A Millifluidic Chamber for Controlled Shear Stress Testing: Application to Microbial Cultures.

In vitro platforms such as bioreactors and microfluidic devices are commonly designed to engineer tissue models as well as to replicate the crosstalk between cells and microorganisms hosted in the human body. These systems promote nutrient supply and waste removal through culture medium recirculation; consequently, they intrinsically expose cellular structures to shear stress, be it a desired mechanical stimulus to drive the cell fate or a potential inhibitor for the model maturation. Assessing the impact of shear stress on cellular or microbial cultures thus represents a crucial step to define proper environmental conditions for in vitro models. In this light, the aim of this study was to develop a millifluidic device enabling to generate fully controlled shear stress profiles for quantitatively probing its influence on tissue or bacterial models, overcoming the limitations of previous reports proposing similar devices. Relying on this millifluidic tool, we present a systematic methodology to test how adherent cellular structures react to shear forces, which was applied to the case of microbial biofilms as a proof of concept. The results obtained suggest our approach as a suitable testbench to evaluate culture conditions in terms of shear stress faced by cells or microorganisms.

A case of histological diagnosis of Toxoplasma gondii myositis in a person living with HIV.

We report the case of a 58-year-old male with a recent diagnosis of HIV infection admitted for progressive muscular weakness and psychomotor impairment. Cerebrospinal examination documented a mild hyperproteinorrachia, with normal cells count and reduced glycorrhachia. Brain gadolinium-enhanced MRI showed bilateral T2 and FLAIR hyperintensities in the nucleo-capsular region and irregular contrast-enhancement of the globi pallidi and the right putamen. The histologic analysis of a quadriceps biopsy showed several foci of inflammatory infiltrates with concomitant muscular fiber atrophy and degeneration. Scattered intracytoplasmic inclusions were observed in muscle fibers, representing the main pathological feature. A positive PCR for Toxoplasma gondii and a Toxoplasma gondii specific monoclonal antibody immunohistochemical staining confirmed the diagnosis.

Impact of Bacillus cereus on the Human Gut Microbiota in a 3D In Vitro Model.

In vitro models for culturing complex microbial communities are progressively being used to study the effects of different factors on the modeling of in vitro-cultured microorganisms. In previous work, we validated a 3D in vitro model of the human gut microbiota based on electrospun gelatin scaffolds covered with mucins. The aim of this study was to evaluate the effect of Bacillus cereus, a pathogen responsible for food poisoning diseases in humans, on the gut microbiota grown in the model. Real-time quantitative PCR and 16S ribosomal RNA-gene sequencing were performed to obtain information on microbiota composition after introducing B. cereus ATCC 14579 vegetative cells or culture supernatants. The adhesion of B. cereus to intestinal mucins was also tested. The presence of B. cereus induced important modifications in the intestinal communities. Notably, levels of Proteobacteria (particularly Escherichia coli), Lactobacillus, and Akkermansia were reduced, while abundances of Bifidobacterium and Mitsuokella increased. In addition, B. cereus was able to adhere to mucins. The results obtained from our in vitro model stress the hypothesis that B. cereus is able to colonize the intestinal mucosa by stably adhering to mucins and impacting intestinal microbial communities as an additional pathogenetic mechanism during gastrointestinal infection.

Development of an In Vitro Model of the Gut Microbiota Enriched in Mucus-Adhering Bacteria.

Culturing the gut microbiota in in vitro models that mimic the intestinal environment is increasingly becoming a promising alternative approach to study microbial dynamics and the effect of perturbations on the gut community. Since the mucus-associated microbial populations in the human intestine differ in composition and functions from their luminal counterpart, we attempted to reproduce in vitro the microbial consortia adhering to mucus using an already established three-dimensional model of the human gut microbiota. Electrospun gelatin structures supplemented or not with mucins were inoculated with fecal samples and compared for their ability to support microbial adhesion and growth over time, as well as to shape the composition of the colonizing communities. Both scaffolds allowed the establishment of long-term stable biofilms with comparable total bacterial loads and biodiversity. However, mucin-coated structures harbored microbial consortia especially enriched in Akkermansia, Lactobacillus, and Faecalibacterium, being therefore able to select for microorganisms commonly considered mucosa-associated in vivo. IMPORTANCE These findings highlight the importance of mucins in shaping intestinal microbial communities, even those in artificial gut microbiota systems. We propose our in vitro model based on mucin-coated electrospun gelatin structures as a valid device for studies evaluating the effects of exogenous factors (nutrients, probiotics, infectious agents, and drugs) on mucus-adhering microbial communities.

Rationale and design of COLchicine On-admission to Reduce inflammation in Acute Coronary Syndrome (COLOR-ACS) study.

