3 mmol/l) using insulin treatment. HbA_1c after insulin treatment was 6.6 ± 0.3%. For comparison, nine healthy control subjects were also studied. Postprandial glucagon‐like peptide 1 (GLP‐1) and glucose‐dependent insulinotropic polypeptide (GIP) incremental responses were assessed during a mixed meal test. Fasting and postprandial pancreatic B‐cell function was determined from calculations of insulin secretion rates in relation to plasma glucose. Results There was no difference in IAUC_totalGLP‐1 or in IAUC_totalGIP between the two experimental days. B‐cell sensitivity to glucose (insulinogenic index) did not differ before and after insulin treatment in the fasting state (0.21 ± 0.17 vs. 0.25 ± 0.10 pmol kg^?1 min^?1/mmol l^?1), but improved significantly during the first 30 min after start of the meal (0.28 ± 0.07 vs. 0.46 ± 0.06 pmol kg^?1 min^?1/mmol l^?1) and during the following 4 h (0.34 ± 0.09 vs. 0.56 ± 0.07 pmol kg^?1 min^?1/ mmol l^?1). The B‐cell responsiveness to changes in plasma glucose, expressed as the slope of the linear relationship between the insulin secretion rate and the concomitant plasma glucose increased from 0.59 ± 0.16 to 0.94 ± 0.13 pmol kg^?1 min^?1/ mmol l^?1 (P < 0.07). Conclusions Four weeks of near‐normalization of BG had no effect on postprandial secretion of incretin hormones. Nevertheless, several parameters of meal‐induced insulin secretion improved after insulin treatment.     

Validation of a wrist‐type home nocturnal blood pressure monitor in the sitting and supine position according to the ANSI/AAMI/ISO81060‐2:2013 guidelines: Omron HEM‐9600T

The purpose of the present study was to evaluate the performance of the Omron HEM‐9600T, an automatic wrist‐type device for self BP measurement, in the sitting position with the wrist at heart level and supine position according to the ANSI/AAMI/ISO81060‐2:2013 guidelines. In the supine position, we evaluated the device under 3 different conditions: using the supine with sideways palm position, the supine with upwards palm position, and the supine with downwards palm position. After 106 subjects were screened and 21 subjects were excluded, the same 85 subjects (38 men [44.7%] and 47 women [55.3%]) were included in the analyses for each position. The average age of the subjects was 54.5 ± 12.2 years (mean ± SD). The mean wrist circumference was 17.0 ± 2.4 cm. The wrist size distribution fulfilled the requirements of the guidelines. The mean differences between reference BPs and HEM‐9600T readings were 1.0 ± 6.7/1.4 ± 5.7 mm Hg, 6.6 ± 7.2/5.5 ± 6.0 mm Hg, 4.8 ± 7.2/4.9 ± 5.8 mm Hg, and 2.1 ± 7.2/2.8 ± 6.8 mm Hg for SBP/DBP in the sitting position, supine with sideways palm position, supine with upwards palm position, and supine with downwards palm position, respectively. In conclusion, the Omron HEM‐9600T in the sitting position fulfilled the validation criteria of the ANSI/AAMI/ISO81060‐2:2013 guidelines. On the other hand, the accuracies of HEM‐9600T in the supine position differed depending on the positioning of the palm, with only the downwards palm‐position measurement fulfilling both validation criteria of the ANSI/AAMI/ISO81060‐2:2013 guidelines.     

Validation of a wrist‐type home nocturnal blood pressure monitor in the sitting and supine position according to the ANSI/AAMI/ISO81060‐2:2013 guidelines: Omron HEM‐9601T

This study aimed to validate the accuracy of the Omron HEM‐9601T, an automatic wrist‐type device for self‐blood pressure (BP) measurement with a timer function for automatic measurement of nocturnal BP, in the sitting position according to the American National Standards Institute/Association for the Advancement of Medical Instrumentation/International Organization for Standardization (ANSI/AAMI/ISO) 81060‐2:2013 guidelines, and to assess its performance in the supine position by applying the same protocol as conducted in the sitting position. The mean differences between the reference BPs and HEM‐9601T readings were 1.2 ± 6.9/1.1 ± 5.5 mmHg, 2.2 ± 6.5/1.8 ± 5.7 mmHg, 0.1 ± 6.6/1.5 ± 6.2 mmHg, and ?0.8 ± 7.2/0.5 ± 6.4 mmHg for systolic BP/diastolic BP for criterion 1 in the sitting position, supine with sideways palm position, supine with upward palm position, and supine with downward palm position, respectively. In addition, the mean differences and their standard deviations for systolic BP and diastolic BP calculated according to criterion 2 in the ANSI/AAMI/ISO 81060‐2:2013 guidelines were acceptable in all four positions. In conclusion, the Omron HEM‐9601T fulfilled the validation criteria of the ANSI/AAMI/ISO81060‐2:2013 guidelines when used in the sitting position with the wrist at heart level, and its accuracy in the supine position was acceptable and roughly equivalent to that in the sitting position. The wrist‐type home BP monitor could be a more suitable tool for repeated nocturnal BP measurements at home than upper‐arm devices, and could improve the reliability of diagnosis and management of nocturnal hypertension.     

Serum levels of vitamin E forms and risk of cognitive impairment in a Finnish cohort of older adults

Background

Vitamin E includes eight natural antioxidant compounds (four tocopherols and four tocotrienols), but α-tocopherol has been the main focus of investigation in studies of cognitive impairment and Alzheimer's disease.

Objective

To investigate the association between serum levels of tocopherols and tocotrienols, markers of vitamin E oxidative/nitrosative damage (α-tocopherylquinone, 5-nitro-γ-tocopherol) and incidence of cognitive impairment in a population-based study.

Design

A sample of 140 non-cognitively impaired elderly subjects derived from the Cardiovascular Risk Factors, Aging, and Dementia (CAIDE) study was followed-up for 8 years to detect cognitive impairment, defined as development of mild cognitive impairment (MCI) or Alzheimer's dementia. The association between baseline serum vitamin E and cognitive impairment was analyzed with multiple logistic regression after adjusting for several confounders.

Results

The risk of cognitive impairment was lower in subjects in the middle tertile of the γ-tocopherol/cholesterol ratio than in those in the lowest tertile: the multiadjusted odds ratio (OR) with 95% confidence interval (CI) was 0.27 (0.10–0.78). Higher incidence of cognitive impairment was found in the middle [OR (95% CI): 3.41 (1.29–9.06)] and highest [OR (95% CI): 2.89 (1.05–7.97)] tertiles of the 5-NO₂-γ-tocopherol/γ-tocopherol ratio. Analyses of absolute serum levels of vitamin E showed lower risk of cognitive impairment in subjects with higher levels of γ-tocopherol, β-tocotrienol, and total tocotrienols.

Conclusions

Elevated levels of tocopherol and tocotrienol forms are associated with reduced risk of cognitive impairment in older adults. The association is modulated by concurrent cholesterol concentration. Various vitamin E forms might play a role in cognitive impairment, and their evaluation can provide a more accurate measure of vitamin E status in humans.