A novel animal model of metabolic syndrome with non-alcoholic fatty liver disease and skin inflammation

Increased Mortality Risk at Septic Condition in Inflammatory Skin Disorders and the Effect of High-Fat Diet Consumption

In recent years, attention has increasingly focused on various infectious diseases. Although some fatalities are directly attributed to the causative virus, many result from complications and reactive inflammation. Patients with comorbidities are at a higher risk of mortality. Refractory skin conditions such as atopic dermatitis, psoriasis, and epidermolysis bullosa, known for an elevated risk of sepsis, partly owe this to compromised surface barrier function. However, the detailed mechanisms underlying this phenomenon remain elusive. Conversely, although the detrimental effects of a high-fat diet on health, including the onset of metabolic syndrome, are widely recognized, the association between diet and susceptibility to sepsis has not been extensively explored. In this study, we examined the potential causes and pathogenesis of increased sepsis susceptibility in inflammatory skin diseases using a mouse dermatitis model: keratin 14-driven caspase-1 is overexpressed (KCASP1Tg) in mice on a high-fat diet. Our findings reveal that heightened mortality in the dermatitis mouse model is caused by the inflamed immune system due to the chronic inflammatory state of the local skin, and administration of LPS causes a rapid increase in inflammatory cytokine levels in the spleen. Intake of a high-fat diet exacerbates these cytokine levels. Interestingly, we also observed a reduced expression of Toll-like receptor 4 (TLR4) in monocytes from KCASP1Tg mice, potentially predisposing these animals to heightened infection risks and associated complications. Histological analysis showed a clear decrease in T and B cells in the spleen of KCASP1Tg mice fed a high-fat diet. Thickening of the alveolar wall, inflammatory cell infiltration, and alveolar hemorrhage were more prominent in the lungs of KCASP1Tg and KCASP1Tg with fat mice. We postulate that the chronic, non-infectious inflammation induces a negative feedback loop within the inflammatory cascade, and the suppressed expression of TLR4 renders the mice more susceptible to infections. Therefore, it is imperative for individuals with chronic skin inflammation to closely monitor disease progression upon infection and seek timely and appropriate treatment. Additionally, chronic inflammation of adipose tissue, induced by high-fat food intake, combined with dermatitis inflammation, may exacerbate infections, necessitating a review of dietary habits.

A short-term high-sugar diet is an aggravating factor in experimental allergic contact dermatitis

Allergic contact dermatitis (ACD) is an inflammatory skin reaction whose incidence has increased and has been associated with a dietary pattern rich in saturated fats and refined sugars. Considering the increased incidence of ACD and the lack of research about the influence of a short-term high-sugar diet on dermatitis, our aim is to improve understanding of the influence of a high-sugar diet on ACD. We introduced a diet rich in sugar fifteen days before inducing contact dermatitis with oxazolone, in mice, and maintained it until the end of the experiment, which lasted three weeks in total. The dermatitis model increased cholesterol and triglycerides in the liver, and the combination of diet and dermatitis increased weight and worsened liver cholesterol measurements. Furthermore, the high-sugar diet increased the production of IL-6, IFN-γ and TNF-α in the skin, which may be involved in the increase in epithelial skin thickness observed in experimental ACD.

Relationship between bullous pemphigoid and metabolic syndrome: a 12-year case-control study conducted in China

Background

Hypertension, diabetes, dyslipidemia, and obesity are prevalent in patients with bullous pemphigoid (BP) and are all components of metabolic syndrome (MS). However, the prevalence of MS in patients with BP is unknown. We aimed to evaluate the relationship between MS and BP and to define the clinical and laboratory characteristics of patients with both conditions.

Methods

This retrospective case-control study was conducted for 12 years at Peking Union Medical College (162 with BP and 162 age and sex-matched controls). The components of MS were analyzed and logistic regression was used to identify independent risk factors for BP. In addition, the clinical and laboratory characteristics of patients with BP ± MS were compared.

