Arterial Thickness and Immunometabolism: The Mediating role of Chronic Exercise

Calculated Small Dense Low-Density Lipoprotein Cholesterol Level is A Predominant Predictor for New Onset of Ischemic Heart Disease

AIM

A high level of directly measured small dense low-density lipoprotein cholesterol (sdLDL-C) is a strong risk factor for ischemic heart disease (IHD). However, it remains unclear whether estimated sdLDL-C level is a predictor for IHD. We investigated the associations of new onset of IHD with levels of total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), non-HDL-C, triglycerides (TG), LDL-C and calculated sdLDL-C by Sampson's equation.

METHODS

After exclusion of subjects with IHD or those with TG ≥ 800 mg/dL, a total of 18,176 subjects (men/women: 11,712/6,464, mean age: 46 years) were recruited among 28,990 Japanese individuals who received annual health checkups.

RESULTS

During the 10-year follow-up period, 456 men (3.9%) and 121 women (1.9%) newly developed IHD. Multivariable Cox proportional hazard analyses after adjustment of age, sex, obesity, smoking habit, family history of IHD, estimated glomerular filtration rate, hypertension and diabetes mellitus at baseline showed that the hazard ratio (HR) (1.38 [95% confidence interval: 1.03-1.85]) for new onset of IHD in subjects with the 4th quartile (Q4) of sdLDL-C (≥ 42 mg/dL) was significantly higher than that in subjects with the 1st quartile (Q1) (≤ 24 mg/dL) as the reference, though the adjusted HRs in subjects with Q2-Q4 of TC, HDL-C, non-HDL-C, LDL-C and TG were comparable with those in subjects with Q1 of the respective lipid fractions. The adjusted HR with a restricted cubic spline increased with a higher level of calculated sdLDL-C as a continuous value at baseline.

CONCLUSIONS

sdLDL-C level calculated by Sampson's equation is a predominant predictor for the development of IHD in a general Japanese population.

An increase in calculated small dense low-density lipoprotein cholesterol predicts new onset of hypertension in a Japanese cohort

A disorder of lipid metabolism is involved in cardiovascular diseases including hypertension. A high level of small dense low-density lipoprotein cholesterol (sdLDL-C) is a strong risk factor for atherosclerotic cardiovascular disease. However, the association between sdLDL-C and hypertension has not been fully investigated. We investigated the associations between the development of hypertension during a 10-year period and levels of total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), non-HDL-C, triglycerides (TG), and LDL-C and sdLDL-C calculated by using the Sampson equations in 28,990 Japanese subjects who received annual health examinations. After exclusion of subjects with missing data, those with hypertension, and those with TG ≥ 800 mg/dL at baseline, a total of 15,177 subjects (men/women: 9374/5803, mean age: 46 years) were recruited. During the 10-year period, 2379 men (25.4%) and 724 women (12.5%) had new onset of hypertension. Multivariable Cox proportional hazard model analyses showed that levels of HDL-C, non-HDL-C, TG and sdLDL-C, but not levels of TC and LDL-C, were independent risk factors for the development of hypertension after adjustment of age, sex, family history of hypertension, systolic blood pressure, obesity, current smoking habit, alcohol drinking habit, estimated glomerular filtration rate, diagnosis of diabetes mellitus and use of lipid-lowering drugs and that the adjusted risk of sdLDL-C (per 1-standard deviation) was highest (hazard ratio [95% confidence interval: 1.09 [1.05-1.13]). The addition of sdLDL-C to traditional risk factors for hypertension significantly improved the discriminatory capability, which was better than that of other lipid fractions. In conclusion, a high level of calculated sdLDL-C predicts the development of hypertension.

