Glucocorticoid Receptor Signaling in Diabetes

Intermittent Fasting-Improved Glucose Homeostasis Is Not Entirely Dependent on Caloric Restriction in db/db Male Mice

Intermittent fasting (IF), which involves prolonged fasting intervals accompanied by caloric restriction (CR), is an effective dietary treatment for obesity and diabetes. Although IF offers many benefits, it is difficult to determine whether these benefits are the consequences of CR. Every-other-day feeding (EODF) is a commonly used IF research model. This study was designed to identify factors, in addition to CR, responsible for the effects of EODF and the possible underlying mechanisms. Diabetic db/db mice were divided into three groups: ad libitum (AL), meal feeding (MF), and EODF. The MF model was used to attain a level of CR comparable to that of EODF, with food distribution evenly divided between 10:00 a.m. and 6:00 p.m., thereby minimizing the fasting interval. EODF yielded greater improvements in glucose homeostasis than MF in db/db mice by reducing fasting glucose levels and enhancing glucose tolerance. However, these effects on glucose metabolism were less pronounced in lean mice. Furthermore, ubiquitination of the liver-specific glucocorticoid (GC) receptor (GR) facilitated its degradation and downregulation of Kruppel-like factor 9 (KLF9), which ultimately suppressed liver gluconeogenesis in diabetic EODF mice. Although GR and KLF9 might mediate the metabolic benefits of EODF, the potential benefits of EODF might be limited by elevated serum GC levels in diabetic EODF mice. Overall, this study suggests that the metabolic benefits of EODF in improving glucose homeostasis are independent of CR, possibly because of the downstream effects of liver-specific GR degradation.

ARTICLE HIGHLIGHTS

Pregestational Prediabetes Induces Maternal Hypothalamic-Pituitary-Adrenal (HPA) Axis Dysregulation and Results in Adverse Foetal Outcomes

Maternal type 2 diabetes mellitus (T2DM) has been shown to result in foetal programming of the hypothalamic-pituitary-adrenal (HPA) axis, leading to adverse foetal outcomes. T2DM is preceded by prediabetes and shares similar pathophysiological complications. However, no studies have investigated the effects of maternal prediabetes on foetal HPA axis function and postnatal offspring development. Hence, this study investigated the effects of pregestational prediabetes on maternal HPA axis function and postnatal offspring development. Pre-diabetic (PD) and non-pre-diabetic (NPD) female Sprague Dawley rats were mated with non-prediabetic males. After gestation, male pups born from the PD and NPD groups were collected. Markers of HPA axis function, adrenocorticotropin hormone (ACTH) and corticosterone, were measured in all dams and pups. Glucose tolerance, insulin and gene expressions of mineralocorticoid (MR) and glucocorticoid (GR) receptors were further measured in all pups at birth and their developmental milestones. The results demonstrated increased basal concentrations of ACTH and corticosterone in the dams from the PD group by comparison to NPD. Furthermore, the results show an increase basal ACTH and corticosterone concentrations, disturbed MR and GR gene expression, glucose intolerance and insulin resistance assessed via the Homeostasis Model Assessment (HOMA) indices in the pups born from the PD group compared to NPD group at all developmental milestones. These observations reveal that pregestational prediabetes is associated with maternal dysregulation of the HPA axis, impacting offspring HPA axis development along with impaired glucose handling.

The Role of microRNA in the Regulation of Cortisol Metabolism in the Adipose Tissue in the Course of Obesity

The similarity of the clinical picture of metabolic syndrome and hypercortisolemia supports the hypothesis that obesity may be associated with impaired expression of genes related to cortisol action and metabolism in adipose tissue. The expression of genes encoding the glucocorticoid receptor alpha (GR), cortisol metabolizing enzymes (HSD11B1, HSD11B2, H6PDH), and adipokines, as well as selected microRNAs, was measured by real-time PCR in adipose tissue from 75 patients with obesity, 19 patients following metabolic surgery, and 25 normal-weight subjects. Cortisol levels were analyzed by LC-MS/MS in 30 pairs of tissues. The mRNA levels of all genes studied were significantly (p < 0.05) decreased in the visceral adipose tissue (VAT) of patients with obesity and normalized by weight loss. In the subcutaneous adipose tissue (SAT), GR and HSD11B2 were affected by this phenomenon. Negative correlations were observed between the mRNA levels of the investigated genes and selected miRNAs (hsa-miR-142-3p, hsa-miR-561, and hsa-miR-579). However, the observed changes did not translate into differences in tissue cortisol concentrations, although levels of this hormone in the SAT of patients with obesity correlated negatively with mRNA levels for adiponectin. In conclusion, although the expression of genes related to cortisol action and metabolism in adipose tissue is altered in obesity and miRNAs may be involved in this process, these changes do not affect tissue cortisol concentrations.