Results

The prevalence of MS in patients with BP was 35.2% and that in controls was 14.8% (p < 0.001). After adjustment for sex and age, multivariate analysis demonstrated a positive correlation between BP and MS [odds ratio (OR) 2.490, 95% confidence interval (CI) 1.040-5.963], diabetes (OR 1.870, 95% CI 1.029-3.396), and overweight or obesity (OR 1.807, 95% CI 1.026-3.182). In the BP group, participants with MS were older (p = 0.006), were less likely to present erythema (p = 0.028), and had higher serum C3 (p = 0.007) and incidence of infection within 1 year of their diagnosis (p = 0.035) than participants without MS.

Conclusion

MS and its components hyperglycemia and overweight were found to be independently associated with BP. Therefore, clinicians should screen for MS in patients with BP, especially if they are older, present less erythema, or have a high serum C3.

Research status and progress of metabolic associated fatty liver disease

Metabolic associated fatty liver disease (MAFLD) is a more appropriate general predicate to describe non-alcoholic fatty liver disease. The new definition lists metabolic dysfunction as an important cause of liver disease, demonstrates the high heterogeneity of this condition, and speeds up the transformation path to new treatment. The incidence of extrahepatic complications and related diseases of MAFLD far exceed that of the liver disease itself, which seriously threatens human health. In view of the current insufficient understanding of its severity, and the imperfect understanding of the disease scope, pathogenesis, and diagnosis of extrahepatic complications, especially the lack of effective drug treatment, this paper introduces and reviews the research status and progress of extrahepatic complications of MAFLD.

Saroglitazar, a novel dual PPAR-α/γ agonist, reverses high fat-low protein diet-induced metabolic and cognitive aberrations in C57BL/6J male mice

AIMS

Insulin resistance (IR) has become one of the major causative factors for the pathogenesis of various metabolic and neurometabolic diseases. The sedentary lifestyle in association with the consumption of protein-deficient and high-calorie diet results in IR development. This study was aimed to evaluate the neuroprotective effects of Saroglitazar (SGZ), a dual peroxisome-proliferator activated receptor (PPAR-α/γ) in a high fat-low protein diet (HFLPD) fed mouse model of MetS and associated cognitive deficits.

METHODS

Adult male C57BL/6J mice were fed with HFLPD plus 15% oral fructose solution for 16 weeks. Starting at the 13th week, SGZ (5 & 10 mg/kg; p.o.) was administered along with HFLPD for four weeks, i.e., the 12th to 16th week of the study groups. Various physiological, serum metabolic, neurobehavioral, neuroinflammatory, and oxidative stress parameters were assessed. The brain histopathology and mRNA expression of diverse genes in specific brain regions were also estimated.

RESULTS

The treatment with SGZ at both doses have significantly reversed various HFLPD-induced metabolic and cognitive alterations by improving the glucose and lipid profile in the periphery in addition to the enhanced cerebral glucose homeostasis, BBB integrity, reduced oxidative stress, and neuroinflammation. Furthermore, the SGZ improved locomotion and memory retention while reducing the HFLPD-induced anxiety-like behaviors in the mice.

CONCLUSIONS

SGZ treatment showed significant metabo-neuroprotective effects in mice fed with HFLPD, possibly through peripherally mediated activation of PPAR-α/γ and insulin downstream signaling in the cortex and hippocampus.

Modeling Diet-Induced Metabolic Syndrome in Rodents

Standardized animal models represent one of the most valuable tools available to understand the mechanism underlying the metabolic syndrome (MetS) and to seek for new therapeutic strategies. However, there is considerable variability in the studies conducted with this essential purpose. This review presents an updated discussion of the most recent studies using diverse experimental conditions to induce MetS in rodents with unbalanced diets, discusses the key findings in metabolic outcomes, and critically evaluates what we have been learned from them and how to advance in the field. The study includes scientific reports sourced from the Web of Science and PubMed databases, published between January 2013 and June 2020, which used hypercaloric diets to induce metabolic disorders, and address the impact of the diet on metabolic parameters. The collected data are used as support to discuss variables such as sex, species, and age of the animals, the most favorable type of diet, and the ideal diet length to generate metabolic changes. The experimental characteristics propose herein improve the performance of a preclinical model that resembles the human MetS and will guide researchers to investigate new therapeutic alternatives with confidence and higher translational validity.

