Metabolic Profiling Early Post-Allogeneic Haematopoietic Cell Transplantation in the Context of CMV Infection.

Immune dysfunction resulting from allogeneic haematopoietic stem cell transplantation (aHSCT) predisposes one to an elevated risk of cytomegalovirus (CMV) infection. Changes in metabolism have been associated with adverse outcomes, and in this study, we explored the associations between metabolic profiles and post-transplantation CMV infection using plasma samples collected 7-33 days after aHSCT. We included 68 aHSCT recipients from Rigshospitalet, Denmark, 50% of whom experienced CMV infection between days 34-100 post-transplantation. First, we investigated whether 12 metabolites selected based on the literature were associated with an increased risk of post-transplantation CMV infection. Second, we conducted an exploratory network-based analysis of the complete metabolic and lipidomic profiles in relation to clinical phenotypes and biological pathways. Lower levels of trimethylamine N-oxide were associated with subsequent CMV infection (multivariable logistic regression: OR = 0.63; 95% CI = [0.41; 0.87]; p = 0.01). Explorative analysis revealed 12 clusters of metabolites or lipids, among which one was predictive of CMV infection, and the others were associated with conditioning regimens, age upon aHSCT, CMV serostatus, and/or sex. Our results provide evidence for an association between the metabolome and CMV infection post-aHSCT that is independent of known risk factors.

Impact of Antibiotic Treatment on the Gut Microbiome and its Resistome in Hematopoietic Stem Cell Transplant Recipients.

Antibiotic-resistant bacterial infections are increasingly an issue in allogenic hematopoietic stem cell transplant patients. How antibiotic treatment impacts antibiotic resistance in the human gut microbiome remains poorly understood in vivo. Here, a total of 577 fecal samples from 233 heavily antibiotic-treated transplant patients were examined using high-resolution prescription data and shotgun metagenomics. The 13 most frequently used antibiotics were significantly associated with 154 (40% of tested associations) microbiome features. Use of broad-spectrum ß-lactam antibiotics was most markedly associated with microbial disruption and increase in resistome features. The enterococcal vanA gene was positively associated with 8 of the 13 antibiotics, and in particular piperacillin/tazobactam and vancomycin. Here, we highlight the need for a high-resolution approach in understanding the development of antibiotic resistance in the gut microbiome. Our findings can be used to inform antibiotic stewardship and combat the increasing threat of antibiotic resistance.

Pre-Transplant Prediction of Acute Graft-versus-Host Disease Using the Gut Microbiome.

Gut microbiota is thought to influence host responses to allogeneic hematopoietic stem cell transplantation (aHSCT). Recent evidence points to this post-transplant for acute graft-versus-host disease (aGvHD). We asked whether any such association might be found pre-transplant and conducted a metagenome-wide association study (MWAS) to explore. Microbial abundance profiles were estimated using ensembles of Kaiju, Kraken2, and DeepMicrobes calls followed by dimensionality reduction. The area under the curve (AUC) was used to evaluate classification of the samples (aGvHD vs. none) using an elastic net to test the relevance of metagenomic data. Clinical data included the underlying disease (leukemia vs. other hematological malignancies), recipient age, and sex. Among 172 aHSCT patients of whom 42 developed aGVHD post transplantation, a total of 181 pre-transplant tool samples were analyzed. The top performing model predicting risk of aGVHD included a reduced species profile (AUC = 0.672). Beta diversity (37% in Jaccard's Nestedness by mean fold change, p < 0.05) was lower in those developing aGvHD. Ten bacterial species including Prevotella and Eggerthella genera were consistently found to associate with aGvHD in indicator species analysis, as well as relief and impurity-based algorithms. The findings support the hypothesis on potential associations between gut microbiota and aGvHD based on a data-driven approach to MWAS. This highlights the need and relevance of routine stool collection for the discovery of novel biomarkers.

Metabolic Potential of the Gut Microbiome Is Significantly Impacted by Conditioning Regimen in Allogeneic Hematopoietic Stem Cell Transplantation Recipients.

