High-fat diet-induced increases in glucocorticoids contribute to the development of non-alcoholic fatty liver disease in mice.

This study aimed to investigate the causal relationship between chronic ingestion of a high-fat diet (HFD)-induced secretion of glucocorticoids (GCs) and the development of non-alcoholic fatty liver disease (NAFLD). We have produced a strain of transgenic mice (termed L/L mice) that have normal levels of circulating corticosterone (CORT), the major type of GCs in rodents, but unlike wild-type (WT) mice, their circulating CORT was not affected by HFD. Compared to WT mice, 12-week HFD-induced fatty liver was less pronounced with higher plasma levels of triglycerides in L/L mice. These changes were reversed by CORT supplement to L/L mice. By analyzing a sort of lipid metabolism-related proteins, we found that expressions of the hepatic cluster of differentiation 36 (CD36) were upregulated by HFD-induced CORT and involved in CORT-mediated fatty liver. Dexamethasone, an agonist of the glucocorticoid receptor (GR), upregulated expressions of CD36 in HepG2 hepatocytes and facilitated lipid accumulation in the cells. In conclusion, the fat ingestion-induced release of CORT contributes to NAFLD. This study highlights the pathogenic role of CORT-mediated upregulation of hepatic CD 36 in diet-induced NAFLD.

High-fat diet induces depression-like phenotype via astrocyte-mediated hyperactivation of ventral hippocampal glutamatergic afferents to the nucleus accumbens.

Comorbidity exists between metabolic disorders and depressive syndrome with unclear mechanisms. To characterize the causal relationship, we adopted a 12-week high-fat diet (HFD) to induce metabolic disorder and depressive phenotypes in mice. Initially, we identified an enhanced glutamatergic input in the nucleus accumbens of HFD mice. Retrograde tracing and chemogenetic inhibition showed that the hyperactive ventral hippocampal glutamatergic afferents to the nucleus accumbens determined the exhibition of depression-like behavior in HFD mice. Using lentiviral knockdown and overexpression approaches, we proved that HFD-induced downregulation of glial glutamate transporters, GLAST and GLT-1, contributed to the observed circuit maladaptations and subsequent depression-like behaviors. Finally, we identified a potential therapeutic agent, riluzole, which could mitigate the HFD-induced behavioral deficits by normalizing the expressions of GLAST and GLT-1 and ventral hippocampal glutamatergic afferents to the nucleus accumbens. Overall, astrocyte-mediated disturbance in glutamatergic transmission underlies the metabolic disorder-related depressive syndrome and represents a therapeutic target for this subtype of depressive mood disorders.

Exercise-induced increases of corticosterone contribute to exercise-enhanced adult hippocampal neurogenesis in mice.

Adult hippocampal neurogenesis (AHN) is suppressed by chronic stress. The negative effect of stress is mainly attributed to increased levels of stress hormones (e.g. glucocorticoids, GCs). Exercise enhances AHN, yet it also stimulates GC secretion. To delineate the paradoxical role of GCs, we took the advantage of a unique mouse strain (L/L) which exhibits an inert response to stress-induced secretion of GCs to study the role of GCs in exercise-induced AHN. Our results showed that basal corticosterone (CORT), the main GCs in rodents, levels were similar between the L/L mice and wild-type (WT) mice. However, levels of CORT in the L/L mice were barely altered and significantly lower than those of the WT mice during treadmill running (TR). AHN was enhanced by 4 weeks of TR in the WT mice, but not L/L mice. WT mice that received daily injection of CORT to evoke serum CORT levels similar to those during exercise for 4 weeks did not affect AHN, whereas injection with large amount of CORT inhibited AHN. Taken together, our results indicated that exercise-related elevation of CORT participates in exercise-enhanced AHN. CORT alone is not sufficient to elicit AHN and may inhibit AHN if the levels are high.

BDNF reverses aging-related microglial activation.