Inducible nitric oxide synthase activity mediates TNF-α-induced endothelial cell dysfunction

Inducible nitric oxide synthase (iNOS) and vascular endothelial dysfunction have been implicated in the development and progression of atherosclerosis. This study aimed to elucidate the role of iNOS in vascular endothelial dysfunction. Ultrahigh performance liquid chromatography-quadrupole time-of-flight mass spectrometry combined with multivariate data analysis was used to characterize the metabolic changes in human umbilical vein endothelial cells (HUVECs) in response to different treatment conditions. In addition, molecular biology techniques were employed to explain the molecular mechanisms underlying the role of iNOS in vascular endothelial dysfunction. Tumor necrosis factor-α (TNF-α) enhances the expression of iNOS, TXNIP, and the level of reactive oxygen species (ROS) facilitates the entry of nuclear factor-κB (NF-κB) into the nucleus and promotes injury in HUVECs. iNOS deficiency reversed the TNF-α-mediated pathological changes in HUVECs. Moreover, TNF-α increased the expression of tumor necrosis factor receptor-2 (TNFR-2) and the levels of p-IκBα and IL-6 proteins and CD31, ICAM-1, and VCAM-1 protein expression, which was significantly reduced in HUVECs with iNOS deficiency. In addition, treating HUVECs in the absence or presence of TNF-α or iNOS, respectively, enabled the identification of putative endogenous biomarkers associated with endothelial dysfunction. These biomarkers were involved in critical metabolic pathways, including glycosylphosphatidylinositol-anchor biosynthesis, amino acid metabolism, sphingolipid metabolism, and fatty acid metabolism. iNOS deficiency during vascular endothelial dysfunction may affect the expression of TNFR-2, vascular adhesion factors, and the level of ROS via cellular metabolic changes, thereby attenuating vascular endothelial dysfunction.NEW & NOTEWORTHY Inducible nitric oxide synthase (iNOS) deficiency during vascular endothelial dysfunction may affect the expression of tumor necrosis factor receptor-2 and vascular adhesion factors via cellular metabolic changes, thereby attenuating vascular endothelial dysfunction.

Physical Activity as a Modern Intervention in the Fight against Obesity-Related Inflammation in Type 2 Diabetes Mellitus and Gestational Diabetes

Diabetes is one of the greatest healthcare problems; it requires an appropriate approach to the patient, especially when it concerns pregnant women. Gestational diabetes mellitus (GDM) is a common metabolic condition in pregnancy that shares many features with type 2 diabetes mellitus (T2DM). T2DM and GDM induce oxidative stress, which activates cellular stress signalling. In addition, the risk of diabetes during pregnancy can lead to various complications for the mother and foetus. It has been shown that physical activity is an important tool to not only treat the negative effects of diabetes but also to prevent its progression or even reverse the changes already made by limiting the inflammatory process. Physical activity has a huge impact on the immune status of an individual. Various studies have shown that regular training sessions cause changes in circulating immune cell levels, cytokine activation, production and secretion and changes in microRNA, all of which have a positive effect on the well-being of the diabetic patient, mother and foetus.

Analysis of IGHA1 and other salivary proteins post half marathon in female participants

Background

High-intensity exercise (HIE), such as that in marathons and triathlons, suppresses transient local and systemic immunity. Serum and salivary immunoglobulin heavy constant alpha 1 (IGHA1) are major markers of immunosuppression by HIE. Although much is known about the systemic immunosuppressive response, little is known about its local response in the oral cavity, lungs, bronchial tubes, and skin. The oral cavity allows bacteria or viruses to enter the body. Saliva covers the epidermis of the oral cavity and plays an important role in the local stress response by preventing infection. In this study, we examined the properties of saliva secreted during the local stress response for half-marathon (HM) induced IGHA1 protein expression using quantitative proteomics.

Methods

The Exercise Group (ExG) (19 healthy female university students) participated in a HM race. The Non-Exercise Group (NExG) (16 healthy female university students) did not participate in the ExG. The ExG saliva samples were collected 1 h pre and 2 h and 4 h post-HM. The NExG saliva samples were collected at the same time intervals. The saliva volume, protein concentration, and relative IGHA1 expression were analyzed. In addition, 1 h pre and 2 h post- HM saliva samples were analyzed by iTRAQ. The identified factors in iTRAQ were analyzed for the ExG and the NExG using western blotting.

Results

We identified kallikrein 1 (KLK1), immunoglobulin kappa chain (IgK), and cystatin S (CST4) as suppression factors, as well as IGHA1, which has been reported to be an immunological stress marker. IGHA1 (p = 0.003), KLK1 (p = 0.011), IGK (p = 0.002), and CST4 (p = 0.003) were suppressed 2 h post-HM compared with their levels pre HM, and IGHA1 (p < 0.001), KLK1 (p = 0.004), and CST4 (p = 0.006) were suppressed 4 h post-HM. There was also a positive correlation between IGHA1, IGK, and CST4 levels at 2 and 4 h post-HM. In addition, KLK1 and IGK levels at 2 h post-HM were positively correlated.

