Nasopharyngeal lymphatic plexus is a hub for cerebrospinal fluid drainage.

Cerebrospinal fluid (CSF) in the subarachnoid space around the brain has long been known to drain through the lymphatics to cervical lymph nodes1-17, but the connections and regulation have been challenging to identify. Here, using fluorescent CSF tracers in Prox1-GFP lymphatic reporter mice18, we found that the nasopharyngeal lymphatic plexus is a major hub for CSF outflow to deep cervical lymph nodes. This plexus had unusual valves and short lymphangions but no smooth-muscle coverage, whereas downstream deep cervical lymphatics had typical semilunar valves, long lymphangions and smooth muscle coverage that transported CSF to the deep cervical lymph nodes. α-Adrenergic and nitric oxide signalling in the smooth muscle cells regulated CSF drainage through the transport properties of deep cervical lymphatics. During ageing, the nasopharyngeal lymphatic plexus atrophied, but deep cervical lymphatics were not similarly altered, and CSF outflow could still be increased by adrenergic or nitric oxide signalling. Single-cell analysis of gene expression in lymphatic endothelial cells of the nasopharyngeal plexus of aged mice revealed increased type I interferon signalling and other inflammatory cytokines. The importance of evidence for the nasopharyngeal lymphatic plexus functioning as a CSF outflow hub is highlighted by its regression during ageing. Yet, the ageing-resistant pharmacological activation of deep cervical lymphatic transport towards lymph nodes can still increase CSF outflow, offering an approach for augmenting CSF clearance in age-related neurological conditions in which greater efflux would be beneficial.

Cysteine-rich 61 inhibition attenuates hepatic insulin resistance and improves lipid metabolism in high-fat diet fed mice and HepG2 cells.

Metabolic dysfunction-associated steatotic liver disease (MASLD) is strongly associated with insulin resistance development. Hepatic lipid accumulation and inflammation are considered the main drivers of hepatic insulin resistance in MASLD. Cysteine-rich 61 (Cyr61 also called CCN1), a novel secretory matricellular protein, is implicated in liver inflammation, and its role in MASLD is not clearly understood. Therefore, we investigated the role of Cyr61 in hepatic insulin resistance and lipid metabolism as major factors in MASLD pathogenesis. In high-fat diet (HFD)-fed C57BL/6J mice, Cyr61 was downregulated or upregulated via viral transduction. Measurements of glucose homeostasis, histological assessment of liver tissues, and gene expression and signaling pathways of lipogenesis, fatty acid oxidation, and inflammation were performed using liver samples from these mice. Cyr61 levels in HepG2 cells were reduced using RNAi-mediated gene knockdown. Inflammation and insulin resistance were evaluated using real-time polymerase chain reaction and western blotting. HFD/AAV-shCyr61 mice exhibited enhanced glucose tolerance via the protein kinase B pathway, reduced hepatic inflammation, decreased lipogenesis, and increased fatty acid oxidation. Notably, HFD/AAV-shCyr61 mice showed elevated protein expression of sirtuin 6 and phosphorylated-AMP-activated protein kinase. In vitro experiments demonstrated that inhibition of Cyr61 downregulated pro-inflammatory cytokines such as interleukin-1 beta, IL-6, and tumor necrosis factor-alpha via the nuclear factor kappa B/c-Jun N-terminal kinase pathway, and alleviated insulin resistance. Cyr61 affected hepatic inflammation, lipid metabolism, and insulin resistance. Inhibition of Cyr61 reduced inflammation, recovered insulin resistance, and altered lipid metabolism in vivo and in vitro. Therefore, Cyr61 is a potential therapeutic target in MASLD.

Octanuclear Zinc Clusters in Microporous Organic Polymers: Network-Enhanced Reductive CO2 Fixation to Formamides at Room Temperature.