Allogeneic hematopoietic stem cell transplantation (aHSCT) is a putative curative treatment for malignant hematologic disorders. During transplantation, the immune system is suppressed/eradicated through a conditioning regimen (non-myeloablative or myeloablative) and replaced with a donor immune system. In our previous study, we showed changes in gut taxonomic profiles and a decrease in bacterial diversity post-transplant. In this study, we expand the cohort with 114 patients and focus on the impact of the conditioning regimens on taxonomic features and the metabolic functions of the gut bacteria. This is, to our knowledge, the first study to examine the metabolic potential of the gut microbiome in this patient group. Adult aHSCT recipients with shotgun sequenced stool samples collected day -30 to +28 relative to aHSCT were included. One sample was selected per patient per period: pre-aHSCT (day -30-0) and post-aHSCT (day 1-28). In total, 254 patients and 365 samples were included. Species richness, alpha diversity, gene richness and metabolic richness were all lower post-aHSCT than pre-aHSCT and the decline was more pronounced for the myeloablative group. The myeloablative group showed a decline in 36 genera and an increase in 15 genera. For the non-myeloablative group, 30 genera decreased and 16 increased with lower fold changes than observed in the myeloablative group. For the myeloablative group, 32 bacterial metabolic functions decreased, and one function increased. For the non-myeloablative group, three functions decreased, and two functions increased. Hence, the changes in taxonomy post-aHSCT caused a profound decline in bacterial metabolic functions especially in the myeloablative group, thus providing new evidence for associations of myeloablative conditioning and gut dysbiosis from a functional perspective.

Associations of the gut microbiome and clinical factors with acute GVHD in allogeneic HSCT recipients.

Acute graft-versus-host disease (aGVHD) is a leading cause of transplantation-related mortality after allogeneic hematopoietic stem cell transplantation (aHSCT). 16S ribosomal RNA (16S rRNA) gene-based studies have reported that lower gut bacterial diversity and the relative abundance of certain bacteria after aHSCT are associated with aGVHD. Using shotgun metagenomic sequencing and a large cohort, we aimed to confirm and extend these observations. Adult aHSCT recipients with stool samples collected from day -30 to day 100 relative to aHSCT were included. One sample was selected per patient per period (pre-aHSCT (day -30 to day 0), early post-aHSCT (day 1 to day 28), and late post-aHSCT (day 29 to day 100)), resulting in 150 aHSCT recipients and 259 samples. Microbial and clinical factors were tested for differences between time periods and an association with subsequent aGVHD. Patients showed a decline in gut bacterial diversity posttransplant, with several patients developing a dominance of Enterococcus. A total of 36 recipients developed aGVHD at a median of 34 days (interquartile range, 26-50 days) post-aHSCT. Lower microbial gene richness (P = .02), a lower abundance of the genus Blautia (P = .05), and a lower abundance of Akkermansia muciniphila (P = .01) early post-aHSCT was observed in those who developed aGVHD. Myeloablative conditioning was associated with aGVHD along with a reduction in gene richness and abundance of Blautia and A muciniphila. These results confirm low diversity and Blautia being associated with aGVHD. Crucially, we add that pretransplant conditioning is associated with changes in gut microbiota. Investigations are warranted to determine the interplay of gut microbiota and conditioning in the development of aGVHD.

Gut microbiome comparability of fresh-frozen versus stabilized-frozen samples from hospitalized patients using 16S rRNA gene and shotgun metagenomic sequencing.

Collection of faecal samples for microbiome analysis in acutely sick patients is logistically difficult, particularly if immediate freezing is required (i.e. fresh-frozen, or FF sampling). Previous studies in healthy/non-hospitalized volunteers have shown that chemical stabilization (i.e. stabilized-frozen, or SF sampling) allows room-temperature storage with comparable results to FF samples. To test this in a hospital setting we compared FF and SF approaches across 17 patients undergoing haematopoietic stem cell transplantation (HSCT) using both 16S rRNA gene and shotgun metagenomic sequencing. A paired (same stool specimen) comparison of FF and SF samples was made, with an overall comparable level in relative taxonomic abundances between the two sampling techniques. Though shotgun metagenomic sequencing found significant differences for certain bacterial genera (P < 0.001), these were considered minor methodological effects. Within-sample diversity of either method was not significantly different (Shannon diversity P16SrRNA = 0.68 and Pshotgun = 0.89) and we could not reject the null hypothesis that between-sample variation in FF and SF were equivalent (P16SrRNA = 0.98 and Pshotgun = 1.0). This indicates that SF samples can be used to reliably study the microbiome in acutely sick patient populations, thus creating and enabling further outcomes-based metagenomic studies on similarly valuable cohorts.

Surgical Management, Preoperative Tumor Localization, and Histopathology of 80 Patients Operated on for Insulinoma.

