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AIMS: Sodium/glucose transporter 2 (SGLT2 or SLC5A2) inhibitors lower blood glucose and are also approved treatments for heart failure independent of raised glucose. Various studies have showed that SGLT2 inhibitors relax arteries, but the underlying mechanisms are poorly understood and responses variable across arterial beds. We speculated that SGLT2 inhibitor-mediated arterial relaxation is dependent upon calcitonin gene-related peptide (CGRP) released from sensory nerves independent of glucose transport. METHODS AND RESULTS: The functional effects of SGLT1 and 2 inhibitors (mizagliflozin, dapagliflozin, and empagliflozin) and the sodium/hydrogen exchanger 1 (NHE1) blocker cariporide were determined on pre-contracted resistance arteries (mesenteric and cardiac septal arteries) as well as main renal conduit arteries from male Wistar rats using wire myography. SGLT2, CGRP, TRPV1, and NHE1 expression was determined by western blot and immunohistochemistry. Kv7.4/5/KCNE4 and TRPV1 currents were measured in the presence and absence of dapagliflozin and empagliflozin. All SGLT inhibitors (1-100 µM) and cariporide (30 µM) relaxed mesenteric arteries but had negligible effect on renal or septal arteries. Immunohistochemistry with TRPV1 and CGRP antibodies revealed a dense innervation of sensory nerves in mesenteric arteries that were absent in renal and septal arteries. Consistent with a greater sensory nerve component, the TRPV1 agonist capsaicin relaxed mesenteric arteries more effectively than renal or septal arteries. In mesenteric arteries, relaxations to dapagliflozin, empagliflozin, and cariporide were attenuated by the CGRP receptor antagonist BIBN-4096, depletion of sensory nerves with capsaicin, and blockade of TRPV1 or Kv7 channels. Neither dapagliflozin nor empagliflozin activated heterologously expressed TRPV1 channels or Kv7 channels directly. Sensory nerves also expressed NHE1 but not SGLT2 and cariporide pre-application as well as knockdown of NHE1 by translation stop morpholinos prevented the relaxant response to SGLT2 inhibitors. CONCLUSION: SGLT2 inhibitors relax mesenteric arteries by promoting the release of CGRP from sensory nerves in a NHE1-dependent manner.

Pancreatic ductal adenocarcinoma (PDAC) is an extremely aggressive malignancy with minimal treatment options and a global rise in prevalence. PDAC is characterized by frequent driver mutations including KRAS and TP53 (p53), and a dense, acidic tumor microenvironment (TME). The relation between genotype and TME in PDAC development is unknown. Strikingly, when wild type (WT) Panc02 PDAC cells were adapted to growth in an acidic TME and returned to normal pH to mimic invasive cells escaping acidic regions, they displayed a strong increase of aggressive traits such as increased growth in 3‐dimensional (3D) culture, adhesion‐independent colony formation and invasive outgrowth. This pattern of acidosis‐induced aggressiveness was observed in 3D spheroid culture as well as upon organotypic growth in matrigel, collagen‐I and combination thereof, mimicking early and later stages of PDAC development. Acid‐adaptation‐induced gain of cancerous traits was further increased by p53 knockout (KO), but only in specific extracellular matrix (ECM) compositions. Akt‐ and Transforming growth factor‐β (TGFβ) signaling, as well as expression of the Na+/H+ exchanger NHE1, were increased by acid adaptation. Whereas Akt inhibition decreased spheroid growth regardless of treatment and genotype, stimulation with TGFβI increased growth of WT control spheroids, and inhibition of TGFβ signaling tended to limit growth under acidic conditions only. Our results indicate that a complex crosstalk between tumor acidosis, ECM composition and genotype contributes to PDAC development. The findings may guide future strategies for acidosis‐targeted therapies. [ABSTRACT FROM AUTHOR]

It was shown previously that a metabolite of acetaminophen (APAP), N-acetyl-p-benzoquinone imine (NAPQI), is a potent vasodilator, which could underlie the hypotension observed when APAP is administered intravenously. However, it is unknown whether APAP metabolism to NAPQI is possible in the vasculature. In this study, we examine the hypothesis that APAP is metabolized by cytochrome P450 enzymes within the endothelium, which may be accelerated in critically ill patients by the presence of elevated myeloperoxidase (MPO). Exposure of human coronary artery endothelial cells (HCAECs) to APAP resulted in the formation of protein-bound APAP adducts. Proteomic analysis of HCAECs exposed to APAP showed upregulation of CYP20A1, together with proteins involved in the pentose phosphate pathway and maintaining redox homeostasis. Proteomic analyses of mesenteric arteries from rats administered intravenous APAP are consistent with a key role of the vascular wall in APAP metabolism, with similar proteomic pathway changes identified in HCAECs. These changes occurred over a short timeframe and were not seen in the corresponding proteomic analyses of liver tissue. Intracellular thiols were depleted in HCAECs upon APAP treatment, which was partially attenuated by ketoconazole, consistent with the involvement of cytochrome P450 enzymes in the metabolism of APAP to a thiol-reactive metabolite such as NAPQI. Evidence was also obtained for the metabolism of APAP to a thiol-reactive intermediate by MPO in the absence of chloride ions, consistent with NAPQI formation. Taken together, these data provide a putative mechanism to explain the presentation of hypotension in critically ill patients following IV APAP administration., Competing Interests: Declaration of Competing Interest The authors have no declarations of interest to declare, (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)