Fractal analysis of extracellular matrix for observer-independent quantification of intestinal fibrosis in Crohn's disease

Prevention of intestinal fibrosis remains an unresolved problem in the treatment of Crohn's disease (CD), as specific antifibrotic therapies are not yet available. Appropriate analysis of fibrosis severity is essential for assessing the therapeutic efficacy of potential antifibrotic drugs. The aim of this study was to develop an observer-independent method to quantify intestinal fibrosis in surgical specimens from patients with CD using structural analysis of the extracellular matrix (ECM). We performed fractal analysis in fibrotic and control histological sections of patients with surgery for CD (n = 28). To specifically assess the structure of the collagen matrix, polarized light microscopy was used. A score to quantify collagen fiber alignment and the color of the polarized light was established. Fractal dimension as a measure for the structural complexity correlated significantly with the histological fibrosis score whereas lacunarity as a measure for the compactness of the ECM showed a negative correlation. Polarized light microscopy to visualize the collagen network underlined the structural changes in the ECM network in advanced fibrosis. In conclusion, observer-independent quantification of the structural complexity of the ECM by fractal analysis is a suitable method to quantify the degree of intestinal fibrosis in histological samples from patients with CD.

B cell-mediated CD4 T-cell costimulation via CD86 exacerbates pro-inflammatory cytokine production during autoimmune intestinal inflammation

Dysregulated B cell responses have been described in inflammatory bowel disease (IBD) patients; however, the role of B cells in IBD pathology remained incompletely understood. We here provide evidence for the detrimental role of activated B cells during the onset of autoimmune intestinal inflammation. Using Wiskott-Aldrich Syndrome interacting protein deficient (Wipf1-/-) mice as a mouse model of chronic colitis, we identified clusters of differentiation (CD)86 expression on activated B cells as a crucial factor exacerbating pro-inflammatory cytokine production of intestinal CD4 T cells. Depleting B cells through anti-CD20 antibody treatment or blocking costimulatory signals mediated by CD86 through cytotoxic T lymphocyte antigen-4-immunoglobulin (CTLA-4-Ig) diminished intestinal inflammation in our mouse model of chronic IBD at the onset of disease. This was due to a reduction in aberrant humoral immune responses and reduced CD4 T cell pro-inflammatory cytokine production, especially interferon-g (IFN-g) and granulocyte-macrophage colony-stimulating factor (GM-CSF). Interestingly, in addition to B cells isolated from the inflamed colon of Wipf1-/- mice, we also found CD86 mRNA and protein expression upregulated on activated B cells isolated from inflamed tissue of human patients with IBD. B cell activation and CD86 expression were boosted by soluble CD40L in vitro, which we found in the serum of mice and human patients with IBD. In summary, our data provides detailed insight into the contribution of B cells to intestinal inflammation, with implications for the treatment of IBD.

A nationwide population-based study on the clinical and economic burden of anastomotic leakage in colorectal surgery

AIM

Anastomotic leakage (AL) is one of the most dreaded complications in colorectal surgery. In 2013, the International Classification of Diseases code K91.83 for AL was introduced in Germany, allowing nationwide analysis of AL rates and associated parameters. The aim of this population-based study was to investigate the current incidence, risk factors, mortality, clinical management, and associated costs of AL in colorectal surgery.

METHODS

A data query was performed based on diagnosis-related group data of all hospital cases of inpatients undergoing colon or sphincter-preserving rectal resections between 2013 and 2018 in Germany.

RESULTS

A total number of 690,690 inpatient cases were included in this study. AL rates were 6.7% for colon resections and 9.2% for rectal resections in 2018. Regarding the treatment of AL, the application of endoluminal vacuum therapy increased during the studied period, while rates of relaparotomy, abdominal vacuum therapy, and terminal enterostomy remained stable. AL was associated with significantly increased in-house mortality (7.11% vs. 20.11% for colon resections and 3.52% vs. 11.33% for rectal resections in 2018) and higher socioeconomic costs (mean hospital reimbursement volume per case: 14,877€ (no AL) vs. 37,521€ (AL) for colon resections and 14,602€ (no AL) vs. 30,606€ (AL) for rectal resections in 2018).