Conclusion

Our study demonstrated that the salivary proteome is regulated, and antimicrobial proteins are suppressed post-HM. These results suggest that oral immunity was transiently suppressed post-HM. The positive correlation of each protein at 2 and 4 h post-HM suggests that the suppressed state was similarly regulated up to 4 h after a HM. The proteins identified in this study may have applications as stress markers for recreational runners and individuals who perform moderate to HIE on a regular basis.

Danlou Tablet May Alleviate Vascular Injury Caused by Chronic Intermittent Hypoxia through Regulating FIH-1, HIF-1, and Angptl4

Background

Danlou tablet (DLT), the traditional Chinese medicine has been commonly used for dyslipidemia, atherosclerosis, and coronary heart disease. Whether it was effective against vascular injury caused by CIH has remained unknown. The aim of the current study was to observe the effects of DLT on chronic intermittent hypoxia (CIH)-induced vascular injury via regulation of blood lipids and to explore potential mechanisms.

Methods

Sixteen 12-week-old male ApoE^−/− mice were randomly divided into four groups. The sham group was exposed to normal room air, whereas the other three groups were exposed to CIH. Mice in the CIH + normal saline (NS) group were gavaged with NS. Mice in the CIH + Angptl4-ab group were intraperitoneally injected with Angptl4-antibody. Mice in the CIH + DLT group were gavaged with DLT. After four weeks of intervention, serum lipid concentrations, and serum lipoprotein lipase (LPL) activity were detected. The changes in atherosclerosis in vascular tissue were detected by hematoxylin and eosin (H&E) staining. Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot analysis were applied to detect the expression levels of hypoxia-induciblefactor-1 (HIF-1), factor-inhibiting HIF-1 (FIH-1), angiopoietin-like 4 (Angptl4), and LPL in different tissues.

Results

CIH exposure increases serum lipid levels, decreases serum LPL activity, and exacerbates atherosclerosis. Both Angptl4-ab and DLT treatment reversed the changes in lipid concentration, LPL activity, and atherosclerosis caused by CIH. In the epididymal fat pad, CIH exposure decreased the expression of FIH-1 and increased the expression of HIF-1, whereas DLT treatment increased the expression of FIH-1 and LPL and inhibited the expression of HIF-1 and Angptl4. In heart tissue, the expression levels of LPL and Angptl4 were not affected by modeling or treatment.

Conclusions

DLT improved vascular damage by improving the increase in blood lipids induced by CIH, potentially by upregulating FIH-1 and downregulating HIF-1 and Angptl4 in adipose tissue. Therefore, DLT may be a promising agent for the prevention and treatment of CIH-induced vascular injury.

Modulatory Effects of Physical Activity Levels on Immune Responses and General Clinical Functions in Adult Patients with Mild to Moderate SARS-CoV-2 Infections-A Protocol for an Observational Prospective Follow-Up Investigation: Fit-COVID-19 Study

Background: This proposal aims to explain some of the gaps in scientific knowledge on the natural history of coronavirus disease (COVID-19), with a specific focus on immune, inflammatory, and metabolic markers, in parallel with temporal assessment of clinical and mental health in patients with COVID-19. The study will explore the temporal modulatory effects of physical activity and body composition on individual trajectories. This approach will provide a better understanding of the survival mechanisms provided by the immunomodulatory role of physical fitness. Methods: We will conduct a prospective observational cohort study including adult patients previously infected with the SARS-CoV-2 virus who have expressed a mild to moderate COVID-19 infection. Procedures will be conducted for all participants at baseline, six weeks after vaccination, and again at 12 months. At each visit, a venous blood sample will be collected for immune phenotypic characterization and biochemistry assays (inflammatory and metabolic parameters). Also, body composition, physical activity level, cardiovascular and pulmonary function, peripheral and respiratory muscle strength, functional exercise capacity, and mental health will be evaluated. Using the baseline information, participants will be grouped based on physical activity levels (sedentary versus active), body composition (normal weight versus overweight or obese), and SARS-CoV-2 status (positive versus negative). A sub-study will provide mechanistic evidence using an in-vitro assay based on well-trained individuals and age-matched sedentary controls who are negative for SARS-CoV-2 infection. Whole blood will be stimulated using recombinant human coronavirus to determine the cytokine profile. Peripheral blood mononuclear cells (PBMCs) from healthy well-trained participants will be collected and treated with homologous serum (from the main study; samples collected before and after the vaccine) and recombinant coronavirus (inactive virus). The metabolism of PBMCs will be analyzed using Respirometry (Seahorse). Data will be analyzed using multilevel repeated-measures ANOVA. Conclusions: The data generated will help us answer three main questions: (1) Does the innate immune system of physically active individuals respond better to viral infections compared with that of sedentary people? (2) which functional and metabolic mechanisms explain the differences in responses in participants with different physical fitness levels? and (3) do these mechanisms have long-term positive modulatory effects on mental and cardiovascular health? Trial registration number: Brazilian Registry of Clinical Trials: RBR-5dqvkv3. Registered on 21 September 2021.

