Steroidal antibiotics are antimetabolites of Acanthamoeba steroidogenesis with phylogenetic implications

Pathogenic organisms may be sensitive to inhibitors of sterol biosynthesis, which carry antimetabolite properties, through manipulation of the key enzyme, sterol methyltransferase (SMT). Here, we isolated natural suicide substrates of the ergosterol biosynthesis pathway, cholesta-5,7,22,24-tetraenol (CHT) and ergosta-5,7,22,24(28)-tetraenol (ERGT), and demonstrated their interference in Acanthamoeba castellanii steroidogenesis: CHT and ERGT inhibit trophozoite growth (EC50 of 51 nM) without affecting cultured human cell growth. Washout experiments confirmed that the target for vulnerability was SMT. Chemical, kinetic, and protein-binding studies of inhibitors assayed with 24-AcSMT [catalyzing C28-sterol via Δ24(28)-olefin production] and 28-AcSMT [catalyzing C29-sterol via Δ25(27)-olefin production] revealed interrupted partitioning and irreversible complex formation from the conjugated double bond system in the side chain of either analog, particularly with 28-AcSMT. Replacement of active site Tyr62 with Phe or Leu residues involved in cation-π interactions that model product specificity prevented protein inactivation. The alkylating properties and high selective index of 103 for CHT and ERGT against 28-AcSMT are indicative of a new class of steroidal antibiotic that, as an antimetabolite, can limit sterol expansion across phylogeny and provide a novel scaffold in the design of amoebicidal drugs. Animal studies of these suicide substrates can further explore the potential of their antibiotic properties.

Depressive symptoms at 13 years as predictors of depression in older adolescents: a prospective 4-year follow-up study in a nonclinical population

Depression is the most important source of disability in adolescents, partially due to its recurrence. There is a lack of studies on population-based samples investigating the continuity of depressive symptoms during adolescence. This study evaluates depressive symptoms at early adolescence as predictors of depressive symptoms later in adolescence. Urban adolescents born in 1990 and enrolled in schools of Porto, Portugal, in 2003-2004 (EPITeen study) were evaluated at 13 and 17 years (n = 1106, 55.9% females), and completed a questionnaire comprising health behaviors and Beck Depression Inventory II (BDI-II) to assess depressive symptoms. A questionnaire on socio-demographic and clinical characteristics was self-reported. Regression coefficients (β) and 95% confidence intervals (CI) were estimated using simple linear regression. The prevalence of adolescents with depressive symptoms above the cut-off (BDI-II > 13) was 11.9% at 13 years (girls: 17.1%; boys: 5.3%) and 10.8% at 17 years (girls: 14.7%; boys: 5.7%). Almost 6% of girls and 2% of boys had BDI-II > 13 at both assessments, and 35% of girls and boys with BDI-II > 13 at baseline also had BDI-II > 13 at follow-up. For both genders, depressive symptoms at age 13 were independently associated with depressive symptoms at age 17 (girls: β = 0.35, 95% CI 0.28-0.42; boys: β = 0.37, 95% CI 0.30-0.44). Depressive symptoms at age 13 were an independent predictive factor for adolescents' depressive symptoms at age 17. The prevalence of adolescents with BDI-II > 13 was higher in females, but the strength of this association was similar in both genders, highlighting the heavy burden of depressive symptoms already at an early age, among girls and boys.

Efficacy and Safety of Delayed Prolonged-Release Tacrolimus Initiation in De Novo Hepatitis C Virus-Negative Orthotopic Liver Transplant Recipients: A Single-Center, Single-Arm, Prospective Study

Background

Delaying initiation of tacrolimus after liver transplantation (LT) is a potential renal-sparing strategy. We assessed safety and efficacy of delayed initiation of prolonged-release tacrolimus (PR-T) in de novo LT.

Material/Methods

This was a single-center, single-arm, prospective, 12-month observational study of hepatitis C virus-negative orthotopic LT patients. Immunosuppression included PR-T (initially 0.1 or 0.2 mg/kg/day) initiated on Day 3 post LT, basiliximab (20 mg) on post-transplantation Day 0 and Day 4, and intraoperative corticosteroids (500 mg). Patients received maintenance corticosteroids and mycophenolate mofetil (MMF) according to center protocol. MMF dose was adjusted according to thrombocyte count. The primary endpoint was the estimated glomerular filtration rate (eGFR) measured using the Modification of Diet in Renal Disease 4-variable formula at 12 months. Secondary endpoints included biopsy-confirmed acute rejection (BCAR) and dialysis requirement. Adverse events were recorded.