CONCLUSIONS

During the studied time period, AL rates did not decrease, and associated mortality remained at a high level. Our study provides updated population-based data on the clinical and economic burden of AL in Germany. Focused research in the field of AL is still urgently necessary to develop targeted strategies to prevent AL, improve patient care, and decrease socioeconomic costs.

Perioperative low-dose prednisolone treatment has beneficial effects on postoperative recovery and anastomotic healing in a murine colitis model

BACKGROUND AND AIMS

High-dose glucocorticoid treatment has been identified as a risk factor for anastomotic leakage in patients with inflammatory bowel disease (IBD) undergoing bowel resection surgery. On the contrary, active disease during surgery is also associated with elevated morbidity. Perioperative low-dose treatment might be beneficial regarding postoperative outcomes by controlling disease activity. The present study is the first to investigate the dose-dependent effect of perioperative prednisolone therapy in a murine IBD model combining dextran-sodium sulfate (DSS) colitis with intestinal anastomosis surgery.

METHODS

In 84 ten-week-old wild-type mice a colorectal anastomosis was performed using microsurgical technique. Half the animals received induction of chemical colitis with 2% DSS via drinking water prior to surgery. In both groups, one third of the animals received daily oral administration of high-dose (0.533 mg/kg) and one third low-dose (0.133 mg/kg) prednisolone. Evaluation was performed on postoperative day 3 and 7.

RESULTS

While high-dose prednisolone treatment led to an increased anastomotic leakage rate in mice under colitis, low-dose prednisolone treatment limited preoperative disease activity and did not influence the leakage rate. Histologic examination showed a beneficial effect of low-dose prednisolone treatment on microscopic abscess formation at the anastomotic site in DSS mice as well as an increased anastomotic healing score.

CONCLUSIONS

We could demonstrate a beneficial effect of perioperative short-term low-dose prednisolone treatment on intestinal anastomotic healing in the context of colitis. Perioperative use of short-term low-dose prednisolone treatment might be beneficial in IBD patients that need to undergo surgery during active disease.

Gastrectomy for cancer beyond life expectancy. A comprehensive analysis of oncological gastric surgery in Germany between 2008 and 2018

INTRODUCTION

Major gastric surgery for distal esophageal and gastric cancer has a strong impact on the quality of life, morbidity, and mortality. Especially in elderly patients reaching their life expectancy, the responsible use and extent of gastrectomy are imperative to achieve a balance between harm and benefit. In the present study, the reimbursement database (German Diagnosis Related Groups (G-DRG) database) of the Statistical Office of the Federal Republic of Germany was queried to evaluate the morbidity and mortality of patients aged above or below 75 years following gastrectomy.

MATERIAL AND METHODS

All patients in Germany undergoing subtotal gastrectomy (ST), total gastrectomy (T), or gastrectomy combined with esophagectomy (TE) for gastric or distal esophageal cancer (International Statistical Classification of Diseases and Related Health Problems Version 10 (ICD-10) C15.2, C15.5, and C16.0-C16.9) between 2008 and 2018 were included. Intraoperative and postoperative complications as well as comorbidities, in-hospital mortality, and the extent of surgery were assessed by evaluating ICD-10 and operation and procedure key (Operationen- und Prozedurenschlüssel) codes.

RESULTS

A total of 67,389 patients underwent oncologic gastric resection in Germany between 2008 and 2018. In total, 21,794 patients received ST, 41,825 received T, and 3,466 received TE, respectively. In 304 cases, the combinations of these, in fact, mutually exclusive procedures were encoded. The proportion of patients aged 75 years or older was 51.4% (n = 11,207) for ST, 32.6% (n = 13,617) for T, and 28.1% (n = 973) for TE. The in-hospital mortality of elderly patients was significantly increased in all three groups. (p < 0.0001) General complications such as respiratory failure (p = 0.0054), acute renal failure (p < 0.0001), acute myocardial failure (p < 0.0001), and the need for resuscitation (ST/T: p < 0.0001/TE: p = 0.0218) were significantly increased after any kind of gastrectomy. Roux-en Y was the most commonly applied reconstruction technique in both young and elderly patients. Regarding lymphadenectomy, systematic D2 dissection was performed less frequently in older patients than in the younger collective in the case of ST and T as well as D3 dissection. Peritonectomy and hyperthermic intraperitoneal chemotherapy were uncommon in elderly patients alongside ST and T compared to younger patients (p < 0.0001).

