Hannes Hartman

Bio: Hannes Hartman is an academic researcher from Lund University. The author has contributed to research in topics: Acute pancreatitis & Pancreatitis. The author has an hindex of 6, co-authored 11 publications receiving 274 citations.

P-selectin mediates neutrophil rolling and recruitment in acute pancreatitis.

Abstract: BACKGROUND: The adhesive mechanisms regulating leucocyte-endothelium interactions in the pancreas remain elusive, but selectins may play a role. This study examined the molecular mechanisms mediating leucocyte rolling along the endothelium in the pancreas and the therapeutic potential of targeting the rolling adhesive interaction in acute pancreatitis (AP). METHODS: Pancreatitis was induced by retrograde infusion of 5 per cent sodium taurocholate into the pancreatic duct, repeated intraperitoneal administration of caerulein (50 µg/kg) or intraperitoneal administration of L-arginine (4 g/kg) in C57BL/6 mice. A control and a monoclonal antibody against P-selectin were administered before and after induction of AP. Serum and tissue were sampled to assess the severity of pancreatitis, and intravital microscopy was used to study leucocyte rolling. RESULTS: Taurocholate infusion into the pancreatic duct increased the serum level of trypsinogen, trypsinogen activation, pancreatic neutrophil infiltration, macrophage inflammatory protein (MIP) 2 formation and tissue damage. Immunoneutralization of P-selectin decreased the taurocholate-induced increase in serum trypsinogen (median (range) 17·35 (12·20-30·00) versus 1·55 (0·60-15·70) µg/l; P = 0·017), neutrophil accumulation (4·00 (0·75-4·00) versus 0·63 (0-3·25); P = 0·002) and tissue damage, but had no effect on MIP-2 production (14·08 (1·68-33·38) versus 3·70 (0·55-51·80) pg/mg; P = 0·195) or serum trypsinogen activating peptide level (1·10 (0·60-1·60) versus 0·45 (0-1·80) µg/l; P = 0·069). Intravital fluorescence microscopy revealed that anti-P-selectin antibody inhibited leucocyte rolling completely in postcapillary venules of the inflamed pancreas. CONCLUSION: Inhibition of P-selectin protected against pancreatic tissue injury in experimental pancreatitis. Targeting P-selectin may be an effective strategy to ameliorate inflammation in AP. Copyright © 2011 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd. (Less)

Predictive Capacity of Biomarkers for Severe Acute Pancreatitis.

Abstract: Background: Early prediction of severe acute pancreatitis (SAP) substantially improves treatment of patients. A large amount of biomarkers have been studied with this objective. The aim of this work was to study predictive biomarkers using preset cut-off levels in an unselected population of patients with acute pancreatitis (AP). Methods: 232 patients (52.2% males, median age 66 years) with AP admitted to Skane University Hospital, Malmo, were consecutively enrolled. Blood samples were collected upon admission and clinical data were gathered both prospectively at inclusion and through review of medical notes. Cut-off levels were defined based on the reports of prior studies, and through their results eight biomarkers (IL-1β, IL-6, IL-8, IL-10, TNF-α, MCP-1, procalcitonin and D-dimer) were selected for analysis. Results: Of the patients, 83.2% had mild AP and 16.8% had SAP. Levels of IL-1β, IL-6 and IL-10 were significantly (p Conclusions: Previous studies on severity prediction of AP are difficult to compare due to large variations in setups and outcomes. Calculated cut-offs in our cohort were in acceptable range from preset levels, however areas under the curves were low, indicating suboptimal biomarkers for the unselected population investigated. For comparable results and possible clinical implementations, future studies need large consecutive series with a reasonable percentage of severe cases. Additionally, novel biomarkers need to be explored.

Histone Deacetylase Regulates Trypsin Activation, Inflammation, and Tissue Damage in Acute Pancreatitis in Mice.

Abstract: The onset of acute pancreatitis (AP) is characterized by early protease activation followed by inflammation and organ damage, but the mechanisms are poorly understood. We hypothesized that histone deacetylase (HDAC) inhibition might exert protective effects on AP and investigated the role of HDAC in trypsin activation, inflammation, and tissue damage in severe AP. Male C57Bl/6 mice were treated i.p. with the HDAC inhibitor trichostatin A (2 mg/kg) prior to retrograde infusion of taurocholic acid (5 %) into the pancreatic duct. Serum levels of amylase and interleukin (IL)-6, pancreatic levels of macrophage inflammatory protein-2 (MIP-2) as well as tissue morphology and myeloperoxidase activity in the pancreas and lung were determined 24 h after taurocholate challenge. Trypsin activation was analyzed in isolated acinar cells. Quantitative RT-PCR was used to examine the expression of pro-inflammatory mediators in the pancreas. Pretreatment with trichostatin A decreased amylase levels by 70 % and protected against tissue injury in the pancreas. Moreover, HDAC inhibition reduced systemic IL-6 by more than 95 % and pulmonary myeloperoxidase activity by 75 %. Notably, inhibition of HDAC abolished taurocholate-induced gene expression of cyclooxygenase-2, MIP-2, monocyte chemotactic protein-1, IL-6, and IL-1β in the pancreas. In addition, HDAC inhibition reduced cerulein-induced trypsinogen activation in isolated acinar cells. Our findings show that HDAC regulates trypsin activation, inflammation, and tissue damage in AP. Thus, targeting HDAC could serve as novel therapeutic approach in the management of severe AP.

Neutrophil extracellular traps in COVID-19.