Neurological and metabolic related pathophysiologies and treatment of comorbid diabetes with depression

BACKGROUND

The comorbidity between diabetes mellitus and depression was revealed, and diabetes mellitus increased the prevalence of depressive disorder, which ranked 13th in the leading causes of disability-adjusted life-years. Insulin resistance, which is common in diabetes mellitus, has increased the risk of depressive symptoms in both humans and animals. However, the mechanisms behind the comorbidity are multi-factorial and complicated. There is still no causal chain to explain the comorbidity exactly. Moreover, Selective serotonin reuptake inhibitors, insulin and metformin, which are recommended for treating diabetes mellitus-induced depression, were found to be a risk factor in some complications of diabetes.

AIMS

Given these problems, many researchers made remarkable efforts to analyze diabetes complicating depression from different aspects, including insulin resistance, stress and Hypothalamic-Pituitary-Adrenal axis, neurological system, oxidative stress, and inflammation. Drug therapy, such as Hydrogen Sulfide, Cannabidiol, Ascorbic Acid and Hesperidin, are conducive to alleviating diabetes mellitus and depression. Here, we reviewed the exact pathophysiology underlying the comorbidity between depressive disorder and diabetes mellitus and drug therapy.

METHODS

The review refers to the available literature in PubMed and Web of Science, searching critical terms related to diabetes mellitus, depression and drug therapy.

RESULTS

In this review, we found that brain structure and function, neurogenesis, brain-derived neurotrophic factor and glucose and lipid metabolism were involved in the pathophysiology of the comorbidity. Obesity might lead to diabetes mellitus and depression through reduced adiponectin and increased leptin and resistin. In addition, drug therapy displayed in this review could expand the region of potential therapy.

CONCLUSIONS

The review summarizes the mechanisms underlying the comorbidity. It also overviews drug therapy with anti-diabetic and anti-depressant effects.

Gut microbiota and type 2 diabetes mellitus: a focus on the gut-brain axis

Type 2 diabetes mellitus (T2DM) has become one of the most serious public healthcare challenges, contributing to increased mortality and disability. In the past decades, significant progress has been made in understanding the pathogenesis of T2DM. Mounting evidence suggested that gut microbiota (GM) plays a significant role in the development of T2DM. Communication between the GM and the brain is a complex bidirectional connection, known as the "gut-brain axis," via the nervous, neuroendocrine, and immune systems. Gut-brain axis has an essential impact on various physiological processes, including glucose metabolism, food intake, gut motility, etc. In this review, we provide an outline of the gut-brain axis. We also highlight how the dysbiosis of the gut-brain axis affects glucose homeostasis and even results in T2DM.

Association between dietary sugar intake and depression in US adults: a cross-sectional study using data from the National Health and Nutrition Examination Survey 2011-2018

BACKGROUND

Studies examining whether diet sugar intake increases the risk of depression have produced inconsistent results. Therefore, we investigated this relationship, using the US' National Health and Nutrition Examination Survey (NHANES) database.

METHODS

This cross-sectional study included 18,439 adults (aged ≥ 20 years) from NHANES (2011-2018). Depressive symptoms were assessed using the nine-item version of the Patient Health Questionnaire (PHQ-9). Covariates, including age, sex, race/ethnicity, poverty-income ratio, education, marital status, hypertension, diabetes mellitus, cardiovascular disease, alcohol intake, smoking status, physical activity, and dietary energy intake, were adjusted in multivariate logistic regression models. Subgroup and threshold saturation effect analyses were performed.

RESULTS

After adjusting for potential confounders, we found that a 100 g/day increase in dietary sugar intake correlated with a 28% higher prevalence of depression (odds ratio = 1.28, 95% confidence interval = 1.17-1.40, P < 0.001).

CONCLUSION

Dietary sugar intake is positively associated with depression in US adults.

