Cytokines and inflammation in adipogenesis: an updated review

From Maternal Diet to Neurodevelopmental Disorders: A Story of Neuroinflammation

Providing the appropriate quantity and quality of food needed for both the mother's well-being and the healthy development of the offspring is crucial during pregnancy. However, the macro- and micronutrient intake also impacts the body's regulatory supersystems of the mother, such as the immune, endocrine, and nervous systems, which ultimately influence the overall development of the offspring. Of particular importance is the association between unhealthy maternal diet and neurodevelopmental disorders in the offspring. Epidemiological studies have linked neurodevelopmental disorders like autism spectrum disorders, attention-deficit-hyperactivity disorder, and schizophrenia, to maternal immune activation (MIA) during gestation. While the deleterious consequences of diet-induced MIA on offspring neurodevelopment are increasingly revealed, neuroinflammation is emerging as a key underlying mechanism. In this review, we compile the evidence available on how the mother and offspring are both impacted by maternal dietary imbalance. We specifically explore the various inflammatory and anti-inflammatory effects of dietary components and discuss how changes in inflammatory status can prime the offspring brain development toward neurodevelopmental disorders. Lastly, we discuss research evidence on the mechanisms that sustain the relationship between maternal dietary imbalance and offspring brain development, involving altered neuroinflammatory status in the offspring, as well as genetic to cellular programming notably of microglia, and the evidence that the gut microbiome may act as a key mediator.

The Impact of Artificial Sweeteners on Body Weight Control and Glucose Homeostasis

A poor diet is one of the leading causes for non-communicable diseases. Due to the increasing prevalence of overweight and obesity, there is a strong focus on dietary overconsumption and energy restriction. Many strategies focus on improving energy balance to achieve successful weight loss. One of the strategies to lower energy intake is refraining from sugars and replacing them with artificial sweeteners, which maintain the palatability without ingesting calories. Nevertheless, the safety and health benefits of artificial sweeteners consumption remain a topic of debate within the scientific community and society at large. Notably, artificial sweeteners are metabolized differently from each other due to their different properties. Therefore, the difference in metabolic fate of artificial sweeteners may underlie conflicting findings that have been reported related to their effects on body weight control, glucose homeostasis, and underlying biological mechanisms. Thus, extrapolation of the metabolic effects of a single artificial sweetener to all artificial sweeteners is not appropriate. Although many rodent studies have assessed the metabolic effects of artificial sweeteners, long-term studies in humans are scarce. The majority of clinical studies performed thus far report no significant effects or beneficial effects of artificial sweeteners on body weight and glycemic control, but it should be emphasized that the study duration of most studies was limited. Clearly, further well-controlled, long-term human studies investigating the effects of different artificial sweeteners and their impact on gut microbiota, body weight regulation and glucose homeostasis, as well as the underlying mechanisms, are warranted.

Adiponectin/leptin ratio increases after a 12-week very low-carbohydrate, high-fat diet, and exercise training in healthy individuals: A non-randomized, parallel design study

