Galacto-oligosaccharide preconditioning improves metabolic activity and engraftment of Limosilactobacillus reuteri and stimulates osteoblastogenesis ex vivo.

A probiotic-related benefit for the host is inherently linked to metabolic activity and integration in the gut ecosystem. To facilitate these, probiotics are often combined with specific prebiotics in a synbiotic formulation. Here, we propose an approach for improving probiotic metabolic activity and engraftment. By cultivating the probiotic strain in the presence of a specific prebiotic (preconditioning), the bacterial enzymatic machinery is geared towards prebiotic consumption. Today, it is not known if preconditioning constitutes an advantage for the synbiotic concept. Therefore, we assessed the effects galacto-oligosaccharide (GOS) addition and preconditioning on GOS of Limosilactobacillus reuteri DSM 17938 on ex vivo colonic metabolic profiles, microbial community dynamics, and osteoblastogenesis. We show that adding GOS and preconditioning L. reuteri DSM 17938 act on different scales, yet both increase ex vivo short-chain fatty acid (SCFA) production and engraftment within the microbial community. Furthermore, preconditioned supernatants or SCFA cocktails mirroring these profiles decrease the migration speed of MC3T3-E1 osteoblasts, increase several osteogenic differentiation markers, and stimulate bone mineralization. Thus, our results demonstrate that preconditioning of L. reuteri with GOS may represent an incremental advantage for synbiotics by optimizing metabolite production, microbial engraftment, microbiome profile, and increased osteoblastogenesis.

Lactate-Based Difference as a Determinant of Outcomes following Surgery for Type A Acute Aortic Dissection: A Multi-Centre Study.

Type A acute aortic dissection (TAAAD) is a serious condition within the acute aortic syndromes that demands immediate treatment. Despite advancements in diagnostic and referral pathways, the survival rate post-surgery currently sits at almost 20%. Our objective was to pinpoint clinical indicators for mortality and morbidity, particularly raised arterial lactate as a key factor for negative outcomes. METHODS: All patients referred to the three cardiovascular centres between January 2005 and December 2022 were included in the study. The inclusion criteria required the presence of a lesion involving the ascending aorta, symptoms within 7 days of surgery, and referral for primary surgical repair of TAAAD based on recommendations, with consideration for other concomitant major cardiac surgical procedures needed during TAAAD and retrograde extension of TAAAD. We conducted an analysis of both continuous and categorical variables and utilised predictive mean matching to fill in missing numeric features. For missing binary variables, we used logistic regression to impute values. We specifically targeted early postoperative mortality and employed LASSO regression to minimise potential collinearity of over-fitting variables and variables measured from the same patient. RESULTS: A total of 633 patients were recruited for the study, out of which 449 patients had complete preoperative arterial lactate data. The average age of the patients was 64 years, and 304 patients were male (67.6%). The crude early postoperative mortality rate was 24.5% (110 out of 449 patients). The mortality rate did not show any significant difference when comparing conservative and extensive surgeries. However, malperfusion had a significant impact on mortality [48/131 (36.6%) vs. 62/318 (19.5%), p < 0.001]. Preoperative arterial lactates were significantly elevated in patients with malperfusion. The optimal prognostic threshold of arterial lactate for predicting early postoperative mortality in our cohort was ≥2.6 mmol/L. CONCLUSION: The arterial lactate concentration in patients referred for TAAAD is an independent factor for both operative mortality and postoperative complications. In addition to mortality, patients with an upper arterial lactate cut-off of ≥2.6 mmol/L face significant risks of VA ECMO and the need for dialysis within the first 48 h after surgery. To improve recognition and facilitate rapid transfer and surgical treatment protocol, more diligent efforts are required in the management of malperfusion in TAAAD.

Current Knowledge on the Interaction of Human Cytomegalovirus Infection, Encoded miRNAs, and Acute Aortic Syndrome.