A building block containing eight zincs and eight iodo groups (8 Zn) is obtained by the Zn complexation of a salen ligand bearing two additional hydroxy groups. Through the Sonogashira-Hagihara coupling of 8 Zn with 1,3,5,7-tetra(4-ethynylphenyl) adamantane, microporous organic polymers bearing octanuclear zinc clusters (MOP-8 Zn) are prepared, exhibiting a high surface area of 562 m2 g-1, microporosity, and a particulate morphology with an average diameter of 249 nm. The MOP-8 Zn exhibits significantly enhanced catalytic performance, compared to molecular counterparts, in the reductive carbon dioxide fixation to formamides, possibly due to the cooperative adsorption and confinement effect of networks on substrates.

Imeglimin attenuates NLRP3 inflammasome activation by restoring mitochondrial functions in macrophages.

Imeglimin is a novel oral antidiabetic drug for treating type 2 diabetes. However, the effect of imeglimin on NLRP3 inflammasome activation has not been investigated yet. Here, we aimed to investigate whether imeglimin reduces LPS-induced NLRP3 inflammasome activation in THP-1 macrophages and examine the associated underlying mechanisms. We analyzed the mRNA and protein expression levels of NLRP3 inflammasome components and IL-1ß secretion. Additionally, reactive oxygen species (ROS) generation, mitochondrial membrane potential, and mitochondrial permeability transition pore (mPTP) opening were measured by flow cytometry. Imeglimin inhibited NLRP3 inflammasome-mediated IL-1ß production in LPS-stimulated THP-1-derived macrophages. In addition, imeglimin reduced LPS-induced mitochondrial ROS production and mitogen-activated protein kinase phosphorylation. Furthermore, imeglimin restored the mitochondrial function by modulating mitochondrial membrane depolarization and mPTP opening. We demonstrated for the first time that imeglimin reduces LPS-induced NLRP3 inflammasome activation by inhibiting mPTP opening in THP-1 macrophages. These results suggest that imeglimin could be a promising new anti-inflammatory agent for treating diabetic complications.

Acute Metabolic Stress Induces Lymphatic Dysfunction through KATP Channel Activation.

Lymphatic dysfunction is an underlying component of multiple metabolic diseases, including diabetes, obesity, and metabolic syndrome. We investigated the roles of KATP channels in lymphatic contractile dysfunction in response to acute metabolic stress induced by inhibition of the mitochondrial electron transport chain. Ex vivo popliteal lymphatic vessels from mice were exposed to the electron transport chain inhibitors antimycin A and rotenone, or the oxidative phosphorylation inhibitor/protonophore, CCCP. Each inhibitor led to a significant reduction in the frequency of spontaneous lymphatic contractions and calculated pump flow, without a significant change in contraction amplitude. Contraction frequency was restored by the KATP channel inhibitor, glibenclamide. Lymphatic vessels from mice with global Kir6.1 deficiency or expressing a smooth muscle-specific dominant negative Kir6.1 channel were resistant to inhibition. Antimycin A inhibited the spontaneous action potentials generated in lymphatic muscle and this effect was reversed by glibenclamide, confirming the role of KATP channels. Antimycin A, but not rotenone or CCCP, increased dihydrorhodamine fluorescence in lymphatic muscle, indicating ROS production. Pretreatment with tiron or catalase prevented the effect of antimycin A on wild-type lymphatic vessels, consistent with its action being mediated by ROS. Our results support the conclusion that KATP channels in lymphatic muscle can be directly activated by reduced mitochondrial ATP production or ROS generation, consequent to acute metabolic stress, leading to contractile dysfunction through inhibition of the ionic pacemaker controlling spontaneous lymphatic contractions. We propose that a similar activation of KATP channels contributes to lymphatic dysfunction in metabolic disease.

A Multicenter, Randomized, Open-Label Study to Compare the Effects of Gemigliptin Add-on or Escalation of Metformin Dose on Glycemic Control and Safety in Patients with Inadequately Controlled Type 2 Diabetes Mellitus Treated with Metformin and SGLT-2 Inhibitors (SO GOOD Study).