This study aimed to investigate the effect of a 12-week very low-carbohydrate, high-fat (VLCHF) diet and exercise on biomarkers of inflammation in healthy individuals. Since the anti-inflammatory effects of a ketogenic diet have been established, we hypothesized that the VLCHF diet, along with exercise, would have an additional favorable effect on biomarkers of inflammation. Twenty-four healthy individuals were allocated to the VLCHF diet (VLCHF: N = 12, age 25.3 ± 2.0 years, body mass 66.7 ± 9.8 kg, fat mass 21.5% ± 4.9%), or habitual diet (HD: N = 12, age 23.9 ± 3.8 years, body mass 72.7 ± 15.0 kg, fat mass 23.4 ± 8.4 %) group. Biomarkers of inflammation (adiponectin, leptin, and high-sensitive interleukin-6 [hs-IL-6]) and substrate metabolism (glycated hemoglobin, fasting glucose, triacylglycerides, and cholesterol) were analyzed from blood at baseline and after 12 weeks. The adiponectin-leptin ratio significantly increased in the VLCHF group after the intervention period (ES [95% CL]: -0.90 [-0.96, -0.77], P ≤ .001, BF₁₀ = 22.15). The adiponectin-leptin ratio changes were associated with both a significant increase in adiponectin (-0.79 [-0.91, -0.54], P ≤ .001, BF₁₀ = 9.43) and a significant decrease in leptin (0.58 [0.19, 0.81], P = .014, BF₁₀ = 2.70). There was moderate evidence of changes in total cholesterol (-1.15 [-2.01, -0.27], P = .010, BF₁₀ = 5.20), and LDL cholesterol (-1.12 [-2.01, -0.21], P = .016, BF₁₀ = 4.56) in the VLCHF group. Body weight (kg) and fat mass (%) decreased in the VLCHF group by 5.4% and 14.9%, respectively. We found that in healthy young individuals, consuming a VLCHF diet while performing regular exercise over a 12-week period produced favorable changes in body weight and fat mass along with beneficial changes in serum adiponectin and leptin concentrations. These data support the use of a VLCHF diet strategy for the primary prevention of chronic diseases associated with systemic low-grade inflammation.

LKB1 Differently Regulates Adipogenesis in Intramuscular and Subcutaneous Adipocytes through Metabolic and Cytokine-Related Signaling Pathways

Liver kinase B1 (LKB1) plays important and various roles in the differentiation and lipid metabolism of adipocytes. However, the current knowledge of the respective roles of LKB1 in subcutaneous fat (SCF) and intramuscular fat (IMF) adipocytes remains unclear. This study aimed to discover the different regulatory mechanisms of LKB1 in SCF and IMF adipocytes. We found that LKB1 overexpression inhibited adipogenesis in both SCF and IMF adipocytes, and SCF adipocytes were more sensitive to regulation by LKB1. Transcriptomics results showed that IMF adipocytes had many more differentially expressed genes (DEGs) than SCF adipocytes. Pathway analysis of the shared and distinct DEGs revealed that the main adipogenesis mechanism was similar between SCF and IMF adipocytes upon LKB1 overexpression, while regulatory and metabolic signaling pathways, such as MAPK, PPAR signaling pathways, were differently regulated by LKB1. Several cytokine-related pathways were only enriched in LKB1-overexpressing IMF adipocytes. Our study reveals different regulators and signaling pathways between SCF and IMF adipocytes under LKB1 overexpression, which may be potential targets to differentially control SCF and IMF deposition and improve our understanding of the regulatory mechanisms of IMF deposition.

Inflammation Precedes Fat Deposition in an Experimental Model of Lymphedema

Background: Chronic lymphedema is a common complication of lymphatic obstruction, particularly after cancer treatment, characterized by an increased volume of the affected extremity, partly caused by the accumulation of excessive adipose tissue. The relationship between lymph vessels' obstruction and fat deposit is, however, poorly understood. Objective: Our central hypothesis was that the inflammatory process caused by lymph stasis precedes the adipocyte differentiation and fat deposition. Methods and Results: We used a modified mouse tail model to produce secondary lymphedema. Animals were treated with dexamethasone, or the procedure was performed in nitric oxide synthase 2 (NOS2)-deficient mice to evaluate the role of inflammation in lymphedema formation. Adipose tissue (Lipin) and inflammatory markers (IL-6, MCP-1, and F4-80) were analyzed in histological samples and by quantitative polymerase chain reaction. We observed an increased deposition of fat into the affected area that starts 3 weeks after lymph vessel ligation; it further increased after 6 weeks. Genes involved in the inflammatory process were upregulated before adipocyte maturation. Treatment with dexamethasone or the use of inducible nitric oxide synthase knockout mice blocked the inflammatory reaction and inhibited the accumulation of fat distal to the lymphatic obstruction. Conclusion: In the modified mouse tail lymphedema, inflammation precedes adipogenesis. Our data suggest that MCP-1 and nitric oxide may be potential targets for lymphedema management.

