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Excess weight and obesity relate to multiple comorbidities, lost quality of life and mortality and cause major burden to healthcare and society. Most obesity seems to trace to changes in lifestyle and the food environment in the last few decades. The comorbidities related to obesity are increasingly viewed as a result of low-grade inflammation characterizing the state of excess adiposity. On microscopic level, this associates with the infiltration of immune cells, particularly macrophages, into adipose tissue. Bariatric surgery and weight loss repeal these alterations. In this thesis, two behaviorally distinct macrophage pools are identified in subcutaneous adipose tissue of subjects with obesity. Of these, only the macrophages associated with pyroptotic adipocyte deaths decreased after laparoscopic Roux-en-Y gastric bypass for obesity. These macrophages were also highly imbued by known pro-inflammatory proteins, NLRP3 inflammasome and Caspase-1. The surgery associated with a shift of adipocyte size towards smaller populations. In addition, a novel method was developed for fat cell size and count analysis using free open-source software., Tiivistelmä Ylipainoon ja lihavuuteen liittyy lukuisia liitännäissairauksia, alentunut elämänlaatu ja lisääntynyt kuolleisuus sekä kasvanut terveyspalvelujen kulutus. Viime vuosikymmenten lihavuusepidemia selittynee ensisijaisesti länsimaalaistuneella elämäntavalla ja ruokaympäristön muutoksilla. Viime aikoina on herätty ylimääräisen rasvakudoksen aiheuttamaan matala-asteisen tulehduksen ja liitännäissairauksien yhteyksiin. Rasvakudoksessa tulehdus ilmenee erityisesti paikallisena syöjäsolujen eli makrofagien kertymisenä. Lihavuuskirurgia ja painonpudotus vähentävät sekä rasvakudoksen että elimistön yleistä tulehdustilaa. Tässä väitöskirjassa tunnistettiin kaksi eri tavoin mahalaukun ohitusleikkaukseen reagoivaa makrofagiryhmää. Osoitamme, että ainoastaan rasvasolujen tulehdukselliseen hajoamiseen ja kuolemaan liittyvät makrofagit vähentyvät leikkauksen jälkeen muun makrofagimäärän pysyessä muuttumattomana. Erityisesti rasvasolujen hajoamiseen liittyvien makrofagien osoitettiin myös ilmentävän runsaasti tulehduksellisia NLRP3- ja Caspase-1-proteiineja. Leikkauksen jälkeen rasvasolujen keskimääräinen koko pieneni. Kolmantena osatyönä esitetään uusi, ilmaista avoimen lähdekoodin ohjelmistoa käyttävä menetelmä rasvasolujen koon ja määrän mittaamiseen.

Background: Preoperative esophageal stenting is proposed to have a negative effect on outcomes. The aim was to compare a 5-year survival in patients undergoing esophagectomy for esophageal cancer with and without preoperative esophageal stent in a population-based nationwide cohort from Finland. The secondary outcome was 90-day mortality. Methods: This study included curatively intended esophagectomies for esophageal cancer in Finland between 1999 and 2016, with follow-up until December 31, 2019. Cox proportional hazards models provided hazard ratios (HRs) with 95% confidence intervals (CIs) of overall 5-year and 90-day mortality. Model 1 was adjusted for age, sex, year of the surgery, comorbidities, histology, pathological stage, and neoadjuvant therapy. Model 2 included also albumin level and BMI. Result: Of 1064 patients, a total of 134 patients underwent preoperative stenting and 930 did not. In both adjusted models 1 and 2, higher 5-year mortality was seen in patients with preoperative stent with HRs of 1.29 (95% CI 1.00–1.65) and 1.25 (95% CI 0.97–1.62), respectively, compared to no stenting. The adjusted HR of 90-day mortality was 2.49 (95% CI 1.27–4.87) in model 1 and 2.49 (95% CI 1.25–4.99) in model 2. When including only neoadjuvant-treated patients, those with preoperative stent had a 5-year survival of 39.2% compared to 46.4% without stent (adjusted HR 1.34, 95% CI 1.00–1.80), and a 90-day mortality rate of 8.5% and 2.5% (adjusted HR 3.99, 95% CI 1.51–10.50). Discussion: This nationwide study reports worse 5-year and 90-day outcomes in patients with preoperative esophageal stent. Since residual confounding remains possible, observed difference could be only an association rather than the cause.