Results

Sixty-nine patients (mean age 55.0 years) were included. Most patients started MMF on Day 1 (60.9%) or Day 2 (10.1%), and PR-T on Day 3 (55.1%) or Day 4 (29.0%). Mean tacrolimus trough levels (ng/mL) were: Day 7, 9.5±6.3; Day 10, 9.4±5.4; Month 1, 8.0±3.1; Month 3, 7.8±3.7; Month 6, 8.0±4.1; and Month 12, 7.2±3.1. Mean 12-month eGFR was 77.2±24.5 mL/min/1.73 m²; 72.5% of patients had eGFR >60 mL/min/1.73 m² at 12 months; 89.9% had no eGFR measurements <40 mL/min/1.73 m² during the study. Renal insufficiency (any eGFR <60 mL/min/1.73 m²) was diagnosed in 27.5% of patients; one patient required dialysis. There were no BCAR episodes; the infection rate was 36.2%, and 3 patients died. Overall, 19 patients (27.5%) developed de novo diabetes mellitus, 18 patients (26.1%) had hypercholesterolemia, and 12 patients (17.4%) had hypertriglyceridemia.

Conclusions

Quadruple therapy with delayed administration of PR-T was well tolerated and efficacious, and was associated with acceptable renal function over 12 months.

Long-term expanding human airway organoids for disease modeling

Organoids are self-organizing 3D structures grown from stem cells that recapitulate essential aspects of organ structure and function. Here, we describe a method to establish long-term-expanding human airway organoids from broncho-alveolar resections or lavage material. The pseudostratified airway organoids consist of basal cells, functional multi-ciliated cells, mucus-producing secretory cells, and CC10-secreting club cells. Airway organoids derived from cystic fibrosis (CF) patients allow assessment of CFTR function in an organoid swelling assay. Organoids established from lung cancer resections and metastasis biopsies retain tumor histopathology as well as cancer gene mutations and are amenable to drug screening. Respiratory syncytial virus (RSV) infection recapitulates central disease features, dramatically increases organoid cell motility via the non-structural viral NS2 protein, and preferentially recruits neutrophils upon co-culturing. We conclude that human airway organoids represent versatile models for the in vitro study of hereditary, malignant, and infectious pulmonary disease.

Randomized trial of two types of gastrojejunostomy after pancreatoduodenectomy and risk of delayed gastric emptying (PAUDA trial)

BACKGROUND

Delayed gastric emptying (DGE) is the most important cause of an extended hospital stay after pancreatoduodenectomy. Reports suggest that a Roux-en-Y gastroenteric anastomosis may have lower incidence of DGE than a Billroth II reconstruction. The primary aim of this RCT was to compare Billroth II (single loop) and Roux-en-Y (double loop) after pancreatoduodenectomy to determine whether Roux-en-Y reconstruction is associated with a lower incidence of DGE. Secondary endpoints were postoperative complications.

METHODS

This was a randomized unblinded single-centre trial without masked evaluation of the main outcome. Patients undergoing pancreatoduodenectomy between 2013 and 2015 were randomized to undergo one of two types of gastroenteric anastomosis for reconstruction.

RESULTS

A total of 80 patients were randomized, 40 in each group. The incidence of DGE was the same in patients undergoing Billroth II or Roux-en-Y gastroenteric anastomosis (both 18 of 40 patients; P = 1·000). The grade of DGE was also similar in the Billroth II and Roux-en-Y groups (grade A, both 10 of 40; grade B, 5 of 40 versus 6 of 40; grade C, 3 of 40 versus 2 of 40; P = 0·962). The mortality rate was 3 per cent, with no significant difference between the two groups. There were no differences in the overall rate of postoperative morbidity, relaparotomy rate or duration of hospital stay.

CONCLUSION

The incidence and severity of DGE does not differ between single- or double-loop gastroenteric anastomosis performed after pancreatoduodenectomy. Registration number: NCT00915863 (http://www.clinicaltrials.gov).