Aortic dissection is a clinicopathological entity caused by rupture of the intima, leading to a high mortality if not treated. Over time, diagnostic and investigative methods, antihypertensive therapy, and early referrals have resulted in improved outcomes according to registry data. Some data have also emerged from recent studies suggesting a link between Human Cytomegalovirus (HCMV) infection and aortic dissection. Furthermore, the use of microRNAs has also become increasingly widespread in the literature. These have been noted to play a role in aortic dissections with elevated levels noted in studies as early as 2017. This review aims to provide a broad and holistic overview of the role of miRNAs, while studying the role of HCMV infection in the context of aortic dissections. The roles of long non-coding RNAs, circular RNAs, and microRNAs are explored to identify changes in expression during aortic dissections. The use of such biomarkers may one day be translated into clinical practice to allow early detection and prognostication of outcomes and drive preventative and therapeutic options in the future.

Surgical Strategy for the Repair of Acute Type A Aortic Dissection: A Multicenter Study.

Type A acute aortic dissection is associated with significant morbidity and mortality, with prompt referral imaging and management to tertiary referral centers needed urgently. Surgery is usually needed emergently, but the choice of surgery often varies depending on the patient and the presentation. Staff and center expertise also play a major role in determining the surgical strategy employed. The aim of this study was to compare the early- and medium-term outcomes of patients undergoing a conservative approach extended only to the ascending aorta and the hemiarch to those of patients subjected to extensive surgery (total arch reconstruction and root replacement) across three European referral centers. A retrospective study was conducted across three sites between January 2008 and December 2021. In total, 601 patients were included within the study, of which 30% were female, and the median age was 64.4 years. The most common operation was ascending aorta replacement (n = 246, 40.9%). The aortic repair was extended proximally (i.e., root n = 105; 17.5%) and distally (i.e., arch n = 250; 41.6%). A more extensive approach, extending from the root to the arch, was employed in 24 patients (4.0%). Operative mortality occurred in 146 patients (24.3%), and the most common morbidity was stroke (75, 12.6%). An increased length of ICU admission was noted in the extensive surgery group, which comprised younger and more frequently male patients. No significant differences were noted in surgical mortality between patients managed with extensive surgery and those managed conservatively. However, age, arterial lactate levels, "intubated/sedated" status on arrival, and "emergency or salvage" status at presentation were independent predictors of mortality both within the index hospitalization and during the follow-up. The overall survival was similar between the groups.

Low Bone Turnover Due to Hypothyroidism or Anti-Resorptive Treatment Does Not Affect Whole-Body Glucose Homeostasis in Male Mice.

Bone is a large and dynamic tissue and its maintenance requires high amounts of energy as old or damaged bone structures need to be replaced during the process of bone remodeling. Glucose homeostasis is an essential prerequisite for a healthy bone and vice versa, the skeleton can act as an endocrine organ on energy metabolism. We recently showed that hypothyroidism in mice leads to an almost complete arrest of bone remodeling. Here, we aimed to investigate whether the profound suppression of bone remodeling affects whole-body glucose homeostasis. To that end, male C57BL/6JRj mice were rendered hypothyroid over 4 weeks using methimazole and sodium perchlorate in the drinking water. We confirmed trabecular bone gain due to decreased bone turnover in hypothyroid mice with decreased cortical but increased vertebral bone strength. Further, we found impaired glucose handling but not insulin resistance with hypothyroidism. In hypothyroid bone, glucose uptake and expression of glucose transporter Glut4 were reduced by 44.3% and 13.9%, respectively, suggesting lower energy demands. Nevertheless, hypothyroidism led to distinct changes in glucose uptake in muscle, liver, and epididymal white adipose tissue (eWAT). Reduced glucose uptake (-30.6%) and Glut1/Glut4 transcript levels (-31.9%/-67.5%) were detected in muscle tissue. In contrast, in liver and eWAT we observed increased glucose uptake by 25.6% and 68.6%, respectively, and upregulated expression of glucose transporters with hypothyroidism. To more specifically target bone metabolism and discriminate between the skeletal and systemic effects of hypothyroidism on energy metabolism, male mice were treated with zoledronate (ZOL), a bisphosphonate, that led to decreased bone turnover, trabecular bone gain, and reduced local glucose uptake into bone (-40.4%). However, ZOL-treated mice did not display alterations of systemic glucose handling nor insulin tolerance. Despite the close mutual crosstalk of bone and glucose metabolism, in this study, we show that suppressing bone remodeling does not influence whole-body glucose homeostasis in male mice.

