Matrigel plug assay: evaluation of the angiogenic response by reverse transcription-quantitative PCR

The subcutaneous Matrigel plug assay in mice is a method of choice for the in vivo evaluation of pro- and anti-angiogenic molecules. However, quantification of the angiogenic response in the plug remains a problematic task. Here we report a simple, rapid, unbiased and reverse transcription-quantitative PCR (RT-qPCR) method to investigate the angiogenic process occurring in the Matrigel plug in response to fibroblast growth factor-2 (FGF2). To this purpose, a fixed amount of human cells were added to harvested plugs at the end of the in vivo experimentation as an external cell tracer. Then, mRNA levels of the pan endothelial cell markers murine CD31 and vascular endothelial-cadherin were measured by species-specific RT-qPCR analysis of the total RNA and data were normalized for human GAPDH or β-actin mRNA levels. RT-qPCR was used also to measure the levels of expression in the plug of various angiogenesis/inflammationrelated genes. The procedure allows the simultaneous, quantitative evaluation of the newly-formed endothelium and of non endothelial/inflammatory components of the cellular infiltrate in the Matrigel implant, as well as the expression of genes involved in the modulation of the angiogenesis process. Also, the method consents the quantitative assessment of the effect of local or systemic administration of anti-angiogenic compounds on the neovascular response triggered by FGF2

Parathyroid Retrospective Analysis of Neoplasms Incidence (pTRANI Study): An Italian Multicenter Study on Parathyroid Carcinoma and Atypical Parathyroid Tumour

Background: Parathyroid cancer (PC) is a rare sporadic or hereditary malignancy whose histologic features were redefined with the 2022 WHO classification. A total of 24 Italian institutions designed this multicenter study to specify PC incidence, describe its clinical, functional, and imaging characteristics and improve its differentiation from the atypical parathyroid tumour (APT). Methods: All relevant information was collected about PC and APT patients treated between 2009 and 2021. Results: Among 8361 parathyroidectomies, 351 patients (mean age 59.0 ± 14.5; F = 210, 59.8%) were divided into the APT (n = 226, 2.8%) and PC group (n = 125, 1.5%). PC showed significantly higher rates (p < 0.05) of bone involvement, abdominal, and neurological symptoms than APT (48.8% vs. 35.0%, 17.6% vs. 7.1%, 13.6% vs. 5.3%, respectively). Ultrasound (US) diameter >3 cm (30.9% vs. 19.3%, p = 0.049) was significantly more common in the PC. A significantly higher frequency of local recurrences was observed in the PC (8.0% vs. 2.7%, p = 0.022). Mortality due to consequences of cancer or uncontrolled hyperparathyroidism was 3.3%. Conclusions: Symptomatic hyperparathyroidism, high PTH and albumin-corrected serum calcium values, and a US diameter >3 cm may be considered features differentiating PC from APT. 2022 WHO criteria did not impact the diagnosis

2020 WSES guidelines for the detection and management of bile duct injury during cholecystectomy.

Bile duct injury (BDI) is a dangerous complication of cholecystectomy, with significant postoperative sequelae for the patient in terms of morbidity, mortality, and long-term quality of life. BDIs have an estimated incidence of 0.4-1.5%, but considering the number of cholecystectomies performed worldwide, mostly by laparoscopy, surgeons must be prepared to manage this surgical challenge. Most BDIs are recognized either during the procedure or in the immediate postoperative period. However, some BDIs may be discovered later during the postoperative period, and this may translate to delayed or inappropriate treatments. Providing a specific diagnosis and a precise description of the BDI will expedite the decision-making process and increase the chance of treatment success. Subsequently, the choice and timing of the appropriate reconstructive strategy have a critical role in long-term prognosis. Currently, a wide spectrum of multidisciplinary interventions with different degrees of invasiveness is indicated for BDI management. These World Society of Emergency Surgery (WSES) guidelines have been produced following an exhaustive review of the current literature and an international expert panel discussion with the aim of providing evidence-based recommendations to facilitate and standardize the detection and management of BDIs during cholecystectomy. In particular, the 2020 WSES guidelines cover the following key aspects: (1) strategies to minimize the risk of BDI during cholecystectomy; (2) BDI rates in general surgery units and review of surgical practice; (3) how to classify, stage, and report BDI once detected; (4) how to manage an intraoperatively detected BDI; (5) indications for antibiotic treatment; (6) indications for clinical, biochemical, and imaging investigations for suspected BDI; and (7) how to manage a postoperatively detected BDI

The SIFIPAC/WSES/SICG/SIMEU guidelines for diagnosis and treatment of acute appendicitis in the elderly (2019 edition).

