Interleukin-12 as a biomarker of the beneficial effects of food restriction in mice receiving high fat diet or high carbohydrate diet

Plasma Proteins Associated with the Mediterranean-Dietary Approaches to Stop Hypertension Intervention for Neurodegenerative Delay (MIND) Diet and Incident Dementia

BACKGROUND

The Mediterranean-Dietary Approaches to Stop Hypertension Intervention for Neurodegenerative Delay (MIND) diet slows cognitive decline and protects brain health, but the mechanisms are poorly understood.

OBJECTIVES

We aimed to determine the plasma proteins associated with the MIND diet score and their ability to predict incident dementia in the Atherosclerosis Risk in Communities study.

METHODS

We analyzed 10,230 Black and White participants at visit 3 (1993-1995) with food frequency questionnaire and proteomics data and randomly divided them into discovery (n = 6850) and replication (n = 3380) samples. We examined associations between the MIND diet score and 4955 proteins using multivariable linear regression and elastic net regression. C-statistics were calculated to assess if proteins improved the prediction of high MIND diet adherence beyond participant characteristics. Cox proportional hazards models were used to assess associations between significant diet-related proteins and incident dementia over 2 decades. C-statistics assessed the ability of significant proteins to improve dementia prediction beyond known risk factors.

RESULTS

Of 316 proteins associated with the MIND diet score in the discovery sample at a false discovery rate <0.05, 62 were internally replicated. Of these, 21 proteins selected by the elastic net individually improved MIND diet score prediction. After a median follow-up of 21 y, there were 2311 dementia cases. Five diet-related proteins, thrombospondin-2 [hazard ratio (HR): 1.19; 95% confidence interval (CI): 1.11, 1.29], protein ABHD14A (HR: 1.23; 95% CI: 1.11, 1.37), structural maintenance of chromosomes protein 3 (HR: 1.19; 95% CI: 1.08, 1.31), epidermal growth factor receptor (HR: 0.68; 95% CI: 0.53, 0.86), and interleukin-12 subunit beta (HR: 1.14; 95% CI: 1.05, 1.25) were significantly associated with incident dementia. All 5 proteins individually and together improved the prediction of dementia risk.

CONCLUSIONS

Using high-throughput proteomics, we identified candidate biomarkers of the MIND diet score and incident dementia, which are implicated in neural signaling, angiogenesis, and anti-inflammatory pathways.

Linseed oil attenuates fatty liver disease in mice fed a high-carbohydrate diet

The impact of linseed oil as a lipid source on liver disease induced by a high-carbohydrate diet (HCD) was evaluated. Adult male Swiss mice received an HCD containing carbohydrates (72.1%), proteins (14.2%), and lipids (4.0%). The Control HCD group (HCD-C) received an HCD containing lard (3.6%) and soybean oil (0.4%) as lipid sources. The L10 and L100 groups received an HCD with 10 and 100% linseed oil as lipid sources, respectively. A group of mice were euthanized before receiving the diets (day 0) and the remaining groups after 56 days of receiving the diets (HCD-C, L10, and L-100 groups). Morphological and histopathological analyses, as well as collagen deposition were evaluated. Perivenous hepatocytes (PVH) of the HCD-C group were larger (P<0.05) than periportal hepatocytes (PPH) in the median lobe (ML) and left lobe (LL). There was a greater (P<0.05) deposition of type I collagen in PPH (vs PVH) and in the ML (vs LL). The ML exhibited a higher proportion of apoptotic bodies, inflammatory infiltrate, and hepatocellular ballooning. All these alterations (hepatocyte size, deposition of type I collagen, apoptotic bodies, inflammatory infiltrate, and hepatocellular ballooning) induced by HCD were prevented or attenuated in L10 and L100 groups. Another indicator of the beneficial effects of linseed oil was the lower (P<0.05) number of binucleated hepatocytes (HCD-C vs L10 or L100 group). In general, the L100 group had greater effects than the L10 group. In conclusion, linseed oil impedes or reduces the liver injury progression induced by an HCD.

Mechanistic Targets and Nutritionally Relevant Intervention Strategies to Break Obesity-Breast Cancer Links

The worldwide prevalence of overweight and obesity has tripled since 1975. In the United States, the percentage of adults who are obese exceeds 42.5%. Individuals with obesity often display multiple metabolic perturbations, such as insulin resistance and persistent inflammation, which can suppress the immune system. These alterations in homeostatic mechanisms underlie the clinical parameters of metabolic syndrome, an established risk factor for many cancers, including breast cancer. Within the growth-promoting, proinflammatory milieu of the obese state, crosstalk between adipocytes, immune cells and breast epithelial cells occurs via obesity-associated hormones, angiogenic factors, cytokines, and other mediators that can enhance breast cancer risk and/or progression. This review synthesizes evidence on the biological mechanisms underlying obesity-breast cancer links, with emphasis on emerging mechanism-based interventions in the context of nutrition, using modifiable elements of diet alone or paired with physical activity, to reduce the burden of obesity on breast cancer.