Gut microbiome alterations induced by tributyltin exposure are associated with increased body weight, impaired glucose and insulin homeostasis and endocrine disruption in mice

Tributyltin (TBT), an organotin compound once widely used in agriculture and industry, has been reported to induce obesity and endocrine disruption. Gut microbiota has a strong connection with the host's physiology. Nevertheless, the influences of TBT exposure on gut microbiota and whether TBT-influenced gut microbiota is related to TBT-induced toxicity remain unclear. To fill these gaps, ICR (CD-1) mice were respectively exposed to TBT at NOEL (L-TBT) and tenfold NOEL (H-TBT) daily by gavage for 8 weeks in the current study. The results showed that TBT exposure significantly increased body weight as well as epididymal fat, and led to adipocyte hypertrophy, dyslipidemia and impaired glucose and insulin homeostasis in mice. Additionally, TBT exposure significantly decreased the levels of T4, T3 and testosterone in serum. Also of note, TBT exposure changed gut microbiota composition mainly by decreasing Bacteroidetes and increasing Firmicutes proportions. To confirm the role of gut microbiota in TBT-induced overweight and hormonal disorders, fecal microbiota transplantation was performed and the mice receiving gut microbiota from H-TBT mice had similar phenotypes with their donor mice including significant body weight and epididymal fat gain, glucose and insulin dysbiosis and hormonal disorders. These results suggested that gut microbiome altered by TBT exposure was involved in the TBT-induced increased body weight, impaired glucose and insulin homeostasis and endocrine disruption in mice, providing significant evidence and a novel perspective for better understanding the mechanism by which TBT induces toxicity.

Severe hyperlipemia-induced pseudoerythrocytosis - Implication for misdiagnosis and blood transfusion: A case report and literature review

BACKGROUND

Severe hyperlipemia (SHLE) has an impact on the results of many kinds of laboratory tests. Complete blood count (CBC) examination by automated blood cell counter (ABCC) is a quick and convenient measurement for screening abnormalities of blood cells that are triggered by various pathogenic insults in disease diagnosis and for monitoring changes in the treatment of existing hematological conditions. However, CBC results are frequently affected by many intrinsic and extrinsic factors from blood samples, such as in the setting of hypergammaglobulinemia and certain anticoagulants. SHLE could also affect CBC results.

CASE SUMMARY

A 33-year-old Chinese male presented with painful foot numbness and abdominal pain. He was initially misdiagnosed as having a myeloproliferative neoplasm (MPN) because of the marked abnormalities in CBC examination by the ABCC. Morphological evaluation of the bone marrow smears and biopsy showed no evidence of MPN. Gene mutations in Breakpoint cluster regions-Abelson murine leukemia viral oncogene homologue 1 (BCR-ABL1), Janus kinase 2 (JAK2), calreticulin (CALR), myeloproliferative leukemia virus (MPL), and colony-stimulating factor 3 receptor (CSF3R) were negative. Having noticed the thick chylomicron layer on blood samples and the dramatically fluctuating CBC results, we speculated that the fat droplets formed by shaking the blood samples in the setting of SHLE were mistakenly identified as blood cells due to the limited parameters of ABCC. Therefore, we removed a large part of the chylomicron layer and then reexamined the CBC, and the CBC results, as we expected, differed significantly from that of the sample before the chylomicron layer was removed. These significant differences had been validated by the subsequently repeated laboratory tests by measuring dual blood samples that the chylomicron layer was removed in one sample and was not in another, and comparing the CBC results. Computerized tomography reexamination of the upper abdomen revealed an exudative lesion surrounding his pancreas. After intensive consultation, definitive diagnosis was made as recurrent pancreatitis, hyperlipemia and pseudoerythrocytosis.