Case Report: Laryngotracheal Post-Intubation/Tracheostomy Stenosis in COVID-19 Patients.

Introduction: The novel Coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARSCoV-2), has spread rapidly to become a major global public health emergency since March 2020. Laryngotracheal stenosis (LTS) has been observed more frequently since the onset of the COVID-19 pandemic. Methods: All patients referred to our 24/7 Airway Diseases Center for laryngotracheal post-intubation/tracheostomy stenosis from May 2020 to May 2021were evaluated retrospectively. Patient data on comorbidities, diagnosis, type of procedures, lengths of ICU stay and invasive mechanical ventilation, medical treatment, and the severity of illness were recorded. Results: This case series included nine patients (five women and four men), with a mean age of 52.9 years, most with a BMI >30, all with a severe illness revealed by the Simplified Acute Physiology Score (SAPS) II >31. From May 2020 to May 2021, 21 procedures were performed on seven patients, consisting of bronchoscopic rigid interventions, T-tube Montgomery tracheostomy, and one cricotracheal resection with end-to-end anastomosis. Histologic examination of tracheal biopsies showed an inflammatory state of the airway mucosa. Two patients only had medical therapy. Discussion and Conclusions: Pneumonia caused by SARSCoV-2 can lead to severe acute respiratory distress syndrome (ARDS) requiring invasive mechanical ventilation. The time of intubation, the drugs used, the prone position, comorbidities (diabetes, obesity), and the inflammatory state of the upper airways linked to the viral infection, predispose to an increased tendency to stenosis and its recurrence. A conservative approach with medical and endoscopic treatment should be preferred in case of persistence of local airways inflammation. Further studies with a larger sample of patients will help to a better understanding of the disease, reduce the prevalence, and improve its treatment.

A simplified delivery frozen elephant trunk technique to reduce circulatory arrest time in hybrid aortic arch surgery.

A simplified delivery technique for the frozen elephant trunk procedure allows the distal suture to be performed on a perfused and loaded aorta in moderate hypothermia-or even normothermia-reducing circulatory arrest time to just a few minutes. Two surgical sealing tourniquets are placed around the aortic arch, usually between the brachiocephalic trunk (BCT) and the left common carotid artery and the aorta is cross-clamped and cardioplegia started. Once in mild hypothermia, the BCT is disconnected and circulatory arrest is initiated while cerebral perfusion is maintained. This modified technique can be used in all pathologies, including dissections.

Lack of Adiponectin Drives Hyperosteoclastogenesis in Lipoatrophic Mice.

Long bones from mammals host blood cell formation and contain multiple cell types, including adipocytes. Physiological functions of bone marrow adipocytes are poorly documented. Herein, we used adipocyte-deficient PPARγ-whole body null mice to investigate the consequence of total adipocyte deficiency on bone homeostasis in mice. We first highlighted the dual bone phenotype of PPARγ null mice: one the one hand, the increased bone formation and subsequent trabecularization extending in the long bone diaphysis, due to the well-known impact of PPARγ deficiency on osteoblasts formation and activity; on the other hand, an increased osteoclastogenesis in the cortical bone. We then further explored the cause of this unexpected increased osteoclastogenesis using two independent models of lipoatrophy, which recapitulated this phenotype. This demonstrates that hyperosteoclastogenesis is not intrinsically linked to PPARγ deficiency, but is a consequence of the total lipodystrophy. We further showed that adiponectin, a cytokine produced by adipocytes and mesenchymal stromal cells is a potent inhibitor of osteoclastogenesis in vitro and in vivo. Moreover, pharmacological activation of adiponectin receptors by the synthetic agonist AdipoRon inhibited mature osteoclast activity both in mouse and human cells by blocking podosome formation through AMPK activation. Finally, we demonstrated that AdipoRon treatment blocks bone erosion in vivo in a murine model of inflammatory bone loss, providing potential new approaches to treat osteoporosis.

