Role of the VEGFC/VEGFR3 pathway, beyond developmental lymphangiogenesis

There are two vascular systems in the body, for blood and lymph, and both are indispensable for embryonic development. The closed circuit of blood vessels is responsible for oxygen and nutrient delivery to all compartments of the body and removal of CO2 and waste products from tissues. The open-ended lymphatic system works as a return route for fluid, immune cells and dietary lipids into the blood circulation. The heart is the central engine for blood flow whereas lymphatic flow is achieved by skeletal and smooth muscle contraction around the lymphatic vessels. Differences between the blood vascular and lymphatic systems are apparent, from the molecular to the functional level. However, the two types of vessels also share a number of signaling molecules and building blocks of vessels. The purpose of the studies presented in this thesis was to expand our knowledge about Vascular Endothelial Growth Factors (VEGFs) and their receptors in development and pathological conditions. In the first study, we found, surprisingly, that VEGFR-3, the receptor for the principal lymphatic vessel growth factor, VEGF-C, is crucial for the normal patterning of the developing blood vessels and that endothelial deletion of Vegfr3, but not VEGFR-3-blocking antibodies, leads to excessive blood vessel sprouting and branching. Furthermore, macrophages that express the VEGFR-3 and VEGFR- 2 ligand VEGF-C localized to the vessel branchpoints, and Vegfc heterozygous mice exhibited inefficient angiogenesis characterized by decreased vascular branching. Our second study focused on the pathological aspect of the atherosclerosis. By using the transgenic mouse that overexpress soluble VEGFR-3 (VEGF-C/D trap) we could link the impaired lymphatic vessels to lipoprotein metabolism, increased plasma cholesterol levels, and enhanced atherogenesis. In the third project we focused on the role of lymphangiogenic growth factors in the steady-state homeostasis of lymphatic vessels in adult mice. Our findings from this study indicated that the lymphangiogenic growth factors provide trophic and dynamic regulation of the intestinal lymphatic vasculature, which could be especially important in the dietary regulation of adiposity and cholesterol metabolism. Finally in the last study we discovered a new role of VEGF-C in the embryonic development. To our surprise, we found a striking VEGF-C dependent phenotype with defective fetal liver erythropoiesis that resulted severe anemia in the Vegfc deteled embryos. These studies have revealed a new viewpoint regarding the VEGF-C/VEGFR-3 pathway in embryonic and pathological conditions. With these results, our understanding of the VEGF family members has expanded beyond the blood and lymphatic vessel. Hopefully, this new knowledge will improve the possibilities to target the VEGF-C/VEGFR-3 pathway for the treatment of human diseases such as atherosclerosis, obesity, and vascular diseases.Ihmisillä ja muilla kehittyneillä eläimillä on kaksi erillistä nesteenkuljetus järjestelmää kehossa. Nämä järjestelmät tunnetaan verisuonistona ja imusuonina. Suljetun verenkiertojärjestelmän tehtävänä on kuljettaa happea ja ravintoaineita ympäri kehoa ja samalla poistaa hiilidioksidia ja muita kuona-aineita. Imusuonten tehtävänä on kerätä verisuonista poistunutta nestettä, vastata immuunisolujen kuljetuksesta sekä osallistuvat ravintoaineiden keräämiseen suolesta. Sydän toimii moottorina suljetulle verenkierrolle, mutta imunesteen liikkumisesta vastaa lihassolujen paikallinen supistuminen kudostasolla. Imusuonet eroavat rakenteellisesti verisuonista, sillä imusuoni verkosto koostuu suonista, jotka ovat umpipussisia kudosten sisällä. Rakenteellisista ja toiminnallisista eroista huolimatta nämä kaksi suonistoverkostoa jakavat suurenmäärän yhteisiä piirteitä. Tämän väitöskirja tutkimuksen tarkoituksena on lisätä tietoa suonistokasvutekijöistä (Vascular Endothelial Growth Factors VEGFs) kehitysbiologisessa kontekstissa ja patologisissa tilanteissa. Väitöskirjan ensimmäisessä tutkimuksessa pystyimme osoittamaan kuinka VEGFR-3, joka on pääsääntöisesti kuvattu olevan imusuoni spesifinen kasvutekijä, on erittäin tärkeässä roolissa verisuonten kehittymisessä ja reseptorin toiminnan estäminen johtaa epänormaaliin verisuonten kasvuun. Toisessa tutkimuksessa pystyimme todentamaan, että estämällä imusuonten kasvuun vaikuttavan VEGF-C/VEGFR-3 interaktion, valtimotauti kehittyy vakavammaksi kuin kontrolli hiirillä. Kolmannessa osatyössä näytimme, että VEGF-C on tarpeellinen suoliston imusuonten normaaliin toimintaan myös aikuisella eläimellä ja tämän geenin poistaminen johtaa hiirellä ilmiasuun jossa rasva-aineiden imeytyminen suolesta häiriintyy. Viimeisessä osakokeessa löysimme aikaisemmin tuntemattoman roolin VEGF-C kasvutekijälle yksilönkehityksen aikaisessa verisolujen kehityksessä. Kaiken kaikkiaan tämä väitöskirja sisältää osatöitä, jotka ovat lisänneet tietoisuutta VEGFR-3/VEGF-C interaktiosta niin kehitysbiologisesti kuin patologisissa malleissa. Tämän väitöskirjan osatyöt ovat avartaneet kyseisten molekyylien aikaisemmin tunnettuja rooleja, jotka ovat keskittyneet imusuonten kehittymiseen, avarammaksi ja siten mahdollisesti tulevaisuudessa kliinisesti tärkeiksi kohteiksi