Mfat-1 ameliorates cachexia after hypoxic-ischemic brain damage in mice by protecting the hypothalamus-pituitary-adrenal axis

AIMS

Cachexia, a metabolic syndrome, affects 21 % of patients suffering from ischemic encephalopathy. However, the specific mechanism and prevention measures are still unclear. Omega-3 polyunsaturated fatty acids (n-3 PUFAs) have been proven to reduce inflammatory cytokine levels during ischemic events, but whether they have a protective effect against cachexia after hypoxic-ischemic brain damage (HIBD) remains unclear.

MAIN METHODS

C57BL/6J wild-type and mfat-1 transgenic male mice were treated with and without HIBD. One day after HIBD, the epididymal white fat, gastrocnemius muscle and hypothalamus were weighed and analyzed the phenotypic changes. RNA sequencing was applied to gastrocnemius muscle to identify differential genes and pathways in HIBD groups. The effect of HPA axis on cachexia post-HIBD was examined via adrenalectomy, dexamethasone (0.1 mg/kg), and corticosterone injection (100 mg/kg).

KEY FINDINGS

The results showed that the incidence of cachexia in mfat-1 mice, which produce high proportion of n-3 PUFAs, was significantly lower than that in wild-type mice post-HIBD. Cachexia-related factors, such as inflammation, muscle atrophy and lipid metabolism were significantly improved in mfat-1 HIBD. RNA sequencing revealed that catabolic and proteasome pathways were significantly downregulated. In hypothalamus, inflammatory cytokines, lipid peroxidation levels were reduced. Corticosterone, glucocorticoid receptor, and dexamethasone suppression test all showed that mfat-1 improved the dysfunction of the HPA axis post-HIBD. The present study elucidated for the first time that mfat-1 reduced HIBD-induced hyperactivation of the HPA axis in mice by reducing inflammation and oxidative stress and contributed to the reduction of metabolic imbalance in peripheral tissues.

SIGNIFICANCE

Our study provides mechanistic information for the development of intervention strategies to prevent cachexia.

Obesity-related cardiometabolic indicators modify the associations of personal noise exposure with heart rate variability: A further investigation on the Study among Obese and Normal-weight Adults (SONA)

Elucidating the associations between environmental noise and heart rate variability (HRV) would be beneficial for the prevention and control of detrimental cardiovascular changes. Obese people have been found to manifest heightened susceptibility to the adverse effects of noise on HRV. However, the underlying mechanisms remain unclear. Based on 53 normal-weight and 44 obese young adults aged 18-26 years in Beijing, China, this study aimed to investigate the role of obesity-related cardiometabolic indicators for associations between short-term environmental noise exposure and HRV in the real-world context. The participants underwent personal noise exposure and ambulatory electrocardiogram monitoring using portable devices at 5-min intervals for 24 continuous hours. Obesity-related blood pressure, glucose and lipid metabolism, and inflammatory indicators were subsequently examined. Generalized mixed-effect models were used to estimate the associations between noise exposure and HRV parameters. The C-peptide, homeostasis model assessment of insulin resistance (HOMA-IR), and leptin levels were higher in obese participants compared to normal-weight participants. We observed amplified associations between short-term noise exposure and decreases in HRV among participants with higher C-peptide, HOMA-IR, and leptin levels. For instance, a 1 dB(A) increment in 3 h-average noise exposure level preceding each measurement was associated with changes of -0.20% (95%CI: -0.45%, 0.04%) and -1.35% (95%CI: -1.85%, -0.86%) in standard deviation of all normal to normal intervals (SDNN) among participants with lower and higher C-peptide levels, respectively (P for interaction <0.05). Meanwhile, co-existing fine particulate matter (PM2.5) could amplify the associations between noise and HRV among obese participants and participants with higher C-peptide, HOMA-IR, and leptin levels. The more apparent associations of short-term exposure to environmental noise with HRV and the effect modification by PM2.5 may be partially explained by the higher C-peptide, HOMA-IR, and leptin levels of obese people.