CONCLUSION

The clinical outcome of major oncological gastric surgery is highly dependent on a patient's age. The elderly show a tremendously increased likelihood of in-hospital mortality and morbidity.

The Effect of Anti-Tumor Necrosis Factor-Alpha Therapy within 12 Weeks Prior to Surgery on Postoperative Complications in Inflammatory Bowel Disease: A Systematic Review and Meta-Analysis

The rate of abdominal surgical interventions and associated postoperative complications in inflammatory bowel disease (IBD) patients is still substantially high. There is an ongoing debate as to whether or not patients who undergo treatment with anti-tumor necrosis factor-alpha (TNF-α) agents may have an increased risk for general and surgical postoperative complications. Therefore, a systematic review and meta-analysis was conducted in order to assess the effect of anti-TNF-α treatment within 12 weeks (washout period) prior to abdominal surgery on 30-day postoperative complications in patients with IBD. The results of previously published meta-analyses examining the effect of preoperative anti-TNF-α treatment on postoperative complications reported conflicting findings which is why we specifically focus on the effect of anti-TNF-α treatment within 12 weeks prior to surgery. PubMed, Cochrane, Scopus, Web of Science, World Health Organization Trial Registry, ClinicalTrials.gov and reference lists were searched (June 1995−February 2022) to identify studies, investigating effects of anti-TNF-α treatment prior to abdominal surgery on postoperative complications in IBD patients. Pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated and subgroup analyses were performed. In this case, 55 cohort studies (22,714 patients) were included. Overall, postoperative complications (OR, 1.23; 95% CI, 1.04−1.45; p = 0.02), readmission (OR, 1.39; 95% CI, 1.11−1.73; p = 0.004), and intra-abdominal septic complications (OR, 1.89; 95% CI, 1.44−2.49; p < 0.00001) were significantly higher for anti-TNF-α-treated patients. Significantly higher intra-abdominal abscesses and readmission were found for anti-TNF-α-treated CD patients (p = 0.05; p = 0.002). Concomitant treatment with immunosuppressives in <50% of anti-TNF-α-treated patients was associated with significantly lower mortality rates (OR, 0.32; 95% CI, 0.12−0.83; p = 0.02). Anti-TNF-α treatment within 12 weeks prior to surgery is associated with higher short-term postoperative complication rates (general and surgical) for patients with IBD, especially CD.

Anastomotic Rings and Inflammation Values as Biomarkers for Leakage of Stapled Circular Colorectal Anastomoses

Reliable markers to predict or diagnose anastomotic leakage (AL) of stapled circular anastomoses following colorectal resections are an important clinical need. Here, we aim to quantitatively investigate the morphology of anastomotic rings as an early available prognostic marker for AL and compare them to established inflammatory markers. We perform a prospective single-center cohort study, including patients undergoing stapled circular anastomosis between August 2020 and August 2021. The predictive value of the anastomotic ring configuration and the neutrophil-to-lymphocyte ratio (NLR) regarding anastomotic leakage is examined by ROC analyses and compared to the C-reactive protein (CRP) as an established marker. We included 204 patients, of which 19 suffered from anastomotic leakage (LEAK group), while in 185 patients the anastomoses healed well (HEAL group). The minimal height of the anastomotic rings as a binary classifier had a good ROC-AUC of 0.81 but was inferior to the NLR at postoperative day (POD) 5, with an excellent ROC-AUC of 0.93. Still, it was superior to the NLR at POD 3 (0.74) and the CRP at POD 3 (ROC-AUC 0.54) and 5 (ROC-AUC 0.70). The minimal height of the anastomotic rings as indicator for technically insufficient anastomoses is a good predictor of AL, while postoperatively the NLR was superior to the CRP in prediction of AL.