RANKL-Induced Increase in Cathepsin K Levels Restricts Cortical Expansion in a Periostin-Dependent Fashion: A Potential New Mechanism of Bone Fragility.

Receptor activator of nuclear factor-κΒ ligand (RANKL) is necessary and sufficient to promote osteoclastogenesis and a key pathogenic factor in osteoporosis. Failure of periosteal apposition to compensate for bone loss due to endosteal resorption further contributes to bone fragility. Whether these two processes are biologically related, however, remains unknown. Using high-resolution peripheral quantitative computed tomography (HR-pQCT), we first examined cortical bone parameters at distal radius and tibia in postmenopausal women (PMW) as well as in cadaveric human adult humeri. Increases in medullary area were negatively correlated with cortical bone volume but positively with total bone volume, and this relationship was stronger in the dominant arm, suggesting a mechanically driven process. To investigate the role of RANKL in this dual process, we used mice overexpressing huRANKL (huRANKLTg+ ). Trabecular and cortical bone volume (Ct.BV) are reduced in these mice, whereas cortical total volume (Ct.TV) is increased. In these bones, Sost mRNA levels are downregulated and periostin (Postn) mRNA levels upregulated, hence providing a positive message for periosteal bone formation. In turn, genetic deletion of Postn in huRANKLTg+  mice prevented the increase in Ct.TV and aggravated bone fragility. In contrast, cathepsin K (Ctsk) ablation improved Ct.TV in both huRANKLTg+  and wild-type (WT) mice and stimulated periosteal bone formation, while augmenting Postn protein levels. Therefore, bone strength in huRANKLTg+ /Ctsk-/- mice was restored to WT levels. These findings suggest that high levels of RANKL not only induce endosteal bone loss but may somewhat restrict periosteal bone formation by triggering periostin degradation through cathepsin K, hence providing a biological mechanism for the observed limited increase in cortical area in postmenopausal women. © 2021 American Society for Bone and Mineral Research (ASBMR).

Primary mouse osteoblast and osteoclast culturing and analysis.

Mesenchymal-derived osteoblasts play a key role in bone formation via synthesis and mineralization of the bone and bone remodeling. Osteoclasts are multinucleated cells of hematopoietic origin with a role in bone resorption. Here, we describe a protocol for generating primary cultures of these two cell types from bone tissue including the femur, tibia, and humerus of young mice. We describe methods for addressing their activity and/or differentiation, enabling studying the effects of various treatments during or following differentiation ex vivo. For further practical example of using these protocols, please refer to Chevalier et al. (2020).

Interstitial lung disease-related pneumomediastinum in COVID-19 patients.

Pneumomediastinum in severe #COVID19 presentations could be due to a lung parenchymal retractive process generated by intense inflammation as in acute exacerbation of idiopathic pulmonary fibrosis or MDA-5 acute interstitial lung disease https://bit.ly/3qzBYMW.

High flow nasal oxygen therapy to avoid invasive mechanical ventilation in SARS-CoV-2 pneumonia: a retrospective study.