The Role of the Adrenal-Gut-Brain Axis on Comorbid Depressive Disorder Development in Diabetes

Diabetic patients are more affected by depression than non-diabetics, and this is related to greater treatment resistance and associated with poorer outcomes. This increase in the prevalence of depression in diabetics is also related to hyperglycemia and hypercortisolism. In diabetics, the hyperactivity of the HPA axis occurs in parallel to gut dysbiosis, weakness of the intestinal permeability barrier, and high bacterial-product translocation into the bloodstream. Diabetes also induces an increase in the permeability of the blood-brain barrier (BBB) and Toll-like receptor 4 (TLR4) expression in the hippocampus. Furthermore, lipopolysaccharide (LPS)-induced depression behaviors and neuroinflammation are exacerbated in diabetic mice. In this context, we propose here that hypercortisolism, in association with gut dysbiosis, leads to an exacerbation of hippocampal neuroinflammation, glutamatergic transmission, and neuronal apoptosis, leading to the development and aggravation of depression and to resistance to treatment of this mood disorder in diabetic patients.

Maternal stress is associated with higher protein-bound amino acid concentrations in human milk

Background

Maternal stress in the postpartum period affects not only the mother but also her newborn child, who is at increased risk of developing metabolic and mental disorders later in life. The mechanisms by which stress is transmitted to the infant are not yet fully understood. Human milk (HM) is a potential candidate as maternal stress affects various components of HM, e.g., fat and immunoglobulin concentrations. To date, it is unknown whether maternal stress also affects the amino acids (AAs) in HM, even though this nutrient is of extreme importance to child health and development. This study aimed to investigate whether and how maternal stress is associated with the AA composition of HM.

Methods

In this observational cohort study (Amsterdam, The Netherlands), lactating women were recruited in two study groups: a high-stress (HS) group; women whose child was hospitalized (n = 24), and a control (CTL) group; women who gave birth to a healthy child (n = 73). HM was collected three times a day, on postpartum days 10, 17, and 24. Perceived psychological stress was measured using validated questionnaires, while biological stress measures were based on hair, saliva, and HM cortisol concentrations. HM protein-bound and free AAs were analyzed by liquid chromatography and compared between groups.

Results

Maternal perceived stress scores were higher in the HS group (p < 0.01). The concentrations of protein-bound AAs in HM were higher in the HS group compared to the CTL group (p = 0.028) and were positively associated with HM cortisol concentrations (p = 0.024). The concentrations of free AAs did not differ between study groups and were unrelated to cortisol concentrations.

Conclusion

Findings from this prospective cohort study suggest that maternal stress in the postpartum period is associated with an altered human milk amino acid composition, which could play a role in the transmission of maternal stress effects to her child. The physiological implications of these stress-induced changes for infant development await future research.

Delineating mouse β-cell identity during lifetime and in diabetes with a single cell atlas

Although multiple pancreatic islet single-cell RNA-sequencing (scRNA-seq) datasets have been generated, a consensus on pancreatic cell states in development, homeostasis and diabetes as well as the value of preclinical animal models is missing. Here, we present an scRNA-seq cross-condition mouse islet atlas (MIA), a curated resource for interactive exploration and computational querying. We integrate over 300,000 cells from nine scRNA-seq datasets consisting of 56 samples, varying in age, sex and diabetes models, including an autoimmune type 1 diabetes model (NOD), a glucotoxicity/lipotoxicity type 2 diabetes model (db/db) and a chemical streptozotocin β-cell ablation model. The β-cell landscape of MIA reveals new cell states during disease progression and cross-publication differences between previously suggested marker genes. We show that β-cells in the streptozotocin model transcriptionally correlate with those in human type 2 diabetes and mouse db/db models, but are less similar to human type 1 diabetes and mouse NOD β-cells. We also report pathways that are shared between β-cells in immature, aged and diabetes models. MIA enables a comprehensive analysis of β-cell responses to different stressors, providing a roadmap for the understanding of β-cell plasticity, compensation and demise.

The Biologist's Guide to the Glucocorticoid Receptor's Structure

The glucocorticoid receptor α (GRα) is a member of the nuclear receptor superfamily and functions as a glucocorticoid (GC)-responsive transcription factor. GR can halt inflammation and kill off cancer cells, thus explaining the widespread use of glucocorticoids in the clinic. However, side effects and therapy resistance limit GR's therapeutic potential, emphasizing the importance of resolving all of GR's context-specific action mechanisms. Fortunately, the understanding of GR structure, conformation, and stoichiometry in the different GR-controlled biological pathways is now gradually increasing. This information will be crucial to close knowledge gaps on GR function. In this review, we focus on the various domains and mechanisms of action of GR, all from a structural perspective.