Annexin A1 based inflammation resolving mediators and nanomedicines for inflammatory bowel disease therapy

Inflammatory bowel diseases (IBD) such as Crohn's Disease (CD) and Ulcerative Colitis (UC) are chronic, progressive, and relapsing disorders of the gastrointestinal tract (GIT), characterised by intestinal epithelial injury and inflammation. Current research shows that in addition to traditional anti-inflammatory therapy, resolution of inflammation and repair of the epithelial barrier are key biological requirements in combating IBD. Resolution mediators include endogenous lipids that are generated during inflammation, e.g., lipoxins, resolvins, protectins, maresins; and proteins such as Annexin A1 (ANXA1). Nanoparticles can specifically deliver these potent inflammation resolving mediators in a spatiotemporal manner to IBD lesions, effectively resolve inflammation, and promote a return to homoeostasis with minimal collateral damage. We discuss these exciting and timely concepts in this review.

Resistance to inflammation underlies enhanced fitness in clonal hematopoiesis

[Figure: see text].

[Reconstruction following gastrectomy]

Minimally invasive surgical techniques with respect to the treatment of gastric cancer have progressed rapidly over the last few years. Especially in Asia, where the incidence of gastric cancer is ten times higher than in Europe, surgery for gastric cancer is steadily evolving, especially regarding laparoscopic and robot-assisted procedures. This review first discusses the different options for reconstruction of the gastrointestinal passage after gastrectomy, ranging from Billroth procedures to the latest developments, such as the double tract reconstruction. In particular, the possibility of function-preserving partial gastrectomy, such as proximal and distal gastric resection and the corresponding reconstruction techniques are presented. The latest studies and technical developments are presented, especially with respect to laparoscopically assisted, completely laparoscopic and robot-assisted gastrectomies.

Crohn's disease: a population-based study of surgery in the age of biological therapy

PURPOSE

Despite primary conservative therapy for Crohn's disease, a considerable proportion of patients ultimately needs to undergo surgery. Presumably, due to the increased use of biologics, the number of surgeries might have decreased. This study aimed to delineate current case numbers and trends in surgery in the era of biological therapy for Crohn's disease.

METHODS

Nationwide standardized hospital discharge data (diagnosis-related groups statistics) from 2010 to 2017 were used. All patients who were admitted as inpatient Crohn's disease cases in Germany were included. Time-related development of admission numbers, rate of surgery, morbidity, and mortality of inpatient Crohn's disease cases were analyzed.

RESULTS

A total number of 201,165 Crohn's disease cases were included. Within the analyzed time period, the total number of hospital admissions increased by 10.6% (n = 23,301 vs. 26,069). While gender and age distribution remained comparable, patients with comorbidities such as stenosis formation (2010: 10.1%, 2017: 13.4%) or malnutrition (2010: 0.8%, 2017: 3.2%) were increasingly admitted. The total number of all analyzed operations for Crohn's disease increased by 7.5% (2010: n = 1567; 2017: n = 1694). On average, 6.8 ± 0.2% of all inpatient patients received ileocolonic resections. Procedures have increasingly been performed minimally invasive (2010: n = 353; 2017: n = 687). The number of postoperative complications remained low.

CONCLUSION

Despite the development of novel immunotherapeutics, the number of patients requiring surgery for Crohn's disease remains stable. Interestingly, patients have been increasingly hospitalized with stenosis and malnutrition. The trend towards more minimally invasive operations has not relevantly changed the rate of overall complications.

Macroscale mesenchymal condensation to study cytokine-driven cellular and matrix-related changes during cartilage degradation

Understanding the pathophysiological processes of cartilage degradation requires adequate model systems to develop therapeutic strategies towards osteoarthritis (OA). Although different in vitro or in vivo models have been described, further comprehensive approaches are needed to study specific disease aspects. This study aimed to combine in vitro and in silico modeling based on a tissue-engineering approach using mesenchymal condensation to mimic cytokine-induced cellular and matrix-related changes during cartilage degradation. Thus, scaffold-free cartilage-like constructs (SFCCs) were produced based on self-organization of mesenchymal stromal cells (mesenchymal condensation) and (i) characterized regarding their cellular and matrix composition or secondly (ii) treated with interleukin-1β (IL-1β) and tumor necrosis factor α (TNFα) for 3 weeks to simulate OA-related matrix degradation. In addition, an existing mathematical model based on partial differential equations was optimized and transferred to the underlying settings to simulate the distribution of IL-1β, type II collagen degradation and cell number reduction. By combining in vitro and in silico methods, we aimed to develop a valid, efficient alternative approach to examine and predict disease progression and effects of new therapeutics.