Optimization of Proprioceptive Stimulation Frequency and Movement Range for fMRI

For vision, audition and tactile sense, the optimal stimulus frequency for fMRI is somewhat known. For proprioception, i.e., the “movement sense”, however, the optimal frequency is unknown. We studied the effect of passive-finger-movement frequency on proprioceptive fMRI responses using a novel pneumatic-movement actuator. Eleven healthy right-handed volunteers participated in the study. The movement actuator passively moved the participant’s right index finger at frequencies of 0.3, 1, 3, 6, 9, or 12 Hz in a blocked design. A functional localizer was used to define regions-of-interest in SI and SII cortices. In addition, effect of movement range on the fMRI responses was tested in a separate session with 1, 3, 5, and 7 mm movement ranges at a fixed 2 Hz frequency. In primary somatosensory (SI) cortex, the responses were stronger at 3 Hz than at 0.3 Hz (p < 0.001) or 1 Hz (p < 0.05), and at ≥6 Hz than 0.3 Hz (p < 0.001 for frequencies ≥ 6 Hz). In secondary somatosensory (SII) cortex, all movements, except at 0.3 Hz, elicited significant responses of similar strength. In addition, 6, 9, and 12-Hz movements elicited a significant offset response in both SI and SII cortices (p < 0.001–0.05). SI cortex required a total stimulation duration of 4 min to elicit significant activations at the group-level whereas for SII cortex 1 min 20 s was sufficient. Increase in the movement range led to stronger responses in SI cortex, but not in SII cortex. Movements above 3 Hz elicited the strongest SI cortex responses, and increase in the movement range enhanced the response strength. We thus recommend that movements at 3–6 Hz with a movement range of 5 mm or higher to be used in future studies of proprioception. Our results are in-line with previous fMRI and PET studies using tactile or median nerve stimulation at different stimulation frequencies

Changes in CRP and CA19-9 during Preoperative Oncological Therapy Predict Postoperative Survival in Pancreatic Ductal Adenocarcinoma

Introduction: Tumor and systemic inflammatory markers predict survival. This retrospective study aimed to explore the changes in CRP, CA19-9, and other routine laboratory tests during preoperative oncological therapy as prognostic factors in pancreatic ductal adenocarcinoma (PDAC). Methods: Between 2000 and 2016, 68 borderline resectable PDAC patients received preoperative oncological therapy and underwent subsequent surgery at Helsinki University Hospital, Finland. We investigated changes in CRP, CA19-9, CEA, albumin, leukocytes, bilirubin, and platelets and examined the impact on survival. Results: In the multivariate analysis, CRP remaining at >= 3 mg/L after preoperative oncological therapy predicted a poorer postoperative outcome when compared to CRP decreasing to or remaining at 90% during preoperative treatment predicted a favorable postoperative outcome (HR 0.297, 95% CI: 0.124-0.708, p = 0.006). In the Kaplan-Meier analysis, the median survival for patients with CRP remaining at = 3 mg/L (42 months vs. 24 months, p = 0.001). Patients with a CA19-9 decrease >90% or level normalization (toPeer reviewe

