Dietary salt intake is related to inflammation and albuminuria in primary hypertensive patients

Adding salt to foods and risk of psoriasis: A prospective cohort study

BACKGROUND

High salt intake may play a critical role in the etiology of psoriasis. Yet, evidence on the association of high salt intake with risk of psoriasis is limited.

OBJECTIVE

To estimate the association between frequency of adding salt to foods and risk of psoriasis.

METHODS

We conducted a prospective cohort study of 433,788 participants from the UK Biobank. Hazard ratios (HRs) and their 95 % confidence intervals (CIs) for risk of psoriasis in relation to frequency of adding salt to foods were estimated using multivariable Cox proportional hazards models. We further evaluated the joint association of adding salt to foods and genetic susceptibility with risk of psoriasis. We conducted a mediation analysis to assess how much of the effect of adding salt to foods on risk of psoriasis was mediated through several selected mediators.

RESULTS

During a median of 14.0 years of follow-up, 4279 incident cases of psoriasis were identified. In the multivariable-adjusted model, a higher frequency of adding salt to foods was significantly associated with an increased risk of psoriasis ("always" versus "never/rarely" adding salt to foods, HR = 1.25, 95 % CI: 1.10, 1.41). The observed positive association was generally similar across subgroups. In the joint association analysis, we observed that participants with a high genetic risk (above the second tertile) and the highest frequency of adding salt to foods experienced 149 % higher risk of psoriasis, when compared with participants with a low genetic risk (below the first tertile) and the lowest frequency of adding salt to foods (HR = 2.49, 95 % CI: 2.05, 3.02). Mediation analysis revealed that 1.8 %-3.2 % of the positive association between frequency of adding salt and risk of psoriasis was statistically significantly mediated by obesity and inflammatory biomarkers such as C-reactive protein and systemic immune-inflammation index (all P values < 0.004).

CONCLUSIONS

Our study demonstrated a positive association between frequency of adding salt to foods and risk of psoriasis. The positive association was independent of multiple other risk factors, and may be partially mediated through obesity and inflammation.

Association of Common Foods with Inflammation and Mortality: Analysis from a Large Prospective Cohort Study

Some dietary patterns are associated with inflammation, while others lower inflammation and improve health. However, many people cannot follow a complete, healthy diet. Therefore, this study's aim was to identify specific foods associated chronic inflammation and mortality. The study used Multi-Ethnic Study of Atherosclerosis (MESA) research materials from the NHLBI Biologic Specimen and Data Repository Information Coordinating Center. Three plant-based and three animal-based MESA food categories were chosen based on perceived availability in the western diet. The assessed food categories were avocado, ham, sausage, eggs, greens, and broccoli. Inflammatory markers assessed were interleukin-6 (IL-6), fibrinogen antigen, C-reactive protein, D-Dimer, interleukin-2, matrix metalloproteinase 3, necrosis factor-a soluble receptors, oxidized LDL (oxLDL), and total homocysteine. The primary outcome was the multivariable association of foods and inflammatory markers with all-cause mortality. All inflammatory makers, except oxLDL, were associated with mortality in univariate analysis. The effect was largest with IL-6 and D-dimer. The category of broccoli had the most consistent association in univariate analyses with lower inflammation and lower mortality odds. Low and high broccoli consumption versus no consumption were associated with lower mortality odds in the multivariable models with IL-6 and D-dimer. Consumption of the MESA-defined food category "broccoli" (i.e., broccoli, cabbage, cauliflower, brussels sprouts, sauerkraut, and kimchee) was associated with lower inflammation and lower mortality odds. These findings should be validated in randomized controlled trials testing a "food is medicine" approach to identify which, if any, of these foods may have potential as an herbal therapeutic for chronic inflammation.

Dietary Salt Can Be Crucial for Food-Induced Vascular Inflammation

Salt enhances the taste as well as the nutritional value of food. Besides, several reports are available on the incidence and epidemiology of various illnesses in relation to salt intake. Excessive salt consumption has been found to be linked with high blood pressure, renal disease, and other cardiovascular disorders due to the result of vascular inflammation. Nevertheless, studies aimed at elucidating the molecular processes that produce vascular inflammation have yet to reach their conclusions. This article emphasizes the significance of investigating the mechanisms underlying both acute and chronic vascular inflammation induced by salt. It also explores the logical inferences behind cellular oxidative stress and the role of endothelial dysfunction as the potential initiator of the inflammatory segments that remain poorly understood. It is therefore hypothesized that salt is one of the causes of chronic vascular inflammation such as atherosclerosis. The hypothesis's secrets, when revealed, can help assure cardiovascular health by proactive efforts and the development of appropriate preventative measures, in combination with medication, dietary and lifestyle adjustments.

Male kidney-specific BMAL1 knockout mice are protected from K+-deficient, high-salt diet-induced blood pressure increases

The circadian clock protein basic helix-loop-helix aryl hydrocarbon receptor nuclear translocator-like protein 1 (BMAL1) is a transcription factor that impacts kidney function, including blood pressure (BP) control. Previously, we have shown that male, but not female, kidney-specific cadherin Cre-positive BMAL1 knockout (KS-BMAL1 KO) mice exhibit lower BP compared with littermate controls. The goal of this study was to determine the BP phenotype and immune response in male KS-BMAL1 KO mice in response to a low-K+ high-salt (LKHS) diet. BP, renal inflammatory markers, and immune cells were measured in male mice following an LKHS diet. Male KS-BMAL1 KO mice had lower BP following the LKHS diet compared with control mice, yet their circadian rhythm in pressure remained unchanged. Additionally, KS-BMAL1 KO mice exhibited lower levels of renal proinflammatory cytokines and immune cells following the LKHS diet compared with control mice. KS-BMAL1 KO mice were protected from the salt-sensitive hypertension observed in control mice and displayed an attenuated immune response following the LKHS diet. These data suggest that BMAL1 plays a role in driving the BP increase and proinflammatory environment that occurs in response to an LKHS diet.NEW & NOTEWORTHY We show here, for the first time, that kidney-specific BMAL1 knockout mice are protected from blood pressure (BP) increases and immune responses to a salt-sensitive diet. Other kidney-specific BMAL1 knockout models exhibit lower BP phenotypes under basal conditions. A salt-sensitive diet exacerbates this genotype-specific BP response, leading to fewer proinflammatory cytokines and immune cells in knockout mice. These data demonstrate the importance of distal segment BMAL1 in BP and immune responses to a salt-sensitive environment.

Being overweight worsens the relationship between urinary sodium excretion and albuminuria: the Wakuya study

BACKGROUND/OBJECTIVES

(Micro)albuminuria (a manifestation of renal microvascular damage) is an independent predictor of mortality risk, even when the urinary albumin/creatinine ratio is ≥ 10 mg/g in the general population. Excessive sodium intake and obesity are strong predictors of cardiovascular disease. However, the effect of obesity on the relationship between sodium intake and albuminuria is not fully understood.

SUBJECTS/METHODS

The purpose of the present study was to investigate the cross-sectional relationships among dietary sodium intake, obesity, and albuminuria in a general population cohort. Subjects were 928 apparently healthy adults. Body mass index was calculated using the height and body weight. Urinary sodium/creatinine and albumin/creatinine ratios were measured in spot urine samples. Estimated 24-h urinary sodium/creatinine ratio (e24UNa/Cr) was assessed using age, height, body weight, and spot urinary sodium/creatinine ratio.

RESULTS

Both the body mass index and e24UNa/Cr positively correlated with the urinary albumin/creatinine ratio (both, P < 0.001), and had a synergistic effect on increasing urinary albumin/creatinine ratio independent of age, sex, mean arterial pressure, and diabetes (interaction P = 0.04). When subjects were divided into 6 groups according to the tertiles of e24UNa/Cr and body mass index < (normal-weight) or ≥ 25 (overweight), the prevalence rate of urinary albumin/creatinine ratio ≥ 10 mg/g increased with rising e24UNa/Cr and being overweight (P < 0.001).

CONCLUSION

An increase in body mass index increases the positive association between urinary sodium excretion and (micro)albuminuria in the general population. Excess sodium intake may strengthen cardiovascular risk by increasing (micro)albuminuria, particularly in overweight individuals.