Chronic stress targets mitochondrial respiratory efficiency in the skeletal muscle of C57BL/6 mice

Episodes of chronic stress can result in psychic disorders like post-traumatic stress disorder, but also promote the development of metabolic syndrome and type 2 diabetes. We hypothesize that muscle, as main regulator of whole-body energy expenditure, is a central target of acute and adaptive molecular effects of stress in this context. Here, we investigate the immediate effect of a stress period on energy metabolism in Musculus gastrocnemius in our established C57BL/6 chronic variable stress (Cvs) mouse model. Cvs decreased lean body mass despite increased energy intake, reduced circadian energy expenditure (EE), and substrate utilization. Cvs altered the proteome of metabolic components but not of the oxidative phosphorylation system (OXPHOS), or other mitochondrial structural components. Functionally, Cvs impaired the electron transport chain (ETC) capacity of complex I and complex II, and reduces respiratory capacity of the ETC from complex I to ATP synthase. Complex I-OXPHOS correlated to diurnal EE and complex II-maximal uncoupled respiration correlated to diurnal and reduced nocturnal EE. Bioenergetics assessment revealed higher optimal thermodynamic efficiencies (ƞ-opt) of mitochondria via complex II after Cvs. Interestingly, transcriptome and methylome were unaffected by Cvs, thus excluding major contributions to supposed metabolic adaptation processes. In summary, the preclinical Cvs model shows that metabolic pressure by Cvs is initially compensated by adaptation of mitochondria function associated with high thermodynamic efficiency and decreased EE to manage the energy balance. This counter-regulation of mitochondrial complex II may be the driving force to longitudinal metabolic changes of muscle physiological adaptation as the basis of stress memory.

Cortisol controls endoplasmic reticulum stress and hypoxia dependent regulation of insulin receptor and related genes expression in HEK293 cells

Objective. Glucocorticoids are important stress-responsive regulators of insulin-dependent metabolic processes realized through specific changes in genome function. The aim of this study was to investigate the impact of cortisol on insulin receptor and related genes expression in HEK293 cells upon induction the endoplasmic reticulum (ER) stress by tunicamycin and hypoxia. Methods. The human embryonic kidney cell line HEK293 was used. Cells were exposed to cortisol (10 µM) as well as inducers of hypoxia (dimethyloxalylglycine, DMOG; 0.5 mM) and ER stress (tunicamycin; 0.2 µg/ml) for 4 h. The RNA from these cells was extracted and reverse transcribed. The expression level of INSR, IRS2, and INSIG2 and some ER stress responsive genes encoding XBP1n, non-spliced variant, XBP1s, alternatively spliced variant of XBP1, and DNAJB9 proteins, was measured by quantitative polymerase chain reaction and normalized to ACTB. Results. We showed that exposure of HEK293 cells to cortisol elicited up-regulation in the expression of INSR and DNAJB9 genes and down-regulation of XBP1s, XBP1n, IRS2, and INSIG2 mRNA levels. At the same time, induction of hypoxia by DMOG led to an up-regulation of the expression level of most studied mRNAs: XBP1s and XBP1n, IRS2 and INSIG2, but did not change significantly INSR and DNAJB9 gene expression. We also showed that combined impact of cortisol and hypoxia introduced the up-regulation of INSR and suppressed XBP1n mRNA expression levels. Furthermore, the exposure of HEK293 cells to tunicamycin affected the expression of IRS2 gene and increased the level of XBP1n mRNA. At the same time, the combined treatment of these cells with cortisol and inductor of ER stress had much stronger impact on the expression of all the tested genes: strongly increased the mRNA level of ER stress dependent factors XBP1s and DNAJB9 as well as INSR and INSIG2, but down-regulated IRS2 and XBP1n. Conclusion. Taken together, the present study indicates that cortisol may interact with ER stress and hypoxia in the regulation of ER stress dependent XBP1 and DNAJB9 mRNA expression as well as INSR and its signaling and that this corticosteroid hormone modified the impact of hypoxia and especially tunicamycin on the expression of most studied genes in HEK293 cells. These data demonstrate molecular mechanisms of glucocorticoids interaction with ER stress and insulin signaling at the cellular level.

