Heart failure is characterized by chronic low-grade vascular inflammation, which in itself can lead to endothelial dysfunction. Clinical trials showed reductions in heart failure-related hospitalizations of type 2 diabetic patients using sodium glucose co-transporter 2 inhibitors (SGLT2i's). Whether and how SGLT2i's directly affect the endothelium under inflammatory conditions is not completely understood. The aim of the study was to investigate whether the SGLT2i Empagliflozin (EMPA) and Dapagliflozin (DAPA) reduce tumor necrosis factor α (TNFα) induced endothelial inflammation in vitro. Human coronary arterial endothelial cells (HCAECs) and human umbilical vein endothelial cells (HUVECs) were (pre-)incubated with 1 µM EMPA or DAPA and subsequently exposed to 10 ng/ml TNFα. ROS and NO were measured using live cell imaging. Target proteins were either determined by infrared western blotting or fluorescence activated cell sorting (FACS). The connection between Cav-1 and eNOS was determined by co-immunoprecipitation. Nitric oxide (NO) bioavailability was reduced by TNFα and both EMPA and DAPA restored NO levels in TNFα-stimulated HCAECs. Intracellular ROS was increased by TNFα, and this increase was completely abolished by EMPA and DAPA in HCAECs by means of live cell imaging. eNOS signaling was significantly disturbed after 24 h when cells were exposed to TNFα for 24h, yet the presence of both SGLT2is did not prevent this disruption. TNFα-induced enhanced permeability at t=24h was unaffected in HUVECs by EMPA. Similarly, adhesion molecule expression (VCAM-1 and ICAM-1) was elevated after 4h TNFα (1.5-5.5 fold increase of VCAM-1 and 4-12 fold increase of ICAM-1) but were unaffected by EMPA and DAPA in both cell types. Although we detected expression of SGLT2 protein levels, the fact that we could not silence this expression by means of siRNA and the mRNA levels of SGLT2 were not detectable in HCAECs, suggests aspecificity or our SGLT2 antibody and absence of SGLT2 in our cells. These data suggest that EMPA and DAPA rather restore NO bioavailability by inhibiting ROS generation than by affecting eNOS expression or signaling, barrier function and adhesion molecules expression in TNFα-induced endothelial cells. Furthermore, the observed effects cannot be ascribed to the inhibition of SGLT2 in endothelial cells.
1 May 2006 in The Journal of Clinical Endocrinology & Metabolism
Context: Fibrotic remodeling, especially of the tubule wall, in testes of infertile men is common, but reasons or consequences of these striking changes are not known. Based on cell culture and ex vivo studies, we previously suggested that mast cells via their products tryptase and histamine are involved in the development of fibrosis. However, studies in a relevant human testicular model are required to further test this hypothesis and the mechanisms of testicular fibrosis in general.Objective: The objective of the study was the isolation, culture, and characterization of adult human testicular peritubular cells.Patients and Interventions: Peritubular cells were obtained from biopsies of men suffering from obstructive azoospermia (n = 8) and varicocele (n = 2) but displaying normal spermatogenesis.Results: Explant cultures were obtained from all biopsies. Immunostaining of the cultured cells and corresponding paraffin-embedded tissues with antibodies against markers of fibroblasts (CD90/Thy-1) and smooth muscle cells (α-smooth muscle actin) clearly proved their origin from the peritubular region. These cells displayed morphological features of myofibroblasts, and gene array analyses as well as immunohistochemistry revealed the predominant expression of extracellular matrix genes and genes coding for basement membrane components. The cultured cells retain receptors for the major mast cell products histamine and tryptase. The addition of histamine (100 μm) and the tryptase agonist peptide SLIGKV (10 μm) resulted in a transient increase in intracellular calcium levels, confirming the functionality of the receptors.Conclusions: We conclude that human peritubular cells are a novel model for the investigation of paracrine, including mast cell initiated, interactions in the human testis, which will allow the study of fibrotic processes underlying male idiopathic infertility.
Testicular peritubular cells are myofibroblastic cells, which represent the major cellular components of the wall of the seminiferous tubules. In men their phenotypic characteristics, including possible secretory activity and regulation, are not well known, in neither normal nor pathologically altered testes. Especially in testes of men with impaired spermatogenesis, the cytoarchitecture of the tubular wall is frequently remodeled and presents fibrotic thickening, increased innervation, and infiltration by macrophages and mast cells. The latter are two sources of TNF-α. The purpose of our study was to explore human testicular peritubular cells and mechanisms of their regulation. To this end we primarily studied cultured human testicular peritubular cells (HTPCs), isolated from adult human testes. Having established that HTPCs express TNF-α receptors 1 and 2 and respond to recombinant human TNF-α by a rapid phosphorylation of ERK1/2, we used complementary approaches, including gene array/RT-PCR studies, Western blotting/immunocytochemistry, and ELISA techniques to study phenotypic characteristics of HTPCs and actions of TNFα. We found that HTPCs express the nerve growth factor gene and TNF-α-stimulated mRNA levels and secretion of nerve growth factor in a dose- and time-dependent manner. Similarly, monocyte chemoattractant protein-1 was identified as a product of HTPCs, which was regulated by TNF-α in a concentration- and time-dependent manner. TNF-α furthermore strongly enhanced expression and/or synthesis of other inflammatory molecules, namely IL-6 and cyclooxygenase-2. Active cyclooxygenase-2 is indicated by increased prostaglandin D2 levels. In addition, intercellular adhesion molecule-1, which was not detected at protein level in the absence of TNF-α, was induced upon TNF-α stimulation. In conclusion, these results provide novel insights into the nature of human peritubular cells, which are able to secrete potent signaling molecules and are regulated by TNF-α. These results also hint to an as-yet-unknown role of peritubular cells in normal human testis and involvement in the pathomechanisms associated with impaired spermatogenesis in men.
