Leptin resistance and hippocampal behavioral deficits

Long-term saturated fat-enriched diets impair hippocampal learning and memory processes in a sex-dependent manner

Consumption of saturated fat-enriched diets during adolescence has been closely associated with the reduction of hippocampal synaptic plasticity and the impairment of cognitive function. Nevertheless, the effect of long-term intake of these foods has not yet been studied. In the present study, we have investigated the effect of a treatment, lasting for 40 weeks, with a diet enriched in saturated fat (SOLF) on i) spatial learning and memory, ii) hippocampal synaptic transmission and plasticity, and iii) hippocampal gene expression levels in aged male and female mice. Our findings reveal that SOLF has a detrimental impact on spatial memory and synaptic plasticity mechanisms, such as long-term potentiation (LTP), and downregulates Gria1 expression specifically in males. In females, SOLF downregulates the gene expression of Gria1/2/3 and Grin1/2A/2B glutamate receptor subunits as well as some proinflammatory interleukins. These findings highlight the importance of considering sex-specific factors when assessing the long-term effects of high-fat diets on cognition and brain plasticity.

Differential effects of high-fat diet on endocrine, metabolic and depressive-like behaviors in male and female rats

The complications of obesity extend beyond the periphery to the central nervous system (CNS) and include an increased risk of developing neuropsychiatric co-morbidities like depressive illness. Preclinical studies support this concept, including studies that have examined the effects of a high-fat diet (HFD) on depressive-like behaviors. Although women are approximately two-fold more likely to develop depressive illness compared to men, most preclinical studies have focused on the effects of HFD in male rodents. Accordingly, the goal of this study was to examine depressive-like behaviors in male and female rats provided access to a HFD. In agreement with prior studies, male and female rats provided a HFD segregate into an obesity phenotype (i.e., diet-induced obesity; DIO) or a diet resistant (DR) phenotype. Upon confirmation of the DR and DIO phenotypes, behavioral assays were performed in control chow, DR, and DIO rats. In the sucrose preference test, male DIO rats exhibited significant decreases in sucrose consumption (i.e., anhedonia) compared to male DR and male control rats. In the forced swim test (FST), male DIO rats exhibited increases in immobility and decreases in climbing behaviors in the pre-test sessions. Interestingly, male DR rats exhibited these same changes in both the pre-test and test sessions of the FST, suggesting that consumption of a HFD, even in the absence of the development of an obesity phenotype, has behavioral consequences. Female rats did not exhibit differences in sucrose preference, but female DIO rats exhibited increases in immobility exclusively in the test session of the FST, behavioral changes that were not affected by the stage of the estrous cycle. Collectively, these studies demonstrate that access to a HFD elicits different behavioral outcomes in male and female rats.

The remarkable impact of Opuntia Ficus Indica fruit administration on metabolic syndrome: Correlations between cognitive functions, oxidative stress and lipid dysmetabolism in the high-fat, diet-fed rat model

BACKGROUND

A wealth of evidence underscores the bioactive properties of nutraceuticals and functional foods in addressing oxyinflammatory-based diseases with implications at both peripheral and central levels. Opuntia ficus-indica (OFI) is well-documented for its health-promoting attributes, though its fruit (OFIF) remains relatively understudied. Not only poses Metabolic Syndrome (MetS) cardiometabolic risks but also contributes significantly to cognitive impairment, especially in crucial brain areas such as hippocampus and hypothalamus.

METHODS

Following 8 weeks of HFD to induce MetS, rats received OFIF oral supplementation for 4 weeks to evaluate cognitive and affective modifications using behavioural paradigms, i.e. open field, burrowing, white-dark box, novelty-suppressed feeding, and object recognition tests. Our investigation extended to biochemical evaluations of lipid homeostasis, central and peripheral oxidative stress and neurotrophic pathways, correlating these measures together with circulating leptin levels.

RESULTS

Our data revealed that OFIF modulation of leptin positively correlates with systemic and brain oxidative stress, with markers of increased anxiety-like behaviour and impaired lipid homeostasis. On the other hand, leptin levels reduced by OFIF are associated with improved antioxidant barriers, declarative memory and neurotrophic signalling.

DISCUSSION

This study underscores OFIF neuroactive potential in the context of MetS-associated cognitive impairment, offering insights into its mechanisms and implications for future therapeutic strategies.

Inhibition of hepatocellular carcinoma cell proliferation through regulation of the Cell Cycle, AGE-RAGE, and Leptin signaling pathways by a compound formulation comprised of andrographolide, wogonin, and oroxylin A derived from Andrographis Paniculata(Burm.f.) Nees

ETHNOPHARMACOLOGICAL RELEVANCE

In 2020, liver cancer contributed to approximately 0.9 million new cases and 0.83 million deaths, making it the third leading cause of mortality worldwide. Andrographis paniculata (Burm.f.) Nees(APN), a traditional Chinese or ethnic medicine extensively utilized in Asia, has been historically employed for treating hepatitis and liver cancer. However, the precise molecular mechanism responsible for its therapeutic efficacy remains unclear.

AIM OF THE STUDY

To identify and replace the active components of APN on liver cancer, which is investigate the potential of a Multi-Component Chinese Medicine derived from Andrographis paniculata (Burm.f.) Nees(APN-MCCN) for the treatment of liver cancer.

MATERIALS AND METHODS

Firstly, the TCMSP database and two liver cancer disease databases were utilized to optimize the chemical constituents of APN and the disease-related targets of liver cancer. The network was constructed using Cytoscape to visualize the relationships between them. Subsequently, the optimal combination of components in APN-MCCN for the treatment of liver cancer was determined using the contribution index method. HPLC analysis was performed to measure the content of each component. Pathway enrichment and gene annotation were conducted using the ClueGo plugin. In vivo efficacy was evaluated by transplanting S180 and H22 tumor-bearing mouse models. In vitro efficacy was determined through MTT assay, morphological observations, flow cytometry analysis, and scratch tests. Western blotting was used to validate the protein expression. The transfection techniques were employed to knockdown the expressions of key protein in different pathway.

RESULTS

We obtained 24 effective compounds, with andrographolide contributing 20.78%, wogonin contributing 41.85%, and oroxylin A contributing 30.26% to the overall composition. Based on the predicted enrichment degree and correlation with liver cancer, we identified a total of 27 pathways, among which the Leptin signaling pathway, AGE-RAGE signaling pathway, and Cell Cycle signaling pathway were selected for further investigation. The content of andrographolide, oroxylin A, and wogonin in APN was found to be 0.104%, 0.0024%, and 0.0052%, respectively. In vivo experiments demonstrated that APN-MCCM significantly reduced tumor weight in S180 tumor-bearing mice and prolonged the survival time of H22 liver cancer-bearing mice. APN-MCCM exhibited inhibitory effects on the proliferation, apoptosis, and migration of liver cancer cells while arresting them in the G2/M phase. Furthermore, APN-MCCM down-regulated the protein expression of NCOA1, PTPN1, and GSK3B in the Leptin signaling pathway, NOS2 and NOS3 in the AGE-RAGE signaling pathway, CCNA2, CDK1, CDK2, and CDK7 in the Cell Cycle signaling pathway. Additionally, it upregulated the protein phosphorylation of p-P38 and p-JUN in the AGE-RAGE signaling pathway. Knockout experiments revealed that the inhibitory effect of APN-MCCM on liver cancer cell migration was prevented when the MAPK or NCOA1 genes were knocked out. Similarly, knocking out the CDK7 gene blocked the G2/M phase arrest induced by APN-MCCM in liver cancer cells.