BACKGROUND: The efficacy of high flow nasal canula oxygen therapy (HFNO) to prevent invasive mechanical ventilation (IMV) is not well established in severe coronavirus disease 2019 (COVID-19). The aim of this study was to compare the risk of IMV between two strategies of oxygenation (conventional oxygenation and HFNO) in critically ill COVID 19 patients. METHODS: This was a bicenter retrospective study which took place in two intensive care units (ICU) of tertiary hospitals in the Paris region from March 11, to May 3, 2020. We enrolled consecutive patients hospitalized for COVID-19 and acute respiratory failure (ARF) who did not receive IMV at ICU admission. The primary outcome was the rate of IMV after ICU admission. Secondary outcomes were death at day 28 and day 60, length of ICU stay and ventilator-free days at day 28. Data from the HFNO group were compared with those from the standard oxygen therapy (SOT) group using weighted propensity score. RESULTS: Among 138 patients who met the inclusion criteria, 62 (45%) were treated with SOT alone, and 76 (55%) with HFNO. In HFNO group, 39/76 (51%) patients received IMV and 46/62 (74%) in SOT group (OR 0.37 [95% CI, 0.18-0.76] p = 0.007). After weighted propensity score, HFNO was still associated with a lower rate of IMV (OR 0.31 [95% CI, 0.14-0.66] p = 0.002). Length of ICU stay and mortality at day 28 and day 60 did not significantly differ between HFNO and SOT groups after weighted propensity score. Ventilator-free days at days 28 was higher in HNFO group (21 days vs 10 days, p = 0.005). In the HFNO group, predictive factors associated with IMV were SAPS2 score (OR 1.13 [95%CI, 1.06-1.20] p = 0.0002) and ROX index > 4.88 (OR 0.23 [95%CI, 0.008-0.64] p = 0.006). CONCLUSIONS: High flow nasal canula oxygen for ARF due to COVID-19 is associated with a lower rate of invasive mechanical ventilation.

Environmental contamination related to SARS-CoV-2 in ICU patients.

BACKGROUND: The coronavirus disease 2019 (COVID-19) outbreak is a primary global concern, and data are lacking concerning risk of novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) environmental contamination. OBJECTIVE: To identify risk factors for SARS-CoV-2 environmental contamination in COVID-19 patients admitted to the intensive care unit (ICU). METHODS: A prospective single centre 1-day study was carried out in an ICU. Four surfaces (the ventilator control screen, the control buttons of the syringe pump, the bed rails and the computer table located >1 m away from the patient) were systematically swabbed at least 8 h after any cleaning process. We analysed clinical, microbiological and radiological data to identify risk factors for SARS-CoV-2 environmental contamination. RESULTS: 40% of ICU patients were found to contaminate their environment. No particular trend emerged regarding the type of surface contaminated. Modality of oxygen support (high-flow nasal cannula oxygenation, invasive mechanical ventilation, standard oxygen mask) was not associated with the risk of environmental contamination. Univariate analysis showed that lymphopenia <0.7×109·L-1 was associated with environmental contamination. CONCLUSION: Despite small sample size, our study generated surprising results. Modality of oxygen support is not associated with risk of environmental contamination. Further studies are needed.

Warmth Prevents Bone Loss Through the Gut Microbiota.

Osteoporosis is the most prevalent metabolic bone disease, characterized by low bone mass and microarchitectural deterioration. Here, we show that warmth exposure (34°C) protects against ovariectomy-induced bone loss by increasing trabecular bone volume, connectivity density, and thickness, leading to improved biomechanical bone strength in adult female, as well as in young male mice. Transplantation of the warm-adapted microbiota phenocopies the warmth-induced bone effects. Both warmth and warm microbiota transplantation revert the ovariectomy-induced transcriptomics changes of the tibia and increase periosteal bone formation. Combinatorial metagenomics/metabolomics analysis shows that warmth enhances bacterial polyamine biosynthesis, resulting in higher total polyamine levels in vivo. Spermine and spermidine supplementation increases bone strength, while inhibiting polyamine biosynthesis in vivo limits the beneficial warmth effects on the bone. Our data suggest warmth exposure as a potential treatment option for osteoporosis while providing a mechanistic framework for its benefits in bone disease.

Applications of Bayesian analysis to proof-of-concept trial planning and decision making.