High fat-low protein diet induces metabolic alterations and cognitive dysfunction in female rats

Approximately one-third of the world population is suffering from MetS, and the same is expected to rise in the years to come. Worldwide, most of the staple diets contain high amounts of carbohydrates, fats and comparatively low quantities of proteins. The goal of this study was to evaluate the effect of high fat-low protein diet in the development of the metabolic syndrome and associated cognitive deficits in the female rats. The rats fed with high fat-low protein diet (HFLPD) and 15% oral fructose solution for 24 weeks. Body weight, food intake, water intake, fasting blood glucose, oral glucose tolerance, glycosylated hemoglobin (HbA_1C), and serum lipid profile were measured after every 4 weeks. Serum insulin, HOMA-IR index, rectal temperature, and systolic blood pressure were measured to confirm the manifestation of the hallmarks of metabolic syndrome. Behavioral tests for locomotion, anxiety, learning, and spatial memory were performed from the 12th week to till the end of the study. At the 24th week, oxidative stress assays and histopathology of liver, kidney, brain, and WAT were also performed. HFLPD significantly altered the physiologic and metabolic parameters which contributed to the manifestation of MetS. HFLPD also impaired the cognitive functions along with significant structural changes in the liver, kidney, WAT, and brain. The findings of this study reveal that HFLPD has the potential to induce the physiological, metabolic and histological alterations in rats, which eventually led to the development of MetS and also disrupted the cognitive functions in female rats.

Modelos experimentais de obesidade: análise crítica do perfil metabólico e da aplicabilidade

Introdução: a prevalência da obesidade e de outras doenças relacionadas está aumentando em todo o mundo de forma preocupante. Caracterizada pelo aumento do peso corporal ou do acúmulo excessivo de gordura corporal, a obesidade tem sido associada ao aumento da mortalidade decorrente de maior incidência de hipertensão, diabetes e vários tipos de câncer. Os modelos animais fornecem dados fundamentais para a compreensão dos parâmetros básicos que regulam os componentes do nosso balanço energético. Objetivo: esta revisão selecionou artigos que utilizaram modelos animais (ratos e camundongos) de obesidade focando nas principais alterações metabólicas causadas pela obesidade com o objetivo de apresentar os principais modelos utilizados nos últimos 5 anos. Material e Métodos: Foram realizadas duas buscas na base de dados PubMed utilizando as expressões: “obesity” AND “metabolism” AND “animal model” AND “mice” e “obesity” AND “metabolism” AND “animal model” AND “rat”, sendo selecionados os estudos considerados mais relevantes a partir dos critérios: descrição detalhada do modelo experimental e análise dos parâmetros metabólicos de interesse: peso, perfil lipídico e perfil glicêmico. Outras referências foram utilizadas para elucidar melhor os modelos encontrados e também aqueles que não foram citados, mas, que possuem importância no entendimento da evolução dos modelos animais de obesidade. Resultados: A espécie mais utilizada foi o camundongo, o sexo predominante foi o masculino, a faixa etária dos roedores variou de neonatos até 44 semanas e o período de acompanhamento chegou até 53 semanas. A obesidade foi confirmada pelo aumento significativo do peso e na maioria dos estudos foram encontradas alterações no metabolismo lipídico e glicêmico. Encontramos cinco grupos de mecanismos de indução da obesidade porém a maioria dos estudos utilizou dietas hiperlipídicas, modelo que mais se assemelha às alterações metabólicas encontradas em humanos. Conclusão: Investigar as causas e efeitos da obesidade induzida em modelos experimentais pode fornecer uma melhor compreensão da fisiopatologia da obesidade, e proporcionar novas opções de prevenção e tratamento.

Comorbidity profiles of psoriasis in Taiwan: A latent class analysis

BACKGROUND

Psoriasis is associated with many comorbidities. An understanding of these comorbidity patterns can help foster better care of patients with psoriasis.