CONCLUSIONS

APN-MCCM, consisting of andrographolide, wogonin, and oroxylin A, exhibits inhibitory effects on the cell proliferation of liver cancer cells by targeting the cell cycle pathway. Additionally, it suppresses the migration of liver cancer cells through the AGE-RAGE and Leptin signaling pathways.

Leptin moderates the relationship between sleep quality and memory function: A population-based study

Sleep is crucial for memory, as it promotes its encoding, consolidation, storage, and retrieval. Sleep periods following learning enhance memory consolidation. Leptin, a hormone that regulates appetite and energy balance, also influences memory and neuroplasticity. It plays a neurotrophic role in the hippocampus, enhancing synaptic function and promoting memory processes. Given these associations between sleep, memory, and leptin, this study aimed to evaluate the interplay between sleep quality, memory complaints and leptin levels. Using data from the São Paulo Epidemiologic Sleep Study (EPISONO) 2007 edition, we analyzed data from 881 participants who underwent evaluations for subjective sleep quality (Pittsburgh Sleep Quality Index), memory function (Prospective and Retrospective Memory Questionnaire), body mass index and plasmatic leptin levels. After confirming that subjects with poor sleep quality had more memory complaints in our cohort, we observed that leptin levels were increased in individuals with more memory complaints, but there was no association between leptin levels and sleep quality. Mediation analysis reinforced the direct effect of sleep quality on memory function, but leptin had no indirect effect as mediator over the sleep-memory association. Moderation analysis revealed that leptin acted as a moderator in the relationship between sleep quality and memory, with increased leptin levels enhancing the effect of sleep quality over memory function. These findings underscore the intricate interplay between sleep, memory, and metabolic factors like leptin, shedding light on potential mechanisms through which sleep influences memory and cognitive functions. Further research is needed to elucidate the exact mechanisms underlying these relationships and their implications for overall health and well-being.

Study of decreased serum levels of C1q/TNF-related protein 4 (CTRP4) in major depressive disorder

BACKGROUND

The adipokines secreted by adipocytes might play an important role through crossing the blood brain barrier to the brain, which could mediate the common physiological pathway between depression and obesity. CTRP4, a member of the CTRP family, is highly expressed in human adipose tissue and brain tissue.

OBJECTIVE

this study aimed to measure serum C1q/TNF-related protein 4 (CTRP4) levels in depressive patients to explore the association between CTRP4 levels and depression.

METHODS

depressive patients (n = 138), healthy controls (n = 100) were enrolled from September 2020 to December 2021. The level of serum CTRP4 was measured by enzymes linked to immunosorbent assay (ELISA). Other biochemical indicators were measured by Advia 2400 automatic biochemistry analyzer. Depressive symptoms of patients were assessed using the Hamilton Depression Scale-24 item (HAMD-24).

RESULTS

this study found that serum CTRP4 levels in the MDD group were lower than that of the health control (P < 0.001). Serum CTRP4 levels were negatively correlated with HAMD-24 scores (r = -0.368; P = 0.001). The serum CTRP4 levels were negatively correlated with Total Cholesterol (TC), Triglyceride (TG) and Low-Density Lipoprotein Cholesterol (LDL-C), but were positively associated with high density lipid-cholesterol (HDL-C) (r = -0.267, r = -0.255, r = -0.312 and r = 0.280; P = 0.017, P = 0.023, P = 0.005 and P = 0.012). The ROC curve of CTRP4 showed that the Area Under Curve (AUC) was 0.856, P < 0.001.

CONCLUSION

the serum CTRP4 levels in MDD patients were lower than that in health control, which might mediate the physiological progress of MDD patients.

Leptin Signaling Could Mediate Hippocampal Decumulation of Beta-Amyloid and Tau Induced by High-Intensity Interval Training in Rats with Type 2 Diabetes

Leptin (LEP) can cross the blood-brain barrier and facilitate cross-talk between the adipose tissue and central nerve system (CNS). This study aimed to investigate the effect of 8-week high-intensity interval training (HIIT) on the LEP signaling in the hippocampus of rats with type 2 diabetes. 20 rats were randomly divided into four groups: (i) control (Con), (ii) type 2 diabetes (T2D), (iii) exercise (EX), and (iv) type 2 diabetes + exercise (T2D + EX). The rats in the T2D and T2D + EX were fed a high-fat diet for two months, then a single dose of STZ (35 mg/kg) was injected to induce diabetes. The EX and T2D + EX groups performed 4-10 intervals of treadmill running at 80-100% of Vmax. Serum and hippocampal levels of LEP as well as hippocampal levels of LEP receptors (LEP-R), Janus kinase 2 (JAK-2), signal transducer and activator of transcription 3 (STAT-3), activated protein kinase (AMP-K), proxy zoster receptor α (PGC-1α), beta-secretase 1 (BACE1), Beta-Amyloid (Aβ), Phosphoinositide 3-kinases (PI3K), protein kinase B (AKT), mammalian target of rapamycin (mTOR), Glycogen Synthase Kinase 3 Beta (GSK3β), and hyperphosphorylated tau proteins (TAU) were measured. One-way ONOVA and Tukey post-hoc tests were used to analyze the data. Serum and hippocampal levels of LEP as well as hippocampal levels of LEP-R, JAK-2, STAT-3, AMP-K, PGC1α, PI3K, AKT, and mTOR were increased while hippocampal levels of BACE1, GSK3B, TAU, and Aβ were decreased in T2D + EX compared with T2D group. Serum LEP and hippocampal levels of LEP, LEP-R, JAK-2, STAT-3, AMP-K, PGC1α, PI3K, AKT, and mTOR were decreased. Conversely hippocampal levels of BACE1, GSK3B, TAU, and Aβ were increased in T2D group compared with CON group. HIIT could improve LEP signaling in the hippocampus of rats with type 2 diabetes and decrease the accumulation of Tau and Aβ, which may reduce the risk of memory impairments.

The Benefits of Switching to a Healthy Diet on Metabolic, Cognitive, and Gut Microbiome Parameters Are Preserved in Adult Rat Offspring of Mothers Fed a High-Fat, High-Sugar Diet

SCOPE

Maternal obesity increases the risk of health complications in children, highlighting the need for effective interventions. A rat model of maternal obesity to examine whether a diet switch intervention could reverse the adverse effects of an unhealthy postweaning diet is used.

METHODS AND RESULTS

Male and female offspring born to dams fed standard chow or a high-fat, high-sugar "cafeteria" (Caf) diet are weaned onto chow or Caf diets until 22 weeks of age, when Caf-fed groups are switched to chow for 5 weeks. Adiposity, gut microbiota composition, and place recognition memory are assessed before and after the switch. Body weight and adiposity fall in switched groups but remain significantly higher than chow-fed controls. Nonetheless, the diet switch improves a deficit in place recognition memory observed in Caf-fed groups, increases gut microbiota species richness, and alters β diversity. Modeling indicate that adiposity most strongly predicts gut microbiota composition before and after the switch.

CONCLUSION

Maternal obesity does not alter the effects of switching diet on metabolic, microbial, or cognitive measures. Thus, a healthy diet intervention lead to major shifts in body weight, adiposity, place recognition memory, and gut microbiota composition, with beneficial effects preserved in offspring born to obese dams.