The role of dietary salt in metabolism and energy balance: Insights beyond cardiovascular disease

Dietary salt (NaCl) is essential to an organism's survival. However, today's diets are dominated by excessive salt intake, which significantly impacts individual and population health. High salt intake is closely linked to cardiovascular disease (CVD), especially hypertension, through a number of well-studied mechanisms. Emerging evidence indicates that salt overconsumption may also be associated with metabolic disorders. In this review, we first summarize recent updates on the mechanisms of salt-induced CVD, the effects of salt reduction and the use of salt substitution as a therapy. Next, we focus on how high salt intake can impact metabolism and energy balance, describing the mechanisms through which this occurs, including leptin resistance, the overproduction of fructose and ghrelin, insulin resistance and altered hormonal factors. A further influence on metabolism worth noting is the reported role of salt in inducing thermogenesis and increasing body temperature, leading to an increase in energy expenditure. While this result could be viewed as a positive metabolic effect because it promotes a negative energy balance to combat obesity, caution must be taken with this frame of thinking given the deleterious consequences of chronic high salt intake on cardiovascular health. Nevertheless, this review highlights the importance of salt as a noncaloric nutrient in regulating whole-body energy homeostasis. Through this review, we hope to provide a scientific framework for future studies to systematically address the metabolic impacts of dietary salt and salt replacement treatments. In addition, we hope to form a foundation for future clinical trials to explore how these salt-induced metabolic changes impact obesity development and progression, and to elucidate the regulatory mechanisms that drive these changes, with the aim of developing novel therapeutics for obesity and CVD.

Tff3-/- Knock-Out Mice with Altered Lipid Metabolism Exhibit a Lower Level of Inflammation following the Dietary Intake of Sodium Chloride for One Week

A high salt intake causes hemodynamic changes and promotes immune response through cell activation and cytokine production, leading to pro-inflammatory conditions. Transgenic Tff3^-/- knock-out mice (TFF3ko) (n = 20) and wild-type mice (WT) (n = 20) were each divided into the (1) low-salt (LS) group and (2) high-salt (HS) group. Ten-week-old animals were fed with standard rodent chow (0.4% NaCl) (LS) or food containing 4% NaCl (HS) for one week (7 days). Inflammatory parameters from the sera were measured by Luminex assay. The integrin expression and rates of T cell subsets of interest from the peripheral blood leukocytes (PBLs) and mesenteric lymph nodes (MLNs) were measured using flow cytometry. There was a significant increase in high-sensitivity C reactive protein (hsCRP) only in the WT mice following the HS diet, while there were no significant changes in the serum levels of IFN-γ, TNF-α, IL-2, IL-4, or IL-6 as a response to treatment in either study groups. The rates of CD4⁺CD25⁺ T cells from MLNs decreased, while CD3⁺γδTCR⁺ from peripheral blood increased following the HS diet only in TFF3ko. γδTCR expressing T cell rates decreased in WT following the HS diet. The CD49d/VLA-4 expression decreased in the peripheral blood leukocytes in both groups following the HS diet. CD11a/LFA-1 expression significantly increased only in the peripheral blood Ly6C^-CD11a^high monocytes in WT mice following salt loading. In conclusion, salt-loading in knock-out mice caused a lower level of inflammatory response compared with their control WT mice due to gene depletion.

Combination of the effect of ginger and anti-inflammatory diet on children with obesity with nonalcoholic fatty liver disease: A randomized clinical trial

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of liver disease in children. Following earlier reports on an increase in the prevalence of childhood obesity, NAFLD is now becoming increasingly common in children. Although no definitive cure exists, early management, early diagnosis, and treatment can reduce its complications. This study aims to determine the effectiveness of the combination of ginger and an anti-inflammatory diet (AID) in children with obesity on fatty liver management. This randomized clinical trial was conducted on 160 children with obesity aged 8-11 years, with a mean (SD) weight of 65.01 (9.67) kg, mean (SD) height of 139.87 (7.37) cm, and mean (SD) body mass index of 33.40 (5.59) kg/m2. The study duration was 12 weeks. Children were divided into four groups: ginger (G), AID, ginger plus an AID (GPA), and control. Ginger capsules comprised 1000 mg of ginger, whereas the AID comprised fruits and vegetables, fish, turkey, and chicken (without skin) with lean meat, omega-3 sources, nuts, legumes, probiotic products, and elimination of inflammatory food. Following the intervention, serum fasting blood sugar and high-sensitivity C-reactive protein levels were significantly decreased in the AID (p = .006 and .002, respectively), G (p = .04 and <.001, respectively), and GPA (p <.001 in both cases, respectively) groups. Further, in the G and GPA groups, there was a significant decrease in body mass index (p = .04 in both cases, respectively), waist circumference (p = .009 and .003, respectively), waist-to-height ratio (p = .02 and .005, respectively), alanine aminotransferase (p = .004 and <.001, respectively), total cholesterol (p = .0002 and .0001, respectively) and low-density lipoprotein-cholesterol (p < .001 and <.001, respectively). Eventually, serum aspartate aminotransferase was decreased (p < .001) and high-density lipoprotein-cholesterol (p = .03) was increased significantly in the GPA group. As a main finding of this study, hepatic steatosis significantly decreased in the G and GPA groups. Ginger supplementation can effectively improve NAFLD in children, and its effectiveness was further increased when combined with an AID.

Low-Grade Inflammation and Ultra-Processed Foods Consumption: A Review

Low-grade inflammation alters the homeostasis of the organism and favors the onset of many chronic diseases. The global growth in the prevalence of noncommunicable diseases in recent years has been accompanied by an increase in the consumption of ultra-processed foods (UPF). Known to be hyperpalatable, economic and ready-to-eat, increased consumption of UPF has already been recognized as a risk factor for several chronic diseases. Different research groups have tried to investigate whether UPF consumption could promote low-grade inflammation and thus favor the development of noncommunicable diseases. Current evidence highlights the adverse health effects of UPF characteristics, not only due to the nutrients provided by a diet rich in UPF, but also due to the non-nutritive components present in UPF and the effect they may have on gut health. This review aims to summarize the available evidence on the possible relationship between excessive UPF consumption and modulation of low-grade inflammation, as potential promoters of chronic disease.

Longitudinal changes in blood pressure are preceded by changes in albuminuria and accelerated by increasing dietary sodium intake

BACKGROUND

Dietary sodium is a well-known risk factor for cardiovascular and renal disease; however, direct evidence of the longitudinal changes that occur with aging, and the influence of dietary sodium on the age-associated alterations are scarce.

METHODS

C57BL/6 mice were maintained for 13 months on a low (LS, 0.02 % Na+), normal (NS, 0.3 % Na+) or high (HS, 1.6 % Na+) salt diet. We assessed 1) the longitudinal trajectories for two markers of cardiovascular and renal dysfunction (blood pressure (BP) and albuminuria), as well as hormonal changes, and 2) end-of-study cardiac and renal parameters.

RESULTS

The effect of aging on BP and kidney damage did not reach significance levels in the LS group; however, relative to baseline, there were significant increases in these parameters for animals maintained on NS and HS diets, starting as early as month 7 and month 5, respectively. Furthermore, changes in albuminuria preceded the changes in BP relative to baseline, irrespective of the diet. Circulating aldosterone and plasma renin activity displayed the expected decreasing trends with age and dietary sodium loading. As compared to LS - higher dietary sodium consumption associated with increasing trends in left ventricular mass and volume indices, consistent with an eccentric dilated phenotype. Functional and molecular markers of kidney dysfunction displayed similar trends with increasing long-term sodium levels: higher renovascular resistance, increased glomerular volumes, as well as higher levels of renal angiotensin II type 1 and mineralocorticoid receptors, and lower renal Klotho levels.

CONCLUSION

Our study provides a timeline for the development of cardiorenal dysfunction with aging, and documents that increasing dietary salt accelerates the age-induced phenotypes. In addition, we propose albuminuria as a prognostic biomarker for the future development of hypertension. Last, we identified functional and molecular markers of renal dysfunction that associate with long-term dietary salt loading.

Old, Nonagenarians, and Centenarians in Cilento, Italy and the Association of Lifespan with the Level of Some Physicochemical Elements in Tap Drinking Water

Longevity, as a complex life-history trait, shares an ontogenetic relationship with other quantitative traits, such as epigenetic and environmental factors. Therefore, it is important to identify environmental factors that may modify the epigenome to establish healthy aging. This study explored the association between tap drinking water and longevity in Cilento, Italy, to understand whether trace elements in local drinking water may have an influence on old, nonagenarian, and centenarian people and promote their health and longevity. Data on population and water sources were collected through the National Demographic Statistics, the Cilento Municipal Archives, and the Cilento Integrated Water Service. Ordinary least squares (OLS) regression and a geographically weight regression (GWR) model were used to study the spatial relationship between the explanatory and outcome variables of longevity. The results of the study showed that the prevalence of longevity is concentrated in the central, northern and southeastern areas of the territory and that some trace elements present in tap water may contribute to local longevity in Cilento. Specifically, all Cilento municipalities had alkaline tap water, and the municipalities with the highest longevity concentrations had higher alkalinity levels than the other municipalities, soft to medium-hard water hardness, an amount of total dissolved solids equivalent to the level of excellent water, lower amounts of sodium, adequate iron concentration, and adequate dietary intake of manganese per day.