BACKGROUND: Excessive microglial activation is implicated in the pathogenesis of various age-related neurodegenerative diseases. In addition to neurons, brain-derived neurotrophic factor (BDNF) and its receptor TrkB are also expressed in microglia. However, the direct effect of BDNF on age-related microglial activation has rarely been investigated. METHODS: We began to address this question by examining the effect of age on microglial activation and the BDNF-TrkB pathway in mice. By using pharmacological and genetic approaches, the roles of BDNF and downstream signaling pathways in microglial activation and related neurotoxicity were examined in microglial cell line and primary microglial cells. RESULTS: We showed that microglial activation was evident in the brains of aged mice. The levels of BDNF and TrkB in microglia decreased with age and negatively correlated with their activation statuses in mice during aging. Interestingly, aging-related microglial activation could be reversed by chronic, subcutaneous perfusion of BDNF. Peripheral lipopolysaccharide (LPS) injection-induced microglial activation could be reduced by local supplement of BDNF, while shTrkB induced local microglial activation in naïve mice. In cultured microglial cell line and primary microglial cells, BDNF inhibited LPS-induced microglial activation, including morphological changes, activations of p38, JNK, and NF-кB, and productions of proinflammatory cytokines. These effects were blocked by shTrkB. BDNF induced activations of ErK and CREB which then competed with LPS-induced activation of NF-кB for binding to a common coactivator, CREB-binding protein. CONCLUSIONS: Decreasing BDNF-TrkB signaling during aging favors microglial activation, while upregulation BDNF signaling inhibits microglial activation via the TrkB-Erk-CREB pathway.

Chronic exposure to high fat diet triggers myelin disruption and interleukin-33 upregulation in hypothalamus.

BACKGROUND: Hypothalamic inflammation including astrogliosis and microglia activation occurs after intake of high fat diet (HFD) in rodent models or in obese individuals. However, the effect of chronic HFD feeding on oligodendrocytes (OLGs), a myelin-producing glial population in the central nervous system (CNS), remains unclear. In this study, we used 8-week old male C57BL/6 mice fed by HFD for 3-6 months to induce chronic obesity. RESULTS: The transmission electron microscopy imaging analysis showed that the integrity of hypothalamic myelin was disrupted after HFD feeding for 4 and 6 months. Moreover, the accumulation of Iba1+-microglia with an amoeboid hypertrophic form was continually observed in arcuate nucleus of HFD-fed mice during the entire feeding time period. Interleukin-33 (IL-33), a tissue alarmin upon injury to the CNS, was detected with an increased level in hypothalamus after HFD feeding for 3 and 4 months. Furthermore, the in vitro study indicated that exposure of mature OLGs to IL-33 impaired OLG cell structure along with a decline in the expression of myelin basic protein. CONCLUSIONS: Altogether, our findings demonstrate that chronic HFD feeding triggers hypothalamic myelin disruption in accompany with IL-33 upregulation and prolonged microglial activation in hypothalamus. Given that the addition of exogenous IL-33 was harmful for the maturation of OLGs, an increase in IL-33 by chronic HFD feeding might contribute to the induction of hypothalamic myelin disruption.

Stress Aggravates High-Fat-Diet-Induced Insulin Resistance via a Mechanism That Involves the Amygdala and Is Associated with Changes in Neuroplasticity.

BACKGROUND: The notion that exposure to chronic stress predisposes individuals to developing type 2 diabetes (T2D) has gained much attention in recent decades. Long-term stress induces neuroadaptation in the amygdala and increases corticosterone levels. Corticosterone, the major stress hormone in rodents, induces insulin resistance and obesity in mice. However, little is known about whether the stress-induced amygdalar neuroadaptation could promote the risk of T2D. METHODS: We used an 11-week high-fat diet (HFD) feeding paradigm to induce insulin dysfunction in mice, followed by implementation of a 10-day social defeat (SD) stress protocol. RESULTS: Mice receiving SD at the beginning of the HFD feeding aggravated HFD-induced insulin resistance and white adipose tissue expansion. HFD mice had higher levels of plasma corticosterone, which was not affected by the SD. The SD stress upregulated the expression of TrkB and synaptotagmin-4 in the amygdala of HFD mice. Bilateral lesions of the central amygdalae before SD stress inhibited the stress-induced aggravating effect without affecting the HFD-induced elevation of plasma corticosterone. CONCLUSIONS: Stress aggravates HFD-induced insulin resistance and neuroadaptation in the amygdala. The HFD-induced insulin resistance is amygdala-dependent. Understanding the role of stress-induced amygdalar adaptation in the development of T2D could inform therapies aimed at reducing chronic stressors to decrease the risk for T2D.