Vitamin D Status in Children with Autism Spectrum Disorders: Determinants and Effects of the Response to Probiotic Supplementation

A relationship between the presence of clinical symptoms and gastrointestinal (GI) disturbances associated with nutritional deficiencies, including vitamin D (25(OH)D) deficiency, has been observed in autism spectrum disorder (ASD). The aim was to evaluate 25(OH)D levels according to the annual rhythm cycle, gender, the severity of autism, nutritional or clinical status, inflammatory and metabolic biomarkers, GI symptoms, and the clinical response to probiotic/placebo supplementation in preschooler children with ASD. Eighty-one ASD preschoolers (67 males) were assessed with standardized tools for ASD severity (ADOS score) and GI symptoms (by GI-Index at six-items and at nine-items, the latter defined as the Total GI-Index). The 25(OH)D levels were compared among different ASD subgroups according to metabolic and inflammatory biomarkers (leptin, insulin, resistin, PAI-1, MCP-1, TNF-alfa, and IL-6), gender, and the presence or absence of: (i) GI symptoms, (ii) the response to probiotic supplementation (the improvement of GI symptomatology), (iii) the response to probiotic supplementation (improvement of ASD severity). Only 25% of the ASD children presented an adequate 25(OH)D status (≥30 ng/mL according to the Endocrine Society guidelines). All the 25(OH)D levels falling in the severe deficiency range (<10 ng/mL) were observed in the male subgroup. A significant inverse correlation between 25(OH)D and leptin was observed (R = −0.24, p = 0.037). An inverse correlation was found between 25(OH)D levels and the GI Index 6-Items and Total GI-Index (R = −0.25, p = 0.026; −0.27, = 0.009) and a direct relationship with the probiotic response (R = 0.4, p = 0.05). The monitoring of 25(OH)D levels and the co-administration of 25(OH)D and probiotic supplementation could be considered in ASD from early ages.

Association Between Self-rating Depression Scores and Total Ghrelin and Adipokine Serum Levels in a Large Population-Based Sample

Background

Ghrelin and the adipokines leptin and adiponectin have been suggested to be involved in mood and anxiety regulation and to be altered in affective disorders. However, studies investigating the association between ghrelin, leptin and adiponectin and depressive symptomatology are scarce but might contribute to a better understanding of their involvement in mood regulation. We thus aimed investigating the association between depressive symptomatology and total ghrelin as well as leptin and adiponectin serum levels in a large population-based sample.

Methods

Total serum ghrelin, adiponectin and leptin levels were determined in 1666 subjects of a population-based cross-sectional study ("LIFE"). The Center for Epidemiological Studies Depression Scale (CES-D) and the Inventory of Depressive Symptoms - Self Rating (IDS-SR) were administered. Multiple linear regression analyses were conducted to examine the association between total serum ghrelin, leptin and adiponectin and the intensity of depressive symptoms.

Results

In the total sample (n = 1,092), neither ghrelin nor leptin or adiponectin serum levels showed a significant association with CES-D or IDS-SR sum scores (N = 1,092) or in depressed/non-depressed subjects. Leptin serum levels showed a significantly positive association with IDS-SR sum scores in elderly men (≥60 years; β = 0.122, 95% CI: 0.009; 0.236; p = 0.035).

Conclusion

Our study suggests that peripheral levels of ghrelin and adipokines in a cross-sectional study design might not be sufficient to measure their involvement in depression, suggesting that associations are more complex and multi-layered.

Impact of fasting on stress systems and depressive symptoms in patients with major depressive disorder: a cross-sectional study

Major depressive disorder (MDD) is frequently associated with poor response to treatment. Common antidepressants target neurotransmission and neuronal plasticity, which require adequate energy supply. As imaging studies indicate disturbances in central energy metabolism, and caloric restriction improves neuroplasticity and impacts mood and cognition, correction of energy status might increase the effectiveness of antidepressant treatments and reduce the psychopathological symptoms of depression. Metabolic parameters, stress hormones, and brain-derived neurotrophic factor (BDNF) levels were assessed in serum of depressed inpatients (MDD, N = 21) and healthy volunteers (Ctrl, N = 28) before and after a 72 h fasting period during which only water was consumed. Depression severity was assessed by Beck's Depression Inventory (BDI)-2 sum-score and cognitive-affective and somatic sub-scores. Fasting similarly impacted metabolic parameters and stress systems in both groups. Fasting elevated BDI-2 sum-scores and somatic sub-scores in Ctrl. In MDD, fasting increased somatic-, but decreased cognitive-affective symptoms. Sub-group analyses based on BDI-2 sum-scores pre-fasting showed that cognitive-affective symptoms decreased in patients with moderate/severe but not in those with mild symptoms. This was associated with differential changes in BDNF levels. In conclusion, fasting improved cognitive-affective sub-scores in MDD patients with moderate/severe symptoms that had not responded to prior therapy. Interventions that modulate energy metabolism might directly improve cognitive-affective symptoms and/or augment therapeutic efficacy in moderate-to-severely depressed patients.

Leptin: an entry point for the treatment of peripheral tissue fibrosis and related diseases

Leptin is a small peptide mainly secreted by adipocyte, which acts on the central nervous system of the hypothalamus to regulate the body's energy balance by inhibiting food intake, it also can directly act on specific cells through leptin receptors (for example, ObRa, which exists in the blood-brain barrier or kidneys), thereby affect cell metabolism. Excessive deposition of extracellular matrix (ECM) causes damage to normal tissues or destruction of organ structure, which will eventually lead to tissue or organ fibrosis. The sustainable development of fibrosis can lead to structural damage and functional decline of organs, and even exhaustion, which seriously threatens human health and life. In recent years, studies have found that leptin directly alleviates the fibrosis process of various tissues and organs in mammals. Therefore, we speculate that leptin may become a significant treatment for fibrosis of various tissues and organs in the future. So, the main purpose of this review is to explore the specific mechanism of leptin in the process of fibrosis in multiple tissues and organs, and to provide a theoretical basis for the treatment of various tissues and organs fibrosis and related diseases caused by it, which is of great significance in the future.

Peripheral versus central insulin and leptin resistance: Role in metabolic disorders, cognition, and neuropsychiatric diseases

Insulin and leptin are classically regarded as peptide hormones that play key roles in metabolism. In actuality, they serve several functions in both the periphery and central nervous system (CNS). Likewise, insulin and leptin resistance can occur both peripherally and centrally. Metabolic disorders such as diabetes and obesity share several key features including insulin and leptin resistance. While the peripheral effects of these disorders are well-known (i.e. cardiovascular disease, hypertension, stroke, dyslipidemia, etc.), the CNS complications of leptin and insulin resistance have come into sharper focus. Both preclinical and clinical findings have indicated that insulin and leptin resistance are associated with cognitive deficits and neuropsychiatric diseases such as depression. Importantly, these studies also suggest that these deficits in neuroplasticity can be reversed by restoration of insulin and leptin sensitivity. In view of these observations, this review will describe, in detail, the peripheral and central functions of insulin and leptin and explain the role of insulin and leptin resistance in various metabolic disorders, cognition, and neuropsychiatric diseases.

Protective Effects of Melatonin against Obesity-Induced by Leptin Resistance

Consumption of an exceedingly high-fat diet with irregular eating and sleeping habits is typical in the current sedentary lifestyle, leading to chronic diseases like obesity and diabetes mellitus. Leptin is a primary appetite-regulating hormone that binds to its receptors in the hypothalamic cell membrane and regulates downstream appetite-regulating neurons NPY/AgRp and POMC in the hypothalamus. Based on the fat content of the adipose tissue, leptin is secreted, and excess accumulation of fat in adipose tissue stimulates the abnormal secretion of leptin. The secreted leptin circulating in the bloodstream uses its transporters to cross the blood-brain barrier (BBB) and reach the CSF. There is a saturation limit for leptin bound to its transporters to cross the BBB, and increased leptin secretion in adipose tissue has a defect in its transport across the BBB. Leptin resistance is due to excess leptin, a saturation of its transporters, and deficiency in either the receptor level or signalling in the hypothalamus. Leptin resistance leads to obesity due to excess food intake and less energy expenditure. Normal leptin secretion follows a rhythm, and alteration in the lifestyle leads to hormonal imbalances and increases ROS generation leading to oxidative stress. The sleep disturbance causes obesity with increased lipid accumulation in adipose tissue. Melatonin is the master regulator of the sleep-wake cycle secreted by the pineal gland during the night. It is a potent antioxidant with anti-inflammatory properties. Melatonin is secreted in a pattern called the circadian rhythm in humans as well. Research indicates that melatonin plays a vital role in hormonal regulation and energy metabolism, including leptin signalling and secretion. Studying the role of melatonin in leptin regulation will help us combat the pathologies of obesity caused by leptin resistance.