Sodium-glucose co-transporter 2 inhibitor therapy: use in chronic kidney disease and adjunctive sodium restriction

The global burden of chronic kidney disease (CKD) has increased significantly over the past few decades. This reflects the rising prevalence of type 2 diabetes mellitus (T2DM) and hypertension, two leading causes of CKD. Hypertension, which can also be a complication of CKD, accelerates renal disease progression and augments cardiovascular risk, especially in individuals with diabetic kidney disease. Hence, blood pressure (BP) reduction is a vital component of CKD management. Sodium-glucose co-transporter 2 (SGLT2) inhibitors are a relatively novel class of medications developed to treat T2DM by inducing glycosuria and hence, lowering glycaemia. Additionally, SGLT2 inhibitors are antihypertensive, renoprotective and cardioprotective, even in individuals without T2DM, making them effective therapeutic agents for CKD. Another therapy that has proven to be antihypertensive, renoprotective and cardioprotective is dietary sodium restriction. This review evaluates the potential combined benefits of SGLT2 inhibition and dietary sodium restriction on the BP and renal parameters of individuals with CKD.

Potential role of inflammation in relation to dietary sodium and β-carotene with non-alcoholic fatty liver disease: a mediation analysis

Background

High sodium intake has been linked to the prevalence of non-alcoholic fatty liver disease (NAFLD), but underlying mechanism remains unclear. This study aims to explore the role of chronic inflammation in the association between sodium and NAFLD. We also observed whether β-carotene, which had a strong anti-inflammatory effect, lowers the odds of NAFLD.

Methods

We performed mediation analyses to assess the mediating effects of C-reactive protein (CRP) and red cell distribution width (RDW) on the relationship between dietary sodium and NAFLD defined by the hepatic steatosis index (HSI) and the fatty liver index (FLI), respectively.

Results

A total of 6725 participants were included in this study. Compared with the high sodium-low carotene group, participants in the high sodium-high carotene group had 16% and 26% lower odds for HSI and FLI-defined NAFLD, respectively. There were positive indirect effects of dietary sodium intake on the HSI-defined NAFLD (indirect effect: 0.0057, 95% CI: 0.0021–0.0091, P < 0.0001), as well as the FLI defined NAFLD (indirect effect: 0.0081, 95% CI: 0.0024–0.0162, P < 0.0001) when C-reactive protein (CRP) was considered as a mediator. The mediating effects were somewhat attenuated after further adjusting for dietary β-carotene intake. Similar results were found when RDW was considered as a mediator in the HSI-defined NAFLD analysis.

Conclusions

Higher sodium intake increases the odds of NAFLD by upregulating inflammation. Dietary β-carotene may attenuate this association by down regulating inflammation.

The gut-brain axis and sodium appetite: Can inflammation-related signaling influence the control of sodium intake?

Sodium is the main cation present in the extracellular fluid. Sodium and water content in the body are responsible for volume and osmotic homeostasis through mechanisms involving sodium and water excretion and intake. When body sodium content decreases below the homeostatic threshold, a condition termed sodium deficiency, highly motivated sodium seeking, and intake occurs. This is termed sodium appetite. Classically, sodium and water intakes are controlled by a number of neuroendocrine mechanisms that include signaling molecules from the renin-angiotensin-aldosterone system acting in the central nervous system (CNS). However, recent findings have shown that sodium and water intakes can also be influenced by inflammatory agents and mediators acting in the CNS. For instance, central infusion of IL-1β or TNF-α can directly affect sodium and water consumption in animal models. Some dietary conditions, such as high salt intake, have been shown to change the intestinal microbiome composition, stimulating the immune branch of the gut-brain axis through the production of inflammatory cytokines, such as IL-17, which can stimulate the brain immune system. In this review, we address the latest findings supporting the hypothesis that immune signaling in the brain could produce a reduction in thirst and sodium appetite and, therefore, contribute to sodium intake control.

Sodium in relation with nonalcoholic fatty liver disease: A systematic review and meta-analysis of observational studies

Findings on the association of sodium with nonalcoholic fatty liver disease (NAFLD) are conflicting. The present systematic review and meta‐analysis study aimed to assess the association between salt or sodium intake or serum sodium levels and NAFLD risk. Relevant articles were identified by searching PubMed, Web of Knowledge, Scopus, Proquest, and Embase databases through May 1, 2021, without language restriction. The pooled odds ratio (OR) and 95% confidence interval (CI) were estimated using Der‐Simonian and Laird method and random‐effects meta‐analysis. The certainty of the evidence was rated using the GRADE method. Out of 6470 documents, 7 epidemiological/observational (1 cohort, 1 case–control, and 5 cross‐sectional) studies on the relationship between dietary salt/sodium intakes and NAFLD risk met our inclusion criteria. The meta‐analysis of all studies showed a significant positive association between the highest salt/sodium intake and NALFD risk (OR = 1.60, 95% CI: 1.19–2.15) with a meaningful heterogeneity among studies (I² = 96.70%, p‐value <.001). The NAFLD risk was greater in the studies with higher quality (OR = 1.81, 95% CI: 1.24–2.65) or using the equation‐based methods for NAFLD ascertainment (OR = 2.02, 95% CI: 1.29–3.17) or urinary sodium collection as a sodium intake assessment (OR = 2.48, 95% CI: 1.52–4.06). The overall certainty of the evidence was very low. In conclusion, high sodium intake seems to be related to increased NAFLD risk. Further well‐designed studies are needed to clarify this association and shed light on the underlying mechanisms.

Clarifying Optimal Sodium InTake In Cardiovasular and Kidney (COSTICK) Diseases: a study protocol for two randomised controlled trials

Background: While low sodium intake (<2.3g/day) is recommended for all, there is uncertainty about feasibility and net cardiovascular effects. In COSTICK, we evaluated the effects of a dietary counselling intervention (reduced sodium intake) on intermediate cardiorenal outcomes in patients with (STICK) and without (COSIP) mild/moderate kidney disease. Methods: This is a protocol for two phase IIb randomised, two-group, parallel, open-label, controlled, single centre trials. Participants were aged >40 years with stable blood pressure, unchanged anti-hypertensive medications, willing to modify diet and provided written informed consent. Participants were excluded for abnormal sodium handling, heart failure, high dose diuretics, immunosuppression, pregnancy/lactation, postural hypotension, cognitive impairment, high or low body mass index (BMI) or inclusion in another trial. STICK participants had estimated glomerular filtration rate (eGFR) 30-60ml/min/1.73m 2 and were excluded for acute kidney Injury, rapidly declining eGFR; known glomerular disease or current use of non-steroidal anti-inflammatory drugs. For COSIP, participants were excluded for known kidney or cardiovascular disease. Participants were randomized to usual care only (healthy eating) or an additional sodium lowering intervention (target <100mmol/day) through specific counseling (sodium use in foods, fresh over processed foods, sodium content of foods and eating outside of home). In STICK the primary outcome is change in 24-hour urinary creatinine clearance. In COSIP, the primary outcome is change in five biomarkers (renin, aldosterone, high sensitivity troponin T, pro-B-type natriuretic peptide and C-reactive protein). Our primary report (COSTICK), reports six biomarker outcome measures in the entire population at 2 years follow-up. Discussion: These Phase II trials will explore uncertainty about low sodium intake and cardiovascular and kidney biomarkers, and help determine the feasibility of low sodium intake. Trial results will also provide preliminary information to guide a future definitive clinical trial, if indicated. Trial registration: STICK: ClinicalTrials.gov NCT02738736 (04/04/2016); COSIP: ClinicalTrials.gov NCT02458248 (15/05/2016).

High Estimated 24-Hour Urinary Sodium Excretion Is Related to Symptomatic Knee Osteoarthritis: A Nationwide Cross-Sectional Population-Based Study

OBJECTIVES

High salt intake results in various harmful effects on human health including hypertension, cardiovascular disease, and reduced bone density. Despite this, there are very few studies in the literature that have investigated the association between sodium intake and osteoarthritis (OA). Therefore, we aimed to explore these associations in a Korean population.