The Scaffold Immunophilin FKBP51 Is a Phosphoprotein That Undergoes Dynamic Mitochondrial-Nuclear Shuttling

The immunophilin FKBP51 forms heterocomplexes with molecular chaperones, protein-kinases, protein-phosphatases, autophagy-related factors, and transcription factors. Like most scaffold proteins, FKBP51 can use a simple tethering mechanism to favor the efficiency of interactions with partner molecules, but it can also exert more complex allosteric controls over client factors, the immunophilin itself being a putative regulation target. One of the simplest strategies for regulating pathways and subcellular localization of proteins is phosphorylation. In this study, it is shown that scaffold immunophilin FKBP51 is resolved by resolutive electrophoresis in various phosphorylated isoforms. This was evidenced by their reactivity with specific anti-phosphoamino acid antibodies and their fade-out by treatment with alkaline phosphatase. Interestingly, stress situations such as exposure to oxidants or in vivo fasting favors FKBP51 translocation from mitochondria to the nucleus. While fasting involves phosphothreonine residues, oxidative stress involves tyrosine residues. Molecular modeling predicts the existence of potential targets located at the FK1 domain of the immunophilin. Thus, oxidative stress favors FKBP51 dephosphorylation and protein degradation by the proteasome, whereas FK506 binding protects the persistence of the post-translational modification in tyrosine, leading to FKBP51 stability under oxidative conditions. Therefore, FKBP51 is revealed as a phosphoprotein that undergoes differential phosphorylations according to the stimulus.

11β-Hydroxysteroid Dehydrogenase Type 1 as a Potential Treatment Target in Cardiovascular Diseases

Glucocorticoids (GCs) belong to the group of steroid hormones. Their representative in humans is cortisol. GCs are involved in most physiological processes of the body and play a significant role in important biological processes, including reproduction, growth, immune responses, metabolism, maintenance of water and electrolyte balance, functioning of the central nervous system and the cardiovascular system. The availability of cortisol to the glucocorticoid receptor is locally controlled by the enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1). Evidence of changes in intracellular GC metabolism in the pathogenesis of obesity, metabolic syndrome (MetS) and cardiovascular complications highlights the role of selective 11β-HSD1 inhibition in the pharmacotherapy of these diseases. This paper discusses the role of 11β-HSD1 in MetS and its cardiovascular complications and the importance of selective inhibition of 11β-HSD1.

The modified outer membrane protein Amuc_1100 of Akkermansia muciniphila improves chronic stress-induced anxiety and depression-like behavior in mice

Akkermansia muciniphila is a next-generation probiotic. The interaction between outer membrane protein Amuc_1100 of A. muciniphila and toll-like receptor 2 (TLR2) in intestinal epithelial cells influences the level of intestinal 5-hydroxytryptamine (5-HT). Amuc_1100^Δ80 is a truncated form of Amuc_1100 lacking the first 80 N-terminal amino acids and has a higher affinity for TLR2 than the wild-type protein. Here, we report that Amuc_1100^Δ80 could significantly reduce anxiety and depression-like behavior of mice when they were exposed to chronic unpredictable mild stress (CUMS). The experimental results of the rat insulinoma cell line RIN-14B showed that Amuc_1100^Δ80 also induced a significantly higher upregulation of tryptophan hydroxylase 1 (Tph1), a rate-limiting enzyme of intestinal 5-HT synthesis. The imbalance of the gut microflora could be diminished when CUMS mice were fed with Amuc_1100^Δ80. These results reveal that Amuc_1100^Δ80 could affect the 5-HT level and the downstream 5-HTR1A-CREB-BDNF signal pathway via interacting with TLR2 and by altering the gut microbial composition. In parallel, the downregulation exerted by Amuc_1100^Δ80 on the inflammation and hyperactivated HPA axis was closely related to the improvement of depression-like symptoms in CUMS mice. This study not only provides new insights into the antidepressant effect of A. muciniphila and its outer membrane protein Amuc_1100 but also identifies new potential targets and pathways in the gut for future research and the development of antidepressant drugs.