Ghrelin, leptin and high-molecular-weight adiponectin in relation to depressive symptoms in older adults: Results from the Longitudinal Aging Study Amsterdam

BACKGROUND

Ghrelin, leptin and high-molecular-weight (HMW) adiponectin have been linked to depression in middle-aged adults. Pathophysiological mechanisms of depression change as age progresses and it is unclear whether the same associations exist in older adults.

METHODS

We analyzed the associations between ghrelin, leptin and HMW adiponectin and depressive symptoms (Center for Epidemiologic Studies Depression (CES-D) score ≥ 16) in a community-dwelling cohort of 898 participants in a multivariable logistic regression analysis at baseline and after three years of follow-up, were applicable stratified by sex, age and waist-hip-ratio (WHR).

RESULTS

At baseline no significant associations were found. After three years of follow-up ghrelin was associated with higher odds for depressive symptoms (fully adjusted continuous analysis OR 2.27, 95% CI 1.42 - 3.61). There was effect modification for age and WHR, with significant associations in participants younger than 69.7 years (median) and with a WHR below 0.9554 (mean). In the sex-stratified analysis for leptin we found significant associations in men (fully adjusted continuous analysis OR 1.07, 95% CI 1.02 - 1.12). For HMW adiponectin there were no significant associations in the multivariable analysis.

LIMITATIONS

As our cohort consisted of relatively healthy participants with intact cognitive function, selection bias may have contributed to lack of significant baseline associations.

CONCLUSIONS

Our results show significant associations between ghrelin and - for men only - leptin and depressive symptoms after three years of follow up. This may provide a new therapeutic window for treatment of depressive symptoms in older adults, as both ghrelin and leptin are positively influenced by weight loss.

Sex Differences in the Association between Different Obesity Parameters and Cognitive Function in Older Adults: A Cross-Sectional Study in Rural China

BACKGROUND

Early identification of risk factors for cognition decline may contribute to the interventions for Alzheimer's disease. Obesity is a common modifiable risk factor for chronic diseases. The association between obesity and cognition in older adults is limited, and sex differences in this area have not been well recognized.

OBJECTIVE

The aim of the study was to observe the sex differences in the relationship between obesity and cognition in a rural community-dwelling older population of Guizhou, China.

METHODS

Data were gathered from the baseline survey of a cohort study of older people in rural areas of Guizhou, China. Demographic and behavioral data (sex, age, education, household income, smoking history, drinking history, history of head injury, diet, and level of physical exercise time) were collected. The Mini-Mental State Examination (MMSE) was used to assess cognitive function. Body mass index (BMI), waist circumference (WC), hip circumference (HC), and waist-to-hip ratio (WHR) were used as different measures of obesity. Comparisons between the groups were made by the Wilcoxon rank-sum test or Kruskal-Wallis H test. Restricted cubic spline regression was used to examine a dose-response relationship between obesity indicators and cognitive function. Linear relationships were performed by the multivariable linear regression model.

RESULTS

A total of 1,654 participants including 964 women and 690 men were enrolled in this study. After adjustment, BMI showed a nonlinear relationship with MMSE scores in women. There was a significant trend toward increasing MMSE scores at the low end of BMI (13.52-20.10 kg/m2, p = 0.014). The multivariable linear regression model showed that MMSE increased by 0.631 (p < 0.001) for every one standard deviation increase in HC in women. No association was found between obesity parameters and cognitive function in men.

CONCLUSION

Our results suggest that there are significant sex differences in some obesity parameters and cognition in an older Chinese population. BMI and HC are positively associated with cognitive function in women. No association was found between obesity measures and cognitive function in men.

DHA Supplementation of Obese Rats throughout Pregnancy and Lactation Modifies Milk Composition and Anxiety Behavior of Offspring

We investigated if supplementing obese mothers (MO) with docosahexaenoic acid (DHA) improves milk long-chain polyunsaturated fatty acid (LCPUFA) composition and offspring anxiety behavior. From weaning throughout pregnancy and lactation, female Wistar rats ate chow (C) or a high-fat diet (MO). One month before mating and through lactation, half the mothers received 400 mg DHA kg⁻¹ d⁻¹ orally (C+DHA or MO+DHA). Offspring ate C after weaning. Maternal weight, total body fat, milk hormones, and milk nutrient composition were determined. Pups’ milk nutrient intake was evaluated, and behavioral anxiety tests were conducted. MO exhibited increased weight and total fat, and higher milk corticosterone, leptin, linoleic, and arachidonic acid (AA) concentrations, and less DHA content. MO male and female offspring had higher ω-6/ ω-3 milk consumption ratios. In the elevated plus maze, female but not male MO offspring exhibited more anxiety. MO+DHA mothers exhibited lower weight, total fat, milk leptin, and AA concentrations, and enhanced milk DHA. MO+DHA offspring had a lower ω-6/ω-3 milk intake ratio and reduced anxiety vs. MO. DHA content was greater in C+DHA milk vs. C. Supplementing MO mothers with DHA improves milk composition, especially LCPUFA content and ω-6/ω-3 ratio reducing offspring anxiety in a sex-dependent manner.

Saturated and unsaturated fat diets impair hippocampal glutamatergic transmission in adolescent mice

Consumption of high-fat diets (HFD) has been associated with neuronal plasticity deficits and cognitive disorders linked to the alteration of glutamatergic disorders in the hippocampus. As young individuals are especially vulnerable to the effects of nutrients and xenobiotics on cognition, we studied the effect of chronic consumption of saturated (SOLF) and unsaturated oil-enriched foods (UOLF) on: i) spatial memory; ii) hippocampal synaptic transmission and plasticity; and iii) gene expression of glutamatergic receptors and hormone receptors in the hippocampus of adolescent and adult mice. Our results show that both SOLF and UOLF impair spatial short-term memory. Accordingly, hippocampal synaptic plasticity mechanisms underlying memory, and gene expression of NMDA receptor subunits are modulated by both diets. On the other hand, PPARγ gene expression is specifically down-regulated in adolescent SOLF individuals and up-regulated in adult UOLF mice.

Potential new therapeutic target for Alzheimer's disease: Glucagon-like peptide-1

Increasing evidence shows a close relationship between Alzheimer's disease (AD) and type 2 diabetes mellitus (T2DM). Recently, glucagon-like peptide-1 (GLP-1), a gut incretin hormone, has become a well-established treatment for T2DM and is likely to be involved in treating cognitive impairment. In this mini review, the similarities between AD and T2DM are summarised with the main focus on GLP-1-based therapeutics in AD.

Pre-treatment allostatic load and metabolic dysregulation predict SSRI response in major depressive disorder: a preliminary report

BACKGROUND

Major depressive disorder (MDD) is associated with increased allostatic load (AL; a measure of physiological costs of repeated/chronic stress-responding) and metabolic dysregulation (MetD; a measure of metabolic health and precursor to many medical illnesses). Though AL and MetD are associated with poor somatic health outcomes, little is known regarding their relationship with antidepressant-treatment outcomes.