Epigenetic Regulation of Inflammatory Responses in the Context of Physical Activity

Epigenetic modifications occur in response to environmental changes and play a fundamental role in the regulation of gene expression. PA is found to elicit an inflammatory response, both from the innate and adaptive divisions of the immunological system. The inflammatory reaction is considered a vital trigger of epigenetic changes that in turn modulate inflammatory actions. The tissue responses to PA involve local and general changes. The epigenetic mechanisms involved include: DNA methylation, histone proteins modification and microRNA. All of them affect genetic expression in an inflammatory milieu in physical exercise depending on the magnitude of physiological stress experienced by the exerciser. PA may evoke acute or chronic biochemical and physiological responses and have a positive or negative immunomodulatory effect.

The central role of mitochondrial fitness on antiviral defenses: An advocacy for physical activity during the COVID-19 pandemic

Mitochondria are central regulators of cellular metabolism, most known for their role in energy production. They can be "enhanced" by physical activity (including exercise), which increases their integrity, efficiency and dynamic adaptation to stressors, in short "mitochondrial fitness". Mitochondrial fitness is closely associated with cardiorespiratory fitness and physical activity. Given the importance of mitochondria in immune functions, it is thus not surprising that cardiorespiratory fitness is also an integral determinant of the antiviral host defense and vulnerability to infection. Here, we first briefly review the role of physical activity in viral infections. We then summarize mitochondrial functions that are relevant for the antiviral immune response with a particular focus on the current Coronavirus Disease (COVID-19) pandemic and on innate immune function. Finally, the modulation of mitochondrial and cardiorespiratory fitness by physical activity, aging and the chronic diseases that represent the most common comorbidities of COVID-19 is discussed. We conclude that a high mitochondrial - and related cardiorespiratory - fitness should be considered as protective factors for viral infections, including COVID-19. This assumption is corroborated by reduced mitochondrial fitness in many established risk factors of COVID-19, like age, various chronic diseases or obesity. We argue for regular analysis of the cardiorespiratory fitness of COVID-19 patients and the promotion of physical activity - with all its associated health benefits - as preventive measures against viral infection.

Regular exercise stimulates endothelium autophagy via IL-1 signaling in ApoE deficient mice

Regular exercise maintains arterial endothelial cell homeostasis and protects the arteries from vascular disease, such as peripheral artery disease and atherosclerosis. Autophagy, which is a cellular process that degrades misfolded or aggregate proteins and damaged organelles, plays an important role in maintaining organ and cellular homeostasis. However, it is unknown whether regular exercise stimulates autophagy in aorta endothelial cells of mice prone to atherosclerosis independently of their circulating lipid profile. Here, we observed that 16 weeks of voluntary exercise reduced high-fat diet-induced atherosclerotic plaque formation in the aortic root of ApoE deficient mice, and that this protection occurred without changes in circulating triglycerides, total cholesterol, and lipoproteins. Immunofluorescence analysis indicated that voluntary exercise increased levels of the autophagy protein LC3 in aortic endothelial cells. Interestingly, human umbilical vein endothelial cells (HUVECs) exposed to serum from voluntarily exercised mice displayed significantly increased LC3-I and LC3-II protein levels. Analysis of circulating cytokines demonstrated that voluntary exercise caused changes directly relevant to IL-1 signaling (ie, decreased interleukin-1 receptor antagonist [IL-1ra] while also increasing IL-1α). HUVECs exposed to IL-1α and IL-1β recombinant protein significantly increased LC3 mRNA expression, LC3-I and LC3-II protein levels, and autophagy flux. Collectively, these results suggest that regular exercise protects arteries from ApoE deficient mice against atherosclerosis at least in part by stimulating endothelial cell autophagy via enhanced IL-1 signaling.