METHODS

This study used cross-sectional data from adult subjects aged 50-75 years from two consecutive periods of the Korean National Health and Nutrition Examination Survey V-VII (2010-2011 and 2014-2016). The estimated 24-hour urinary sodium excretion (24HUNa) was used as a surrogate marker of salt intake. In the 2010-2011 dataset, knee OA (KOA) was defined as the presence of the radiographic features of OA and knee pain. The association between KOA and salt intake was analysed using univariable and multivariable logistic regression methods. For the sensitivity analysis, the same procedures were conducted on subjects with self-reported OA (SR-OA) with knee pain in the 2010-2011 dataset and any site SR-OA in the 2014-2016 dataset.

RESULTS

Subjects with KOA had significantly lower energy intake, but higher 24HUNa than those without KOA. The restricted cubic spline plots demonstrated a J-shaped distribution between 24HUNa and prevalent KOA. When 24HUNa was stratified into five groups (<2, 2-3, 3-4, 4-5 and ≥5 g/day), subjects with high sodium intake (≥5 g/day) had a higher risk of KOA (odds ratio [OR] = 1.64, 95% confidence interval [CI] 1.03-2.62) compared to the reference group (3-4 g/day) after adjusting for covariates. The sensitivity analysis based on SR-OA with knee pain showed that high sodium intake was also significantly associated with increased prevalence of OA (OR = 1.84, 95% CI 1.10-3.10) compared with the reference group. Regarding SR-OA at any site in the 2014-2016 dataset, estimated 24HUNa showed a significantly positive association with the presence of SR-OA after adjusting for potential confounders.

CONCLUSIONS

This nationwide Korean representative study showed a significant association between symptomatic KOA and high sodium intake (≥5 g/day). Avoidance of a diet high in salt might be beneficial as a non-pharmacologic therapy for OA.

Antioxidant, Anti-Inflammatory, and Immunomodulatory Properties of Tea-The Positive Impact of Tea Consumption on Patients with Autoimmune Diabetes

The physiological markers of autoimmune diabetes include functional disorders of the antioxidative system as well as progressing inflammation and the presence of autoantibodies. Even though people with type 1 diabetes show genetic predispositions facilitating the onset of the disease, it is believed that dietary factors can stimulate the initiation and progression of the disease. This paper analyses the possibility of using tea as an element of diet therapy in the treatment of type 1 diabetes. Based on information available in literature covering the last 10 years, the impact of regular tea consumption or diet supplements containing tea polyphenols on the oxidative status as well as inflammatory and autoimmune response of the organism was analyzed. Studies conducted on laboratory animals, human patients, and in vitro revealed positive effects of the consumption of tea or polyphenols isolated therefrom on the diabetic body. Few reports available in the literature pertain to the impact of tea on organisms affected by type 1 diabetes as most (over 85%) have focused on cases of type 2 diabetes. It has been concluded that by introducing tea into the diet, it is possible to alleviate some of the consequences of oxidative stress and inflammation, thus limiting their destructive impact on the patients' organisms, consequently improving their quality of life, regardless of the type of diabetes. Furthermore, elimination of inflammation should reduce the incidence of immune response. One should consider more widespread promotion of tea consumption by individuals genetically predisposed to diabetes, especially considering the drink's low price, easy availability, overall benefits to human health, and above all, the fact that it can be safely used over extended periods of time, regardless of the patient's age.

Sodium intake, health implications, and the role of population-level strategies

Evidence to date suggests that high sodium intake affects health adversely, yet the role of a population-level strategy to reduce sodium intake is often contested. This review focuses on current available evidence on regional sodium intake levels, health implications of sodium intake, and population-level strategies implemented worldwide. The limitations in evidence, the difficulties in implementing population-wide strategies to reduce sodium intake, and the need for such strategies are critically reviewed. Evidence clearly shows that sodium has an adverse effect on blood pressure, cardiovascular disease, and mortality. However, whether reduced sodium intake benefits all individuals or only hypertensive individuals is still unclear. Methodological issues and publication bias in current evidence are other matters of concern in sodium-related research. While it is essential to continue working toward the World Health Organization's target of 30% reduction in sodium intake, due consideration should be given to improving the quality of research, reducing bias in publications, and reviewing evidence more critically.

TNFα Triggers an Augmented Inflammatory Response in Brain Neurons from Dahl Salt-Sensitive Rats Compared with Normal Sprague Dawley Rats

Tumor Necrosis Factor (TNF)-α is a proinflammatory cytokine (PIC) and has been implicated in a variety of illness including cardiovascular disease. The current study investigated the inflammatory response trigged by TNFα in both cultured brain neurons and the hypothalamic paraventricular nucleus (PVN), a key cardiovascular relevant brain area, of the Sprague Dawley (SD) rats. Our results demonstrated that TNFα treatment induces a dose- and time-dependent increase in mRNA expression of PICs including Interleukin (IL)-1β and Interleukin-6 (IL6); chemokines including C-C Motif Chemokine Ligand 5 (CCL5) and C-C Motif Chemokine Ligand 12 (CCL12), inducible nitric oxide synthase (iNOS), as well as transcription factor NF-kB in cultured brain neurons from neonatal SD rats. Consistent with this finding, immunostaining shows that TNFα treatment increases immunoreactivity of IL1β, CCL5, iNOS and stimulates activation or expression of NF-kB, in both cultured brain neurons and the PVN of adult SD rats. We further compared mRNA expression of the aforementioned genes in basal level as well as in response to TNFα challenge between SD rats and Dahl Salt-sensitive (Dahl-S) rats, an animal model of salt-sensitive hypertension. Dahl-S brain neurons presented higher baseline levels as well as greater response to TNFα challenge in mRNA expression of CCL5, iNOS and IL1β. Furthermore, central administration of TNFα caused significant higher response in CCL12 in the PVN of Dahl-S rats. The increased inflammatory response to TNFα in Dahl-S rats may be indicative of an underlying mechanism for enhanced pressor reactivity to salt intake in the Dahl-S rat model.

Clarifying Optimal Sodium InTake In Cardiovasular and Kidney (COSTICK) Diseases: a study protocol for two randomised controlled trials

Background: While low sodium intake (<2.3g/day) is recommended for all, there is uncertainty about feasibility and net cardiovascular effects. In COSTICK, we evaluated the effects of a dietary counselling intervention (reduced sodium intake) on intermediate cardiorenal outcomes in patients with (STICK) and without (COSIP) mild/moderate kidney disease. Methods: This is a protocol for two phase IIb randomised, two-group, parallel, open-label, controlled, single centre trials. Participants were aged >40 years with stable blood pressure, unchanged anti-hypertensive medications, willing to modify diet and provided written informed consent. Participants were excluded for abnormal sodium handling, heart failure, high dose diuretics, immunosuppression, pregnancy/lactation, postural hypotension, cognitive impairment, high or low body mass index (BMI) or inclusion in another trial. STICK participants had estimated glomerular filtration rate (eGFR) 30-60ml/min/1.73m 2 and were excluded for acute kidney Injury, rapidly declining eGFR; known glomerular disease or current use of non-steroidal anti-inflammatory drugs. For COSIP, participants were excluded for known kidney or cardiovascular disease. Participants were randomized to usual care only (healthy eating) or an additional sodium lowering intervention (target <100mmol/day) through specific counseling (sodium use in foods, fresh over processed foods, sodium content of foods and eating outside of home). In STICK the primary outcome is change in 24-hour urinary creatinine clearance. In COSIP, the primary outcome is change in five biomarkers (renin, aldosterone, high sensitivity troponin T, pro-B-type natriuretic peptide and C-reactive protein). Our primary report (COSTICK), reports six biomarker outcome measures in the entire population at 2 years follow-up. Discussion: These Phase II trials will explore uncertainty about low sodium intake and cardiovascular and kidney biomarkers, and help determine the feasibility of low sodium intake. Trial results will also provide preliminary information to guide a future definitive clinical trial, if indicated. Trial registration: STICK: ClinicalTrials.gov NCT02738736 (04/04/2016); COSIP: ClinicalTrials.gov NCT02458248 (15/05/2016).