Abstract: In severe cases of coronavirus disease 2019 (COVID-19), viral pneumonia progresses to respiratory failure. Neutrophil extracellular traps (NETs) are extracellular webs of chromatin, microbicidal proteins, and oxidant enzymes that are released by neutrophils to contain infections. However, when not properly regulated, NETs have the potential to propagate inflammation and microvascular thrombosis - including in the lungs of patients with acute respiratory distress syndrome. We now report that sera from patients with COVID-19 have elevated levels of cell-free DNA, myeloperoxidase-DNA (MPO-DNA), and citrullinated histone H3 (Cit-H3); the latter 2 are specific markers of NETs. Highlighting the potential clinical relevance of these findings, cell-free DNA strongly correlated with acute-phase reactants, including C-reactive protein, D-dimer, and lactate dehydrogenase, as well as absolute neutrophil count. MPO-DNA associated with both cell-free DNA and absolute neutrophil count, while Cit-H3 correlated with platelet levels. Importantly, both cell-free DNA and MPO-DNA were higher in hospitalized patients receiving mechanical ventilation as compared with hospitalized patients breathing room air. Finally, sera from individuals with COVID-19 triggered NET release from control neutrophils in vitro. Future studies should investigate the predictive power of circulating NETs in longitudinal cohorts and determine the extent to which NETs may be novel therapeutic targets in severe COVID-19.

Neutrophil: A Cell with Many Roles in Inflammation or Several Cell Types?

Abstract: Neutrophils are the most abundant leukocytes in the circulation, and have been regarded as first line of defense in the innate arm of the immune system. They capture and destroy invading microorganisms, through phagocytosis and intracellular degradation, release of granules, and formation of neutrophil extracellular traps after detecting pathogens. Neutrophils also participate as mediators of inflammation. The classical view for these leukocytes is that neutrophils constitute a homogenous population of terminally differentiated cells with a unique function. However, evidence accumulated in recent years, has revealed that neutrophils present a large phenotypic heterogeneity and functional versatility, which place neutrophils as important modulators of both inflammation and immune responses. Indeed, the roles played by neutrophils in homeostatic conditions as well as in pathological inflammation and immune processes are the focus of a renovated interest in neutrophil biology. In this review, I present the concept of neutrophil phenotypic and functional heterogeneity and describe several neutrophil subpopulations reported to date. I also discuss the role these subpopulations seem to play in homeostasis and disease.

Cancer cells induce metastasis-supporting neutrophil extracellular DNA traps

Abstract: Neutrophils, the most abundant type of leukocytes in blood, can form neutrophil extracellular traps (NETs). These are pathogen-trapping structures generated by expulsion of the neutrophil's DNA with associated proteolytic enzymes. NETs produced by infection can promote cancer metastasis. We show that metastatic breast cancer cells can induce neutrophils to form metastasis-supporting NETs in the absence of infection. Using intravital imaging, we observed NET-like structures around metastatic 4T1 cancer cells that had reached the lungs of mice. We also found NETs in clinical samples of triple-negative human breast cancer. The formation of NETs stimulated the invasion and migration of breast cancer cells in vitro. Inhibiting NET formation or digesting NETs with deoxyribonuclease I (DNase I) blocked these processes. Treatment with NET-digesting, DNase I-coated nanoparticles markedly reduced lung metastases in mice. Our data suggest that induction of NETs by cancer cells is a previously unidentified metastasis-promoting tumor-host interaction and a potential therapeutic target.

2019 WSES guidelines for the management of severe acute pancreatitis

Abstract: Although most patients with acute pancreatitis have the mild form of the disease, about 20–30% develops a severe form, often associated with single or multiple organ dysfunction requiring intensive care. Identifying the severe form early is one of the major challenges in managing severe acute pancreatitis. Infection of the pancreatic and peripancreatic necrosis occurs in about 20–40% of patients with severe acute pancreatitis, and is associated with worsening organ dysfunctions. While most patients with sterile necrosis can be managed nonoperatively, patients with infected necrosis usually require an intervention that can be percutaneous, endoscopic, or open surgical. These guidelines present evidence-based international consensus statements on the management of severe acute pancreatitis from collaboration of a panel of experts meeting during the World Congress of Emergency Surgery in June 27–30, 2018 in Bertinoro, Italy. The main topics of these guidelines fall under the following topics: Diagnosis, Antibiotic treatment, Management in the Intensive Care Unit, Surgical and operative management, and Open abdomen.

New insights into acute pancreatitis

Abstract: The incidence of acute pancreatitis continues to increase worldwide, and it is one of the most common gastrointestinal causes for hospital admission in the USA. In the past decade, substantial advancements have been made in our understanding of the pathophysiological mechanisms of acute pancreatitis. Studies have elucidated mechanisms of calcium-mediated acinar cell injury and death and the importance of store-operated calcium entry channels and mitochondrial permeability transition pores. The cytoprotective role of the unfolded protein response and autophagy in preventing sustained endoplasmic reticulum stress, apoptosis and necrosis has also been characterized, as has the central role of unsaturated fatty acids in causing pancreatic organ failure. Characterization of these pathways has led to the identification of potential molecular targets for future therapeutic trials. At the patient level, two classification systems have been developed to classify the severity of acute pancreatitis into prognostically meaningful groups, and several landmark clinical trials have informed management strategies in areas of nutritional support and interventions for infected pancreatic necrosis that have resulted in important changes to acute pancreatitis management paradigms. In this Review, we provide a summary of recent advances in acute pancreatitis with a special emphasis on pathophysiological mechanisms and clinical management of the disorder.