Decision making is a critical component of a new drug development process. Based on results from an early clinical trial such as a proof of concept trial, the sponsor can decide whether to continue, stop, or defer the development of the drug. To simplify and harmonize the decision-making process, decision criteria have been proposed in the literature. One of them is to exam the location of a confidence bar relative to the target value and lower reference value of the treatment effect. In this research, we modify an existing approach by moving some of the "stop" decision to "consider" decision so that the chance of directly terminating the development of a potentially valuable drug can be reduced. As Bayesian analysis has certain flexibilities and can borrow historical information through an inferential prior, we apply the Bayesian analysis to the trial planning and decision making. Via a design prior, we can also calculate the probabilities of various decision outcomes in relationship with the sample size and the other parameters to help the study design. An example and a series of computations are used to illustrate the applications, assess the operating characteristics, and compare the performances of different approaches.

Fatal Legionella pneumophila serogroup 1 pleural empyema: A case report.

BACKGROUND: Legionella pneumophila (L. pneumophila) is a gram-negative intracellular bacillus composed of sixteen different serogroups. It is mostly known to cause pneumonia in individuals with known risk factors as immunocompromised status, tobacco use, chronic organ failure or age older than 50 years. Although parapneumonic pleural effusion is frequent in legionellosis, pleural empyema is very uncommon. In this study, we report a case of fatal pleural empyema caused by L. pneumophila serogroup 1 in an 81-year-old man with multiple risk factors. CASE SUMMARY: An 81-year-old man presented to the emergency with a 3 wk dyspnea, fever and left chest pain. His previous medical conditions were chronic lymphocytic leukemia, diabetes mellitus, chronic kidney failure, hypertension and hyperlipidemia, without tobacco use. Chest X-ray and comouted tomography-scan confirmed a large left pleural effusion, which puncture showed a citrine exudate with negative standard bacterial cultures. Despite intravenous cefotaxime antibiotherapy, patient's worsening condition after 10 d led to thoracocentesis and evacuation of 2 liters of pus. The patient progressively developed severe hypoxemia and multiorgan failure occurred. The patient was treated by antibiotherapy with cefepime and amikacin and with adequate symptomatic shock treatment, but died of uncontrolled sepsis. The next day, cultures of the surgical pleural liquid samples yielded L. pneumophila serogroup 1, consistent with the diagnosis of pleural legionellosis. CONCLUSION: L. pneumophila should be considered in patients with multiple risk factors and undiagnosed pleural empyema unresponsive to conventional antibiotherapy.

RANKL inhibition improves muscle strength and insulin sensitivity and restores bone mass.

Receptor activator of Nfkb ligand (RANKL) activates, while osteoprotegerin (OPG) inhibits, osteoclastogenesis. In turn a neutralizing Ab against RANKL, denosumab improves bone strength in osteoporosis. OPG also improves muscle strength in mouse models of Duchenne's muscular dystrophy (mdx) and denervation-induce atrophy, but its role and mechanisms of action on muscle weakness in other conditions remains to be investigated. We investigated the effects of RANKL inhibitors on muscle in osteoporotic women and mice that either overexpress RANKL (HuRANKL-Tg+), or lack Pparb and concomitantly develop sarcopenia (Pparb-/-). In women, denosumab over 3 years improved appendicular lean mass and handgrip strength compared to no treatment, whereas bisphosphonate did not. HuRANKL-Tg+ mice displayed lower limb force and maximal speed, while their leg muscle mass was diminished, with a lower number of type I and II fibers. Both OPG and denosumab increased limb force proportionally to the increase in muscle mass. They markedly improved muscle insulin sensitivity and glucose uptake, and decrease anti-myogenic and inflammatory gene expression in muscle, such as myostatin and protein tyrosine phosphatase receptor-γ. Similarly, in Pparb-/-, OPG increased muscle volume and force, while also normalizing their insulin signaling and higher expression of inflammatory genes in skeletal muscle. In conclusions, RANKL deteriorates, while its inhibitor improves, muscle strength and insulin sensitivity in osteoporotic mice and humans. Hence denosumab could represent a novel therapeutic approach for sarcopenia.