METHODS

We determined pre-treatment AL and MetD in 67 healthy controls and 34 unmedicated, medically healthy MDD subjects. Following this, MDD subjects completed 8-weeks of open-label selective serotonin reuptake inhibitor (SSRI) antidepressant treatment and were categorized as 'Responders' (⩾50% improvement in depression severity ratings) or 'Non-responders' (<50% improvement). Logistic and linear regressions were performed to determine if pre-treatment AL or MetD scores predicted SSRI-response. Secondary analyses examined cross-sectional differences between MDD and control groups.

RESULTS

Pre-treatment AL and MetD scores significantly predicted continuous antidepressant response (i.e. absolute decreases in depression severity ratings) (p = 0.012 and 0.014, respectively), as well as post-treatment status as a Responder or Non-responder (p = 0.022 and 0.040, respectively), such that higher pre-treatment AL and MetD were associated with poorer SSRI-treatment outcomes. Pre-treatment AL and MetD of Responders were similar to Controls, while those of Non-responders were significantly higher than both Responders (p = 0.025 and 0.033, respectively) and Controls (p = 0.039 and 0.001, respectively).

CONCLUSIONS

These preliminary findings suggest that indices of metabolic and hypothalamic-pituitary-adrenal-axis dysregulation are associated with poorer SSRI-treatment response. To our knowledge, this is the first study to demonstrate that these markers of medical disease risk also predict poorer antidepressant outcomes.

Ginkgo biloba Extract (GbE) Restores Serotonin and Leptin Receptor Levels and Plays an Antioxidative Role in the Hippocampus of Ovariectomized Rats

Since Ginkgo biloba extract (GbE) was reported to improve the hypothalamic serotonergic system of ovariectomized (OVX) rats, the present study aimed to verify the GbE effects on hippocampal oxidative stress, inflammation, and levels of the serotonin transporter (5-HTT), and both the serotonin (5-HT1A, 5-HT1B) and leptin receptors of OVX rats. Two-month-old female Wistar rats had their ovaries surgically removed (OVX) or not (SHAM). After 60 days, OVX rats were gavaged daily with GbE 500 mg kg-1 (OVX+GbE), while SHAM and OVX groups received saline 0.9% (vehicle) for 14 days. Rats were then euthanized, and hippocampi were collected. Both 5-HT1A and 5-HT1B levels were significantly reduced in OVX rats compared to SHAM rats, while 5-HT1A was higher in OVX+GbE rats in comparison to OVX rats. Similarly, LepR levels were increased in OVX+GbE rats compared to OVX rats, reaching similar levels to SHAM rats. Superoxide dismutase activity increased in OVX rats in relation to SHAM rats, which was restored to SHAM levels by GbE treatment. Additionally, GbE significantly increased the glutathione peroxidase activity in comparison to the SHAM group. No differences were observed either in catalase activity or in the levels of 5-HTT, PKCα, TLR-4, NF-κBp50, ERK, and CREB. In summary, our results show a potential effect of GbE on hippocampal pathways involved in feeding behavior, and thus, they suggest that GbE activity might improve menopausal-related hippocampal disorders, offering an alternative therapeutic tool particularly for women to whom hormone replacement therapy may be contraindicated.

Examining the Role of Microbiota in Emotional Behavior: Antibiotic Treatment Exacerbates Anxiety in High Anxiety-Prone Male Rats

Intestinal microbiota are essential for healthy gastrointestinal function and also broadly influence brain function and behavior, in part, through changes in immune function. Gastrointestinal disorders are highly comorbid with psychiatric disorders, although biological mechanisms linking these disorders are poorly understood. The present study utilized rats bred for distinct emotional behavior phenotypes to examine relationships between emotionality, the microbiome, and immune markers. Prior work showed that Low Novelty Responder (LR) rats exhibit high levels of anxiety- and depression-related behaviors as well as myriad neurobiological differences compared to High Novelty Responders (HRs). Here, we hypothesized that the divergent HR/LR phenotypes are accompanied by changes in fecal microbiome composition. We used next-generation sequencing to assess the HR/LR microbiomes and then treated adult HR/LR males with an antibiotic cocktail to test whether it altered behavior. Given known connections between the microbiome and immune system, we also analyzed circulating cytokines and metabolic factors to determine relationships between peripheral immune markers, gut microbiome components, and behavioral measures. There were no baseline HR/LR microbiome differences, and antibiotic treatment disrupted the microbiome in both HR and LR rats. Antibiotic treatment exacerbated aspects of HR/LR behavior, increasing LRs' already high levels of anxiety-like behavior while reducing passive stress coping in both strains. Our results highlight the importance of an individual's phenotype to their response to antibiotics, contributing to the understanding of the complex interplay between gut microbes, immune function, and an individual's emotional phenotype.

Targeting the microbiome-gut-brain axis for improving cognition in schizophrenia and major mood disorders: A narrative review

Cognitive impairment has been consistently found to be a core feature of serious mental illnesses such as schizophrenia and major mood disorders (major depression and bipolar disorder). In recent years, a great effort has been made in elucidating the biological causes of cognitive deficits and the search for new biomarkers of cognition. Microbiome and gut-brain axis (MGB) hormones have been postulated to be potential biomarkers of cognition in serious mental illnesses. The main aim of this review was to synthesize current evidence on the association of microbiome and gut-brain hormones on cognitive processes in schizophrenia and major mood disorders and the association of MGB hormones with stress and the immune system. Our review underscores the role of the MGB axis on cognitive aspects of serious mental illnesses with the potential use of agents targeting the gut microbiota as cognitive enhancers. However, the current evidence for clinical trials focused on the MGB axis as cognitive enhancers in these clinical populations is scarce. Future clinical trials using probiotics, prebiotics, antibiotics, or faecal microbiota transplantation need to consider potential mechanistic pathways such as the HPA axis, the immune system, or gut-brain axis hormones involved in appetite control and energy homeostasis.

The Important Role of Leptin in Modulating the Risk of Dermatological Diseases

It is an indisputable fact that obesity is associated with a series of health problems. One important hallmark of obesity is excessive accumulation of lipids in the adipocyte, especially triglyceride (TG). Currently, the adipocyte has been considered not only as a huge repository of excess energy in the form of fat but also as an important source of multiple hormones and cytokines called adipokines. In obesity, the adipocyte is dysfunctional with excessive production and secretion of pro-inflammatory adipokines, such as tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), and leptin. On the other hand, accumulating evidence has shown that leptin plays a vital role in stimulating angiogenesis, controlling lipid metabolism, and modulating the production of pro-inflammatory cytokines. Furthermore, the various activities of leptin are related to the wide distribution of leptin receptors. Notably, it has been reported that enhanced leptin levels and dysfunction of the leptin signaling pathway can influence diverse skin diseases. Recently, several studies revealed the roles of leptin in wound healing, the hair cycle, and the pathogenic development of skin diseases, such as psoriasis, lupus erythematosus, and dermatological cancers. However, the exact mechanisms of leptin in modulating the dermatological diseases are still under investigation. Therefore, in the present review, we summarized the regulatory roles of leptin in the pathological progression of diverse diseases of skin and skin appendages. Furthermore, we also provided evidence to elucidate the complicated relationship between leptin and different dermatological diseases, such as systemic lupus erythematosus (SLE), psoriasis, hidradenitis suppurativa, and some skin tumors.