Background: We aimed to compare efficacy and safety between gemigliptin add-on and escalation of the metformin dose in patients with inadequately controlled type 2 diabetes mellitus (T2DM) despite treatment with metformin and SGLT2 inhibitors. Methods: This study was a multicenter, randomized, open-label, active-controlled, parallel-group comparative study. Patients with T2DM uncontrolled on metformin and SGLT2 inhibitors were randomized to receive gemigliptin 50 mg as an add-on (GEM group, n = 37) or escalation of the metformin dose (500 mg, MET group, n = 38) for 24 weeks. The primary endpoint was the change in glycosylated hemoglobin (HbA1c) from baseline to week 24. Results: At weeks 12 and 24, the reduction in HbA1c levels was significantly greater in the GEM group than in the MET group (GEM vs. MET = -0.64% ± 0.34% vs. -0.36% ± 0.50%, p = 0.009 at week 12; -0.61% ± 0.35% vs. -0.33% ± 0.70%, p = 0.045 at week 24). The proportions of patients who achieved target HbA1c levels of <7.0% at weeks 12 and 24 and <6.5% at week 12 were greater in the GEM group than in the MET group. An index of ß-cell function was also significantly improved in the GEM group. The safety profiles were similar between the two groups. Conclusions: Gemigliptin add-on therapy may be more effective than metformin dose escalation in patients with T2DM insufficiently controlled using metformin and SGLT2 inhibitors, without safety concerns. This trial is registered with CRIS_number: KCT0003520.

Effect of Pravastatin on Kidney Function in Patients with Dyslipidemia and Type 2 Diabetes Mellitus: A Multicenter Prospective Observational Study.

INTRODUCTION: Several studies have reported that pravastatin can mitigate the progression of kidney disease, but limited evidence exists regarding its effects on kidney function in Asian patients. This multicenter prospective observational study aimed to assess the effect of pravastatin on kidney function in Korean patients with dyslipidemia and type 2 diabetes mellitus (T2DM) in clinical practice. METHODS: This 48-week prospective multicenter study included 2604 of 2997 eligible patients with dyslipidemia and T2DM who had available estimated glomerular filtration rate (eGFR) measurements. The primary endpoint was eGFR percent change at week 24 from baseline. We also assessed secondary endpoints, which included percent changes in eGFR at weeks 12 and 48 from baseline, as well as changes in eGFR, metabolic profiles (lipid and glycemic levels) at 12, 24, and 48 weeks from baseline, and safety. RESULTS: We noted a significant improvement in eGFR, with mean percent changes of 2.5%, 2.5%, and 3.0% at 12, 24, and 48 weeks, respectively (all adjusted p < 0.05). The eGFR percent changes significantly increased in subgroups with baseline eGFR 30-90 mL/min/1.73 m2, glycated hemoglobin (HbA1c) ≥ 7 at baseline, no hypertension history, T2DM duration > 5 years, or previous statin therapy. Lipid profiles were improved and remained stable throughout the study, and interestingly, fasting glucose and HbA1c were improved at 24 weeks. CONCLUSION: Our findings suggest that pravastatin may have potential benefits for improving eGFR in Korean patients with dyslipidemia and T2DM. This could make it a preferable treatment option for patients with reduced kidney function. TRIAL REGISTRATION NUMBER: NCT05107063 submitted October 27, 2021.

Protective effect of empagliflozin against palmitate-induced lipotoxicity through AMPK in H9c2 cells.

Sodium-glucose cotransporter 2 (SGLT2) inhibitors have recently emerged as novel cardioprotective agents. However, their direct impact on cardiomyocyte injury is yet to be studied. In this work, we investigate the underlying molecular mechanisms of empagliflozin (EMPA), an SGLT2 inhibitor, in mitigating palmitate (PA)-induced cardiomyocyte injury in H9c2 cells. We found that EMPA significantly attenuated PA-induced impairments in insulin sensitivity, ER stress, inflammatory cytokine gene expression, and cellular apoptosis. Additionally, EMPA elevated AMP levels, activated the AMPK pathway, and increased carnitine palmitoyl transferase1 (CPT1) gene expression, which collectively enhanced fatty acid oxidation and reduced stress signals. This study reveals a novel mechanism of EMPA's protective effects against PA-induced cardiomyocyte injury, providing new therapeutic insights into EMPA as a cardioprotective agent.