Analysis of human neutrophil phenotypes as biomarker to monitor exercise-induced immune changes

The amplitude of the innate immune response reflects the degree of physiological stress imposed by exercise load. An optimal balance of exercise intensity and duration is essential for a balanced immune system and reduces the risk of dysfunction of the immune system. Therefore, it is hypothesized that neutrophils, as key players in the innate immune system, can be used as biomarker in detecting overtraining. The aim was to monitor the state of the innate immune system by phenotyping neutrophils during consecutive bouts of prolonged exercise. Study subjects were recruited from a cohort of walkers participating in a walking event on 3 consecutive days. Participants with immune deficiencies were excluded. Questionnaires to determine the physiological status of the participants were completed. Analysis of neutrophil receptor expression was done by a point-of-care fully automated flow cytometer. A total of 45 participants were recruited, of whom 39 participants were included for data analysis. Study participants had a median age of 64 (58-70) years. The absolute numbers CD16^dim /CD62L^bright and CD16^bright /CD62L^dim neutrophils were increased after the first 2 days of exercise followed by an adaptation/normalization after the third day. Participants with activated neutrophils (high CD11b expression) had an impaired physical feeling indicated by the participant on a lower visual analog scale compared to participants who did not have activated neutrophils (P = 0.017, P = 0.022). Consecutive days of prolonged exercise results in an initial systemic innate immune response, followed by normalization/adaptation. Increased neutrophil activation was associated with impaired physical feeling measured by a validated VAS score indicated by the participant. Fully automated point-of-care flow cytometry analysis of neutrophil phenotypes in a field laboratory might be a useful tool to monitor relevant differences in the systemic innate immune response in response to exercise.

Influence of Acute and Chronic High-Intensity Intermittent Aerobic Plus Strength Exercise on BDNF, Lipid and Autonomic Parameters

The purpose of the present study is two-fold. First, we evaluated whether 8-weeks of combined training (high-intensity intermittent plus strength training) may change brain derived neurotropic factor (BDNF) and lipid parameters (triacylglycerol, HDL-c and non-HDL) in a fasted state. Second, we investigated the effect of an acute session of high-intensity intermittent exercise followed by strength training on systemic BDNF and lipid parameters pre- and post 8-weeks of training. Twenty-one healthy and physically active men were divided into two groups: high-intensity intermittent exercise combined with strength training (HSG; n = 11) and control (CG; n = 10). The HSG exercised for one minute at 100% of speedVO₂max (sVO₂max) interspersed with one minute of passive recovery followed by strength training (8 exercises with 8-12 repetition maximum loads) for 8-weeks. Heart rate variability, blood pressure, lipid profile, and BDNF concentrations were measured in the fasted state pre- and post-exercise and before and after the 8-week training period. After 8-weeks of exercise training, there was an increase in spectral high frequency component (ms²) and RR interval (p < 0.05), a decreased spectral low frequency component (nu) and heart rate values (p < 0.05), an increase in HDL-c (p < 0.001), and lower BDNF concentrations (p < 0.001). These results suggest that 8-weeks of high-intensity intermittent exercise combined with strength exercise is an effective protective cardio-metabolic strategy capable of increasing HDL-c and BDNF concentrations after an acute exercise session. In the long-term, the modulation on BDNF and HDL-c concentrations may be a determining factor for protection against neurological and cardiovascular diseases.

