Medicine

Intravesical instillation is an efficient therapeutic technique based on targeted administration of a drug directly into the lesion for the treatment of bladder diseases. This is an alternative to traditional systemic administration of drugs. However, this technique requires repeated procedures, which can lead to even greater inflammation and infection of the urethra. To date, novel systems that allow prolonged drug retention in the bladder cavity are actively being developed. We recently reported a targeted drug delivery system based on the mucoadhesive emulsion microgels consisting of the natural component whey protein isolate. Such micron-sized carriers possess high loading capacity, a prolonged drug release profile, and efficient mucoadhesive properties to the bladder urothelium. As a continuation of this work, we present a protocol for the synthesis of mucoadhesive emulsion microgels. Detailed procedures for preparing precursor solutions as well as studying the physico-chemical parameters of microgels (including loading capacity and drug release rate) and the mucoadhesive properties using the model of porcine bladder urothelium are discussed. Precautionary measures and nuances that are worth paying attention to during each experimental stage are given as well.

Anemia is a common and serious health problem, nearly universally diagnosed in preterm infants, and is associated with increased morbidity and mortality worldwide. Red blood cell (RBC) transfusion is a lifesaving and mainstay therapy; however, it has critical adverse effects. One consequence is necrotizing enterocolitis (NEC), an inflammatory bowel necrosis disease in preterm infants. The murine model of phlebotomy-induced anemia and RBC transfusion–associated NEC enables a detailed study of the molecular mechanisms underlying these morbidities and the evaluation of potential new therapeutic strategies. This protocol describes a detailed procedure for obtaining murine pups with phlebotomy-induced anemia and delivering an RBC transfusion that develops NEC.

Apolipoprotein B (APOB) is the primary structural protein of atherogenic lipoproteins, which drive atherogenesis and thereby lead to deadly cardiovascular diseases (CVDs). Plasma levels of APOB-containing lipoproteins are tightly modulated by LDL receptor–mediated endocytic trafficking and cargo receptor–initiated exocytic route; the latter is much less well understood. This protocol aims to present an uncomplicated yet effective method for detecting APOB/lipoprotein secretion. We perform primary mouse hepatocyte isolation and culture coupled with well-established techniques such as immunoblotting for highly sensitive, specific, and semi-quantitative analysis of the lipoprotein secretion process. Its inherent simplicity facilitates ease of operation, rendering it a valuable tool widely utilized to explore the intricate landscape of cellular lipid metabolism and unravel the mechanistic complexities underlying lipoprotein-related diseases.

Mannan from yeast induces psoriasis-like inflammation in the skin of inbred mouse strains. Limitations of available models led us to develop a new psoriasis model with a rapid disease onset, severe disease course, short duration, and a simple and easy-to-induce protocol with much more practically convenient features and cost-benefits. Mannan-induced skin inflammation (MISI) is more severe than the classical imiquimod (IMQ)-induced skin inflammation (IISI), with characteristic features resembling human plaque psoriasis but with relatively fewer toxicity issues. Epicutaneous application of mannan (5 mg) in incomplete Freund’s adjuvant or Vaseline induces severe psoriasis in BALB/c female mice. Psoriasis area and severity index (PASI) and histological evaluation of the skin could help assess the disease development. MISI mimics natural environmental factors affecting the skin relatively more closely than IISI. This disease model can be used to dissect inflammatory pathways in the skin, identify genetic and environmental factors affecting psoriasis, and test potential pharmacological agents or new combinations of available drugs for treatment before designing clinical trials.

Key features

• S. cerevisiae mannan induces psoriasis-like skin inflammation(MISI) when applied on the skin of inbred mice.

• The MISI model has a rapid onset, severe disease, short duration, and simple and easy-to-induce protocol.

• MISI is more severe than imiquimod-induced skin inflammation (IISI).

• Female mice had a more severe disease than males in the MISI model, thereby allowing the study of sex-dependent disease mechanisms.

• The MISI model identifies skin inflammatory pathways and genetic/environmental factors affecting psoriasis.

• The MISI model can be used as a drug testing platform for potential pharmaceuticals to develop new therapeutics for psoriasis patients.

• The MISI model can be used to explore the relative contribution of different pattern recognition receptors in the development and severity of psoriasis.