The expression and prognostic value of toll-like receptors (TLRs) in pancreatic cancer patients treated with neoadjuvant therapy

Publisher Copyright: Copyright: © 2022 Nurmi et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Objectives Toll-like receptors (TLRs) play a pivotal role in the immune system and carcinogenesis. There is no research on TLR expression and association with survival among preoperatively treated pancreatic cancer patients. We studied the expression intensity and prognostic value of TLRs in pancreatic cancer patients treated with neoadjuvant therapy (NAT) and compared the results to patients undergoing upfront surgery (US). Method Between 2000 and 2015, 71 borderline resectable patients were treated with NAT and surgery and 145 resectable patients underwent upfront surgery at Helsinki University Hospital, Finland. We immunostained TLRs 1–5, 7, and 9 on sections of tissue-microarray. We classified TLR expression as 0 (negative), 1 (mild), 2 (moderate), or 3 (strong) and divided into high (2–3) and low (0–1) expression for statistical purposes. Results Among TLRs 1, 3, and 9 (TLR1 81% vs 70%, p = 0.008; TLR3 92% vs 68%, p = 0.001; TLR9 cytoplasmic 83% vs 42%, p<0.001; TLR9 membranous 53% vs 25%, p = 0.002) NAT patients exhibited a higher immunopositivity score more frequently than patients undergoing upfront surgery. Among NAT patients, a high expression of TLR1 [Hazards ratio (HR) 0.48, p<0.05] associated with a longer postoperative survival, whereas among US patients, high expression of TLR5 (HR 0.64, p<0.05), TLR7 (HR 0.59, p<0.01, and both TLR7 and TLR9 (HR 0.5, p<0.01) predicted a favorable postoperative outcome in separate analysis adjusted for background variables. Conclusions We found higher immunopositive intensities among TLRs 1, 3, and 9 in NAT patients. A high TLR1 expression associated with a longer survival among NAT patients, however, among US patients, high expression intensity of TLR5 and TLR7 predicted a favorable postoperative outcome in the adjusted analysis.Peer reviewe

Identification of proprioceptive thalamocortical tracts in children : comparison of fMRI, MEG, and manual seeding of probabilistic tractography

Studying white matter connections with tractography is a promising approach to understand the development of different brain processes, such as proprioception. An emerging method is to use functional brain imaging to select the cortical seed points for tractography, which is considered to improve the functional relevance and validity of the studied connections. However, it is unknown whether different functional seeding methods affect the spatial and microstructural properties of the given white matter connection. Here, we compared functional magnetic resonance imaging, magnetoencephalography, and manual seeding of thalamocortical proprioceptive tracts for finger and ankle joints separately. We showed that all three seeding approaches resulted in robust thalamocortical tracts, even though there were significant differences in localization of the respective proprioceptive seed areas in the sensorimotor cortex, and in the microstructural properties of the obtained tracts. Our study shows that the selected functional or manual seeding approach might cause systematic biases to the studied thalamocortical tracts. This result may indicate that the obtained tracts represent different portions and features of the somatosensory system. Our findings highlight the challenges of studying proprioception in the developing brain and illustrate the need for using multimodal imaging to obtain a comprehensive view of the studied brain process.Peer reviewe

Neoadjuvant therapy offers longer survival than upfront surgery for poorly differentiated and higher stage pancreatic cancer

