| 1. |
- Bednarska, Olga, 1973-
(författare)
-
Peripheral and Central Mechanisms in Irritable Bowel Syndrome : in search of links
- 2019
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Irritable bowel syndrome (IBS) is a chronic visceral pain disorder with female predominance, characterized by recurrent abdominal pain and disturbed bowel habits in the absence of an identifiable organic cause. This prevalent and debilitating disease, which accounts for a substantial economic and individual burden, lacks exact diagnostic tools and effective treatment, since its pathophysiology remains uncertain. The bidirectional and multilayered brain-gut axis is a well-established disease model, however, the interactions between central and peripheral mechanisms along the brain-gut axis remain incompletely understood. One of the welldescribed triggering factors, yet accounting for only a fraction of IBS prevalence, is bacterial gastroenteritis that affects mucosal barrier function. Altered gut microbiota composition as well as disturbed intestinal mucosal barrier function and its neuroimmune regulation have been reported in IBS, however, the impact of live bacteria, neither commensal nor pathogenic, on intestinal barrier has not been studied yet. Furthermore, abnormal central processing of visceral sensations and psychological factors such as maladaptive coping have previously been suggested as centrally-mediated pathophysiological mechanisms of importance in IBS. Brain imaging studies have demonstrated an imbalance in descending pain modulatory networks and alterations in brain regions associated with interoceptive awareness and pain processing and modulation, particularly in anterior insula (aINS), although biochemical changes putatively underlying these central alterations remain poorly understood. Most importantly, however, possible associations between these documented changes on central and peripheral levels, which may as complex interactions contribute to disease onset and chronification of symptoms, are widely unknown.This thesis aimed to investigate the peripheral and central mechanisms in women with IBS compared to female healthy controls (HC) and to explore possible mutual associations between these mechanisms.In Paper I, we studied paracellular permeability and passage of live bacteria, both commensal and pathogenic through colonic biopsies mounted in Ussing chambers. We explored the regulation of the mucosal barrier function by mast cells and the neuropeptide vasoactive intestinal polypeptide (VIP) as well as a correlation between mucosal permeability and gastrointestinal and psychological symptoms. We observed increased paracellular permeability and the passage of commensal and pathogenic live bacteria in patients with IBS compared with HC, which was diminished by blocking the VIP receptors as well as after stabilizing mast cells in both groups. Moreover, higher paracellular permeability was associated with less somatic and psychological symptoms in patients.In Paper II, we aimed to determine the association between colonic mucosa paracellular permeability and structural and resting state functional brain connectivity. We demonstrated different patterns of associations between mucosa permeability and functional and structural brain connectivity in IBS patients compared to HC. Specifically, lower paracellular permeability in IBS, similar to the levels detected in HC, was associated with more severe IBS symptoms and increased functional and structural connectivity between intrinsic brain resting state network and descending pain modulation brain regions. Our findings further suggested that this association between mucosa permeability and functional brain connectivity was mainly mediated by coping strategies.In Paper III, we investigated putative alterations in excitatory and inhibitory neurotransmission of aINS, as the brain’s key node of the salience network crucially involved in cognitive control, in IBS patients relative to HC and addressed possible connections with both symptoms and psychological factors. We found decreased concentrations of the excitatory neurotransmitter Glx in bilateral aINS in IBS patients compared to HC, while inhibitory neurotransmitter GABA+ levels were comparable. Further, we demonstrated hemisphere-specific associations between abdominal pain, coping and aINS excitatory neurotransmitter concentration.In conclusion, this thesis broadens the knowledge on peripheral and central mechanisms in IBS and presents novel findings that bring together the ends of brain-gut axis. Our results depict association between mucosal permeability, IBS symptoms and functional and structural connectivity engaging brain regions involved in emotion and pain modulation as well as underlying neurotransmitter alterations.
|
|
| 2. |
- Ostman, Maria, et al.