Background: The prognostic value of preoperative hemoglobin in patients undergoing esophagectomy is unknown. The aim of this study was to examine whether preoperative hemoglobin is associated with prognosis in patients undergoing esophagectomy for cancer. Materials and methods: This was a population-based nationwide retrospective cohort study in Finland, using Finnish National Esophago-Gastric Cancer Cohort (FINEGO). Esophagectomy patients with available preoperative hemoglobin measurement were included. Multivariable cox regression provided hazard ratios (HR) with 95% confidence intervals (CI), adjusted for calendar period of surgery, age at surgery, sex, comorbidity (Charlson Comorbidity Index), tumor histology, tumor stage, neoadjuvant therapy, type of surgery (minimally invasive or open) and annual hospital volume. Results: Of the 1313 patients, 932 (71.0%) were men and 799 (60.9%) had esophageal adenocarcinoma. Overall all-cause mortality was significantly higher in the lowest hemoglobin count tertile (HR 1.26 (1.07–1.47)) compared to the highest tertile, but this association was attenuated after adjustment for confounding. No differences were found between the preoperative hemoglobin groups in the adjusted analyses of 90-day all-cause, 5-year all-cause, and 5-year cancer-specific mortality. Conclusions: In this population-based nationwide study, preoperative hemoglobin count had no independent prognostic significance in esophageal cancer.

Cancer is a deadly disease worldwide. In light of the requisite of convincing therapeutic methods for cancer, immune checkpoint inhibition methods such as anti-PD-1/PD-L1 therapy appear promising. Human microbiota have been exhibited to regulate susceptibility to cancer as well as the response to anti-PD-1/PD-L1 therapy. However, the probable contribution of bacterial extracellular vesicles (bEVs) in cancer pathophysiology and treatment has not been investigated much. bEVs illustrate the ability to cross physiological barriers, assemble around the tumor cells, and likely modify the tumor microenvironment (EVs). This systematic review emphasizes the correlation between cancer-associated extracellular vesicles, particularly bEVs and the efficacy of anti-PD-1/PD-L1 therapy. The clinical and pharmacological prospective of bEVs in revamping the contemporary treatments for cancer has been further discussed.

Objective: This case–control study aimed to analyze the dynamics of macrophage infiltration in subcutaneous adipose tissue following bariatric surgery or conservative treatment of obesity and to clarify whether these features predict the weight loss outcome after the surgery. Methods: Subcutaneous tissue samples taken before and 12 months after laparoscopic Roux-en-Y gastric bypass surgery (n = 39) or conservative (n = 43) treatment for obesity were analyzed. Fat cell size was determined, and with CD68 immunohistochemistry, crown-like structures (CLS) were counted and single macrophages were quantitated. Results: A major decline in CLS density from 4.1 (SD 3.5) to 1.1 (SD 0.8) per 1000 fat cells (p < 0.000) was found, regardless of the degree of weight loss after the surgery. Surgery had no effect on the fraction of infiltrating single-cell macrophages in subcutaneous adipose tissue. The abundance of these macrophage populations before the intervention did not predict the degree of postsurgery weight loss or suboptimal response to the surgery. Conclusions: The effect of gastric bypass on adipose tissue inflammatory status associates closely with CLS density even in subjects with suboptimal weight loss. The study suggests that factors related to bypass surgery other than weight loss modify the inflammatory response in adipose tissue.

Obesity is associated with low-grade inflammation and increased systemic oxidative stress. Roux-en-Y gastric bypass (RYGB) surgery is known to ameliorate the obesity-induced metabolic dysfunctions. We aimed to study the levels of natural antibodies in feces, before and 6 months after RYGB surgery in obese individuals with and without type 2 diabetes (T2D). Sixteen individuals with T2D and 14 non-diabetic (ND) individuals were operated. Total IgA, IgG and IgM antibody levels and specific antibodies to oxidized low-density lipoprotein (oxLDL), malondialdehyde-acetaldehyde adducts (MAA adducts), Porphyromonas gingivalis gingipain A hemagglutinin domain (Rgp44) and phosphocholine (PCho) were measured using chemiluminescence immunoassay. Total fecal IgA was elevated, while total IgM and IgG were not affected by the surgery. Fecal natural IgM specific to oxLDL decreased significantly in both T2D and ND individuals, while fecal IgM to Rgp44 and PCho decreased significantly in T2D individuals. A decrease in IgG to MAA-LDL, Rgp44 and PCho was detected. RYGB surgery increases the levels of total fecal IgA and decreases fecal natural IgG and IgM antibodies specific to oxLDL. Natural antibodies and IgA are important in maintaining the normal gut homeostasis and first-line defense against microbes, and their production is markedly altered with RYGB surgery.

Changes in adipose tissue morphology, depicted by cell morphology alterations such as enlargement of fat cells, always accompany over-weight and obesity. The variables related to cell size have been shown to associate with low-grade inflammation of adipose tissue and common obesity-related comorbidities including metabolic syndrome and type 2 diabetes. Quantifying fat cell morphology from images of histological specimens can be tedious. Here, we present a straightforward method for the task using the free open-source software QuPath with its inbuilt tools only. Measurements of human adipose tissue samples with the described protocol showed an excellent correlation with those obtained with ImageJ software with Adipocyte Tools plugin combined with manual correction of misdetections. Intraclass correlation between the two methods was at good to excellent level. The method described here can be applied to considerably large tissue areas, even whole-slide analysis.