Food intake and high-sensitivity C-reactive protein levels in adolescents

BACKGROUND AND AIMS

Diet comprises factors with anti and pro-inflammatory potential that can contribute to modulate obesity-induced inflammation. We aimed to assess the association between food intake and high-sensitivity C-reactive protein (hsCRP) levels in adolescents.

METHODS AND RESULTS

A cross-sectional analysis of 991 adolescents aged 13 years old was conducted as part of the EPITeen cohort, Porto, Portugal. Food intake was assessed by a food frequency questionnaire and thirteen food groups were defined. Anthropometric assessment was performed and serum hsCRP was measured in a fasting blood sample. hsCRP concentrations above the 75th percentile were considered high. Logistic regression was fitted to estimate the association between the intake frequency of the food groups and hsCRP, stratified by BMI and adjusted for sex, parental education and total energy intake. Median (25-75th percentiles) hsCRP concentrations increased with increasing values of BMI [normal weight: 0.20 (0.10-0.50); overweight: 0.40 (0.20-0.80); obese: 1.10 (0.40-2.15) mg/l, p < 0.001]. After adjustment for sex, parental education and total energy intake, no statistically significant associations were found amongst normal weight and overweight participants. However, among obese individuals, having as reference the first frequency category (<1 per day), a higher frequency of vegetables/legumes intake showed a decreased odds of high hsCRP levels (OR: 0.10, 95%CI 0.03-0.38, 1-3 per day; and OR: 0.14, 95%CI 0.04-0.52, >3 per day).

CONCLUSION

Among participants with obesity-induced higher hsCRP levels, a higher frequency of vegetable/legume intake was inversely related to hsCRP.

Functional importance for developmental regulation of sterol biosynthesis in Acanthamoeba castellanii

The sterol metabolome of Acanthamoeba castellanii (Ac) yielded 25 sterols. Substrate screening of cloned AcCYP51 revealed obtusifoliol as the natural substrate which converts to ∆8,14-sterol (<95%). The combination of [2H3-methyl]methionine incubation to intact cultures showing C28-ergosterol incorporates 2-2H atoms and C29-7-dehydroporiferasterol incorporates 5 2H-atoms, the natural distribution of sterols, CYP51 and previously published sterol methyltransferase (SMT) data indicate separate ∆24(28)- and ∆25(27)-olefin pathways to C28- and C29-sterol products from the protosterol cycloartenol. In cell-based culture, we observed a marked change in sterol compositions during the growth and encystment phases monitored microscopically and by trypan blue staining; trophozoites possess C28/C29-∆5,7-sterols, viable encysted cells (mature cyst) possess mostly C29-∆5-sterol and non-viable encysted cells possess C28/C29-∆5,7-sterols that turnover variably from stress to 6-methyl aromatic sterols associated with changed membrane fluidity affording lysis. An incompatible fit of steroidal aromatics in membranes was confirmed using the yeast sterol auxotroph GL7. Only viable cysts, including those treated with inhibitor, can excyst into trophozoites. 25-Azacycloartanol or voriconazole that target SMT and CYP51, respectively, are potent enzyme inhibitors in the nanomolar range against the cloned enzymes and amoeba cells. At minimum amoebicidal concentration of inhibitor amoeboid cells rapidly convert to encysted cells unable to excyst. The correlation between stage-specific sterol compositions and the physiological effects of ergosterol biosynthesis inhibitors suggests that amoeba fitness is controlled mainly by developmentally-regulated changes in the phytosterol B-ring; paired interference in the ∆5,7-sterol biosynthesis (to ∆5,7) - metabolism (to ∆5 or 6-methyl aromatic) congruence during cell proliferation and encystment could be a source of therapeutic intervention for Acanthamoeba infections.

Autologous dental pulp mesenchymal stem cells for inferior third molar post-extraction socket healing: A split-mouth randomised clinical trial

Background

Since the discovery of adult mesenchymal stem cells extensive research has been conducted to determine their mechanisms of differentiation and effectiveness in cell therapy and regenerative medicine.