(författare)
-
Novel Calcium Phosphate Promotes Interbody Bony Fusion in a Porcine Anterior Cervical Discectomy and Fusion Model
- 2024
-
Ingår i: Spine. - : Wolters Kluwer. - 0362-2436 .- 1528-1159. ; 49:17, s. 1179-1186
-
Tidskriftsartikel (refereegranskat)abstract
- Study Design: Experimental porcine anterior cervical discectomy and fusion (ACDF) model: a proof-of-concept study.Objective.The effect of monetite synthetic bone graft (SBG) containing calcium pyrophosphate and beta-tricalcium phosphate on cervical spinal fusion in a noninstrumented two-level large animal model.Summary of Background Data: ACDF is the gold standard surgical technique for the treatment of degenerative cervical spinal diseases. However, pseudarthrosis associated with increased patient morbidity occurs in similar to 2.6% of the surgeries. SBG may enhance bony fusion and subsequently decrease the risk of pseudarthrosis. Recent studies on monetite-based SBGs for use in large cranial defects in humans have shown promising bone healing results, necessitating further investigation of their use in cervical spinal fusion.Materials and Methods: Four adult female Danish G & ouml;ttingen minipigs received partial cervical anterior discectomy and intervertebral defects at an upper and lower level. One defect was filled with SBG, and the other was left empty. Bony fusion was evaluated using computed tomography (CT) at three-month intervals for 12 months. Fifteen months postsurgery, the animals were euthanized for further ex vivo qualitative histopathologic and micro-CT evaluations. Fusion rates were compared using the Fisher exact test at each time point.Results.Increased interbody bony fusion rates were observed at SBG levels (4/4) compared with control levels (0/4) evaluated by CT at 6 and 9 months postsurgery (P=0.029). Fusion was observed at all SBG levels 12 months postsurgery and at only one control level. Histopathologic evaluation confirmed high-quality interbody bony fusion at all SBG levels and fusion by spondylosis at one control level.Conclusion: This proof-of-concept study provides preliminary evidence of a novel, calcium pyrophosphate-containing, and beta-tricalcium phosphate-containing monetite SBG that promotes bony fusion compared with a negative control in a clinically relevant porcine model of ACDF.
|
|
| 3. |
- Ristl, Robin, et al.
(författare)
-
Comparing maximum diameter and volume when assessing the growth of small abdominal aortic aneurysms using longitudinal CTA data : cohort study
- 2023
-
Ingår i: International Journal of Surgery. - : Wolters Kluwer. - 1743-9191 .- 1743-9159. ; 109:8, s. 2249-2257
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Monitoring of abdominal aortic aneurysms (AAAs) is currently based on serial measurements of maximum aortic diameter. Additional assessment of aneurysm volume has previously been proposed to possibly improve growth prediction and treatment decisions. To evaluate the use of supplementing volume measurements, the authors aimed to characterise the growth distribution of AAA volume and to compare the growth rates of the maximum diameter and volume at the patient level.Methods: Maximum diameter and volume were monitored every 6 months in 84 patients with small AAAs, with a total of 331 computed tomographic angiographies (with initial maximum diameters of 30-68 mm). A previously developed statistical growth model for AAAs was applied to assess the growth distribution of volume and to compare individual growth rates for volume and for maximum diameter.Results: The median (25-75% quantile) expansion in volume was 13.4 (6.5-24.7) % per year. Cube root transformed volume and maximum diameter showed a closely linear association with a within-subject correlation of 0.77. At the surgery threshold maximum diameter of 55 mm, the median (25-75% quantile) volume was 132 (103-167) ml. In 39% of subjects, growth rates for volume and maximum diameter were equivalent, in 33% growth was faster in volume and in 27% growth was faster in maximum diameter.Conclusion: At the population level, volume and maximum diameter show a substantial association such that the average volume is approximately proportional to the average maximum diameter raised to a power of three. At the individual level, however, in the majority of patient's AAAs grow at different pace in different dimensions. Hence, closer monitoring of aneurysms with sub-critical diameter but suspicious morphology may benefit from complementing maximum diameter by volume or related measurements.
|
|
| 4. |
- Tejedor, Sandra, et al.