A High-Fat Diet Induces Lower Systemic Inflammation than a High-Carbohydrate Diet in Mice

Background: We previously established that male Swiss mice (Mus musculus) receiving a high-fat diet (HFD) during 8 weeks exhibit similar caloric ingestion and body weight (grams) compared with mice fed a high-carbohydrate diet (HCD). HFD mice exhibit a lower inflammatory state than an HCD in the liver, skeletal muscle, and brain. In addition, we demonstrated that HFD and HCD modulated fatty acids (FA) composition in these tissues. In this study, our objective was to compare HFD mice and HCD mice in terms of systemic inflammation. Methods: Saturated FA (SFA), monounsaturated FA, omega-6 polyunsaturated FA (n-6 PUFA), and n-3 PUFA were evaluated at the time points 0, 1, 7, 14, 28, and 56 days after starting the administration of the diets. We investigated n-6 PUFA:n-3 PUFA, SFA:n-3 PUFA, palmitic acid:α-linolenic acid (ALA), and myristic acid:docosahexaenoic acid (DHA) ratios as potential serum biomarkers of systemic inflammation. We also measured the serum levels of basic fibroblast growth factor, granulocyte-macrophage colony-stimulating factor (GM-CSF), inducible protein 10 (IP-10), interferon gamma (IFN-γ), interleukin (IL)-1α, IL-1β, IL-2, IL-4, IL-5, IL-6, IL-10, IL-13, IL-17, macrophage inflammatory protein-1α (MIP-1-α), monocyte chemotactic protein 1 (MCP-1), monokine induced by IFN-γ (MIG), and tumor necrosis factor α (TNF-α). Results: The HFD group had lower (P < 0.05) n-6 PUFA:n-3 PUFA, palmitic acid:ALA, myristic acid:DHA ratios, and lower plasma levels of proinflammatory cytokines (IFN-γ, MIG, GM-CSF, and IL-6). Conclusion: The HFD mice showed lower systemic inflammation compared with a caloric ingestion-body weight-matched control HCD mice.

The Dietary Replacement of Soybean Oil by Canola Oil Does Not Prevent Liver Fatty Acid Accumulation and Liver Inflammation in Mice

A high-carbohydrate diet (HCD) is a well-established experimental model of accelerated liver fatty acid (FA) deposition and inflammation. In this study, we evaluated whether canola oil can prevent these physiopathological changes. We evaluated hepatic FA accumulation and inflammation in mice fed with a HCD (72.1% carbohydrates) and either canola oil (C group) or soybean oil (S group) as a lipid source for 0, 7, 14, 28, or 56 days. Liver FA compositions were analyzed by gas chromatography. The mRNA expression of acetyl-CoA carboxylase 1 (ACC1) was measured as an indicator of lipogenesis. The mRNA expression of F4/80, tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6, and IL-10, as mediators of liver inflammation, were also measured. The C group stored less n-6 polyunsaturated FAs (n-6 PUFAs) and had more intense lipid deposition of monounsaturated FAs (MUFAs), n-3 PUFAs, and total FAs. The C group also showed higher ACC1 expression. Moreover, on day 56, the C group showed higher expressions of the inflammatory genes F4/80, TNF-α, IL-1β, and IL-6, as well as the anti-inflammatory IL-10. In conclusion, a diet containing canola oil as a lipid source does not prevent the fatty acid accumulation and inflammation induced by a HCD.

A high-carbohydrate diet induces greater inflammation than a high-fat diet in mouse skeletal muscle

We previously reported that both the high-carbohydrate diet (HCD) and high-fat diet (HFD) given for two months promote lipid deposition and inflammation in the liver and brain of mice. The results obtained indicate a tissue-specific response to both diets. Herein, we compared the effects of HCD and HFD on fatty acid (FA) composition and inflammation in the gastrocnemius muscle. Male Swiss mice were fed with HCD or HFD for 1 or 2 months. Saturated FA (SFA), monounsaturated FA (MUFA), n-3 polyunsaturated FA (n-3 PUFA), and n-6 PUFA were quantified. The activities of stearoyl-CoA desaturase 1 (SCD-1), Δ-6 desaturase (D6D), elongase 6, and de novo lipogenesis (DNL) were estimated. As for indicators of the inflammatory tissue state, we measured myeloperoxidase (MPO) activity and gene expression of F4/80, tumor necrosis factor-α (TNF-α), interleukin (IL)-4, IL-6, and IL-10. The HCD led to a lower deposition of SFA, MUFA, n-3 PUFA, and n-6 PUFA compared to HFD. However, the HCD increased arachidonic acid levels, SFA/n-3 PUFA ratio, DNL, SCD-1, D6D, and MPO activities, and expression of IL-6, contrasting with the general idea that increased lipid deposition is associated with more intense inflammation. The HCD was more potent to induce skeletal muscle inflammation than the HFD, regardless of the lower lipid accumulation.

Adipose tissue is less responsive to food restriction anti-inflammatory effects than liver, muscle, and brain in mice

High caloric intake promotes chronic inflammation, insulin resistance, and chronic diseases such as type-2 diabetes, which may be prevented by food restriction (FR). The effect of FR on expression of pro-inflammatory and anti-inflammatory genes in adipose tissue, liver, muscle, and brain was compared. Male Swiss mice were submitted to FR (FR group) or had free access to food (control group) during 56 days. The liver, gastrocnemius muscle, brain, and epididymal white adipose tissue (WAT) were collected for analysis of gene expressions. FR attenuated inflammation in the liver, brain, and gastrocnemius muscle but did not markedly change inflammatory gene expression in epididymal WAT. We concluded that adipose tissue was less responsive to FR in terms of gene expression of pro-inflammatory and anti-inflammatory genes.