The effect of body mass index on hippocampal morphology and memory performance in late childhood and adolescence

Childhood obesity is associated with negative physiological and cognitive health outcomes. The hippocampus is a diverse subcortical structure involved in learned feeding behaviors and energy regulation, and research has shown that the hippocampus is vulnerable to the effects of excess adiposity. Previous studies have demonstrated reduced hippocampal volume in overweight and obese children; however, it is unclear if certain subregions are selectively affected. The purpose of this study was to determine how excess body weight influences regional hippocampal surface morphology and memory performance in a large cross-sectional cohort of 588 children and adolescents between 8.33 and 19.92 years of age using body mass index expressed as a percentage of the 95th percentile cutoff (%BMIp95). We demonstrate %BMIp95 is associated with reduced radial thickness in the superior anterior region of the left hippocampus, and this relationship is predominantly driven by children younger than 14 years. We also found %BMIp95 was associated with worse performance on a spatial episodic memory task and this relationship was partially mediated by the radial thickness of the significant shape cluster. These results demonstrate the differential influence of excess body weight on regional hippocampal structure and hippocampal-dependent behavior in children and adolescents.

Leptin in skin disease modulation

In obesity, adipocytes are dysfunctional with excessive production and secretion of pro-inflammatory hormones and cytokines, ie, adipokines, such as tumor necrosis factor α (TNF-α), interleukin 6 (IL-6) and leptin. Accumulating evidence has shown that leptin possesses pleiotropic functions including stimulation of angiogenesis and production of pro-inflammatory cytokines. Furthermore, various leptin associated activities involve a wide distribution of leptin receptors. For example, increased serum leptin was associated with tissue receptor resistance in metabolic syndrome. Although increased serum leptin, receptor and signaling impairment are involved in wound healing, hair cycle and the pathogenesis of many skin diseases such as psoriasis and lupus erythematosus as well as skin cancer, its exact role remains unclear. In the present article, we discuss the biochemistry of leptin action and its potential role in the pathophysiology of diverse skin diseases.

Ginkgo biloba extract (GbE) attenuates obesity and anxious/depressive-like behaviours induced by ovariectomy

While several pieces of evidence link obesity and mood disorders in menopause, the mechanisms involved are not yet fully understood. We have previously demonstrated that Ginkgo biloba extract (GbE) both attenuated diet-induced obesity of male rats and restored serotonin-induced hypophagia in ovariectomized female rats. The present study aimed at exploring whether GbE treatment ameliorates ovariectomy-related obesity and anxious/depressive-like behaviours. Wistar female rats were either ovariectomized (OVX) or sham-operated (Sham). After 2 months, either 500 mg/kg of GbE or vehicle were administered daily by gavage for 14 days. Anxious/depressive-like behaviours were assessed by the Elevated Plus Maze and the Forced Swim Tests, respectively. Ovariectomy caused high visceral adiposity, hyperleptinemia, and hypercholesterolemia, and increased the anxiety index (p = 0.048 vs. Sham + GbE) while it decreased the latency to immobility (p = 0.004 vs. Sham). GbE treatment in OVX rats improved body composition, adiponectin levels and blood lipid profile. It also reduced the anxiety index (p = 0.004) and increased the latency to immobility (p = 0.003) of OVX rats. Linear regression analysis demonstrated that leptin (p = 0.047) and total cholesterol levels (p = 0.022) were associated with anxious-like behaviours while body adiposity (p = 0.00005) was strongly associated with depressive-like behaviours. The results showed that GbE therapy was effective in attenuating the deleterious effects of ovariectomy on body composition, lipid profile, and anxious/depressive-like behaviours. Further studies are warranted to better understand the therapeutic potential of GbE in menopause.

Do Leptin Play a Role in Metabolism-Related Psychopathological Symptoms?

Objectives: Leptin is a crucial regulator of energy balance and is associated with obesity. In recent years, it has also been recognized as involved in the psychopathological mechanism. Our study aimed to elucidate the relationships between serum leptin levels, body mass index (BMI), and psychopathology symptoms in patients with schizophrenia. Methods: A cross-sectional assessment of 324 inpatients with schizophrenia was conducted. Schizophrenia symptoms were measured using the Positive and Negative Syndrome Scale (PANSS) and the Brief Psychiatric Rating Scale (BPRS). Serum leptin levels were assessed by the Enzyme-Linked Immunosorbent Assay (ELISA). Results: Significant differences in sex, BMI, and negative symptom subscale (PANSS-N) scores were found between the groups with high and low leptin levels in the study. Leptin levels were positively correlated with BMI (B = 2.322, t = 9.557, P < 0.001) and negatively correlated with PANSS-N scores (B = -0.303, t = -2.784, P = 0.006). Conclusions: Our results suggest that the increase in leptin levels is responsible for antipsychotic-induced weight gain and improved psychopathological symptoms.

The Association Between High-Molecular-Weight Adiponectin, Ghrelin and Leptin and Age-Related Cognitive Decline: Results From Longitudinal Aging Study Amsterdam

BACKGROUND

Age-related cognitive decline has large-scale functional and economic consequences and understanding its' pathophysiological mechanisms is therefore essential. Previous research has suggested associations between hormones adiponectin, ghrelin and leptin and neurodegenerative disease. However, their association with age-related cognitive decline has not been fully described. We examine the association between serum high-molecular-weight (HMW) adiponectin, ghrelin and leptin and age-related cognitive decline in older adults.

METHODS

The associations between HMW adiponectin, ghrelin and leptin and the Mini-Mental-State-Examination, Coding task (Coding), 15 Words Test (15WT) and composite Z-score (general cognitive function) were analyzed by means of a sex-stratified multivariable linear regression analysis in a population-based cohort of 898 older adults at baseline and after 3 years of follow-up.

RESULTS

In women, we found a positive association between HMW adiponectin and general cognitive function at baseline (fully adjusted model composite Z-score standardized regression co-efficient beta [β] = .089, p = .025). After 3 years of follow-up, HMW adiponectin was associated with more decline in general cognitive function and information processing speed (fully adjusted model composite Z-score β = -.123, p = .018; Coding β = -.116, p = .027). Ghrelin and leptin were significantly associated with memory in a baseline subgroup analysis of older women. For men, we found no significant associations at baseline or follow-up.

CONCLUSION

Our results show variable associations between hormones HMW adiponectin, ghrelin and leptin and age-related cognitive decline in women but not in men. As there was no clear trend, all our results should be interpreted with caution.

Dietary vitamin A supplementation prevents early obesogenic diet-induced microbiota, neuronal and cognitive alterations

BACKGROUND

Early consumption of obesogenic diets, rich in saturated fat and added sugar, is associated with a plethora of biological dysfunctions, at both peripheral and brain levels. Obesity is also linked to decreased vitamin A bioavailability, an essential molecule for brain plasticity and memory function.

METHODS

Here we investigated in mice whether dietary vitamin A supplementation (VAS) could prevent some of the metabolic, microbiota, neuronal and cognitive alterations induced by obesogenic, high-fat and high-sugar diet (HFSD) exposure from weaning to adulthood, i.e. covering periadolescent period.

RESULTS

As expected, VAS was effective in enhancing peripheral vitamin A levels as well as hippocampal retinoic acid levels, the active metabolite of vitamin A, regardless of the diet. VAS attenuated HFSD-induced excessive weight gain, without affecting metabolic changes, and prevented alterations of gut microbiota α-diversity. In HFSD-fed mice, VAS prevented recognition memory deficits but had no effect on aversive memory enhancement. Interestingly, VAS alleviated both HFSD-induced higher neuronal activation and lower glucocorticoid receptor phosphorylation in the hippocampus after training.

CONCLUSION

Dietary VAS was protective against the deleterious effects of early obesogenic diet consumption on hippocampal function, possibly through modulation of the gut-brain axis.