Functional near-infrared spectroscopy of prefrontal cortex during memory encoding and recall in elderly with type 2 diabetes mellitus

Low-frequency Fahræus-Lindqvist-driven oscillations in the small vessels are crucial because oscillations in small vessels support nutrient supply. Understanding of this is critical in type 2 diabetes mellitus (T2DM) to develop therapeutic measures in order to prevent Alzheimer's Disease Related Dementias. Indeed, vascular factors are known to contribute to cerebrovascular disease as well as mild cognitive impairment and dementia, which are predicted to affect 152 million people by 2050 (Alzheimer's Disease International London, UK, 2019). In this clinical study, we performed functional near-infrared spectroscopy (fNIRS) of the forehead to investigate the effect of the Mini-Cog with three-item recall test on the prefrontal cortex (PFC) activation and the relative oscillatory power in the 0.01-0.02-Hz (FahræΣus-Lindqvist effect) and 0.021-0.052 Hz (smooth muscle autonomic innervation) frequency bands in elderly (60 years and older) T2DM and age-matched controls. We found a significant (p<0.01) difference in the PFC activation between elderly subjects with T2DM and age-matched elderly controls. Moreover, power spectral density (PSD) analysis revealed a significantly lower relative power in 0.021-0.052 Hz (smooth muscle autonomic innervation) frequency band in elderly subjects with T2DM during the Mini-Cog three-item recall test. Furthermore, a drop in the oscillatory power in the 0.01-0.02 Hz frequency band during Mini-Cog three-item recall test was found more pronounced in the elderly subjects with T2DM. Therefore, our study highlighted portable brain imaging to capture cerebrovascular reactivity to cognitive load that may provide a biomarker of cerebrovascular dysfunction in T2DM. Clinical Relevance-Our study establishes forehead portable brain imaging under cognitive load for monitoring cerebrovascular function in T2DM.

Pathophysiology of Mild Hypercortisolism: From the Bench to the Bedside

Mild hypercortisolism is defined as biochemical evidence of abnormal cortisol secretion without the classical detectable manifestations of overt Cushing’s syndrome and, above all, lacking catabolic characteristics such as central muscle weakness, adipose tissue redistribution, skin fragility and unusual infections. Mild hypercortisolism is frequently discovered in patients with adrenal incidentalomas, with a prevalence ranging between 5 and 50%. This high variability is mainly due to the different criteria used for defining this condition. This subtle cortisol excess has also been described in patients with incidentally discovered pituitary tumors with an estimated prevalence of 5%. To date, the mechanisms responsible for the pathogenesis of mild hypercortisolism of pituitary origin are still not well clarified. At variance, recent advances have been made in understanding the genetic background of bilateral and unilateral adrenal adenomas causing mild hypercortisolism. Some recent data suggest that the clinical effects of glucocorticoid (GC) exposure on peripheral tissues are determined not only by the amount of the adrenal GC production but also by the peripheral GC metabolism and by the GC sensitivity. Indeed, in subjects with normal cortisol secretion, the combined estimate of cortisol secretion, cortisone-to-cortisol peripheral activation by the 11 beta-hydroxysteroid dehydrogenase enzyme and GC receptor sensitizing variants have been suggested to be associated with the presence of hypertension, diabetes and bone fragility, which are three well-known consequences of hypercortisolism. This review focuses on the pathophysiologic mechanism underlying both the different sources of mild hypercortisolism and their clinical consequences (bone fragility, arterial hypertension, subclinical atherosclerosis, cardiovascular remodeling, dyslipidemia, glucose metabolism impairment, visceral adiposity, infections, muscle damage, mood disorders and coagulation).

Association between exposure to earthquake in early life and diabetes mellitus incidence in adulthood with the modification of lifestyles: Results from the Kailuan study

BACKGROUND

Exposure to disasters in early life may induce lifetime health risk, but investigation on earthquake exposure and DM in later life is still limited. The aim of the current study is to evaluate the association between exposure to the Tangshan Earthquake in early life and diabetes mellitus (DM) incidence in adulthood, and explore the modification of lifestyles on DM development.

METHODS

Participants who were free of DM at baseline from the Kailuan Study were included in this study. All participants were divided into fetal-exposed, infant-exposed, early childhood-exposed and nonexposed group. The effect of earthquake exposure on DM and modification of lifestyles were examined by multivariable-adjusted Cox proportional hazard model.

RESULTS

The exposed group had a higher risk of DM than nonexposed group, especially in infant-exposed and early childhood-exposed group, with hazard ratio (HR) of 1.62 [95% confidence intervals (CI), 1.21-2.17] and 1.46 (95% CI, 1.06-1.99), respectively. After stratifying by lifestyles, a significant modification was observed in alcohol consumption.

CONCLUSION

Exposing to earthquake in early life could increase DM incidence in later life, and alcohol consumption might modify the effect of earthquake exposure on DM development. More attention should be paid on the preventions of DM among adults who exposed to earthquake in their early life.