Androgens sensitise mice to glucocorticoid-induced insulin resistance and fat accumulation

AIMS/HYPOTHESIS

Chronic glucocorticoid therapy causes insulin resistance, dyslipidaemia, abnormal fat accumulation, loss of muscle mass and osteoporosis. Here we describe a hitherto unknown sexual dimorphism in the metabolic response to chronic glucocorticoid exposure in mice. This led us to investigate whether glucocorticoid-induced insulin resistance and obesity were dependent on sex hormones.

METHODS

Male and female CD1 mice were treated for 4 weeks with supraphysiological doses (~250 μg/day) of corticosterone, the main glucocorticoid in rodents, or equivalent volume of vehicle (drinking water without corticosterone). To investigate the effects of sex hormones, a separate group of mice were either orchidectomised or ovariectomised prior to corticosterone treatment, with or without dihydrotestosterone replacement. Body composition was determined before and after corticosterone treatment, and insulin tolerance was assessed after 7 and 28 days of treatment. Adipocyte morphology was assessed in white and brown adipose tissues by immunohistochemistry, and fasting serum concentrations of NEFA, triacylglycerols, total cholesterol and free glycerol were measured using colorimetric assays. Obesity- and diabetes-related hormones were measured using multiplex assays, and RNA and protein expression in adipose tissues were measured by RT-PCR and immunoblotting, respectively.

RESULTS

Chronic corticosterone treatment led to insulin resistance, fasting hyperinsulinaemia, increased adiposity and dyslipidaemia in male, but not female mice. In males, orchidectomy improved baseline insulin sensitivity and attenuated corticosterone-induced insulin resistance, but did not prevent fat accumulation. In androgen-deficient mice (orchidectomised males, and intact and ovariectomised females) treated with dihydrotestosterone, corticosterone treatment led to insulin resistance and dyslipidaemia. In brown adipose tissue, androgens were required for corticosterone-induced intracellular lipid accumulation ('whitening'), and dihydrotestosterone specifically exacerbated corticosterone-induced accumulation of white adipose tissue by increasing adipocyte hypertrophy. Androgens also suppressed circulating adiponectin concentrations, but corticosterone-induced insulin resistance did not involve additional suppression of adiponectin levels. In white adipose tissue, androgens were required for induction of the glucocorticoid target gene Gilz (also known as Tsc22d3) by corticosterone.

CONCLUSIONS/INTERPRETATION

In mice, androgens potentiate the development of insulin resistance, fat accumulation and brown adipose tissue whitening following chronic glucocorticoid treatment.

Collagen I-based scaffolds negatively impact fracture healing in a mouse-osteotomy-model although used routinely in research and clinical application

Although several biomaterials for bone regeneration have been developed in the last decades, clinical application of bone morphogenetic protein 2 is clinically only approved when applied on an absorbable bovine collagen I scaffold (ACS) (Helistat; ACS-H). In research, another ACS, namely Lyostypt (ACS-L) is frequently used as a scaffold in bone-linked studies. Nevertheless, until today, the influence of ACS alone on bone healing remains unknown. Unexpectedly, in vitro studies using ASC-H revealed a suppression of osteogenic differentiation and a significant reduction of cell vitality when compared to ASC-L. In mice, we observed a significant delay in bone healing when applying ACS-L in the fracture gap during femoral osteotomy. The results of our study show for the first time a negative influence of both ACS-H and ACS-L on bone formation demonstrating a substantial need for more sophisticated delivery systems for local stimulation of bone healing in both clinical application and research. STATEMENT OF SIGNIFICANCE: Our study provides evidence-based justification to promote the development and approval of more suitable and sophisticated delivery systems in bone healing research. Additionally, we stimulate researchers of the field to consider that the application of those scaffolds as a delivery system for new substances represents a delayed healing approach rather than a normal bone healing which could greatly impact the outcome of those studies and play a pivotal role in the translation to the clinics. Moreover, we provide impulses on underlying mechanism involving the roles of small-leucine rich proteoglycans (SLRP) for further detailed investigations.

Patient Reported Outcomes (PROs) im rheumatologischen Praxisalltag – App hat sich bewährt

Hintergrund Patient-reported-outcomes (PROs) haben einen zunehmenden Einfluss auf die unmittelbare Therapieentscheidung des Arztes in der klinischen Praxis.