Long-Term Moderate Exercise Rescues Age-Related Decline in Hippocampal Neuronal Complexity and Memory.

BACKGROUND: Aging impairs hippocampal neuroplasticity and hippocampus-related learning and memory. In contrast, exercise training is known to improve hippocampal neuronal function. However, whether exercise is capable of restoring memory function in old animals is less clear. OBJECTIVE: Here, we investigated the effects of exercise on the hippocampal neuroplasticity and memory functions during aging. METHODS: Young (3 months), middle-aged (9-12 months), and old (18 months) mice underwent moderate-intensity treadmill running training for 6 weeks, and their hippocampus-related learning and memory, and the plasticity of their CA1 neurons was evaluated. RESULTS: The memory performance (Morris water maze and novel object recognition tests), and dendritic complexity (branch and length) and spine density of their hippocampal CA1 neurons decreased as their age increased. The induction and maintenance of high-frequency stimulation-induced long-term potentiation in the CA1 area and the expressions of neuroplasticity-related proteins were not affected by age. Treadmill running increased CA1 neuron long-term potentiation and dendritic complexity in all three age groups, and it restored the learning and memory ability in middle-aged and old mice. Furthermore, treadmill running upregulated the hippocampal expressions of brain-derived neurotrophic factor and monocarboxylate transporter-4 in middle-aged mice, glutamine synthetase in old mice, and full-length TrkB in middle-aged and old mice. CONCLUSION: The hippocampus-related memory function declines from middle age, but long-term moderate-intensity running effectively increased hippocampal neuroplasticity and memory in mice of different ages, even when the memory impairment had progressed to an advanced stage. Thus, long-term, moderate intensity exercise training might be a way of delaying and treating aging-related memory decline.

Targeting Cellular Stress Mechanisms and Metabolic Homeostasis by Chinese Herbal Drugs for Neuroprotection.

Traditional Chinese medicine has been practiced for centuries in East Asia. Herbs are used to maintain health and cure disease. Certain Chinese herbs are known to protect and improve the brain, memory, and nervous system. To apply ancient knowledge to modern science, some major natural therapeutic compounds in herbs were extracted and evaluated in recent decades. Emerging studies have shown that herbal compounds have neuroprotective effects or can ameliorate neurodegenerative diseases. To understand the mechanisms of herbal compounds that protect against neurodegenerative diseases, we summarize studies that discovered neuroprotection by herbal compounds and compound-related mechanisms in neurodegenerative disease models. Those compounds discussed herein show neuroprotection through different mechanisms, such as cytokine regulation, autophagy, endoplasmic reticulum (ER) stress, glucose metabolism, and synaptic function. The interleukin (IL)-1ß and tumor necrosis factor (TNF)-α signaling pathways are inhibited by some compounds, thus attenuating the inflammatory response and protecting neurons from cell death. As to autophagy regulation, herbal compounds show opposite regulatory effects in different neurodegenerative models. Herbal compounds that inhibit ER stress prevent neuronal death in neurodegenerative diseases. Moreover, there are compounds that protect against neuronal death by affecting glucose metabolism and synaptic function. Since the progression of neurodegenerative diseases is complicated, and compound-related mechanisms for neuroprotection differ, therapeutic strategies may need to involve multiple compounds and consider the type and stage of neurodegenerative diseases.

The Therapeutic Potential of Anti-Inflammatory Exerkines in the Treatment of Atherosclerosis.