The epidemiology and the outcomes of acute appendicitis in elderly patients are very different from the younger population. Elderly patients with acute appendicitis showed higher mortality, higher perforation rate, lower diagnostic accuracy, longer delay from symptoms onset and admission, higher postoperative complication rate and higher risk of colonic and appendiceal cancer. The aim of the present work was to investigate age-related factors that could influence a different approach, compared to the 2016 WSES Jerusalem guidelines on general population, in terms of diagnosis and management of elderly patient with acute appendicitis. During the XXIX National Congress of the Italian Society of Surgical Pathophysiology (SIFIPAC) held in Cesena (Italy) in May 2019, in collaboration with the Italian Society of Geriatric Surgery (SICG), the World Society of Emergency Surgery (WSES) and the Italian Society of Emergency Medicine (SIMEU), a panel of experts participated to a Consensus Conference where eight panelists presented a number of statements, which were developed for each of the four topics about diagnosis and management of acute appendicitis in elderly patients, formulated according to the GRADE system. The statements were then voted, eventually modified and finally approved by the participants to the Consensus Conference. The current paper is reporting the definitive guidelines statements on each of the following topics: diagnosis, non-operative management, operative management and antibiotic therapy

The SIFIPAC/WSES/SICG/SIMEU guidelines for diagnosis and treatment of acute appendicitis in the elderly (2019 edition).

The epidemiology and the outcomes of acute appendicitis in elderly patients are very different from the younger population. Elderly patients with acute appendicitis showed higher mortality, higher perforation rate, lower diagnostic accuracy, longer delay from symptoms onset and admission, higher postoperative complication rate and higher risk of colonic and appendiceal cancer. The aim of the present work was to investigate age-related factors that could influence a different approach, compared to the 2016 WSES Jerusalem guidelines on general population, in terms of diagnosis and management of elderly patient with acute appendicitis. During the XXIX National Congress of the Italian Society of Surgical Pathophysiology (SIFIPAC) held in Cesena (Italy) in May 2019, in collaboration with the Italian Society of Geriatric Surgery (SICG), the World Society of Emergency Surgery (WSES) and the Italian Society of Emergency Medicine (SIMEU), a panel of experts participated to a Consensus Conference where eight panelists presented a number of statements, which were developed for each of the four topics about diagnosis and management of acute appendicitis in elderly patients, formulated according to the GRADE system. The statements were then voted, eventually modified and finally approved by the participants to the Consensus Conference. The current paper is reporting the definitive guidelines statements on each of the following topics: diagnosis, non-operative management, operative management and antibiotic therapy

Regulation of VEGFR2 signaling in angiogenesis and vascular permeability

Angiogenesis and vascular permeability occur in physiological and pathological conditions. Angiogenesis denotes the process of blood vessel formation from preexisting quiescent vessels. Angiogenesis is initiated by proangiogenic factors, inducing endothelial cell sprouting, migration and anastomosis, followed by regression of the new vessels or maturation into a quiescent status. Vascular permeability is the process where blood vessels exchange nutrients, solutes and inflammatory cells with the surrounding tissue. Small molecules freely cross the endothelial wall, however macromolecules and cells leak out from the vasculature only after stimulation by certain factors, including VEGF. Angiogenesis and vascular permeability are tightly regulated physiological processes, but uncontrolled angiogenesis and excessive leakage lead to pathological conditions and the progression of several diseases. VEGF and its receptor VEGFR2 are critical players in angiogenesis and in vascular permeability. The binding of the ligand to the receptor is not the only event involved in the activation and regulation of the signaling cascade. Coreceptors, kinases, phosphatases, and other proteins involved in the trafficking of the complex modulate the signal amplitude and duration. VEGF/VEGFR2 complex combined with the coreceptor NRP1 has a strong pro-angiogenic action and a critical role in angiogenesis. Both VEGFR2 and NRP1 bind VEGF and can present VEGF in cis, when both VEGFR2 and NRP1 are expressed on the same endothelial cell or in trans, when NRP1 is expressed on an adjacent endothelial cell or another type of cell. Y949 and Y1212 are two of the main phosphorylation sites of VEGFR2 induced by VEGFA. The binding of phosphorylated Y949 to the SH2 domain of TSAd regulates vascular permeability leading to Src activation and adherens junction opening in vitro. Phospho-Y1212 is implicated in actin stress fiber remodeling via the adapter Nck, affecting the actin cytoskeleton and endothelial cell migration in vitro. Paladin is a vascular-enriched phosphatase-domain containing protein without reported phosphatase activity and is a negative regulator of insulin receptor and Toll-like receptor 9 signaling. In this thesis work, I have investigated the spatial dynamics of NRP1/VEGFR2 complex formation (in cis and in trans) for coordinating VEGF-mediated angiogenesis in physiological and in pathological conditions (Paper I). I have studied, in vivo, the role of VEGFR2 Y949 in vascular permeability and metastatic spread (Paper II) and the role of VEGFR2 Y1212 in angiogenic remodeling and vessel stability (Paper III). Furthermore, I have examined paladin’s role in regulating VEGF/VEGFR2 signaling and VE-cadherin junction stability, in angiogenic sprouting and vascular permeability (Paper IV). In conclusion, VEGF/VEGFR2 signaling is regulated by a multifactor system and each individual regulatory mechanism leads to a specific outcome in angiogenesis, vascular permeability and vessel stability