The compelling link between physical activity and the body's defense system

This review summarizes research discoveries within 4 areas of exercise immunology that have received the most attention from investigators: (1) acute and chronic effects of exercise on the immune system, (2) clinical benefits of the exercise-immune relationship, (3) nutritional influences on the immune response to exercise, and (4) the effect of exercise on immunosenescence. These scientific discoveries can be organized into distinctive time periods: 1900-1979, which focused on exercise-induced changes in basic immune cell counts and function; 1980-1989, during which seminal papers were published with evidence that heavy exertion was associated with transient immune dysfunction, elevated inflammatory biomarkers, and increased risk of upper respiratory tract infections; 1990-2009, when additional focus areas were added to the field of exercise immunology including the interactive effect of nutrition, effects on the aging immune system, and inflammatory cytokines; and 2010 to the present, when technological advances in mass spectrometry allowed system biology approaches (i.e., metabolomics, proteomics, lipidomics, and microbiome characterization) to be applied to exercise immunology studies. The future of exercise immunology will take advantage of these technologies to provide new insights on the interactions between exercise, nutrition, and immune function, with application down to the personalized level. Additionally, these methodologies will improve mechanistic understanding of how exercise-induced immune perturbations reduce the risk of common chronic diseases.

Cardiorespiratory fitness and age-related arterial stiffness in women with systemic lupus erythematosus

BACKGROUND

The aim of this study was twofold: (i) to examine the association of cardiorespiratory fitness with arterial stiffness in women with systemic lupus erythematosus; (ii) to assess the potential interaction of cardiorespiratory fitness with age on arterial stiffness in this population.

MATERIALS AND METHODS

A total of 49 women with systemic lupus erythematosus (mean age 41.3 [standard deviation 13.8] years) and clinical stability during the previous 6 months were included in the study. Arterial stiffness was assessed through pulse wave velocity (Mobil-O-Graph® 24 hours pulse wave velocity monitor). Cardiorespiratory fitness was estimated with the Siconolfi step test and the 6-minute walk test.

RESULTS

Cardiorespiratory fitness was inversely associated with pulse wave velocity in crude analyses (P < .05), although this relationship was attenuated when age and other cardiovascular risk factors were controlled. There was a cardiorespiratory fitness × age interaction effect on pulse wave velocity, regardless of the test used to estimate cardiorespiratory fitness (P < .001 for the Siconolfi step test; P = .005 for the 6-minute walk test), indicating that higher cardiorespiratory fitness was associated with a lower increase in pulse wave velocity per each year increase in age.

CONCLUSIONS

The results of this study suggest that cardiorespiratory fitness might attenuate the age-related arterial stiffening in women with systemic lupus erythematosus and might thus contribute to the primary prevention of cardiovascular disease in this population. As the cross-sectional design precludes establishing causal relationships, future clinical trials should confirm or contrast these findings.

Piperine enhances carbohydrate/fat metabolism in skeletal muscle during acute exercise in mice

Background

Exercise promotes energy metabolism (e.g., metabolism of glucose and lipids) in skeletal muscles; however, reactive oxygen species are also generated during exercise. Various spices have been reported to have beneficial effects in sports medicine. Here, we investigated the effects of piperine, an active compound in black pepper, to determine its effects on metabolism during acute endurance exercise.

Methods

ICR mice (n = 18) were divided into three groups: nonexercise (CON), exercise (EX), and exercise with piperine (5 mg/kg) treatment (EP). Mice were subjected to enforced exercise on a treadmill at a speed of 22 m/min for 1 h. To evaluate the inflammatory responses following exercise, fluorescence-activated cell sorting analysis was performed to monitor changes in CD4⁺ cells within the peripheral blood mononuclear cells (PBMCs) of mice. The expression levels of metabolic pathway components and redox-related factors were evaluated in the soleus muscle by reverse transcription polymerase chain reaction and western blotting.

Results

There were no changes in the differentiation of immune cells in PBMCs in both the EX and EP groups compared with that in the CON group. Mice in the EX group exhibited a significant increase in the expression of metabolic pathway components and redox signal-related components compared with mice in the CON group. Moreover, mice in the EP group showed greater metabolic (GLUT4, MCT1, FAT/CD36, CPT1, CS) changes than mice in the EX group, and changes in the expression of redox signal components were lower in the EP group than those in the EX group.

Conclusion

Our findings demonstrate that piperine promoted beneficial metabolism during exercise by regulating carbohydrate/fat metabolism and redox signals. Therefore, piperine may be a candidate supplement for improvement of exercise ability.

Electronic supplementary material

The online version of this article (doi:10.1186/s12986-017-0194-2) contains supplementary material, which is available to authorized users.