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Obesity induces chronic inflammation resulting in insulin resistance and metabolic disorders. Cold exposure can improve insulin sensitivity in humans and rodents, but the mechanisms have not been fully elucidated. Here, we find that cold resolves obesity-induced inflammation and insulin resistance and improves glucose tolerance in diet-induced obese mice. The beneficial effects of cold exposure on improving obesity-induced inflammation and insulin resistance depend on brown adipose tissue (BAT) and liver. Using targeted liquid chromatography with tandem mass spectrometry, we discovered that cold and β3-adrenergic stimulation promote BAT to produce maresin 2 (MaR2), a member of the specialized pro-resolving mediators of bioactive lipids that play a role in the resolution of inflammation. Notably, MaR2 reduces inflammation in obesity in part by targeting macrophages in the liver. Thus, BAT-derived MaR2 could contribute to the beneficial effects of BAT activation in resolving obesity-induced inflammation and may inform therapeutic approaches to combat obesity and its complications.

Occurrence of hyperglycemia upon infection is associated with worse clinical outcome in COVID-19 patients. However, it is still unknown whether SARS-CoV-2 directly triggers hyperglycemia. Herein, we interrogated whether and how SARS-CoV-2 causes hyperglycemia by infecting hepatocytes and increasing glucose production. We performed a retrospective cohort study including patients that were admitted at a hospital with suspicion of COVID-19. Clinical and laboratory data were collected from the chart records and daily blood glucose values were analyzed to test the hypothesis on whether COVID-19 was independently associated with hyperglycemia. Blood glucose was collected from a subgroup of nondiabetic patients to assess pancreatic hormones. Postmortem liver biopsies were collected to assess the presence of SARS-CoV-2 and its transporters in hepatocytes. In human hepatocytes, we studied the mechanistic bases of SARS-CoV-2 entrance and its gluconeogenic effect. SARS-CoV-2 infection was independently associated with hyperglycemia, regardless of diabetic history and beta cell function. We detected replicating viruses in human hepatocytes from postmortem liver biopsies and in primary hepatocytes. We found that SARS-CoV-2 variants infected human hepatocytes in vitro with different susceptibility. SARS-CoV-2 infection in hepatocytes yields the release of new infectious viral particles, though not causing cell damage. We showed that infected hepatocytes increase glucose production and this is associated with induction of PEPCK activity. Furthermore, our results demonstrate that SARS-CoV-2 entry in hepatocytes occurs partially through ACE2- and GRP78-dependent mechanisms. SARS-CoV-2 infects and replicates in hepatocytes and exerts a PEPCK-dependent gluconeogenic effect in these cells that potentially is a key cause of hyperglycemia in infected patients.

Hyperaldosteronism (HA), characterized by an autonomous production of aldosterone, promotes increased blood pressure and cardiovascular damage. The perivascular adipose tissue (PVAT) participates of the control of vascular function and is inflamed in HA. Autophagy is a recycling process of unnecessary or dysfunctional components and it is important for inflammatory tolerance, but whether the autophagic flux is dysregulated in the PVAT during HA, which would contribute to the inflammation and dysfunction of this tissue, is still to be elucidated. Herein, we hypothesize that treatment with autophagy inducer will rescue the autophagic unbalance, subsequently decreasing inflammation, and improving PVAT function during HA. 10-12-weeks-old male C57BL/6J mice were infused with aldosterone for 14 days (600ug/Kg/day via osmotic mini-pump). Vascular function was studied in PVAT-intact thoracic aortae and blood pressure was analyzed by the tail-cuff. Brown adipocyte cells (WT1) were used to evaluate the molecular mechanisms by which HA induces PVAT dysfunction. HA promoted an increase in systolic blood pressure [mmHg – before HA: 123.8±0.9 vs. after HA: 149.5±1.1]. Furthermore, PVAT decreased the contractile response [Emax (% KCl)] in control arteries [Control PVAT (-): 137.2±1.9 vs. Control PVAT (+): 107.4±2.7], whereas HA promoted loss of PVAT anti-contractile effect [HA PVAT (-): 159.9±2.9 vs. HA PVAT (+): 164.1±3.4]. We found that PVAT from HA mice presents an unbalance in LC3II/LC3I ratio, an important autophagy marker, inflammation, characterized by elevated TNF-α, IL-6, IL-1β, IL-17, and IFN-γ gene expression, and elevated reactive oxygen species (ROS). To induce autophagy, we treated mice with TB-peptide (16mg/Kg/day via ip for 7 days). TB-peptide partially improved the PVAT function of mice with HA [HA PVAT (+): 122.5±4.1]. On mechanistic levels, aldosterone (100nM, 12-96 h) induced an oscillatory autophagy flux in WT1 cells, characterized by an initial increase in LC3II/LC3I ratio at 12 and 24 h, followed by a decrease at 48 and 96 h. These effects were not observed in the presence of the mineralocorticoid receptor antagonist (Eplerenone, 1μM). Aldosterone also led to the expression of pro-inflammatory genes (TNF-α, IL-6, IL-1β, IL-17, and IFN-γ) and elevated ROS, such effects were prevented by inducing autophagy with TB-peptide. In summary, these findings reveal a new mechanism in vascular injury associated with HA, aldosterone impairs autophagic flux in PVAT, inducing inflammation, oxidative stress, and dysfunction. Our study places PVAT and autophagic process as attractive targets to reduce cardiovascular risk in HA. FAPESP (2022/06639-2), NHLBI-R00 (R00HL14013903), AHA-CDA (CDA857268), Vascular Medicine Institute, the Hemophilia Center of Western Pennsylvania Vitalant, and Children's Hospital of Pittsburgh of the UPMC Health System. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Urinary bladder dysfunction is rarely spontaneously reported by sickle cell disease (SCD) patients to their caregivers. With increasing survival of these patients, physicians may expect that urinary complaints increase in association with classical urological disorders associated with advanced age. Nocturia has long been attributed to constant increased urinary volumes in SCD. As part of the renal complications of sickling, renal medullary infarcts lead to decreased ability to concentrate urine, yielding higher daily urinary volumes, compensatory polydipsia and, eventually, the need for nocturnal bladder voiding. For comparison, the effects of alterations on bladder function have been better characterized in diabetic bladder dysfunction (DBD). It has been suggested that DBD comprehends so-called “early” and “late” phases of the disease. In the early phase of DBD, the bladder is hyperactive, leading to nocturia and urge incontinence. Later in the course of the disease, the detrusor smooth muscle becomes atonic, leading to an underactive bladder. Moreover, Berkeley sickle cell disease (SS) transgenic mice display several clinical manifestations similar to those seen in humans. Thus, the aim of this study was to evaluate the contractile mechanisms of isolated DSM (in vitro) and urinary function by cystometry (in vivo) in young (early) and old (late) SS mice. Young (3 month) old (1 year and 3 month) SS mice and young (3 month) C57BL/6 mice (control) tissues were removed and placed in Krebs solution. The strips were mounted in isolated organ baths. Cumulative concentration-response curves to muscarinic agonist, carbachol (CCh; 0.01-100 μM), hyperpolarizing solution, chloride potassium (KCl; 1-300mM) and frequency-response curves for electrical field stimulation (EFS; 1-32Hz) were obtained in DSM. Cystometry was used to evaluate the urinary function in vivo. The cumulative addition of the CCh (10nM-100µM) produced concentration dependent contractions in strips of isolated DSM. The maximal contractions induced by CCh were markedly lower in bladder muscle from the young-SS mice (0.58 ± 0.11 mN/mg of tissue; n=7; P Financial Support: FAPESP/CNPq/INCTS Disclosures: No relevant conflicts of interest to declare.