Differential effects of sodium chloride and monosodium glutamate on kidney of adult and aging mice

Monosodium Glutamate (MSG) is used as flavour enhancer, with potential beneficial effects due to its nutritional value. Given the decline in kidney functions during aging, we investigated the impact of MSG voluntary intake on the kidney of male mice, aged 6 or 18 months. For 2 months, they freely consumed water (control group), sodium chloride (0.3% NaCl) or MSG (1% MSG) in addition to standard diet. Young animals consuming sodium chloride presented signs of proteinuria, hyperfiltration, enhanced expression and excretion of Aquaporin 2 and initial degenerative reactions suggestive of fibrosis, while MSG-consuming mice were similar to controls. In old mice, aging-related effects including proteinuria and increased renal corpuscle volume were observed in all groups. At an advanced age, MSG caused no adverse effects on the kidney compared to controls, despite the presence of a sodium moiety, similar to sodium chloride. These data show that prolonged MSG intake in mice has less impact on kidney compared to sodium chloride, that already in young animals induced some effects on kidney, possibly related to hypertension.

High-salt intake reduces renal tissue levels of inflammatory cytokines in mice

High salt (HS) intake is usually considered as an aggravating factor to induce inflammatory renal injury. However, the changes in the renal levels of inflammatory cytokines during HS intake is not yet clearly defined. We hypothesize that HS increases renal levels of tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) but decreases interleukin-10 (IL-10; anti-inflammatory cytokine) and these responses exacerbate in NO deficient conditions. Both wild-type (WT) and endothelial NO synthase knockout (eNOSKO) mice (~8 weeks old, n = 6 in each group) were given normal-salt (NS; 0.3% NaCl) and HS (4% NaCl) containing diets for 2 weeks. Systolic blood pressure (SBP) was determined by tail-cuff plethysmography and urine collections were made using metabolic cages. Basal SBP was higher in eNOSKO than WT mice (131 ± 7 vs 117 ± 3 mmHg; p < .05). HS intake for 2 weeks increased SBP in eNOSKO (161 ± 5 mmHg) but not in WT mice. In NS groups, the cytokine levels in renal tissues (measured using ELISA kits and expressed in pg/mg protein) were significantly higher in eNOSKO than WT mice (TNF-α, 624 ± 67 vs. 325 ± 73; IL-6, 619 ± 106 vs. 166 ± 61; IL-10, 6,087 ± 567 vs. 3,929 ± 378). Interestingly, these cytokine levels in HS groups were significantly less both in WT (TNF-α, 114 ± 17; IL-6, 81 ± 14; IL-10, 865 ± 130) and eNOSKO (TNF-α, 115 ± 18; IL-6, 56 ± 7; IL-10, 882 ± 141) mice. These findings indicate that HS induces downregulation of cytokines in the kidney. Such HS-induced reduction in cytokines, particularly TNF-α (a natriuretic agent), would facilitate more salt-retention, and thus, leading to salt-sensitive hypertension in NO deficient conditions.

Evaluating postoperative anal fistula prognosis by diffusion-weighted MRI

PURPOSE

The purpose of this study was to explore whether preoperative diffusion-weighted magnetic resonance imaging (DW-MRI) can be used to evaluate the prognosis of anal fistula and identify the influence factors of postoperative recurrence.

METHODS

This is a retrospective study of 117 patients with anal fistula who have undergone preoperative DW-MRI and surgery. All patients were followed up by telephone or reexamination within 2 years after surgery. Of the 117 patients, 35 were excluded due to loss of follow-up and only 82 were included in this study. MRI fistula imaging-related data were analyzed, and fistula severity was scored using criteria of both local extension of fistulas and active inflammation for a total maximum score of 22. The apparent diffusion coefficient (ADC) value of the fistula in patients with anal fistula during preoperative MRI examination was measured. According to whether anal fistula patients are accompanied by perianal abscess, they are divided into two groups, namely anal fistula group and anal fistula with abscess group. Based on whether patients with anal fistula recur after surgery, they were further divided into recurrent group and non-recurrent group.

RESULTS

82 patients with anal fistula were included in this analysis, 23 of them recurred and 59 were cured. Among patients with perianal abscess, the mean ADC value of the recurrent group was (1.19 ± 0.21)×10^-3 mm²/s, which is significantly lower than that of the non-recurrent group (1.36 ± 0.19)×10^-3 mm²/s. There were significant statistical differences in ADC values between the two groups (p = 0.03). Among patients with anal fistulas without abscesses, 15 patients recurred after surgery, with a mean ADC value of (1.45 ± 0.27) ×10^-3 mm²/s, and 33 patients didn't occur, with a mean ADC value of (1.44 ± 0.31)×10^-3 mm²/s. The ADC value of preoperative fistula in patients was negative significant correlation with MRI findings score (r= -0.332, P = 0.002). Risk factors for the recurrence after anal fistula surgery include the time interval between MRI and operation, multiple fistula tracks. Fatigue, excessive intake of spicy or greasy food and diarrhea may also be external risk factors for postoperative recurrence of patients with anal fistula.

CONCLUSIONS

DW-MRI has important application value for the prognosis evaluation of anal fistula. Complex type of anal fistula and improper lifestyle are the main risk factors affecting the recurrence after anal fistula surgery.

Salt Reduction to Prevent Hypertension and Cardiovascular Disease: JACC State-of-the-Art Review

There is strong evidence for a causal relationship between salt intake and blood pressure. Randomized trials demonstrate that salt reduction lowers blood pressure in both individuals who are hypertensive and those who are normotensive, additively to antihypertensive treatments. Methodologically robust studies with accurate salt intake assessment have shown that a lower salt intake is associated with a reduced risk of cardiovascular disease, all-cause mortality, and other conditions, such as kidney disease, stomach cancer, and osteoporosis. Multiple complex and interconnected physiological mechanisms are implicated, including fluid homeostasis, hormonal and inflammatory mechanisms, as well as more novel pathways such as the immune response and the gut microbiome. High salt intake is a top dietary risk factor. Salt reduction programs are cost-effective and should be implemented or accelerated in all countries. This review provides an update on the evidence relating salt to health, with a particular focus on blood pressure and cardiovascular disease, as well as the potential mechanisms.

Prepregnancy adherence to dietary recommendations for the prevention of cardiovascular disease in relation to risk of hypertensive disorders of pregnancy

BACKGROUND

It is unclear whether adherence to diet recommendations for the prevention of cardiovascular disease (CVD) in the general population is also related to the risk of hypertensive disorders of pregnancy, including pre-eclampsia and gestational hypertension (GHTN).

OBJECTIVES

The aim was to evaluate the relation of prepregnancy adherence to the American Heart Association (AHA) diet recommendations and the Dietary Approaches to Stop Hypertension (DASH) with the risk of pre-eclampsia and GHTN.

METHODS

Between 1991 and 2009, we prospectively followed 16,892 singleton pregnancies among 11,535 women who participated in the Nurses' Health Study II. Prepregnancy diet was assessed every 4 y, from which we calculated dietary pattern scores from the DASH diet (8 components) and the diet recommendations from the AHA 2020 Strategic Impact Goals (primary score: 5 components; secondary score: primary score plus 3 components). Pregnancy outcomes were self-reported, and we estimated the RR (95% CI) of pre-eclampsia and GHTN with log-binomial regression using generalized estimating equations to account for repeat pregnancies and adjusting for potential confounders.

RESULTS

Women had a mean (SD) age of 34.4 (34.0) y at pregnancy. Pre-eclampsia was reported in 495 (2.9%) pregnancies and GHTN in 561 (3.3%) pregnancies. The RR (95% CI) of pre-eclampsia for women in the highest quintile of the DASH was 0.65 (0.48, 0.87) compared with women in the lowest score quintile. A similar inverse trend was observed for the AHA primary (0.74; 95% CI: 0.55, 1.00) and secondary (0.81; 95% CI: 0.61, 1.07) scores comparing women in the highest versus the lowest score quintile. Neither the DASH nor the AHA scores were related to GHTN.

CONCLUSIONS

Women with higher adherence to dietary recommendations for the prevention of CVD in the general population had a lower risk of pre-eclampsia-a common pregnancy complication related to higher CVD risk among women-than women with lower adherence to these recommendations.

Nutrition Disparities and Cardiovascular Health

PURPOSE OF REVIEW

This review is an assessment of the state of the science on nutrition disparities and their contribution to disparities in cardiovascular health.

RECENT FINDINGS

Nutrition disparities remain pervasive by race/ethnicity, sex/gender, socioeconomic status, and geography. They are rooted in differences in social, cultural, and environmental determinants of health, behavioral and lifestyle factors, and the impact of policy interventions. Systematic differences in diet quality, dietary patterns, and nutrient intakes contribute to cardiovascular disparities and are mediated by microbiota, and CVD risk factors including high levels of blood pressure, low density lipoprotein cholesterol (LDL), and glucose; oxidative stress, pro-inflammatory cytokines, and endothelial dysfunction. Despite the progress made in nutrition research, important gaps persist that signal the need for more effective interventions at multiple levels to reduce cardiovascular disparities. Research opportunities include (1) exploring the gene-nutrient-environment interactions in the context of ancestral diversity; (2) investigating the causal link between diet and gut microbiota and impact of social determinants of health; (3) understanding resilience; (4) testing the effectiveness of multi-level interventions that address social and environmental determinants; and (4) supporting intervention research informed by validated implementation science frameworks.