(författare)
-
The Combination of Vascular Endothelial Growth Factor A (VEGF-A) and Fibroblast Growth Factor 1 (FGF1) Modified mRNA Improves Wound Healing in Diabetic Mice : An Ex Vivo and In Vivo Investigation
- 2024
-
Ingår i: Cells. - : MDPI. - 2073-4409. ; 13:5
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Diabetic foot ulcers (DFU) pose a significant health risk in diabetic patients, with insufficient revascularization during wound healing being the primary cause. This study aimed to assess microvessel sprouting and wound healing capabilities using vascular endothelial growth factor (VEGF-A) and a modified fibroblast growth factor (FGF1). Methods: An ex vivo aortic ring rodent model and an in vivo wound healing model in diabetic mice were employed to evaluate the microvessel sprouting and wound healing capabilities of VEGF-A and a modified FGF1 both as monotherapies and in combination. Results: The combination of VEGF-A and FGF1 demonstrated increased vascular sprouting in the ex vivo mouse aortic ring model, and topical administration of a combination of VEGF-A and FGF1 mRNAs formulated in lipid nanoparticles (LNPs) in mouse skin wounds promoted faster wound closure and increased neovascularization seven days post-surgical wound creation. RNA-sequencing analysis of skin samples at day three post-wound creation revealed a strong transcriptional response of the wound healing process, with the combined treatment showing significant enrichment of genes linked to skin growth. Conclusion: f-LNPs encapsulating VEGF-A and FGF1 mRNAs present a promising approach to improving the scarring process in DFU.
|
|
| 5. |
|
|
| 6. |
- Malmström, Annika, 1957-
(författare)
-
Studies for Better Treatment of Patients with Glioma
- 2019
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In Sweden annually over 500 people will be diagnosed with the malignant brain tumor glioma. They are graded from I-IV. The majority are glioblastoma (grade IV) (GBM), these being the most aggressive type. Median survival for those treated with standard of care is expected to be around 15 months. This tumor will mainly affect those 60 years or older.The studies in this thesis focus on treatment of patients with malignant gliomas grade III and IV. The aim of the studies is to improve the care of glioma patients. Papers I and II explored different therapeutic options in randomized trials, to facilitate individualized treatment recommendations. Findings from studies I and II, together with additional trials, demonstrated the importance of analyzing the tumor marker O6-methylguanine DNA methyltransferase (MGMT) methylation status for survival of GBM patients treated with Temozolomide (TMZ). The third paper investigated how the analysis of this marker is implemented internationally.The first study (paper I, Nordic trial) investigated treatment options for patients 60 years or older with GBM. The trial compared standard radiotherapy (SRT) over 6 weeks versus hypofractionated radiotherapy (HRT) over 2 weeks versus single agent TMZ administered in up to six 4 weekly cycles. In all, 342 patients were included in the trial. This study demonstrated that those randomized to TMZ had superior survival as compared to SRT. In addition, quality of life (QoL) data also suggested a better QoL for TMZ treatment than for radiotherapy. The benefit of TMZ treatment seemed to be limited to those with the tumor molecular marker MGMT methylated (inactivated).The second trial (paper II, Neoadjuvant trial) studied whether integrating TMZ treatment with SRT for patients younger than 60 years with GBM (grade IV) and astrocytoma grade III would confer a survival benefit, if administered postoperatively, before the start of SRT (neoadjuvant). TMZ was provided for 2-3 four weekly cycles followed by SRT to patients randomized to neoadjuvant treatment and was compared to postoperative SRT alone. Although this trial could not illustrate any advantage of delaying the start of SRT while administering TMZ for the study cohort in general, for those included as astrocytoma grade III the median survival was found to be superior by 5 years when randomized to neoadjuvant TMZ. This trial also confirmed the importance of MGMT promoter methylation for the efficacy of TMZ.The third study (paper III) investigated international practices for analyzing tumor MGMT promoter methylation status. MGMT analysis can be conducted by various laboratory methods, which in some cases can provide opposing results regarding the MGMT methylation status of the patient´s tumor. This can lead to incorrect treatment recommendations. To establish which methods and cut-offs that are regularly used to determine tumor MGMT status in the clinic, an international survey was provided to those working in the field. We also inquired about opinions regarding an international consensus on how MGMT should be tested. The 152 respondents reported several methodologies and different cut-off levels also for the same method. A majority of respondents warrant international guidelines.In conclusion, the results of the 2 randomized trials contribute to individualized treatment recommendations for patients affected by GBM or astrocytoma grade III. The results of the survey regarding analyses of MGMT clarify the current problematic situation. The request of the respondents regarding international guidelines might contribute to their future development, so that personalized treatment recommendations can be improved.
|
|
| 7. |
- Gerdtsson, Axel, et al.