Zielstellung Überprüfung der Integration und des Nutzens von elektronisch erhobenen PROs per ScoreCheck Rheuma®-App (SCR App) im klinischen Praxisalltag der rheumatologischen Fachambulanz (Dispensaire) der Charité - Universitätsmedizin Berlin in Hinblick auf Praxistauglich, Patientenakzeptanz und medizinischen Mehrwert.

Patienten und Methoden N=190 Patienten (63% weiblich, mittleres Alter: 55 Jahre, min 23-max 82; Diagnosen: 52,9% Rheumatoide Arthritis, 28,6% Spondyloarthritis, 9,3% Kollagenosen, 3,6% Vaskulitis, 5,6% sonstiges) sowie 3 medizinische Fachangestellte (MFA) und 3 Ärzte (Rheumatologen) haben an diesem Pilotprojekt teilgenommen. Die folgenden PROs wurden elektronisch mittels SCR App von den eingeschlossenen Patienten ausgefüllt: FFbH (Funktionsfragebogen Hannover), BASDAI (Bath Ankylosing Spondylitis Disease Activity Index) und BASFI (Bath Ankylosing Spondylitis Functional Index) sowie ein Fragebogen zur Selbsteinschätzung. Zusätzlich wurde für jeden eingeschlossenen Patienten je ein Beurteilungs-Protokoll vom Patienten selbst, von der zuständigen MFA und vom betreuenden Arzt ausgefüllt.

Ergebnisse Von den 190 teilnehmenden Patienten gaben 147 (77%) an, Vorerfahrungen mit Touchpad-Geräten zu haben. 96% der Patienten fühlten sich außerdem gut bis sehr gut in die Bedienung des iPADs und der SCR App durch die MFAs eingewiesen und fanden das Ausfüllen der Fragebögen auf dem iPAD einfach; Schwierigkeiten, wie z. B. mit der Schriftgröße, der Handhabung, usw. wurden nur von 10% der Patienten angegeben. Immerhin 74% der Patienten wünschten sich den vermehrten Einsatz elektronischer Hilfsmittel beim Arztbesuch und 75% bevorzugten den Einsatz des iPADs gegenüber dem Ausfüllen der Fragebögen auf Papier. Die MFAs gaben in über 80% der Fälle an, dass die Patienten die Fragebögen zu den PROs ohne oder mit nur wenig Hilfe selbstständig ausfüllen konnten. In ca. 2/3 der Fälle sahen die MFAs Vorteile durch die Anwendung der SCR App sowohl bezüglich der Qualität der Patientenbetreuung als auch bezüglich der Erfassung der Funktionsscores. Die Ärzte sahen in 2/3 der Fälle eher keine Zeitersparnis durch den Einsatz des iPADs. In 78% der Fälle konnte der Patientenscore in das Arzt-Patienten-Gespräch eingebracht werden, jedoch sparte die Anwendung der SCR App nur in 50% der Fälle Zeit im Praxisalltag. Die Ärzte sahen v. a. Vorteile bezüglich der Anamneseerhebung und der Therapieempfehlungen.

Schlussfolgerung Insgesamt zeigt das vorgestellte Pilotprojekt zur Anwendung und Integration der SCR App eine gute Resonanz bei den Patienten, MFAs und Ärzten. Die Arztbewertung ergibt, dass durch die SCR App bei jedem zweiten Patienten ein Vorteil bei der Therapieempfehlung gesehen wurde.

Continuous corticosterone delivery via the drinking water or pellet implantation: A comparative study in mice

In order to investigate the effects of glucocorticoid excess in rodent models, reliable methods of continuous glucocorticoid delivery are essential. The current study compares two methods of corticosterone (CS) delivery in regards to their ability to induce typical adverse outcomes such as fat accrual, insulin resistance, sarcopenia and bone loss. Eight-week-old mice received CS for 4weeks either via the drinking water (25-100μgCS/mL) or through weekly surgical implantation of slow release pellets containing 1.5mg CS. Both methods induced abnormal fat mass accrual, inhibited lean mass accretion and bone expansion, suppressed serum osteocalcin levels and induced severe insulin resistance. There was a clear dose dependant relationship between the CS concentrations in the drinking water and the severity of the phenotype, with a concentration of 50μg CS/mL drinking water most closely matching the metabolic changes induced by weekly pellet implantations. In contrast to pellets, however, delivery of CS via the drinking water resulted in a consistent diurnal exposure pattern, closely mimicking the kinetics of clinical glucocorticoid therapy. In addition, the method is safe, inexpensive, easily adjustable, non-invasive and avoids operative stress to the animals. Our data demonstrate that delivery of CS via the drinking water has advantages over weekly implantations of slow-release pellets. A dose of 50μg CS/mL drinking water is appropriate for the investigation of chronic glucocorticoid excess in mice.