Short-Term High-NaCl Dietary Intake Changes Leukocyte Expression of VLA-4, LFA-1, and Mac-1 Integrins in Both Healthy Humans and Sprague-Dawley Rats: A Comparative Study

This study is aimed at assessing the effects of a short-term high-salt (HS) diet on the peripheral blood leukocyte (PBL) activation status in healthy rats and young human individuals. Distribution of PBL subpopulations and surface expression of integrins were determined using flow cytometry in 36 men and women on a 7-day low-salt diet (<3.2 g salt/day) immediately followed by a 7-day HS diet (~14 g salt/day) or in Sprague-Dawley (SD) rats (n = 24) on a 0.4% NaCl diet (aLS group) or a 4% NaCl diet (aHS group) for 7 days. The aHS group presented with an increased frequency of granulocytes, while the frequency of lymphocytes was reduced. Although in humans HS diet reduced the expression of CD11b(act) integrin on lymphocytes, the frequency of CD11b(act)-bearing cells among all PBL subsets was increased. The aHS group of rats exhibited increased expression of total CD11b/c in granulocytes and CD3 lymphocytes. The expression of CD11a was significantly reduced in all PBL subsets from human subjects and increased in the aHS group. CD49d expression on all PBL subsets was significantly decreased in both humans and rats. In human subjects, we found reduced frequencies of intermediate monocytes accompanied by a reciprocal increase in classical monocytes. Present results suggest that a short-term HS diet can alter leukocytes' activation status and promote vascular low-grade inflammation.

Adherence to low-sodium Dietary Approaches to Stop Hypertension-style diet may decrease the risk of incident chronic kidney disease among high-risk patients: a secondary prevention in prospective cohort study

Background

Considering the fact that subjects with dysglycemia, dyslipidemia or high blood pressure are at high risk for chronic kidney disease (CKD), long-term adherence to the Dietary Approaches to Stop Hypertension (DASH)-style diet may contribute to the prevention of CKD. This study, examined the association between adherence to the low-sodium DASH-style diet and incident CKD among high-risk adults over 3 years of follow-up.

Methods

In this prospective cohort study (followed up for 3 years, 2012-15), we selected 1100 subjects with dysglycemia, 2715 with dyslipidemia and 2089 with high blood pressure, all of whom were free of CKD at baseline (2009-11) in a subgroup of the Tehran Lipid and Glucose Study. The low-sodium DASH-style diet was designed based on eight foods and nutrients using a food frequency questionnaire. Estimated glomerular filtration rate (eGFR) was calculated and CKD was defined as eGFR <60 mL/min/1.73 m2.

Results

After 3 years of follow-up, among subjects with dysglycemia, dyslipidemia or high blood pressure, the rate of incident CKD was ∼16%. In multivariable-adjusted analyses for participants in the highest compared with the lowest quartile of the low-sodium DASH-style diet score, the odds ratio was 0.58 [95% confidence interval (CI) 0.36-0.92] for subjects with dysglycemia, 0.64 (95% CI 0.48-0.87) for subjects with dyslipidemia and 0.62 (95% CI 0.44-0.87) for subjects with high blood pressure.

Conclusions

Higher adherence to the low-sodium DASH-style diet might be associated with a lower risk of incident CKD among high-risk adults, highlighting the importance of adherence to the low-sodium DASH-style diet in substantially reducing both the occurrence of CKD and the burden imposed by it in the future.

Chronic Kidney Disease as a Risk Factor for Heart Failure With Preserved Ejection Fraction: A Focus on Microcirculatory Factors and Therapeutic Targets

Heart failure (HF) and chronic kidney disease (CKD) co-exist, and it is estimated that about 50% of HF patients suffer from CKD. Although studies have been performed on the association between CKD and HF with reduced ejection fraction (HFrEF), less is known about the link between CKD and heart failure with preserved ejection fraction (HFpEF). Approximately, 50% of all patients with HF suffer from HFpEF, and this percentage is projected to rise in the coming years. Therapies for HFrEF are long established and considered quite successful. In contrast, clinical trials for treatment of HFpEF have all shown negative or disputable results. This is likely due to the multifactorial character and the lack of pathophysiological knowledge of HFpEF. The typical co-existence of HFpEF and CKD is partially due to common underlying comorbidities, such as hypertension, dyslipidemia and diabetes. Macrovascular changes accompanying CKD, such as hypertension and arterial stiffening, have been described to contribute to HFpEF development. Furthermore, several renal factors have a direct impact on the heart and/or coronary microvasculature and may underlie the association between CKD and HFpEF. These factors include: (1) activation of the renin-angiotensin-aldosterone system, (2) anemia, (3) hypercalcemia, hyperphosphatemia and increased levels of FGF-23, and (4) uremic toxins. This review critically discusses the above factors, focusing on their potential contribution to coronary dysfunction, left ventricular stiffening, and delayed left ventricular relaxation. We further summarize the directions of novel treatment options for HFpEF based on the contribution of these renal drivers.

Metabolic Adaptations of CD4+ T Cells in Inflammatory Disease

A controlled and self-limiting inflammatory reaction generally results in removal of the injurious agent and repair of the damaged tissue. However, in chronic inflammation, immune responses become dysregulated and prolonged, leading to tissue destruction. The role of metabolic reprogramming in orchestrating appropriate immune responses has gained increasing attention in recent years. Proliferation and differentiation of the T cell subsets that are needed to address homeostatic imbalance is accompanied by a series of metabolic adaptations, as T cells traveling from nutrient-rich secondary lymphoid tissues to sites of inflammation experience a dramatic shift in microenvironment conditions. How T cells integrate information about the local environment, such as nutrient availability or oxygen levels, and transfer these signals to functional pathways remains to be fully understood. In this review, we discuss how distinct subsets of CD4⁺ T cells metabolically adapt to the conditions of inflammation and whether these insights may pave the way to new treatments for human inflammatory diseases.

Urinary potassium is a potential biomarker of disease activity in Ulcerative colitis and displays in vitro immunotolerant role

We evaluated the in-vitro effect of potassium on CD4⁺ T cells and the role of urinary potassium as a potential biomarker of disease activity in patients with ulcerative colitis (UC). This prospective observational cohort study included healthy controls (n = 18) and UC patients [n = 30, median age: 40 (IQR: 28–46) years, 17 males)] with active disease(assessed by Mayo score) from September 2015–May 2016. Twenty-four hours urinary potassium along with fecal calprotectin (FCP) were estimated in UC patients (at baseline and follow-up after 3–6 months) and controls. In healthy volunteers, we also assessed the effect of potassium on CD4⁺ T cells differentiated in the presence of Th17 polarizing condition. UC patients had significantly higher FCP (368.2 ± 443.04 vs 12.44 ± 27.51, p < 0.001) and significantly lower urinary potassium (26.6 ± 16.9 vs 46.89 ± 35.91, p = 0.01) levels than controls. At follow-up, a significant increase in urinary potassium among patients who had clinical response [n = 22, 21.4 (14.4–39.7) to 36.5 (20.5–61.6), p = 0.04] and remission [n = 12, 18.7 (9.1–34.3) to 36.5 (23.4–70.5), p = 0.05] was accompanied with a parallel decline in FCP. On in-vitro analysis, potassium under Th17 polarizing conditions significantly inhibited IL-17 and interferon-\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\gamma $$\end{document}γ expression while favoring the induction of FoxP3⁺ T cells. Therefore, urinary potassium levels are inversely associated with disease activity in UC with in-vitro data supporting an immune-tolerant role of potassium.