(författare)
-
Surgical Complications in Postchemotherapy Retroperitoneal Lymph Node Dissection for Nonseminoma Germ Cell Tumour : A Population-based Study from the Swedish Norwegian Testicular Cancer Group
- 2020
-
Ingår i: European Urology Oncology. - : Elsevier BV. - 2588-9311. ; 3:3, s. 382-389
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Reports on perioperative complications after postchemotherapy retroperitoneal lymph node dissection (PC-RPLND) for nonseminoma germ cell tumour (NSGCT) are from experienced single centres, with a lack of population-based studies. OBJECTIVE: To assess the complications of bilateral and unilateral PC-RPLND. DESIGN, SETTING, AND PARTICIPANTS: A prospective, population-based, observational multicentre study included all patients with NSGCT who underwent PC-RPLND in Norway and Sweden during 2007-2014. Of a total of 318 patients, 87 underwent bilateral PC-RPLND and 231 underwent unilateral PC-RPLND. The median follow-up was 6 yr. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Bilateral and unilateral PC-RPLND were compared for the outcomes of intra- and postoperative complications (graded by Clavien-Dindo) and retrograde ejaculation (with or without nerve-sparing surgery). Complications were reported as absolute counts and percentages. The χ2 test was used for comparisons. RESULTS AND LIMITATIONS: The incidence of intraoperative complications was higher for bilateral PC-RPLND than for unilateral PC-RPLND (14% vs 4.3%, p = 0.003), with ureteral injury as the most frequent reported complication (2% of the patients). Postoperative complications were more common after bilateral than after unilateral PC-RPLND (45% vs 25%, p = 0.001) with Clavien ≥3b reported in 8.3% and 2.2%, respectively (p = 0.009). Lymphatic leakage was the most common complication occurring in 11% of the patients. Retrograde ejaculation occurred more frequently after bilateral than after unilateral surgery (59% vs 32%, p < 0.001). Limitations of the study include reporting of retrograde ejaculation, which was based on a chart review. CONCLUSIONS: Intra- and postoperative complications including retrograde ejaculation are more frequent after bilateral PC-RPLND than after unilateral PC-RPLND. PATIENT SUMMARY: Lymph node dissection in patients with testicular cancer puts them at risk of complications. In this study, we present the complications after lymph node dissection.
|
|
| 8. |
- Selin, Daniel, et al.
(författare)
-
Cohort profile : the swedish pancreatitis cohort (SwePan)
- 2022
-
Ingår i: BMJ Open. - : BMJ Publishing Group Ltd. - 2044-6055. ; 12:5
-
Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: The Swedish Pancreatitis Cohort (SwePan) was designed to study long-term outcomes following an episode of acute pancreatitis. It can also be used to study various risk factors for developing acute pancreatitis.PARTICIPANTS: The SwePan is a register-based nationwide matched cohort. It includes all Swedish cases of acute pancreatitis during 1990-2019. It contains 95 632 individuals with acute pancreatitis and 952 783 pancreatitis-free individuals matched on sex, age and municipality of residence. Follow-up was censored at death, emigration or end of study (31 December 2019). The dataset includes comprehensive information based on several registries, and includes diagnoses, prescribed medications and socioeconomic factors both prior to inclusion and during follow-up.FINDINGS TO DATE: During the study period, the number of cases of acute pancreatitis in Sweden has more than doubled from 1977 cases in 1990 to 4264 cases in 2019. The median age of first episode of acute pancreatitis has increased from 58 years (IQR 44-73 years) in 1990 to 64 years (IQR 49-76 years) in 2019. Cases with acute pancreatitis were generally less healthy compared with the pancreatitis-free individuals (Charlson Comorbidity Index of 0 in 59.2% and 71.4%, respectively).FUTURE PLANS: SwePan will be used to determine the incidence of acute pancreatitis in Sweden over time and assess long-term all-cause and cause-specific mortality after an episode of acute pancreatitis. Some examples of additional planned studies are (1) assessment of long-term risk of diabetes and (2) risk of malignancy in adjacent organs following acute pancreatitis and (3) assessment of risk factors for development of acute pancreatitis including various drugs.