INTRODUCTION: Diagnosis and pathological classification of insulinomas are challenging. AIM: To characterize localization of tumors, surgery outcomes, and histopathology in patients with insulinoma. METHODS: Patients with surgically resected sporadic insulinoma were included. RESULTS: Eighty patients were included. Seven had a malignant tumor. A total of 312 diagnostic examinations were performed: endoscopic ultrasonography (EUS; n = 59; sensitivity, 70%), MRI (n = 33; sensitivity, 58%), CT (n = 55; sensitivity, 47%), transabdominal ultrasonography (US; n = 45; sensitivity, 40%), somatostatin receptor imaging (n = 17; sensitivity, 29%), 18F-fluorodeoxyglucose positron emission tomography/CT (n = 1; negative), percutaneous transhepatic venous sampling (n = 10; sensitivity, 90%), arterial stimulation venous sampling (n = 20; sensitivity, 65%), and intraoperative US (n = 72; sensitivity, 89%). Fourteen tumors could not be visualized. Invasive methods were used in 7 of these 14 patients and localized the tumor in all cases. Median tumor size was 15 mm (range, 7 to 80 mm). Tumors with malignant vs benign behavior showed less staining for insulin (3 of 7 vs 66 of 73; P = 0.015) and for proinsulin (3 of 6 vs 58 of 59; P < 0.001). Staining for glucagon was seen in 2 of 6 malignant tumors and in no benign tumors (P < 0.001). Forty-three insulinomas stained negative for somatostatin receptor subtype 2a. CONCLUSION: Localization of insulinomas requires many different diagnostic procedures. Most tumors can be localized by conventional imaging, including EUS. For nonvisible tumors, invasive methods may be a useful diagnostic tool. Malignant tumors showed reduced staining for insulin and proinsulin and increased staining for glucagon.

Incidence Rates and Risk Factors of Clostridioides difficile Infection in Solid Organ and Hematopoietic Stem Cell Transplant Recipients.

BACKGROUND: Transplant recipients are an immunologically vulnerable patient group and are at elevated risk of Clostridioides difficile infection (CDI) compared with other hospitalized populations. However, risk factors for CDI post-transplant are not fully understood. METHODS: Adults undergoing solid organ (SOT) and hematopoietic stem cell transplant (HSCT) from January 2010 to February 2017 at Rigshospitalet, University of Copenhagen, Denmark, were retrospectively included. Using nationwide data capture of all CDI cases, the incidence and risk factors of CDI were assessed. RESULTS: A total of 1687 patients underwent SOT or HSCT (1114 and 573, respectively), with a median follow-up time (interquartile range) of 1.95 (0.52-4.11) years. CDI was diagnosed in 15% (164) and 20% (114) of the SOT and HSCT recipients, respectively. CDI rates were highest in the 30 days post-transplant for both SOT and HSCT (adjusted incidence rate ratio [aIRR], 6.64; 95% confidence interval [CI], 4.37-10.10; and aIRR, 2.85; 95% CI, 1.83-4.43, respectively, compared with 31-180 days). For SOT recipients, pretransplant CDI and liver and lung transplant were associated with a higher risk of CDI in the first 30 days post-transplant, whereas age and liver transplant were risk factors in the later period. Among HSCT recipients, myeloablative conditioning and a higher Charlson Comorbidity Index were associated with a higher risk of CDI in the early period but not in the late period. CONCLUSIONS: Using nationwide data, we show a high incidence of CDI among transplant recipients. Importantly, we also find that risk factors can vary relative to time post-transplant.

Neuroendocrine Carcinomas of the Gastroenteropancreatic System: A Comprehensive Review.

To date, empirical literature has generally been considered lacking in relation to neuroendocrine carcinomas (NECs), the highly malignant subgroup of neuroendocrine neoplasms. NECs are often found in the lungs or the gastroenteropancreatic (GEP) system and can be of small or large cell type. Concentrating on GEP-NECs, we can conclude that survival times are poor, with a median of only 4-16 months depending on disease stage and primary site. Further, this aggressive disease appears to be on the rise, with incidence numbers increasing while survival times are stagnant. Treatment strategies concerning surgery are often undecided and second-line chemotherapy is not yet established. After an analysis of over 2600 articles, we can conclude that there is indeed more empirical literature concerning GEP-NECs available than previously assumed. This unique review is based on 333 selected articles and contains detailed information concerning all aspects of GEP-NECs. Namely, the classification, histology, genetic abnormalities, epidemiology, origin, biochemistry, imaging, treatment and survival of GEP-NECs are described. Also, organ-specific summaries with more detail in relation to disease presentation, diagnosis, treatment and survival are presented. Finally, key points are discussed with directions for future research priorities.

[HIV-positive individuals still have shorter life-expectancy than the general population]. / Patienter med hiv-infektion lever stadig væsentlig kortere end baggrundsbefolkningen.

Despite more than 15 years of available highly active anti-retroviral therapy treatment, HIV-positive individuals still have a two-third shorter life-expectancy in comparison with the general population. Six studies of individuals with HIV (n = 235,854) were analysed with 7,898 deaths, of which 90% had a known cause. 42% were still due to AIDS, followed by liver-related deaths (12%), non-AIDS cancer (12%), cardiovascular disease (10%), suicide/overdose/accidents (8%), non-AIDS infection (7%) and other non-AIDS causes (11%). Recognising the causes of death among HIV-positive individuals may aid in reducing mortality.