AIMS: The aim of the colchicine on-admission to reduce inflammation in acute coronary syndrome (COLOR-ACS) study is to evaluate the effects of the addition of short-term, low-dose colchicine to high-dose atorvastatin in limiting levels of inflammatory markers, such as high-sensitivity C-reactive protein (hs-CRP), in patients with non-ST-elevation acute coronary syndrome (NSTE-ACS). METHODS: The COLOR-ACS study is a multicenter, randomized, open-label, two-arm trial. Statin-naive patients with NSTE-ACS, scheduled for an early invasive strategy, are randomized on admission to receive standard treatment of atorvastatin 80 mg or standard treatment plus colchicine (1 mg loading dose followed by 0.5 mg/day until discharge). The main exclusion criteria are prior statin and/or colchicine treatment, current treatment with potent inhibitors of CYP3A4, P-glycoprotein or immunosuppressive drugs, known active malignancy, severe kidney, cardiac, liver disease. There is clinical and biochemical follow-up at 30 days after discharge and telephone interview at 6 months. The primary end point is the change in hs-CRP from admission to discharge. Secondary end points include: incidence of acute kidney injury; MB fraction of creatine kinase peak value; glomerular filtration rate change from baseline to 30 days; persistence of hs-CRP ≥2 mg/dl at 30 days; adverse clinical events within 30 days; tolerance to colchicine. CONCLUSION: The COLOR-ACS study will provide evidence on the efficacy of early short-term treatment with colchicine in addition to high-dose atorvastatin compared to atorvastatin alone in ACS patients. The potential anti-inflammatory action of colchicine plus atorvastatin is expected to limit hs-CRP increase with resultant clinical benefits. TRIAL REGISTRATION: ClinicalTrials.gov; NCT05250596.

Study of the Adhesion of the Human Gut Microbiota on Electrospun Structures.

Although the adhesion of bacteria on surfaces is a widely studied process, to date, most of the works focus on a single species of microorganisms and are aimed at evaluating the antimicrobial properties of biomaterials. Here, we describe how a complex microbial community, i.e., the human gut microbiota, adheres to a surface to form stable biofilms. Two electrospun structures made of natural, i.e., gelatin, and synthetic, i.e., polycaprolactone, polymers were used to study their ability to both promote the adhesion of the human gut microbiota and support microbial growth in vitro. Due to the different wettabilities of the two surfaces, a mucin coating was also added to the structures to decouple the effect of bulk and surface properties on microbial adhesion. The developed biofilm was quantified and monitored using live/dead imaging and scanning electron microscopy. The results indicated that the electrospun gelatin structure without the mucin coating was the optimal choice for developing a 3D in vitro model of the human gut microbiota.

Scaling of joint mass and metabolism fluctuations in in silico cell-laden spheroids.

Variations and fluctuations are characteristic features of biological systems and are also manifested in cell cultures. Here, we describe a computational pipeline for identifying the range of three-dimensional (3D) cell-aggregate sizes in which nonisometric scaling emerges in the presence of joint mass and metabolic rate fluctuations. The 3D cell-laden spheroids with size and single-cell metabolic rates described by probability density functions were randomly generated in silico. The distributions of the resulting metabolic rates of the spheroids were computed by modeling oxygen diffusion and reaction. Then, a method for estimating scaling exponents of correlated variables through statistically significant data collapse of joint probability distributions was developed. The method was used to identify a physiologically relevant range of spheroid sizes, where both nonisometric scaling and a minimum oxygen concentration (0.04 mol⋅m-3) is maintained. The in silico pipeline described enables the prediction of the number of experiments needed for an acceptable collapse and, thus, a consistent estimate of scaling parameters. Using the pipeline, we also show that scaling exponents may be significantly different in the presence of joint mass and metabolic-rate variations typically found in cells. Our study highlights the importance of incorporating fluctuations and variability in size and metabolic rates when estimating scaling exponents. It also suggests the need for taking into account their covariations for better understanding and interpreting experimental observations both in vitro and in vivo and brings insights for the design of more predictive and physiologically relevant in vitro models.

A 2-year prospective multicenter study of ultrasound cyclo plasty for glaucoma.

Ultrasound cyclo plasty (UCP) is a recently developed surgical technique for glaucoma allowing a selective and controlled coagulation of the ciliary body. We herein investigated the long-term efficacy and safety of UCP for the treatment of glaucoma. This prospective study included patients with primary and secondary glaucoma. All surgeries were performed using the EyeOP1 device (Eye Tech Care, Rillieux-la-Pape, France). Sixty-six patients were included, and 60 completed regularly the 2-year follow-up. Preoperative IOP was 28.5 ± 9.6 mmHg and significantly decreased to 17.0 ± 5.4 at 2 years (p < 0.001). The daily number of both hypotensive eye drops and acetazolamide tablets decreased significantly (respectively, from 2.6 ± 1.1 to 1.7 ± 1.2 and from 0.7 ± 0.8 to 0.2 ± 0.5; both p < 0.001). At 2 years, 68.1% of patients met the definition of qualified success (IOP < 21 mmHg regardless of glaucoma medications) and 10.3% of patients met the definition of complete success (IOP < 21 mmHg without glaucoma medications). No major intra- or postoperative complications occurred; however, 15 eyes required additional glaucoma surgery. These results suggest that UCP is an effective and safe procedure to reduce IOP in glaucoma patients through a 2-year follow-up period.