As radiações ultravioletas (UV) são as principais responsáveis pelo desenvolvimento de lesões pré-malignas e malignas cutâneas. As duas principais radiações que atingem a superfície terrestre, responsáveis por danos ao DNA, são do tipo UVA (315 - 400nm) e UVB (280 – 315nm). Esta última induz a um ambiente pró-inflamatório quando da exposição aguda e imunossupressor quando crônico. Esta ambiguidade de evento a longo prazo induz ao tipo mais incidente de câncer, o de pele. A irradiação UVB atinge principalmente a camada epidérmica da pele, apresentando dois principais mecanismos de dano. Dano de maneira direta através da formação de dímeros de pirimidina, e a indireta, através de danos oxidativos, que se relacionam por produzir um microambiente inflamatório com oxidação de lipídeos, proteínas e mutação gênica. A imunossupressão também faz parte deste quadro caracterizando, assim, a fotocarcinogênese. Apesar da pele possuir um sistema antioxidante eficiente que controla, em parte, o excesso de espécies reativas de oxigênio produzida pela irradiação, a procura por substâncias que reduzam os efeitos danosos da UVB na pele tem sido intensa. Dentre as substâncias tem-se a selenocisteína, N-acetil-cisteína, metformina. A vitamina E, uma das mais estudadas até o momento, busca reduzir os efeitos oxidativos e imunossupressores causados pela irradiação. A metformina, um medicamento vastamente utilizado no tratamento do diabetes do tipo 2, mostrou diminuir a incidência de câncer de mama em mulheres diabéticas que fazem o seu uso. Entretanto, outros estudos conduzidos em pacientes com outros tipos de câncer não encontram a mesma resposta. Em virtude da pouca informação sobre os possíveis mecanismos envolvidos na redução da proliferação celular ou mesmo inibição do desenvolvimento do câncer quando do uso da metformina, o objetivo do presente trabalho foi trazer novas informações sobre os mecanismos desta droga sobre os efeitos inflamatórios, imunológicos e oxidativos causados pela irradiação UVB. Foi utilizado o modelo experimental murino com irradiação aguda UVB (400mJ/cm2) pré-tratado com metformina (90mg/Kg via i.p) por 11 dias. Os grupos foram divididos em: tratados com tampão fosfato salina (C+PBS); pré-tratados com metformina (C+MET); irradiado tratado com PBS (IRR+PBS); e irradiado pré-tratado com metformina (IRR+MET). Após 24h da irradiação o sangue e a pele foram removidos, o perfil redox e a quantificação de algumas citocinas epidérmicas imunomodulatórias foram quantificados. A epiderme foi separada da derme onde foram analisados a atividade metabólica mitocondrial, os níveis de ânion radical superóxido e a quantidade de células de Langerhans. Dentro das análises oxidativas sistêmicas, o malondialdeído (MDA) apresentou-se elevado (p