Myc-dependent endothelial proliferation is controlled by phosphotyrosine 1212 in VEGF receptor-2

Exaggerated signaling by vascular endothelial growth factor (VEGF)-A and its receptor, VEGFR2, in pathologies results in poor vessel function. Still, pharmacological suppression of VEGFA/VEGFR2 may aggravate disease. Delineating VEGFR2 signaling in vivo provides strategies for suppression of specific VEGFR2-induced pathways. Three VEGFR2 tyrosine residues (Y949, Y1212, and Y1173) induce downstream signaling. Here, we show that knock-in of phenylalanine to create VEGFR2 Y1212F in C57Bl/6 and FVB mouse strains leads to loss of growth factor receptor-bound protein 2- and phosphoinositide 3 '-kinase (PI3K)p85 signaling. C57Bl/6 Vegfr2(Y1212F/Y1212F) show reduced embryonic endothelial cell (EC) proliferation and partial lethality. FVB Vegfr2(Y1212F/Y1212F) show reduced postnatal EC proliferation. Reduced EC proliferation in Vegfr2(Y1212F/Y1212F) explants is rescued by c-Myc overexpression. We conclude that VEGFR2 Y1212 signaling induces activation of extracellular-signal-regulated kinase (ERK)1/2 and Akt pathways required for c-Myc-dependent gene regulation, endothelial proliferation, and vessel stability

Paladin is a phosphoinositide phosphatase regulating endosomal VEGFR2 signalling and angiogenesis

Cell signalling governs cellular behaviour and is therefore subject to tight spatiotemporal regulation. Signalling output is modulated by specialized cell membranes and vesicles which contain unique combinations of lipids and proteins. The phosphatidylinositol 4,5-bisphosphate (PI(4,5)P-2), an important component of the plasma membrane as well as other subcellular membranes, is involved in multiple processes, including signalling. However, which enzymes control the turnover of non-plasma membrane PI(4,5)P-2, and their impact on cell signalling and function at the organismal level are unknown. Here, we identify Paladin as a vascular PI(4,5)P-2 phosphatase regulating VEGFR2 endosomal signalling and angiogenesis. Paladin is localized to endosomal and Golgi compartments and interacts with vascular endothelial growth factor receptor 2 (VEGFR2) in vitro and in vivo. Loss of Paladin results in increased internalization of VEGFR2, over-activation of extracellular regulated kinase 1/2, and hypersprouting of endothelial cells in the developing retina of mice. These findings suggest that inhibition of Paladin, or other endosomal PI(4,5)P-2 phosphatases, could be exploited to modulate VEGFR2 signalling and angiogenesis, when direct and full inhibition of the receptor is undesirable.Shared first authorship: Anja Nitzsche, Riikka Pietilä and Dominic T Love</p

The SIFIPAC/WSES/SICG/SIMEU guidelines for diagnosis and treatment of acute appendicitis in the elderly (2019 edition).

The epidemiology and the outcomes of acute appendicitis in elderly patients are very different from the younger population. Elderly patients with acute appendicitis showed higher mortality, higher perforation rate, lower diagnostic accuracy, longer delay from symptoms onset and admission, higher postoperative complication rate and higher risk of colonic and appendiceal cancer. The aim of the present work was to investigate age-related factors that could influence a different approach, compared to the 2016 WSES Jerusalem guidelines on general population, in terms of diagnosis and management of elderly patient with acute appendicitis. During the XXIX National Congress of the Italian Society of Surgical Pathophysiology (SIFIPAC) held in Cesena (Italy) in May 2019, in collaboration with the Italian Society of Geriatric Surgery (SICG), the World Society of Emergency Surgery (WSES) and the Italian Society of Emergency Medicine (SIMEU), a panel of experts participated to a Consensus Conference where eight panelists presented a number of statements, which were developed for each of the four topics about diagnosis and management of acute appendicitis in elderly patients, formulated according to the GRADE system. The statements were then voted, eventually modified and finally approved by the participants to the Consensus Conference. The current paper is reporting the definitive guidelines statements on each of the following topics: diagnosis, non-operative management, operative management and antibiotic therapy