A new paradigm of sodium regulation in inflammation and hypertension

Dysregulation of sodium (Na⁺) balance is a major cause of hypertensive cardiovascular disease. The current dogma is that interstitial Na⁺ readily equilibrates with plasma and that renal excretion and reabsorption is sufficient to regulate extracellular fluid volume and control blood pressure. These ideas have been recently challenged by the discovery that Na⁺ accumulates in tissues without commensurate volume retention and activates immune cells, leading to hypertension and autoimmune disease. However, objections have been raised to this new paradigm, with some investigators concerned about where and how salt is stored in tissues. Further concerns also include how Na⁺ is mobilized from tissue stores and how it interacts with various organ systems to cause hypertension and end-organ damage. This review assesses these two paradigms of Na⁺ regulation in the context of inflammation-mediated hypertension and cardiovascular disease pathogenesis. Also highlighted are future perspectives and important gaps in our understanding of how Na⁺ is linked to inflammation and hypertension. Understanding mechanisms of salt and body fluid regulation is the sine qua non of research efforts to identify therapeutic targets for hypertension and cardiovascular disease.

Association between 24-h urinary sodium excretion and obesity in Korean adults: A multicenter study

OBJECTIVE

The aim of this study was to explore the association between sodium intake, as assessed by 24-h urinary sodium excretion, and various obesity parameters among South Korean adults. The associations of 24-h urinary sodium excretion and sodium intake calculated from the dietary questionnaire with obesity parameters also were compared.

METHODS

This multicenter, cross-sectional study analyzed data of 640 healthy adults from eight provinces in South Korea. Obesity was assessed by body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR), and waist-to-height ratio (WHtR). Mean 24-h urinary sodium excretion was calculated from repeatedly collected 24-h urine samples. Participants' dietary intake was assessed by 24-h dietary recall interview on the days before 24-h urine collection.

RESULTS

In both sexes, the means of all anthropometric measurements tended to increase proportionally with 24-h urinary sodium excretion quartiles, regardless of adjustment. Men in the highest quartile (Q4) of 24-h urinary sodium excretion had increased odds of obesity (as assessed by BMI, WC, WHR, and WHtR) compared with men in the three lower quartiles (Q1-Q3) of 24-h urinary sodium excretion. Women in Q4 of 24-h urinary sodium excretion exhibited a higher chance of general obesity and abdominal obesity. Sodium intake calculated from the dietary questionnaire was not significantly associated with obesity in either sex.

CONCLUSIONS

In Korean adults, there was a positive association between higher sodium intake as assessed by 24-h urinary sodium excretion and obesity independent of energy intake.

Renal function in relation to sodium intake: a quantitative review of the literature

We undertook a quantitative literature review to search for evidence underpinning current guidelines proposing a reduction of sodium intake to less than 2.4 g/d for the management of chronic kidney disease. We searched PubMed for peer-reviewed articles published from January 1980 through May 2016. Two investigators screened 5072 publications and extracted data from 36, including 11 cross-sectional and 5 longitudinal observational studies and 20 intervention trials. Within-study effect sizes were pooled and standardized to a sodium gradient of 100 mmol/d by using inverse-variance weighted random effects models. Among cross-sectional studies, the pooled odds ratio for albuminuria was 1.23 (95% confidence interval [CI], 0.92-1.64, P = 0.16), and the pooled mean difference in glomerular filtration rate amounted to 8.5 ml/min (CI, -2.3 to 19.2 ml/min; P = 0.12). In the cohort studies, the pooled relative risk of a renal endpoint was 1.08 (CI, 0.92-1.29; P = 0.35). In the intervention trials (median duration, 14 days [range, 4-186 days]), the mean differences in estimated glomerular filtration rate and albuminuria (high vs. low sodium intake) averaged 4.6 ml/min (CI, 3.4-5.8 ml/min; P < 0.0001) and 53% (CI, 21-84; P = 0.001), respectively. Cochran's Q statistic indicated significant heterogeneity among cross-sectional studies for both estimated glomerular filtration rate and albuminuria (P < 0.0001) and among intervention trials for albuminuria (P = 0.04). In conclusion, there is no robust evidence suggesting that long-term reduction of salt intake would prevent chronic kidney disease or delay its progression. However, our current findings, which were mainly obtained in people with slight renal impairment, cannot be extrapolated to patients with moderate or severe chronic kidney disease.

Effects of green tea supplementation on inflammation markers, antioxidant status and blood pressure in NaCl-induced hypertensive rat model

Background: Recent studies indicate the important role of chronic inflammation and oxidative stress in the pathogenesis of hypertension. Green tea, due to the high content of catechins, shows high antioxidant activity. Objective: To determine the effect of supplementation with green tea extract on the blood pressure, on the concentration of selected parameters of inflammation and antioxidant status in the model of high-sodium-diet induced hypertension. Design: The study lasted 42 days. The experimental population consisted of 30 rats. The rats were divided into three groups. The rats in the control group were fed a standard diet with 35 g of NaCl per kg of diet, in the second group hypertensive rats were fed a standard diet with NaCl (35 g/kg diet) and with an extract of green tea (2 g/kg diet). The third group consisted of hypertensive rats fed a standard diet with NaCl (35 g/kg diet), and 4 g of green tea extract/kg diet. Results: Supplementation with green tea had no effect on body mass of rats on a high-sodium diet. At the end of the experiment systolic blood pressures in SH2 and SH4 groups were significantly lower than in the control group SK. The SH4 group was characterized by a significantly lower diastolic blood pressure value and concentration of TNF-α in comparison to the SK group. The rats from both SH2 and SH4 groups were characterized by higher total antioxidant status values compared to the control group. Discussion: The mechanism of the beneficial effects of green tea on blood pressure is not clear, but it is believed that it is related to its omnidirectional properties. Conclusions: Supplementation of green tea has a beneficial effect on blood pressure, markers of inflammation and antioxidant status in an experimental model of hypertension.

GlycA, a novel proinflammatory glycoprotein biomarker, and high-sensitivity C-reactive protein are inversely associated with sodium intake after controlling for adiposity: the Prevention of Renal and Vascular End-Stage Disease study

BACKGROUND

The extent to which dietary sodium intake may confer alterations in the inflammatory status is unclear. GlycA is a novel proton nuclear magnetic resonance spectroscopy-measured biomarker of systemic inflammation, which is associated with the development of cardiovascular disease and diabetes.

OBJECTIVE

We determined associations of the inflammatory markers GlycA and high-sensitivity C-reactive protein (hsCRP) with 24-h sodium excretion.

DESIGN

A cross-sectional, population-based study was performed in 3935 subjects who were not using an antihypertensive medication, lipid-lowering drugs, or a glucose-lowering treatment. Urinary sodium excretion was calculated as the mean of two 24-h urine excretions. Linear regression models were used, with 24-h sodium excretion as an independent variable and GlycA or ln hsCRP as a dependent variable.

RESULTS

The mean ± SD sodium excretion was 143.0 ± 53.4 mmol/24 h. The GlycA concentration was 343.6 ± 58.7 μmol/L, and the geometric mean of the hsCRP concentration was 1.20 mg/L (95% CI: 1.16, 1.25 mg/L). In age- and sex-adjusted analyses, GlycA and ln hsCRP were not significantly associated with 24-h sodium excretion [B: 1.23 (95% CI: -0.67, 3.13; P = 0.21) and 0.03 (95% CI: -0.004, 0.07; P = 0.08), respectively, per 1-SD increase]. After additional adjustment for body mass index (BMI), both GlycA (B: -2.76; 95% CI: -4.65, -0.86; P = 0.004) and ln hsCRP (B: -0.07; 95% CI: -0.11, -0.04; P < 0.001) were inversely associated with 24-h sodium excretion. These associations were similar if adjustment was performed for waist circumference instead of BMI or if additional adjustment was performed for relevant clinical and laboratory variables and were particularly present in men.

CONCLUSIONS

The proinflammatory biomarkers GlycA and hsCRP are inversely related to higher 24-h sodium excretion when taking into account the variation in adiposity. These inverse relations remain present after taking into account other covariates.

A high sodium intake reduces antiproteinuric response to renin-angiotensin-aldosterone system blockade in kidney transplant recipients

BACKGROUND

Post-transplant proteinuria is associated with lower graft and patient survival. Renin-angiotensin-aldosterone system blockers are used to reduce proteinuria and improve renal outcome. Although it is known that a high salt intake blunts the antiproteinuric effect of ACEI and ARB drugs in non-transplant patients, this effect has not been studied in kidney transplant recipients.

OBJECTIVE

To analyse the relationship between sodium intake and the antiproteinuric effect of ACEI/ARB drugs in kidney transplant recipients.

METHODS

We selected 103 kidney transplant recipients receiving ACEI/ARB drugs for more than 6 months due to proteinuria>1 g/day. Proteinuria was analysed at baseline and at 6 months after starting ACEI/ARB treatment. Salt intake was estimated by urinary sodium to creatinine ratio (uNa/Cr).