Antisense modulation of the ICAM-1 phenotype of a model human bone marrow stromal cell line

Efficient stable gene transfer was achieved in a model human bone marrow stromal cell line, KM-102, using both Epstein-Barr virus and BK virus episomal expression vectors. Using this episomal expression system, effective overexpression and inhibition of ICAM-1 expression was achieved in stably transfected KM-102 cells by sense and antisense RNA gene transfer, respectively. Loss of surface ICAM-1 on antisense KM-102 transfectants did not significantly affect adhesion to LFA-1-bearing JY hematopoietic cells. However, KM-102 ICAM-1 overexpressors demonstrated enhanced binding (2.5-fold) to phorbol ester-treated, but not untreated, LFA-1-bearing JY cells. The increased binding could be blocked with anti-ICAM-1 antibodies. These findings suggest that while ICAM-1 is not required for basal adhesion between stromal and hematopoietic cells, stromal ICAM-1 may contribute to stromal:leukemic cellular interaction when bound to the phorbol ester-dependent high-avidity state of hematopoietic LFA-1.

A receptor for the lipocalin placental protein 14 on human monocytes

Human placental protein 14 (PP14), a member of the lipocalin structural superfamily, is an abundant amniotic fluid glycoprotein with documented immunoinhibitory activities. While receptors have been characterized for several other lipocalins, none have been reported to date for PP14. In the present study, two-color immunofluorescence and flow cytometry was used to screen peripheral blood mononuclear cell subpopulations for their capacity to engage fluoresceinated recombinant PP14. The tagged PP14 bound strongly in a specific and saturable fashion to CD14+ (monocyte lineage) cells, but not to CD20+ (B cell lineage) or CD3+ (T cell lineage) cells. This binding was both pH- and temperature-sensitive, and was reduced by proteolytic pre-digestion of the cells with trypsin or proteinase K. Scatchard analysis demonstrated a single class of receptors on CD14+ cells, with a K(D) of approximately 1 x 10(-8) and approximately 10-35,000 receptors per cell. These findings constitute the first report of a cell surface-associated binding protein for PP14 and set the stage for exploring the molecular mechanisms of PP14-mediated signaling and immunomodulation.

Bone marrow stromal cell blockade of human leukemic cell differentiation

Bone marrow (BM) stromal cell inhibition of leukemic cell differentiation was studied in cellular coculture experiments. In coculture, a significant percentage of cells from the human myeloid leukemic cell lines HL-60, PLB-985, and K562 adhere to fibroblastic KM-102 BM stromal cells. A sensitive two-color immunofluorescence assay was developed to monitor stromal cellular effects upon leukemic cell differentiation. After chemical induction with 1 alpha,25-dihydroxyvitamin D3, strongly adherent HL-60 and PLB-985 cells were inhibited from differentiating into more mature monocytic cells, as measured by the monocytic surface marker CD14. In contrast, loosely adherent and nonadherent HL-60 and PLB-985 leukemic cells in the same cocultures, as well as both adherent and nonadherent K562 cells induced with phorbol ester, were not blocked in their capacity to differentiate. Scanning electron microscopy and intercellular dye transfer experiments correlated intimate stromal cell/leukemic cell interaction and intercellular communication with the blockade of leukemic cell differentiation. These studies indicate that there is significant variability among leukemic lines with respect to the nature of their adhesion to stromal cells. Moreover, the data implicate gap-junction formation as a potentially significant event in stromal cell-mediated leukemic cell regulation.