Material and Methods

To assess the efficacy of autologous dental pulp mesenchymal stem cells delivered in a collagen matrix for post-extraction socket healing, a single-centre, double-blind, randomised, split-mouth, controlled clinical trial was performed. Both impacted mandibular third molars were extracted from 32 patients. Dental pulp was collected and dissociated; the resulting cell suspension, obtained by centrifugation, was incorporated into a resorbable collagen matrix and implanted in 32 experimental post-extraction sockets. Collagen matrices alone were implanted in 32 contralateral, control post-extraction sockets. Two neuroradiologists independently assessed the extent of bone repair at 6 months after the extractions. Computed tomography (CT, Philips Brilliance) and an advanced display platform (IntelliSpace Portal) was used to record extraction socket density, expressed as Hounsfield units (HU) and height (mm) of the distal interdental bone septum of the second molar. Measurements at 6 months post-extraction were compared with measurements obtained immediately after extraction. Data were analysed with the statistical program STATA 14.

Results

Two patients dropped out of the study. The final sample consisted of 22 women and 8 men (mean age, 23 years; range: 18–30 years). Clinical, radiological, and surgical characteristics of impacted third molars of the control and experimental groups were homogeneous. Measurements obtained by the two neuroradiologists showed agreement. No significant differences were found in the extent of bone repair during analyses of density (p=0.4203 neuroradiologist 1; p=0.2525 neuroradiologist 2) or interdental septum height (p=0.2280 neuroradiologist 1; p=0.4784 neuroradiologist 2).

Conclusions

In our clinical trial, we were unable to demonstrate that autologous dental pulp mesenchymal stem cells reduce socket bone resorption after inferior third molar extraction.

Key words:Clinical trial, autologous, pulpal stem cells, extraction socket healing.

[Infrapectineal plate for repair with minimal invasion of quadrilateral blade acetabular fractures: description new implant and paramedial access]

INTRODUCTION

Quadrilateral plate fractures are the most difficult to reduce and fix. Different techniques have been developed for quadrilateral plate osteosynthesis. The objective of this work was to create an implant and a novel approach to simplify and improve acetabular fracture osteosynthesis.

MATERIAL AND METHODS

A total of 83 patients were studied. Pelvic CT scan images of both acetabula were measured at the proximal and distal posterior column. Implant length, diameters and morphological characteristics were determined. The anatomical features of a novel surgical approach are described. The paramedian approach was performed on a cadaveric specimen to determine its anatomical safety.

RESULTS

The screws measured 20 × 6 × 8 mm (length × core diameter x head diameter), with internal threads of 4.5 mm. The Kolmogorov-Smirnov (Lilliefors) test was used, where p had to be 0.05. Plates were previously determined to be 10 mm wide and 3 mm thick, of variable length. Instruments were developed to surmount difficulties.

DISCUSSION

This new procedure and implant could make the repair of acetabular fractures easier and offers several advantages. Clinical trials are needed to assess the benefits of this proposal. The newly described method can allow acetabular fracture osteosynthesis to be performed safely, avoid iatrogenic injury to anatomical structures and achieve better results.

Oncological strategies for locally advanced rectal cancer with synchronous liver metastases, interval strategy versus rectum first strategy: a comparison of short-term outcomes

BACKGROUND

The goal of treatment for patients with synchronous liver metastases (SLM) from rectal cancer is to achieve a complete resection of both tumor locations. For patients with symptomatic locally advanced rectal cancer with resectable SLM at diagnosis, our usual strategy has been the rectum first approach (RF). However, since 2014, we advocate for the interval approach (IS) that involves the administration of chemo-radiotherapy followed by the resection of the SLM in the interval of time between rectal cancer radiation and rectal surgery.

METHODS

From 2010 to 2016, 16 patients were treated according to this new strategy and 19 were treated according RF strategy. Data were collected prospectively and analyzed with an intention-to-treat perspective. Complete resection rate, duration of the treatment and morbi-mortality were the main outcomes.

RESULTS

The complete resection rate in the IS was higher (100%, n = 16) compared to the RF (74%, n = 14, p = 0.049) and the duration of the strategy was shorter (6 vs. 9 months, respectively, p = 0.006). The incidence of severe complications after liver surgery was 14% (n = 2) in the RF and 0% in the IS (p = 1.000), and after rectal surgery was 24% (n = 4) and 12% (n = 2), respectively (p = 1.000).

CONCLUSION

The IS is a feasible and safe strategy that procures higher level of complete resection rate in a shorter period of time compared to RF strategy.