Although many cardiovascular (CVD) medications, such as antithrombotics, statins, and antihypertensives, have been identified to treat atherosclerosis, at most, many of these therapeutic agents only delay its progression. A growing body of evidence suggests physical exercise could be implemented as a non-pharmacologic treatment due to its pro-metabolic, multisystemic, and anti-inflammatory benefits. Specifically, it has been discovered that certain anti-inflammatory peptides, metabolites, and RNA species (collectively termed "exerkines") are released in response to exercise that could facilitate these benefits and could serve as potential therapeutic targets for atherosclerosis. However, much of the relationship between exercise and these exerkines remains unanswered, and there are several challenges in the discovery and validation of these exerkines. This review primarily highlights major anti-inflammatory exerkines that could serve as potential therapeutic targets for atherosclerosis. To provide some context and comparison for the therapeutic potential of exerkines, the anti-inflammatory, multisystemic benefits of exercise, the basic mechanisms of atherosclerosis, and the limited efficacies of current anti-inflammatory therapeutics for atherosclerosis are briefly summarized. Finally, key challenges and future directions for exploiting these exerkines in the treatment of atherosclerosis are discussed.

Long-term moderate exercise accelerates the recovery of stress-evoked cardiovascular responses.

Psychological stress is an important global health problem. It is well documented that stress increases the incidences of various cardiovascular disorders. Regular exercise is known to reduce resting blood pressure (BP) and heart rate (HR). This study was designed to clarify the effects of long-term exercise on stress-evoked cardiovascular responses and to emphasize post-stress recovery effects. Male Wistar rats underwent 8 weeks of moderate treadmill training, with cardiovascular responses, autonomic nervous system activities and local Fos reactivity changes in the cardiovascular regulation center were monitored before, during and after immobilization stress. A spectral analysis of cardiovascular parameters was used to examine autonomic nervous activities. We found that long-term exercise (i) lowered resting BP, HR and sympathetic activity, but increased resting parasympathetic activity and baroreflex sensitivity (BRS); (ii) accelerated post-stress recovery of stress-evoked cardiovascular and sympathetic responses along with increased BRS and (iii) accelerated post-stress recovery of stress-evoked neuron activations in the paraventricular nucleus, but delayed it in the nucleus of the tractus solitarius. We conclude that, in rats, long-term exercise accelerated recovery of stress-evoked cardiovascular responses differentially altering hypothalamic and medullar neuron activities.

The Role of Central Oxytocin in Autonomic Regulation.

Oxytocin (OXT), a neuropeptide originating from the hypothalamus and traditionally associated with peripheral functions in parturition and lactation, has emerged as a pivotal player in the central regulation of the autonomic nervous system (ANS). This comprehensive ANS, comprising sympathetic, parasympathetic, and enteric components, intricately combines sympathetic and parasympathetic influences to provide unified control. The central oversight of sympathetic and parasympathetic outputs involves a network of interconnected regions spanning the neuroaxis, playing a pivotal role in the real-time regulation of visceral function, homeostasis, and adaptation to challenges. This review unveils the significant involvement of the central OXT system in modulating autonomic functions, shedding light on diverse subpopulations of OXT neurons within the paraventricular nucleus of the hypothalamus and their intricate projections. The narrative progresses from the basics of central ANS regulation to a detailed discussion of the central controls of sympathetic and parasympathetic outflows. The subsequent segment focuses specifically on the central OXT system, providing a foundation for exploring the central role of OXT in ANS regulation. This review synthesizes current knowledge, paving the way for future research endeavors to unravel the full scope of autonomic control and understand multifaceted impact of OXT on physiological outcomes.

High-fat diet-induced increase in glucocorticoids contributes to adipogenesis in obese mice.