Remote ischemic preconditioning (RIPC) has been shown to enhance the tolerance of remote organs to cope with a subsequent ischemic event. We hypothesized that RIPC reduces postoperative neurocognitive dysfunction (POCD) in patients undergoing complex cardiac surgery. We conducted a prospective, randomized, double-blind, controlled trial including 180 adult patients undergoing elective cardiac surgery with cardiopulmonary bypass. Patients were randomized either to RIPC or to control group. Primary endpoint was postoperative neurocognitive dysfunction 5–7 days after surgery assessed by a comprehensive test battery. Cognitive change was assumed if the preoperative to postoperative difference in 2 or more tasks assessing different cognitive domains exceeded more than one SD (1 SD criterion) or if the combined Z score was 1.96 or greater (Z score criterion). According to 1 SD criterion, 52% of control and 46% of RIPC patients had cognitive deterioration 5–7 days after surgery (p = 0.753). The summarized Z score showed a trend to more cognitive decline in the control group (2.16±5.30) compared to the RIPC group (1.14±4.02; p = 0.228). Three months after surgery, incidence and severity of neurocognitive dysfunction did not differ between control and RIPC. RIPC tended to decrease postoperative troponin T release at both 12 hours [0.60 (0.19–1.94) µg/L vs. 0.48 (0.07–1.84) µg/L] and 24 hours after surgery [0.36 (0.14–1.89) µg/L vs. 0.26 (0.07–0.90) µg/L]. We failed to demonstrate efficacy of a RIPC protocol with respect to incidence and severity of POCD and secondary outcome variables in patients undergoing a wide range of cardiac surgery. Therefore, definitive large-scale multicenter trials are needed. ClinicalTrials.gov NCT00877305
Introduction: Hypothermia improves survival and neurological recovery after cardiac arrest. Pro-inflammatory cytokines have been implicated in focal cerebral ischemia/reperfusion injury. It is unknown whether cardiac arrest also triggers the release of cerebral inflammatory molecules, and whether therapeutic hypothermia alters this inflammatory response. This study sought to examine whether hypothermia or the combination of hypothermia with anesthetic post-conditioning with sevoflurane affect cerebral inflammatory response after cardiopulmonary resuscitation. Methods: Thirty pigs (28 to 34 kg) were subjected to cardiac arrest following temporary coronary artery occlusion. After seven minutes of ventricular fibrillation and two minutes of basic life support, advanced cardiac life support was started according to the current American Heart Association guidelines. Return of spontaneous circulation was achieved in 21 animals who were randomized to either normothermia at 38°C, hypothermia at 33°C or hypothermia at 33°C combined with sevoflurane (each group: n = 7) for 24 hours. The effects of hypothermia and the combination of hypothermia with sevoflurane on cerebral inflammatory response after cardiopulmonary resuscitation were studied using tissue samples from the cerebral cortex of pigs euthanized after 24 hours and employing quantitative RT-PCR and ELISA techniques. Results: Global cerebral ischemia following resuscitation resulted in significant upregulation of cerebral tissue inflammatory cytokine mRNA expression (mean ± SD; interleukin (IL)-1β 8.7 ± 4.0, IL-6 4.3 ± 2.6, IL-10 2.5 ± 1.6, tumor necrosis factor (TNF)α 2.8 ± 1.8, intercellular adhesion molecule-1 (ICAM-1) 4.0 ± 1.9-fold compared with sham control) and IL-1β protein concentration (1.9 ± 0.6-fold compared with sham control). Hypothermia was associated with a significant (P < 0.05 versus normothermia) reduction in cerebral inflammatory cytokine mRNA expression (IL-1β 1.7 ± 1.0, IL-6 2.2 ± 1.1, IL-10 0.8 ± 0.4, TNFα 1.1 ± 0.6, ICAM-1 1.9 ± 0.7-fold compared with sham control). These results were also confirmed for IL-1β on protein level. Experimental settings employing hypothermia in combination with sevoflurane showed that the volatile anesthetic did not confer additional anti-inflammatory effects compared with hypothermia alone. Conclusions: Mild therapeutic hypothermia resulted in decreased expression of typical cerebral inflammatory mediators after cardiopulmonary resuscitation. This may confer, at least in part, neuroprotection following global cerebral ischemia and resuscitation.