RESULTS

Proteinuria fell to less than 1g/day in 46 patients (44.7%). High uNa/Cr was associated with a smaller proteinuria decrease (r=-0.251, P=.011). The percentage proteinuria reduction was significantly lower in patients in the highest uNa/Cr tertile [63.9% (IQR 47.1%), 60.1% (IQR 55.4%), 38.9% (IQR 85.5%), P=.047]. High uNa/Cr independently relates (OR 2.406 per 100 mEq/g, 95% CI: 1.008-5.745, P=.048) to an antiproteinuric response <50% after renin-angiotensin-aldosterone system blockade.

CONCLUSIONS

A high salt intake results in a smaller proteinuria decrease in kidney transplant recipients with proteinuria treated with ACEI/ARB drugs.

High Salt Intake Is Independently Associated With Hypertensive Target Organ Damage

The authors tested the hypothesis that high salt intake is associated with hypertensive target organ damage (TOD) independent of blood pressure (BP), and oxidative stress is a modifying factor of this association. A total of 369 community-dwelling Japanese adults (mean age, 67.5 years; 56.6% women) were examined in this observational study. At the patients' annual health check-ups, urinary salt excretion (U-SALT), 8-hydroxy-2'-deoxyguanosine (8-OHdG), and albumin-creatinine ratio (UACR) were measured from first morning urine. U-SALT (β=0.14, P=.016) and 8-OHdG (β=0.13, P=.018) were both independently associated with logUACR. U-SALT was associated with TOD independent of BP level, and oxidative stress may be a modifying factor in the association between high salt intake and TOD. The elevation of 8-OHdG may be involved in the pathophysiology of TOD induced by salt intake.

Estimated urinary sodium excretion and risk of heart failure in men and women in the EPIC-Norfolk study

AIMS

Interventional trials provide evidence for a beneficial effect of reduced dietary sodium intake on blood pressure. The association of sodium intake with heart failure which is a long-term complication of hypertension has not been examined.

METHODS AND RESULTS

Hazard ratios [HRs, 95% confidence interval (CI)] of heart failure comparing quintiles of estimated 24 h urinary sodium excretion (USE) were calculated in apparently healthy men (9017) and women (10,840) aged 39–79 participating in the EPIC study in Norfolk. During a mean follow-up of 12.9 years, 1210 incident cases of heart failure occurred. Compared with the reference category (128 mmol/day≤USE≤148 mmol/day), the top quintile (USE≥191 mmol/day) was associated with a significantly increased hazard of heart failure (1.32, 1.07–1.62) in multivariable analysis adjusting for age, sex, body mass index, diabetes, cholesterol, social class, educational level, smoking, physical activity, and alcohol consumption, with a marked attenuation (1.21, 0.98–1.49) when further adjusting for blood pressure. The bottom quintile (USE≤127 mmol/day) was also associated with an increased hazard of heart failure (1.29, 1.04–1.60) in multivariable analysis without relevant attenuation by blood pressure adjustment (1.26, 1.02–1.56), but with substantial attenuation when adjusting for interim ischaemic heart disease and baseline C-reactive protein levels and exclusion of events during the first 2 years (1.18, 0.96–1.47).

CONCLUSION

We demonstrate a U-shaped association between USE and heart failure risk in an apparently healthy middle-aged population. The risk associated with the high range of USE was attenuated after adjustment for blood pressure, whereas the risk associated with the low range of USE was attenuated after adjustment for pre-existing disease processes.

Meta-Analysis of the Effect of Dietary Sodium Restriction with or without Concomitant Renin-Angiotensin-Aldosterone System-Inhibiting Treatment on Albuminuria

BACKGROUND AND OBJECTIVES

Urinary albumin excretion and/or albumin to creatinine ratio are associated with CKD and higher risk of cardiovascular events. Several studies investigated the effect of reduced dietary sodium intake on urinary albumin excretion and/or albumin to creatinine ratio in adult patient populations, but the majority was inconclusive because of insufficient statistical power. A meta-analysis of the randomized, controlled trials available could overcome this problem and lead to more definitive conclusions.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A systematic search of the online databases available (from 1996 to October of 2014) was conducted of randomized, controlled trials that expressed urinary albumin excretion or albumin to creatinine ratio as the difference between the effects of two different sodium intake regimens. For each study, the mean difference and 95% confidence intervals were pooled using a random effect model. Heterogeneity, publication bias, subgroup, and meta-regression analyses were performed.

RESULTS

Eleven studies met the predefined inclusion criteria and provided 23 cohorts with 516 participants and 1-6 weeks of follow-up time. In the pooled analysis, an average reduction in sodium intake of 92 mmol/d was associated with a 32.1% (95% confidence interval, -44.3 to -18.8) reduction in urinary albumin excretion. The effect of sodium restriction was higher in the cohorts including patients on concomitant renin-angiotensin-aldosterone system-blocking therapy, in the studies with intervention lasting at least 2 weeks, and among participants with evidence of kidney damage. A greater reduction of urinary albumin excretion was associated with a higher decrease in BP during the intervention. The analysis of changes in albumin to creatinine ratio provided similar results.

CONCLUSIONS

This meta-analysis indicates that sodium intake reduction markedly reduces albumin excretion, more so during concomitant renin-angiotensin-aldosterone system-blocking therapy and among patients with kidney damage.

Increase in Vascular Injury of Sodium Overloaded Mice May be Related to Vascular Angiotensin Modulation

This study aimed to analyzing the effect of chronic sodium overload upon carotid and femoral injury, and its relation to vascular angiotensin modulation. Male C57Bl6 mice were divided in: control (cont), receiving 1% NaCl solution for 2 weeks (salt-2) or 12 weeks (salt-12). Two-weeks before the end of the study, a 2mm catheter was implanted around the left femoral and carotid arteries to induce injury. Blood pressure (BP) and heart rate (HR) were measured at the end of the study by tail plethysmography. Arteries were collected and prepared for histological analysis to determine arterial thickening and perivascular collagen deposition. Angiotensin II and Ang(1-7) were quantified in fresh arteries using the HPLC method. There were no differences in body weight, BP and HR. Intima/media ratio had a similar increase in both injured arteries of cont and salt-2 mice, but a more pronounced increase was observed in salt-12 mice (31.1±6%). On the other hand, sodium overload modified perivascular collagen deposition, increasing thick fibers (cont: 0.5%; salt-2: 3.4%; salt-12: 0.6%) and decreasing thin fibers (cont: 7.4%; salt-2: 0.5%; salt-12: 6.8%) in non-injured arteries. Injured arteries presented similar collagen fiber distribution. Angiotensin quantification showed increased Ang(1-7) in salt treated mice (salt-2: +72%; salt-12: +45%) with a concomitant decrease in Ang II (salt-2: -54%; salt-12: -60%). Vascular injury increased significantly Ang(1-7) in salt-12 mice (+80%), maintaining Ang II reduction similar to that of a non-injured artery. The lack of changes in BP and HR suggests that the structural changes observed may be due to non-hemodynamic mechanisms such as local renin-angiotensin system. Collagen evaluation suggests that sodium overload induces time-related changes in vascular remodeling. The increase of artery injury with concomitant increase in Ang(1-7) in 12-week treated mice shows a direct association between the duration of salt treatment and the magnitude of vascular injury.

Sodium intake and cardiovascular health

Sodium is an essential nutrient. Increasing sodium intake is associated with increasing blood pressure, whereas low sodium intake results in increased renin and aldosterone levels. Randomized controlled trials have reported reductions in blood pressure with reductions in sodium intake, to levels of sodium intake <1.5 g/d, and form the evidentiary basis for current population-wide guidelines recommending low sodium intake. Although low sodium intake (<2.0 g/d) has been achieved in short-term feeding clinical trials, sustained low sodium intake has not been achieved by any of the longer term clinical trials (>6-month duration). It is assumed that the blood pressure-lowering effects of reducing sodium intake to low levels will result in large reductions in cardiovascular disease globally. However, current evidence from prospective cohort studies suggests a J-shaped association between sodium intake and cardiovascular events, based on studies from >300 000 people, and suggests that the lowest risk of cardiovascular events and death occurs in populations consuming an average sodium intake range (3-5 g/d). The increased risk of cardiovascular events associated with higher sodium intake (>5 g/d) is most prominent in those with hypertension. A major deficit in the field is the absence of large randomized controlled trials to provide definitive evidence on optimal sodium intake for preventing cardiovascular events. Pending such trials, current evidence would suggest a recommendation for moderate sodium intake in the general population (3-5 g/d), with targeting the lower end of the moderate range among those with hypertension.