A glycosylphosphatidylinositol-anchored cytokine can function as an artificial cellular adhesin

A novel strategy for altering the adhesive properties of cells has been developed which is based upon the use of artificial adhesins. Specifically, a glycosylphosphatidylinositol (GPI)-modified variant of the cytokine macrophage colony stimulating factor (M-CSF), designated M-CSF.GPI, was expressed on the surface of human bone marrow stromal cells. A chimeric M-CSF:decay-accelerating factor expression construct was used for M-CSF.GPI expression. Cell:cell binding assays established that this artificially membrane-tethered cytokine functions as a potent cellular adhesin, allowing for enhanced binding to M-CSF receptor-expressing cellular transfectants. Antibody blocking analyses confirmed the M-CSF:M-CSF receptor dependence of the enhanced intercellular binding. This capacity to direct the cellular interactive repertoire of selected cells can in principle be applied to other cell types and other molecular pairs to be used in cell-based therapies.

Regulation of allogeneic responses by expression of CD8 alpha chain on stimulator cells

By antisense-mediated inhibition of CD8 expression in T cell clones and expression of CD8 in non-T cell lines, we have produced several sets of CD8+/CD8- paired cell lines. These cellular reagents have allowed us to assess the effect of CD8 surface expression on the immunogenic potential of stimulator cells. We found that the presence of CD8 on stimulator cells markedly decreased their capacity to stimulate proliferative responses or to induce the generation of cytotoxic activity. The CD8 alpha chain, in the absence of the beta chain, was sufficient to mediate this inhibitory effect. Our findings support the notion that CD8 functions as an immunoregulatory ligand and that auxiliary cell surface molecules on stimulator cells can have profound effects on the immunogenic capabilities of these cells.

Isolation and characterization of BHK cells sensitive to ionizing radiation and alkylating agents

A host-cell viral suicide enrichment procedure was used to isolate BHK strains sensitive to ionizing radiation. Of six strains surviving infection with irradiated herpes simplex virus (HSV), three were found to be more sensitive to ionizing radiation than the parental BHK cells. Thus the D0's of strains V1, V2, and V5 were 1.59, 1.41, and 1.49 Gy, respectively, while the D0 for the parental BHK strain was 1.79. Strains V1 and V2 were studied in more detail and found to exhibit hypersensitivity to ethyl methanesulfonate (EMS), methyl methanesulfonate, and N-methyl-N'-nitro-N-nitrosoguanidine, but not to uv radiation. Susceptibility to mutation in response to EMS was also compared in BHK and strains V1 and V2. The frequency of induction of ouabain-resistant cells was 140% of the parental strain in the case of strain V1 and 58% of the parental strain in the case of strain V2.

Field trial of metrifonate in the treatment and prevention of schistosomiasis infection in man

A field trial was set up to test the prophylactic properties of the organophosphorous drug metrifonate (Bilarcil Bayer AG). Subjects were rural African children living in an area of Rhodesia where Schistosoma haematobium and S. mansoni are highly endemic. The trial was conducted in three stages, a preliminary period of therapy followed by two six-month periods of prophylaxis. Parasitological and haematological tests were carried out monthly and major assessments (including clinical examinations) were carried out prior to the start of the trial and at the end of each of the three stages. Drug was given to the appropriate groups at a dose rate of 7-5 mg/kg once per fortnight for three doses during the therapy stage and four-weekly during the prophylaxis stage. Results with S. haematobium were very good. A 60% cure-rate was observed six weeks aection was obtained in those children continuing to receive the drug as a prophylactic, even during the season of highest transmission; intensities of infection in those who became infected were very low. Infection rates in the treated but unprotected group rose steadily from 40% at week 11 to 95% at week 70. There was a sigificant effect upon the intensity of S. mansoni infections only when pre- and post-trial data were compared. Apart from the anticipated (and previously reported) depression of plasma cholinesterase values no side effects were recorded. Drug tolerance and acceptibility were very high. It is likely that the costs of a year's protection against S. Haematobium using metrifonate will be significantly lower than protection by molluscicidal techniques or single courses of treatment with established drugs.

Dose-finding trials of oral oxamniquine in Rhodesia

Oral oxamniquine at a total dose of 60 mg/kg (given in 4 equal doses morning and evening over 2 days, after food) is an efficient and apparently very safe drug for the treatment of Schistosoma mansoni infections. Lower doses, or shorter schedules of treatment, are less efficient. The drug has little or no effect on S. haematobium infections. Side-effects are mild and infrequent.