BACKGROUND: This study was designed to examine how glucocorticoids (GCs) induced by a long-term ingestion of high-fat diet (HFD) mediate the HFD-induced adipose expansion and obesity. MATERIAL AND METHODS: To address this goal, we used a unique L/L mouse model that fails to induce its corticosterone (CORT) level, a major type of GCs in rodents, after prolonged exposure to an HFD. RESULTS: We found that, after receiving a 12-week HFD feeding, the L/L mice show less weight gain, milder adipose expansion, and higher plasma levels of triglycerides than the wild-type mice. These changes were reversed by replenishing CORT to L/L mice. When examining the expression levels of various molecules linked to lipid uptake and de novo lipogenesis in CORT-induced adipose expansion, we observed a reduction in the expression of adipose preadipocyte factor 1 (Pref-1), a key regulator in adipogenesis. In 3T3-L1 preadipocyte-like cells, dexamethasone, an agonist of the glucocorticoid receptor, also reduced expressions of Pref-1 and facilitated intracellular accumulation of lipids. CONCLUSIONS: Our results suggest that fat ingestion-induced release of CORT contributes to adipose expansion and development of obesity and highlight the pathogenic role of CORT-mediated downregulation of adipose Pref-1 in diet-induced obesity.

Dietary fatty acids differentially affect secretion of pro-inflammatory cytokines in human THP-1 monocytes.

Monocytes are a major population of circulating immune cells that play a crucial role in producing pro-inflammatory cytokines in the body. The actions of monocytes are known to be influenced by the combinations and concentrations of certain fatty acids (FAs) in blood and dietary fats. However, systemic comparisons of the effects of FAs on cytokine secretion by monocytes have not be performed. In this study, we compared how six saturated FAs (SFAs), two monounsaturated FAs (MUFAs), and seven polyunsaturated FAs (PUFAs) modulate human THP-1 monocyte secretion of TNF, IL-1ß, and IL-6 in the absence or presence of lipopolysaccharide. SFAs generally stimulated resting THP-1 cells to secrete pro-inflammatory cytokines, with stearic acid being the most potent species. In contrast, MUFAs and PUFAs inhibited lipopolysaccharide-induced secretion of pro-inflammatory cytokines. Interestingly, the inhibitory potentials of MUFAs and PUFAs followed U-shaped (TNF and IL-1ß) or inverted U-shaped (IL-6) dose-response curves. Among the MUFAs and PUFAs that were analyzed, docosahexaenoic acid (C22:6 n-3) exhibited the largest number of double bonds and was found to be the most potent anti-inflammatory compound. Together, our findings reveal that the chemical compositions and concentrations of dietary FAs are key factors in the intricate regulation of monocyte-mediated inflammation.

High-Spatiotemporal-Resolution Ultrasound Flow Imaging to Determine Cerebrovascular Hemodynamics in Alzheimer's Disease Mice Model.

Although the relationships of cerebrovascular hemodynamic dysfunction with neurodegenerative diseases remain unclear, many studies have indicated that poor cerebral perfusion accelerates the progression of neurodegenerative diseases, such as Alzheimer's disease (AD). Small animal models are widely used in AD research. However, providing an imaging modality with a high spatiotemporal resolution and sufficiently large field of view to assess cerebrovascular hemodynamics in vivo remains a challenge. The present study proposes a novel technique for high-spatiotemporal-resolution vector micro-Doppler imaging (HVµDI) based on contrast-free ultrafast high frequency ultrasound imaging to visualize the cerebrovascular hemodynamics of the mouse, with a data acquisition time of 0.4 s, a minimal detectable vessel size of 38 µm, and a temporal resolution of 500 Hz. In vivo experiments are conducted on wild-type and AD mice. Cerebrovascular hemodynamics are quantified using the cerebral vascular density, diameter, velocity, tortuosity, cortical flow pulsatility, and instant flow direction variations. Results reveal that AD significantly change the cerebrovascular hemodynamics. HVµDI offers new opportunities for in vivo analysis of cerebrovascular hemodynamics in neurodegenerative pathologies in preclinical animal research.

Inhibition of Nigral Microglial Activation Reduces Age-Related Loss of Dopaminergic Neurons and Motor Deficits.