|
|
| 9. |
- Hedenqvist, Patricia, et al.
(författare)
-
The effect of housing environment on bone healing in a critical radius defect in New Zealand White rabbits
- 2020
-
Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 15:5
-
Tidskriftsartikel (refereegranskat)abstract
- In animal studies on bone healing, the effect of housing space and physical activity are seldom taken into account. Bone formation was evaluated in New Zealand White rabbits (mean ± SEM BW: 3.9 ± 0.11 kg) with a critical bone defect after 12 weeks of rehabilitation in pair-housing in 3 m2 large floor pens (Floor, n = 10) or standard single housing in 0.43 m2 cages (Cage, n = 10). In the randomised full-factorial study, a bone replica of calcium phosphate cement (CPC, n = 10) or autologous bone (AB, n = 10) was implanted in the unilateral 20 mm radius defect. Post-mortem, the oxidative capacity was measured by citrate synthase (CS) activity in M. quadriceps and the defect filling volume and density evaluated by microcomputer tomography (μ-CT). Histology sections were evaluated by subjective scoring and histomorphometry. Fourteen rabbits remained until the end of the study. Group Floor (n = 7; 3 CPC + 4 AB) had a higher CS activity and a larger bone defect filling volume and lower density by μ-CT measurements than group Cage (n = 7; 3 CPC + 4 AB). Three out of four rabbits in AB-Floor presented fusion of the defect with reorganisation of trabecular bone, whereas three of four in AB-Cage showed areas of incomplete healing. Floor rabbits had a higher score of bony fusion between the radius and ulna than Cage rabbits. There were no differences between groups in histomorphometry. The study found that a larger housing space increased physical activity and promoted bone formation. © 2020 Hedenqvist 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.
|
|
| 10. |
- Suh, Ga Young, et al.
(författare)
-
Multiaxial pulsatile dynamics of the thoracic aorta and impact of thoracic endovascular repair
- 2021
-
Ingår i: European Journal of Radiology Open. - : Elsevier BV. - 2352-0477. ; 8
-
Tidskriftsartikel (refereegranskat)abstract
- Purpose: The thoracic aorta is a highly mobile organ whose dynamics are altered by thoracic endovascular aorta repair (TEVAR). The aim of this study was to quantify cardiac pulsatility-induced multi-axial deformation of the thoracic aorta before and after descending aortic TEVAR. Methods: Eleven TEVAR patients (8 males and 3 females, age 57–89) underwent retrospective cardiac-gated CT angiography before and after TEVAR. 3D geometric models of the thoracic aorta were constructed, and lumen centerlines, inner and outer surface curves, and cross-sections were extracted to measure aortic arclength, centerline, inner surface, and outer surface longitudinal curvatures, as well as cross-sectional effective diameter and eccentricity for the ascending and stented aortic portions. Results: From pre- to post-TEVAR, arclength deformation was increased at the ascending aorta from 5.9 ± 3.1 % to 8.8 ± 4.4 % (P < 0.05), and decreased at the stented aorta from 7.5 ± 5.1 % to 2.7 ± 2.5 % (P < 0.05). Longitudinal curvature and diametric deformations were reduced at the stented aorta. Centerline curvature, inner surface curvature, and cross-sectional eccentricity deformations were increased at the distal ascending aorta. Conclusions: Deformations were reduced in the stented thoracic aorta after TEVAR, but increased in the ascending aorta near the aortic arch, possibly as a compensatory mechanism to maintain overall thoracic compliance in the presence of reduced deformation in the stiffened stented aorta.
|
|