CONCLUSION

SHLE may become a potential cause of misdiagnosis of hyperlipemia-related diseases as MPNs and the resultant mistreatment. It may also lead to the misinterpretation of transfusion indications in patients with hematological disorders who critically need blood transfusion for supportive treatment.

Brucella abortus Infection Modulates 3T3-L1 Adipocyte Inflammatory Response and Inhibits Adipogenesis

Brucellosis is a prevalent global zoonotic infection but has far more impact in developing countries. The adipocytes are the most abundant cell type of adipose tissue and their secreted factors play an important role in several aspects of the innate and adaptive immune response. Here, we demonstrated the ability of Brucella abortus to infect and replicate in both adipocytes and its precursor cells (pre-adipocytes) derived from 3T3-L1 cell line. Additionally, infection of pre-adipocytes also inhibited adipogenesis in a mechanism independent of bacterial viability and dependent on lipidated outer membrane protein (L-Omp19). B. abortus infection was able to modulate the secretion of IL-6 and the matrix metalloproteases (MMPs) -2 and-9 in pre-adipocytes and adipocytes, and also modulated de transcription of adiponectin, leptin, and resistin in differentiated adipocytes. B. abortus-infected macrophages also modulate adipocyte differentiation involving a TNF-α dependent mechanism, thus suggesting a plausible interplay between B. abortus, adipocytes, and macrophages. In conclusion, B. abortus is able to alter adipogenesis process in adipocytes and its precursors directly after their infection, or merely their exposure to the B. abortus lipoproteins, and indirectly through soluble factors released by B. abortus-infected macrophages.

Predicting the Benefit of Adjuvant Aromatase Inhibitor Therapy in Postmenopausal Breast Cancer Patients with Phosphorylated S6K1 Expression Status

Purpose

Phosphorylated ribosomal S6 kinase 1 (pS6K1) is a major downstream regulator of the mammalian target of rapamycin (mTOR) pathway. Recent studies have addressed the role of S6K1 in adipogenesis. pS6K1 may affect the outcome of estrogen depletion therapy in patients with hormone-sensitive breast cancer due to its association with adipogenesis and increased local estrogen levels. This study aimed to investigate the potential of pS6K1 as a predictive marker of adjuvant aromatase inhibitor (AI) therapy outcome in postmenopausal or ovarian function-suppressed patients with hormone-sensitive breast cancer.

Methods

Medical records were retrospectively reviewed in postmenopausal or ovarian function-suppressed patients with estrogen receptor-positive and node-positive primary breast cancer. pS6K1 expression status was scored on a scale from 0 (negative) to 3+ (positive) based on immunohistochemical analysis.

Results

A total of 428 patients were eligible. The median follow-up duration was 44 months (range, 1–90). In patients with positive pS6K1 expression, AIs significantly improved disease-free survival (DFS) compared to selective estrogen receptor modulators (SERMs) (5 year-DFS: 83.5% vs. 50.7%, p = 0.016). However, there was no benefit of AIs on DFS in the pS6K1 negative group (5 year-DFS 87.6% vs. 91.4%, p = 0.630). On multivariate analysis, AI therapy remained a significant predictor for DFS in the pS6K1 positive group (hazard ratio, 0.39; 95% confidence interval, 0.16–0.96; p = 0.041). pS6K1 was more effective in predicting the benefit of AI therapy in patients with ages < 50 (p = 0.021) compared to those with ages ≥ 50 (p = 0.188).

Conclusion

pS6K1 expression may predict AI therapy outcomes and serve as a potential predictive marker for adjuvant endocrine therapy in postmenopausal and ovarian function-suppressed patients with hormone-sensitive breast cancer. AIs may be more effective in patients with pS6K1 positive tumors, while SERM could be considered an alternative option for patients with pS6K1 negative tumors.