Background: Neoadjuvant therapy for pancreatic cancer remains controversial. Our aim was to assess differences in survival, disease recurrence and histopathological tumor characteristics between patients treated with neoadjuvant therapy followed by subsequent surgery and patients undergoing upfront surgery.Material and methods: Out of 399 consecutive pancreatic ductal adenocarcinoma (PDAC) patients operated at Helsinki University Hospital in 2000-2015, 75 borderline resectable patients were treated with neoadjuvant therapy. Resectable propensity scored patients (n=150) underwent upfront surgery. Neoadjuvant therapy consisted of folfirinox, single gemcitabine or combined with cisplatin, nab-paclitaxel or capecitabine with or without radiation. Survival was calculated with Kaplan-Meier and compared with the Breslow test. Survival was determined from the start of treatment, being the first day of treatment for patients treated with neoadjuvant therapy and the date of surgery for others.Results: Between 2000 and 2015 median disease-specific survival (DSS) [34 vs. 26 months, p=.016] and disease-free survival (DFS) [22 vs. 13 months, p=.001] were longer in patients treated with neoadjuvant therapy than in those undergoing upfront surgery. Survival differences were not significant in the 2000s but were, in turn, among patients treated in the 2010s with better survival for patients treated with neoadjuvant therapy [DSS 35 vs. 26 months, p=.008 and DFS 25 vs. 13 months, p=.001]. Especially patients with poorly differentiated G3 tumors [DSS 30 vs. 11 months, p=.004 and DFS 21 vs. 7 months, p=.001] and higher stage IIB-III [DSS 34 vs. 20 months, p=.006 and DFS 21 vs. 10 months, p=.001] had longer survival when treated with neoadjuvant therapy.Conclusions: PDAC patients treated with neoadjuvant therapy had longer DSS and DFS than those undergoing upfront surgery. Neoadjuvant therapy benefits especially borderline resectable patients with higher stage and poorly differentiated tumors.Peer reviewe

Use of self-expandable metallic stents for endoscopic biliary decompression decreases stent complications in pancreatic cancer patients receiving chemotherapy

Background Both plastic stents and self-expandable metallic stents (SEMSes) are used for endoscopic biliary decompression (BD) among patients with pancreatic cancer (PAC). Cholangitis or stent occlusion often interrupts or ends chemotherapy. We investigated cholangitis, stent occlusion, and chemotherapy interruption rates for SEMSes and plastic stents among patients receiving chemotherapy for PAC. Materials and methods We retrospectively analyzed data for 293 PAC patients who received a biliary stent at Helsinki University Hospital during 2000-2017. Patients received chemotherapy as palliative treatment (PT: n = 187) or neoadjuvant treatment (NAT: n = 106). Among participants, 229 had a plastic stent (PT: n = 138, NAT: n = 91) and 64 had a SEMS (PT: n = 49, NAT: n = 15). Results Overall, 15.6% (n = 10) of patients with SEMSes (PT: 20.4%, n = 10, NAT: 0%) and 53.0% (n = 121) of patients with plastic stents (PT: 69.3%, n = 95, NAT: 28.5%, n = 26) experienced one or more stent complications (p <0.001). Cholangitis developed in 6.3% (n = 8) of PT patients with SEMSes. No patients with SEMSes receiving NAT (n = 15) experienced cholangitis. However, 31.9% (PT: 42.8%, n = 59, p = 0.001; NAT: 15.4%, n = 14, p = 0.211) of patients with plastic stents developed cholangitis. Among all patients receiving NAT or PT, cholangitis interrupted chemotherapy 6 times (9.4%) in SEMS patients and 61 times (26.6%) in plastic stent patients (p = 0.004). Stent occlusion without cholangitis interrupted NAT or PT 2 times (2.1%) in SEMS patients and 31 times (13.5%) in plastic stent patients (p = 0.023). Conclusions SEMS is recommended for BD among patients with PAC receiving chemotherapy. Among both PT and NAT patients, patients with SEMS experience a lower stent failure rate, lower rate of cholangitis, and fewer chemotherapy interruptions than patients with plastic stents.Peer reviewe

Impact of histological response after neoadjuvant therapy on podocalyxin as a prognostic marker in pancreatic cancer

Podocalyxin overexpression associates with poor survival in pancreatic cancer (PDAC). We investigated whether podocalyxin expression correlates with treatment response or survival in neoadjuvant-treated PDAC. Through immunohistochemistry, we evaluated podocalyxin expression in 88 neoadjuvant and 143 upfront surgery patients using two antibodies. We developed a six-tier grading scheme for neoadjuvant responses evaluating the remaining tumor cells in surgical specimens. Strong podocalyxin immunopositivity associated with poor survival in the patients responding poorly to the neoadjuvant treatment (HR 4.16, 95% CI 1.56-11.01, p=0.004), although neoadjuvant patients exhibited generally low podocalyxin expression (p=0.017). Strong podocalyxin expression associated with perineural invasion (p=0.003) and lack of radiation (p=0.036). Two patients exhibited a complete neoadjuvant response, while a strong neoadjuvant response (Peer reviewe

Bioabsorbable Versus Metal Screw in the Fixation of Tibial Tubercle Transfer

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