OBJECTIVE

To identify the heterogeneity of psoriasis comorbidities using latent class analysis (LCA).

METHODS

LCA was used to empirically identify psoriasis comorbidity patterns in a nationwide sample of 110,729 incident cases of psoriasis (2002-2012) from the National Health Insurance database in Taiwan.

RESULTS

The mean age of incident psoriasis was 46.1 years. Hypertension (28.8%), dyslipidemia (18.9%), and chronic liver disease/cirrhosis/hepatitis (18.1%) were the top three comorbidities in patients with psoriasis. LCA identified four distinct comorbidity classes among these patients, including 9.9% of patients in the "multi-comorbidity" class, 17.9% in the "metabolic syndrome" class, 11.3% in the "hypertension and chronic obstructive pulmonary disease (COPD)" class, and 60.9% in the "relatively healthy" class. Psoriatic arthritis was evenly distributed among each class. Relative to membership in the "relative healthy" class, an increase of one year of age had a higher probability of membership in the "multi-comorbidity" (odds ratio [OR], 1.25), "metabolic syndrome" (OR, 1.11), or "hypertension and COPD" (OR, 1.34) classes. Relative to membership in the "relative healthy" class, compared to women, men had a higher probability of membership in the "multi-comorbidity" (OR, 1.39), "metabolic syndrome" (OR, 1.77), or "hypertension and COPD" (OR, 1.22) classes.

CONCLUSION

We observed four distinct classes of psoriasis comorbidities, including the "multi-comorbidity", "metabolic syndrome", "hypertension and COPD", and "relatively healthy" classes, as well as the clustering of liver diseases with metabolic syndrome and clustering of COPD with hypertension.

A Mouse Model of Diet-Induced Obesity Resembling Most Features of Human Metabolic Syndrome

Increased chicken-derived fat and fructose consumption in the human diet is paralleled by an increasing prevalence of obesity and metabolic syndrome (MS). Herein, we aimed at developing and characterizing a mouse model of diet-induced obesity (DIO) resembling most of the key features of the human MS. To accomplish this, we fed male C57BL/6J mice for 4, 8, 12, and 16 weeks with either a low-fat diet (LFD) or a high-chicken-fat diet (HFD) and tap water with or without 10% fructose (F). This experimental design resulted in the following four experimental groups: LFD, LFD + F, HFD, and HFD + F. Over the feeding period, and on a weekly basis, the HFD + F group had more caloric intake and gained more weight than the other experimental groups. Compared to the other groups, and at the end of the feeding period, the HFD + F group had a higher adipogenic index, total cholesterol, low-density lipoprotein cholesterol, fasting basal glycemia, insulin resistance, hypertension, and atherogenic index and showed steatohepatitis and systemic oxidative stress/inflammation. A mouse model of DIO that will allow us to study the effect of MS in different organs and systems has been developed and characterized.

Relationship between Non-Alcoholic Fatty Liver Disease and Psoriasis: A Novel Hepato-Dermal Axis?

Over the past 10 years, it has become increasingly evident that nonalcoholic fatty liver disease (NAFLD) is a multisystem disease that affects multiple extra-hepatic organ systems and interacts with the regulation of several metabolic and immunological pathways. In this review we discuss the rapidly expanding body of clinical and epidemiological evidence supporting a strong association between NAFLD and chronic plaque psoriasis. We also briefly discuss the possible biological mechanisms underlying this association, and discuss treatment options for psoriasis that may influence NAFLD development and progression. Recent observational studies have shown that the prevalence of NAFLD (as diagnosed either by imaging or by histology) is remarkably higher in psoriatic patients (occurring in up to 50% of these patients) than in matched control subjects. Notably, psoriasis is associated with NAFLD even after adjusting for metabolic syndrome traits and other potential confounding factors. Some studies have also suggested that psoriatic patients are more likely to have the more advanced forms of NAFLD than non-psoriatic controls, and that psoriatic patients with NAFLD have more severe psoriasis than those without NAFLD. In conclusion, the published evidence argues for more careful evaluation and surveillance of NAFLD among patients with psoriasis.