Depression and Cardiovascular Disease: The Viewpoint of Platelets

Depression is a major cause of morbidity and low quality of life among patients with cardiovascular disease (CVD), and it is now considered as an independent risk factor for major adverse cardiovascular events. Increasing evidence indicates not only that depression worsens the prognosis of cardiac events, but also that a cross-vulnerability between the two conditions occurs. Among the several mechanisms proposed to explain this interplay, platelet activation is the more attractive, seeing platelets as potential mirror of the brain function. In this review, we dissected the mechanisms linking depression and CVD highlighting the critical role of platelet behavior during depression as trigger of cardiovascular complication. In particular, we will discuss the relationship between depression and molecules involved in the CVD (e.g., catecholamines, adipokines, lipids, reactive oxygen species, and chemokines), emphasizing their impact on platelet activation and related mechanisms.

Acute Phase Serum Leptin, Adiponectin, Interleukin-6, and Visfatin Are Altered in Chinese Children With Febrile Seizures: A Cross-Sectional Study

Adipokines, including leptin, visfatin, adiponectin, and interleukin-6 (IL)-6, play multiple roles in the pathophysiology of epilepsy and febrile seizures (FS). We aimed to investigate the associations among plasma adipokines, mainly leptin, visfatin, adiponectin, or IL-6, and the prognosis of FS. This prospective cross-sectional study was conducted from January 2017 to December 2018 at the Wuxi Second People' Hospital China. The levels of serum leptin, visfatin, adiponectin, and IL-6 in 55 children with FS (FS group) were compared with 42 febrile children without seizure (FC group) and 48 healthy children (HC group) in an acute phase. The correlation with clinical indicators was determined by logistic regression analysis. Serum adiponectin and IL-6 levels were significantly higher in the FS group than in the FC and HC groups (p < 0.05), but there was no statistical difference between the FC and HC groups. In addition, logistic regression analysis showed that high concentrations of adiponectin and IL-6 were significantly associated with the occurrence of FS. For leptin and visfatin, they were significantly lower in the FS and FC groups than in the normal control group, but there was no statistical difference between the FS and FC groups. Our results suggest that higher plasma levels of IL-6 and adiponectin may serve as an additional biomarker in the early treatment or follow-up of the FS children.

Caloric restriction, resting metabolic rate and cognitive performance in Non-obese adults: A post-hoc analysis from CALERIE study

Physical activity (PA) has been proposed as a determinant of cognitive function and is one component of energy balance (EB). EB is the difference between energy intake (EI) and the total daily energy expenditure (TDEE). TDEE is a combination of resting metabolic rate (RMR), thermic effect of food and PA. The potential role of each of these components on cognitive function has not yet been systemically investigated. We aim to evaluate the association between each component of EB on cognition, using baseline and longitudinal data from a clinical trial of caloric restriction (CR). This is a parallel-group, randomized clinical trial comparing two years of 25% CR with two years of ad libitum diet (AL), with 220 healthy volunteers of both sex, aged between 21 and 50 years and initial BMI ≥ 22 kg/m2 and <28 kg/m2. Body weight, fat mass (FM), fat-free mass (FFM), and bone mineral content were evaluated, as well as RMR, TDEE, cognitive performance and baseline energy intake. A 30 min/day of a moderate level on a minimum of 5 days/week was advised as PA measure. Longitudinal analysis demonstrated that the influence of CR in the improvement of cognitive performance was moderated by changes in RMR, suggesting that in individuals submitted to CR, the cognitive performance and the RMR improved proportionally, independently of changes in EI and body mass. EB and homeostasis are crucial to modulate the RMR. Moreover, RMR presents an important influence on cognitive function in individuals submitted to CR in a long term.

Metabolic and functional interplay between gut microbiota and fat-soluble vitamins

Gut microbiota is a complex ecosystem seen as an extension of human genome. It represents a major metabolic interface of interaction with food components and xenobiotics in the gastrointestinal (GI) environment. In this context, the advent of modern bacterial genome sequencing technology has enabled the identification of dietary nutrients as key determinants of gut microbial ecosystem able to modulate the host-microbiome symbiotic relationship and its effects on human health. This article provides a literature review on functional and molecular interactions between a specific group of lipids and essential nutrients, e.g., fat-soluble vitamins (FSVs), and the gut microbiota. A two-way relationship appears to emerge from the available literature with important effects on human metabolism, nutrition, GI physiology and immune function. First, FSV directly or indirectly modify the microbial composition involving for example immune system-mediated and/or metabolic mechanisms of bacterial growth or inhibition. Second, the gut microbiota influences at different levels the synthesis, metabolism and transport of FSV including their bioactive metabolites that are either introduced with the diet or released in the gut via entero-hepatic circulation. A better understanding of these interactions, and of their impact on intestinal and metabolic homeostasis, will be pivotal to design new and more efficient strategies of disease prevention and therapy, and personalized nutrition.

Relationship of maternal high-fat diet during pregnancy and lactation to offspring health

A balanced maternal diet is essential for proper fetal development, and the consumption of a nutritionally inadequate diet during intrauterine development and early childhood is associated with a significantly increased risk of metabolic and brain disorders in offspring. The current literature indicates that maternal exposure to a high-fat diet exerts an irreversible influence on the general health of the offspring. This review of preclinical research examines the relationship between a maternal high-fat diet during pregnancy or lactation and metabolic changes, molecular alterations in the brain, and behavioral disorders in offspring. Animal models indicate that offspring exposed to a maternal high-fat diet during pregnancy and lactation manifest increased depressive-like and aggressive behaviors, reduced cognitive development, and symptoms of metabolic syndrome. Recently, epigenetic and molecular studies have shown that maternal nutrition during pregnancy and the suckling period modifies the development of neurotransmitter circuits and many other factors important to central nervous system development. This finding confirms the importance of a balanced maternal diet for the health of offspring.

Anhedonia induced by high-fat diet in mice depends on gut microbiota and leptin

Objectives: Imbalanced nutrition and obesity are risk factors for depression, a relationship that in rodents can be modeled by depression-like behavior in response to high-fat diet (HFD). In this work, we examined the role of the intestinal microbiota and the adipocytokine leptin as potential mediators of the effects of HFD to induce anhedonia-like behavior and reduce self-care in mice.Methods: Male mice were fed a control diet or HFD (60 kJ% from fat) for a period of 4 weeks, after which behavioral tests and molecular analyses (gut microbiome composition, intestinal metabolome, fecal fatty acids, plasma hormone levels) were performed. The role of the intestinal microbiota was addressed by selective depletion of gut bacteria with a combination of non-absorbable antibiotics, while the implication of leptin was examined by the use of leptin-deficient ob/ob mice.Results: Antibiotic treatment reduced the HFD-induced weight gain and adiposity and prevented HFD-induced anhedonia-like behavior and self-care reduction. These effects were associated with a decrease in fecal fatty acids and intestinal microbiota-related metabolites including short-chain fatty acids, glucose and amino acids. Gut microbiota depletion suppressed the HFD-induced rise of plasma leptin, and the circulating leptin levels correlated with the anhedonia-like behavior and reduced self-care caused by HFD. The anhedonic effect of HFD was absent in leptin-deficient ob/ob mice although these animals gained more weight and adiposity in response to HFD than wild-type mice.Discussion: The results indicate that anhedonia-like behavior induced by HFD in mice depends on the intestinal microbiome and involves leptin as a signaling hormone.