A novel 3D in vitro model of the human gut microbiota.

Clinical trials and animal studies on the gut microbiota are often limited by the difficult access to the gut, restricted possibility of in vivo monitoring, and ethical issues. An easily accessible and monitorable in vitro model of the gut microbiota represents a valid tool for a wider comprehension of the mechanisms by which microbes interact with the host and with each other. Herein, we present a novel and reliable system for culturing the human gut microbiota in vitro. An electrospun gelatin structure was biofabricated as scaffold for microbial growth. The efficiency of this structure in supporting microbial proliferation and biofilm formation was initially assessed for five microbes commonly inhabiting the human gut. The human fecal microbiota was then cultured on the scaffolds and microbial biofilms monitored by confocal laser and scanning electron microscopy and quantified over time. Metagenomic analyses and Real-Time qPCRs were performed to evaluate the stability of the cultured microbiota in terms of qualitative and quantitative composition. Our results reveal the three-dimensionality of the scaffold-adhered microbial consortia that maintain the bacterial biodiversity and richness found in the original sample. These findings demonstrate the validity of the developed electrospun gelatin-based system for in vitro culturing the human gut microbiota.

Electrospun Structures Made of a Hydrolyzed Keratin-Based Biomaterial for Development of in vitro Tissue Models.

The aim of this study is the analysis and characterization of a hydrolyzed keratin-based biomaterial and its processing using electrospinning technology to develop in vitro tissue models. This biomaterial, extracted from poultry feathers, was mixed with type A porcine gelatin and cross-linked with γ-glycidyloxy-propyl-trimethoxy-silane (GPTMS) to be casted initially in the form of film and characterized in terms of swelling, contact angle, mechanical properties, and surface charge density. After these chemical-physical characterizations, electrospun nanofibers structures were manufactured and their mechanical properties were evaluated. Finally, cell response was analyzed by testing the efficacy of keratin-based structures in sustaining cell vitality and proliferation over 4 days of human epithelial, rat neuronal and human primary skin fibroblast cells.

Ultrasonic mixing chamber as an effective tool for the biofabrication of fully graded scaffolds for interface tissue engineering.

One of the main challenges of the interface-tissue engineering is the regeneration of diseased or damaged interfacial native tissues that are heterogeneous both in composition and in structure. In order to achieve this objective, innovative fabrication techniques have to be investigated. This work describes the design, fabrication, and validation of a novel mixing system to be integrated into a double-extruder bioprinter, based on an ultrasonic probe included into a mixing chamber. To validate the quality and the influence of mixing time, different nanohydroxyapatite-gelatin samples were printed. Mechanical characterization, micro-computed tomography, and thermogravimetric analysis were carried out. Samples obtained from three-dimensional bioprinting using the mixing chamber were compared to samples obtained by deposition of the same final solution obtained by manually operated ultrasound probe, showing no statistical differences. Results obtained from samples characterization allow to consider the proposed mixing system as a promising tool for the fabrication of graduated structures which are increasingly being used in interface-tissue engineering.

Tolerability of ambulatory blood pressure monitoring (ABPM) in cognitively impaired elderly.

OBJECTIVE: Recent guidelines have widened clinical indications for out-of-office blood pressure measurement, including home blood pressure monitoring and ambulatory blood pressure monitoring (ABPM), suggesting the latter as recommended method in cognitively impaired patients. There is, however, a widespread belief that ABPM could be poorly tolerated in dementia, often leading to withdraw from its use in these patients. AIM: To assess the actual tolerability of ABPM in a group of cognitively impaired elderly, affected by dementia or mild cognitive impairment (MCI). METHODS: We evaluated 176 patients aged 65 + years, recruited in two different memory clinics, with a Mini Mental State Examination (MMSE) between 10 and 27. Behavioral and psychological symptoms were assessed with Neuropsychiatric Inventory (NPI). A patient was considered tolerant if able to keep the device on continuously for 24 h. The minimum number of correct measurements required was 70% of the predicted total number. RESULTS: 16% of patients wore the device for less than 24 h. Dividing the study population in tertiles of MMSE performance, 29% failed to tolerate the device in the lowest, 12% in the middle and 7% in the highest tertile (p < 0.01). Dividing the study population in tertiles of NPI performance, 30% of patients failed in the highest, 19% in the middle and 8% in the lowest tertile (p = 0.02); 31% of patients who tolerated the device did not achieve the minimum number of measurements required, with a mean number of 63% of predicted measurements. CONCLUSION: The ABPM proved a generally well-tolerated technique even in cognitively impaired elderly. Only a minority of subjects with poorer cognitive performances and greater behavioral symptoms did not tolerate the monitoring. Among most patients who failed to achieve the minimum number of measurements needed, the number of valid measurements was very close to the minimum required.