Parkinson's disease (PD) is an age-related neurodegenerative disease caused by a selective loss of dopaminergic (DA) neurons in the substantia nigra (SN). Microglial activation is implicated in the pathogenesis of PD. This study aimed to characterize the role of microglial activation in aging-related nigral DA neuron loss and motor deficits in mice. We showed that, compared to 3-month-old mice, the number of DA neurons in the SN and the expression of dopamine transporter (DAT) in the striatum decreased during the period of 9 to 12 months of age. Motor deficits and microglial activation in the SN were also evident during these months. The number of DA neurons was negatively correlated with the degrees of microglial activation. The inhibition of age-related microglial activation by ibuprofen during these 3 months decreased DA neuron loss in the SN. Eliminating the microglia prevented systemic inflammation-induced DA neuron death. Forcing mice to run during these 3 months inhibited microglial activation and DA neuron loss. Blocking the brain-derived neurotrophic factor (BDNF) signaling eliminated the exercise-induced protective effects. In conclusion, nigral DA neurons were susceptible to local microglial activation. Running exercise upregulated BDNF-TrkB signaling and inhibited microglial activation during aging. Long-term exercise can be considered as a non-pharmacological strategy to ameliorate microglial activation and related neurodegeneration.

High glucose enhances lipopolysaccharide-induced inflammation in cultured BV2 microglial cell line.

INTRODUCTION: Diabetes mellitus emerges as a global health crisis and is related to the development of neurodegenerative diseases. Microglia, a population of macrophages-like cells, govern immune defense in the central nervous system. Activated microglia are known to play active roles in the pathogenesis of neurodegenerative diseases. METHODS: This study aimed to investigate the effects of high glucose on low-dose lipopolysaccharide (LPS)-induced activations of inflammation-related signaling molecules in cultured BV2 microglial cells. RESULTS: Compared to cells cultured in the normal glucose medium (NGM, 5.5 mM), the LPS-induced activation of NF-κB lasted longer in cells cultured in high glucose medium (HGM, 25 mM). HGM also enhanced the expression of inducible nitric oxide synthase (iNOS). Among the mitogen-activated protein kinases, HGM enhanced the LPS-induced phosphorylation of p38 without affecting the phosphorylation of Erk1/2 or JNK. BV2 cells cultured in HGM expressed higher levels of TLR4 than those cells cultured in NGM. CONCLUSION: High glucose aggravated LPS-induced inflammatory responses of microglia via enhancing the TLR4/p38 pathway and prolonging the activation of NF-κB/iNOS signaling. Controlling blood glucose levels is advised to manage neuroinflammation and related neurodegenerative diseases.

Surviving the Rookie Virus, Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV2): The Immunopathology of a SARS-CoV2 Infection.

Until July 29th, the number of confirmed coronavirus (COVID-19) cases worldwide has risen to over 16 million, within which 655 k deaths. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) emerges as the 11th global pandemic disease, showing the highest infectivity and lowest infection fatality rate. In this review, we compare the immunopathology among SARS-CoV, Middle East respiratory syndrome coronavirus, and SARS-CoV2. SARS-CoV2 is similar to SARS-CoV; it can cause lymphocytopenia and a rising granulocyte count. Here we point out the human body and concentrated society make for an excellent incubator for virus evolution. Most research energies put into developing the SARS-CoV2 vaccine are trying to block virus infection. Sixty-five percent of severe patients die with multiple organ failure, inflammation, and cytokine storm, which indicates that the patient's immune system maintains functionality. Finding a way to trigger the specific T cell subset and plasmablast in our body is the best shot to get away with SARS-CoV2.

Pioglitazone rescues high-fat diet-induced depression-like phenotypes and hippocampal astrocytic deficits in mice.