Neurometabolic effects of sweetened solution intake during adolescence related to depressive-like phenotype in rats

OBJECTIVE

Exposure to artificial sweeteners, such as aspartame, during childhood and adolescence has been increasing in recent years. However, the safe use of aspartame has been questioned owing to its potentially harmful effects on the developing brain. The aim of this study was to test whether the chronic consumption of aspartame during adolescence leads to a depressive-like phenotype and to investigate the possible mechanisms underlying these behavioral changes.

METHODS

Adolescent male and female rats were given unlimited access to either water, solutions of aspartame, or sucrose in their home cages from postnatal day 21 to 55.

RESULTS

Forced swim test revealed that both chronic aspartame and sucrose intake induced depressive-like behaviord, which was more pronounced in males. Additionally, repeated aspartame intake was associated with increased cerebrospinal fluid (CSF) aspartate levels, decreased hippocampal neurogenesis, and reduced activation of the hippocampal leptin signaling pathways in males. In females, we observed a main effect of aspartame: reducing PI3K/AKT one of the brain-derived neurotrophic factor pathways; aspartame also increased CSF aspartate levels and decreased the immunocontent of the GluN2A subunit of the N-methyl-d-aspartic acid receptor.

CONCLUSION

The findings revealed that repeated aspartame intake during adolescence is associated with a depressive-like phenotype and changes in brain plasticity. Interestingly, males appear to be more vulnerable to the adverse neurometabolic effects of aspartame than females, demonstrating a sexually dimorphic response. The present results highlighted the importance of understanding the effects caused by the constant use of this artificial sweetener in sensitive periods of development and contribute to regulation of its safe use.

Maternal stressors and the developmental origins of neuropsychiatric risk

The maternal environment during pregnancy is critical for fetal development and perinatal perturbations can prime offspring disease risk. Here, we briefly review evidence linking two well-characterized maternal stressors - psychosocial stress and infection - to increased neuropsychiatric risk in offspring. In the current climate of increasing obesity and globalization of the Western-style diet, maternal overnutrition emerges as a pressing public health concern. We focus our attention on recent epidemiological and animal model evidence showing that, like psychosocial stress and infection, maternal overnutrition can also increase offspring neuropsychiatric risk. Using lessons learned from the psychosocial stress and infection literature, we discuss how altered maternal and placental physiology in the setting of overnutrition may contribute to abnormal fetal development and resulting neuropsychiatric outcomes. A better understanding of converging pathophysiological pathways shared between stressors may enable development of interventions against neuropsychiatric illnesses that may be beneficial across stressors.

Interaction Between Circadian Rhythms, Energy Metabolism, and Cognitive Function

The interaction between meal timing and light regulates circadian rhythms in mammals and not only determines the sleep-wake pattern but also the activity of the endocrine system. Related with that, the necessity to fulfill energy needs is a driving force that requires the participation of cognitive skills whose performance has been shown to undergo circadian variations. These facts have led to the concept that cognition and feeding behaviour can be analysed from a chronobiological perspective. In this context, research carried out during the last two decades has evidenced the link between feeding behaviour/nutritional habits and cognitive processes, and has highlighted the impact of circadian disorders on cognitive decline. All that has allowed hypothesizing a tight relationship between nutritional factors, chronobiology, and cognition. In this connection, experimental diets containing elevated amounts of fat and sugar (high-fat diets; HFDs) have been shown to alter in rodents the circadian distribution of meals, and to have a negative impact on cognition and motivational aspects of behaviour that disappear when animals are forced to adhere to a standard temporal eating pattern. In this review, we will present relevant studies focussing on the effect of HFDs on cognitive aspects of behaviour, paying particular attention to the influence that chronobiological alterations caused by these diets may have on hippocampaldependent cognition.

Understanding the Physiological Links Between Physical Frailty and Cognitive Decline

Declines in both physical and cognitive function are associated with increasing age. Understanding the physiological link between physical frailty and cognitive decline may allow us to develop interventions that prevent and treat both conditions. Although there is significant epidemiological evidence linking physical frailty to cognitive decline, a complete understanding of the underpinning biological basis of the two disorders remains fragmented. This narrative review discusses insights into the potential roles of chronic inflammation, impaired hypothalamic-pituitary axis stress response, imbalanced energy metabolism, mitochondrial dysfunction, oxidative stress, and neuroendocrine dysfunction linking physical frailty with cognitive decline. We highlight the importance of easier identification of strategic approaches delaying the progression and onset of physical frailty and cognitive decline as well as preventing disability in the older population.

Prebiotics may reduce serum concentrations of C-reactive protein and ghrelin in overweight and obese adults: a systematic review and meta-analysis

CONTEXT

Biochemical markers correlate positively with the development and severity of obesity, depression, and anxiety, and can be modulated by changes in intestinal microbiota composition.

OBJECTIVE

A systematic review and meta-analysis was conducted to determine the effects of prebiotics or synbiotics on blood biomarkers of obesity, depression, and anxiety (including: ACTH [adrenocorticotropic hormone], cortisol, leptin, ghrelin, TSH [thyroid-stimulating hormone], PTH [parathyroid hormone], vitamin D, BDNF [brain-derived neurotrophic factor], and PCR [polymerase chain reaction]) in individuals with overweight or obesity.

DATA SOURCES

MEDLINE, Web of Science, Scopus, and CENTRAL databases were searched, along with the reference lists of included articles. Authors were contacted for unpublished data.

STUDY SELECTION

RCT in individuals with overweight or obesity, supplemented with prebiotics or synbiotics, assessing any of the outcomes of interest.

DATA EXTRACTION

Data were extracted independently by three researchers.

RESULTS

Thirteen studies were identified up to March 7, 2018. Regarding outcomes, 1 study assessed leptin, 4 studies assessed ghrelin, and 10 studies assessed CRP (C-reactive protein). Meta-analysis showed reduction in serum concentrations of ghrelin (-37.17 pg/mL; 95%CI = -69.62, -4.73; P = 0.025) and CRP (SMD [standardized mean difference] = -0.31; 95%CI = -0.58, -0.04; P = 0.027) after supplementation of inulin-type fructans.

CONCLUSIONS

Prebiotics may help regulate blood concentrations of ghrelin and CRP in overweight or obese individuals.

Leptin Controls Glutamatergic Synaptogenesis and NMDA-Receptor Trafficking via Fyn Kinase Regulation of NR2B

Activation of the leptin receptor, LepRb, by the adipocytokine/neurotrophic factor leptin in the central nervous system has procognitive and antidepressive effects. Leptin has been shown to increase glutamatergic synaptogenesis in multiple brain regions. In contrast, mice that have a mutation in the LepRb gene show abnormal synapse development in the hippocampus as well as deficits in cognition and increased depressive-like symptoms. Leptin increases glutamatergic synaptogenesis, in part, through enhancement of N-methyl-D-aspartic acid (NMDA) receptor function; yet the underlying signaling pathway is not known. In this study, we examine how leptin regulates surface expression of NR2B-containing NMDA receptors in hippocampal neurons. Leptin stimulation increases NR2BY1472 phosphorylation, which is inhibited by the Src family kinase inhibitor, PP1. Moreover, we show that Fyn, a member of the Src family kinases, is required for leptin-stimulated NR2BY1472 phosphorylation. Furthermore, inhibiting Y1472 phosphorylation with either a dominant negative Fyn mutant or an NR2B mutant that lacks the phosphorylation site (NR2BY1472F) blocks leptin-stimulated synaptogenesis. Additionally, we show that LepRb forms a complex with NR2B and Fyn. Taken together, these findings expand our knowledge of the LepRb interactome and the mechanisms by which leptin stimulates glutamatergic synaptogenesis in the developing hippocampus. Comprehending these mechanisms is key for understanding dendritic spine development and synaptogenesis, alterations of which are associated with many neurological disorders.