Sterol methyltransferase a target for anti-amoeba therapy: towards transition state analog and suicide substrate drug design

Ergosterol biosynthesis pathways essential to pathogenic protozoa growth and absent from the human host offer new chokepoint targets. Here, we present characterization and cell-based interference of Acanthamoeba spp sterol 24-/28-methylases (SMTs) that catalyze the committed step in C₂₈- and C₂₉-sterol synthesis. Intriguingly, our kinetic analyses suggest that 24-SMT prefers plant cycloartenol whereas 28-SMT prefers 24(28)-methylene lophenol in similar fashion to the substrate preferences of land plant SMT1 and SMT2. Transition state analog-24(R,S),25-epiminolanosterol (EL) and suicide substrate 26,27-dehydrolanosterol (DHL) differentially inhibited trophozoite growth with IC₅₀ values of 7 nM and 6 µM, respectively, and EL yielded 20-fold higher activity than reference drug voriconazole. Against either SMT assayed with native substrate, EL exhibited tight binding ∼K_i 9 nM. Alternatively, DHL is methylated at C26 by 24-SMT that thereby, generates intermediates that complex and inactivate the enzyme, whereas DHL is not productively bound to 28-SMT. Steroidal inhibitors had no effect on human epithelial kidney cell growth or cholesterol biosynthesis at minimum amoebicidal concentrations. We hypothesize the selective inhibition of Acanthamoeba by steroidal inhibitors representing distinct chemotypes may be an efficient strategy for the development of promising compounds to combat amoeba diseases.

Initial Experience in the Treatment of "Borderline Resectable" Pancreatic Adenocarcinoma

INTRODUCTION

A borderline resectable group (APBR) has recently been defined in adenocarcinoma of the pancreas. The objective of the study is to evaluate the results in the surgical treatment after neoadjuvancy of the APBR.

METHOD

Between 2010 and 2014, we included patients with APBR in a neoadjuvant and surgery protocol, staged by multidetector computed tomography (MDCT). Treatment with chemotherapy was based on gemcitabine and oxaliplatin. Subsequently, MDCT was performed to rule out progression, and 5-FU infusion and concomitant radiotherapy were given. MDCT and resection were performed in absence of progression. A descriptive statistical study was performed, dividing the series into: surgery group (GR group) and progression group (PROG group).

RESULTS

We indicated neoadjuvant treatment to 22 patients, 11 of them were operated, 9 pancreatoduodenectomies, and 2 distal pancreatectomies. Of the 11 patients, 7 required some type of vascular resection; 5 venous resections, one arterial and one both. No postoperative mortality was recorded, 7 (63%) had any complications, and 4 were reoperated. The median postoperative stay was 17 (7-75) days. The pathological study showed complete response (ypT0) in 27%, and free microscopic margins (R0) in 63%. At study clossure, all patients had died, with a median actuarial survival of 13 months (9,6-16,3). The median actuarial survival of the GR group was higher than the PROG group (25 vs. 9 months; p < 0.0001).

CONCLUSION

The neoadjuvant treatment of APBR allows us to select a group of patients in whom resection achieves a longer survival to the group in which progression is observed. Post-adjuvant pancreatic resection requires vascular resection in most cases.

Analgesia with continuous wound infusion of local anesthetic versus saline: Double-blind randomized, controlled trial in hepatectomy

BACKGROUND

Surgical wound is source of pain in hepatectomy with laparotomy. Continuous wound infusion of ropivacaine may provide effective analgesia.

METHODS

This prospective, randomized trial, patients scheduled for hepatectomy received a 48-h preperitoneal continuous wound infusion of either 0.23% ropivacaine or 0.9% saline at 5 ml/h. Primary endpoint was 48 h morphine consumption.

RESULTS

53 patients included in the ropivacaine group and 46 in the saline group. Morphine consumption was 24.63 mg in the ropivacaine group, and 26.78 mg (p = 0.669) in the saline group. Pain was comparable between groups and there were no differences in solid food intake, ambulation, or length of hospital stay. No local or systemic complications were recorded.

CONCLUSIONS

Continuous wound infusion with ropivacaine is safe, but it neither reduced morphine consumption nor enhanced recovery in patients undergoing hepatectomy. Success of enhanced recovery in hepatectomy is not influenced by the analgesic regimen if pain is well controlled.