The prevalence of diabetes is rapidly increasing worldwide and is highly associated with the incidence of depression. Pioglitazone, a Peroxisome proliferator-activated receptor gamma (PPAR-γ) agonist, is widely used for treating patients with type 2 diabetes. However, whether pioglitazone alleviates metabolic disorder-related depression and astrocytic deficits remains unclear. Here we showed that 12 weeks of high-fat diet (HFD) feeding (from 8- to 20-week-old) induced not only obesity and insulin resistance, but also depression-like behaviors in mice. Astrocytic activation, a sign closely associated with depression, was also evident in the ventral hippocampus. Four weeks of pioglitazone (10 or 20 mg/kg, daily, from 20- to 24-week-old) treatment alleviated the HFD-induced glucose-metabolic dysfunctions, upregulation of ventral hippocampal GFAP, reduction of the total process lengths and the number of branch points of the ventral hippocampal CA1 GFAP-immunoreactive astrocytes and depressive phenotypes but had no effect on anxiety-like behaviors or hippocampus-related learning and memory in mice. These findings suggest that pioglitazone could be a potential therapeutic agent for metabolic disorders and associated depression.

Temporal focusing multiphoton microscopy with optimized parallel multiline scanning for fast biotissue imaging.

SIGNIFICANCE: Line scanning-based temporal focusing multiphoton microscopy (TFMPM) has superior axial excitation confinement (AEC) compared to conventional widefield TFMPM, but the frame rate is limited due to the limitation of the single line-to-line scanning mechanism. The development of the multiline scanning-based TFMPM requires only eight multiline patterns for full-field uniform multiphoton excitation and it still maintains superior AEC. AIM: The optimized parallel multiline scanning TFMPM is developed, and the performance is verified with theoretical simulation. The system provides a sharp AEC equivalent to the line scanning-based TFMPM, but fewer scans are required. APPROACH: A digital micromirror device is integrated in the TFMPM system and generates the multiline pattern for excitation. Based on the result of single-line pattern with sharp AEC, we can further model the multiline pattern to find the best structure that has the highest duty cycle together with the best AEC performance. RESULTS: The AEC is experimentally improved to 1.7 µm from the 3.5 µm of conventional TFMPM. The adopted multiline pattern is akin to a pulse-width-modulation pattern with a spatial period of four times the diffraction-limited line width. In other words, ideally only four π / 2 spatial phase-shift scans are required to form a full two-dimensional image with superior AEC instead of image-size-dependent line-to-line scanning. CONCLUSIONS: We have demonstrated the developed parallel multiline scanning-based TFMPM has the multiline pattern for sharp AEC and the least scans required for full-field uniform excitation. In the experimental results, the temporal focusing-based multiphoton images of disordered biotissue of mouse skin with improved axial resolution due to the near-theoretical limit AEC are shown to clearly reduce background scattering.

Clinical Application Potential of Small Molecules that Induce Brown Adipose Tissue Thermogenesis by Improving Fat Metabolism.

Mammalian fat comprises white and brown adipose tissue (WAT and BAT, respectively). WAT stores energy, whereas BAT is used for thermogenesis. In recent years, the incidence of obesity and its associated disorders have increased tremendously. Considering the thermogenic capacity and decreased levels of BAT with increasing age, BAT can be used as a suitable therapeutic target for the treatment of obesity and diabetes. In several studies, using positron emission tomography and computed tomography images, adult humans have been shown to have functional BAT in interscapular fat. Results of these basic research studies on BAT have shed light on the new components of transcriptional regulation and the role of hormones in stimulating BAT growth and differentiation. In this review article, we have summarized the thermogenic regulators identified in the past decades by focusing on peroxisome proliferator-activated receptor gamma/uncoupling protein 1 activators, branched-chain amino acids, fatty acids (lipokine), and adenosine monophosphate-activated protein kinase mediators. We have also presented the progress of a few ongoing clinical trials aimed at the treatment of obesity and its associated metabolic disorders. The main purpose of this review was to provide a comprehensive introduction to the latest knowledge of the representative thermogenic regulators for the treatment of obesity. The fat combustion capacity of BAT may have great potential and can be considered as a suitable target for the therapeutic application of drugs from bench-to-bed treatment of obesity and the associated diseases.