Graphical overview

Tracking macrophages by non-invasive molecular imaging can provide useful insights into the immunobiology of inflammatory disorders in preclinical disease models. Perfluorocarbon nanoemulsions (PFC-NEs) have been well documented in their ability to be taken up by macrophages through phagocytosis and serve as ¹⁹F magnetic resonance imaging (MRI) tracers of inflammation in vivo and ex vivo. Incorporation of near-infrared fluorescent (NIRF) dyes in PFC-NEs can help monitor the spatiotemporal distribution of macrophages in vivo during inflammatory processes, using NIRF imaging as a complementary methodology to MRI. Here, we discuss in depth how both colloidal and fluorescence stabilities of the PFC-NEs are essential for successful and reliable macrophage tracking in vivo and for their detection in excised tissues ex vivo by NIRF imaging. Furthermore, PFC-NE quality assures NIRF imaging reproducibility and reliability across preclinical studies, providing insights into inflammation progression and therapeutic response. Previous studies focused on assessments of colloidal property changes in response to stress and during storage as a means of quality control. We recently focused on the joint evaluation of both colloidal and fluorescence properties and their relationship to NIRF imaging outcomes. In this protocol, we summarize the key assessments of the fluorescent dye–labeled nanoemulsions, which include long-term particle size distribution monitoring as the measure of colloidal stability and monitoring of the fluorescence signal. Due to its simplicity and reproducibility, our protocols are easy to adopt for researchers to assess the quality of PFC-NEs for in vivo NIRF imaging applications.

Pulmonary hypertension (PH) is a group of pulmonary vascular disorders in which mean pulmonary arterial pressure (mPAP) becomes abnormally high because of various pathological conditions, including remodeling of the pulmonary arteries, lung and heart disorders, or congenital conditions. Various animal models, including mouse and rat models, have been used to recapitulate elevated mPAP observed in PH patients. However, the measurement and recording of mPAP and mean systemic arterial pressure (mSAP) in small animals require microsurgical procedures and a sophisticated data acquisition system. In this paper, we describe the surgical procedures for right heart catheterizations (RHC) to measure mPAP in rats. We also explain the catheterization of the carotid artery for simultaneous measurement of mPAP and mSAP using the PowerLab Data Acquisition system. We enumerate the surgical steps involved in exposing the jugular vein and the carotid artery for catheterizing these two blood vessels. We list the tools used for microsurgery in rats, describe the methods for preparing catheters, and illustrate the process for inserting the catheters in the pulmonary and carotid arteries. Finally, we delineate the steps involved in the calibration and setup of the PowerLab system for recording both mPAP and mSAP. This is the first protocol wherein we meticulously explain the surgical procedures for RHC in rats and the recording of mPAP and mSAP. We believe this protocol will be essential for PH research. Investigators with little training in animal handling can reproduce this microsurgical procedure for RHC in rats and measure mPAP and mSAP in rat models of PH. Further, this protocol is likely to help master RHC in rats that are performed for other conditions, such as heart failure, congenital heart disease, heart valve disorders, and heart transplantation.

Anorexia nervosa (AN) is a psychiatric disorder mainly characterized by extreme hypophagia, severe body weight loss, hyperactivity, and hypothermia. Currently, AN has the highest mortality rate among psychiatric illnesses. Despite decades of research, there is no effective cure for AN nor is there a clear understanding of its etiology. Since a complex interaction between genetic, environmental, social, and cultural factors underlines this disorder, the development of a suitable animal model has been difficult so far. Here, we present our protocol that couples a loss-of-function mouse model to the activity-based anorexia model (ABA), which involves self-imposed starvation in response to exposure to food restriction and exercise. We provide insights into a neural circuit that drives survival in AN and, in contrast to previous protocols, propose a model that mimics the conditions that mainly promote AN in humans, such as increased incidence during adolescence, onset preceded by negative energy balance, and increased compulsive exercise. This protocol will be useful for future studies that aim to identify neuronal populations or brain circuits that promote the onset or long-term maintenance of this devastating eating disorder.

Resistance of acute lymphoblastic leukemia (ALL) cells to chemotherapy, whether present at diagnosis or acquired during treatment, is a major cause of treatment failure. Primary ALL cells are accessible for drug sensitivity testing at the time of new diagnosis or at relapse, but there are major limitations with current methods for determining drug sensitivity ex vivo. Here, we describe a functional precision medicine method using a fluorescence imaging platform to test drug sensitivity profiles of primary ALL cells. Leukemia cells are co-cultured with mesenchymal stromal cells and tested with a panel of 40 anti-leukemia drugs to determine individual patterns of drug resistance and sensitivity (“pharmacotype”). This imaging-based pharmacotyping assay addresses the limitations of prior ex vivo drug sensitivity methods by automating data analysis to produce high-throughput data while requiring fewer cells and significantly decreasing the labor-intensive time required to conduct the assay. The integration of drug sensitivity data with genomic profiling provides a basis for rational genomics-guided precision medicine.

Key features

• Analysis of primary acute lymphoblastic leukemia (ALL) blasts obtained at diagnosis from bone marrow aspirate or peripheral blood.

• Experiments are performed ex vivo with mesenchymal stromal cell co-culture and require four days to complete.

• This fluorescence imaging–based protocol enhances previous ex vivo drug sensitivity assays and improves efficiency by requiring fewer primary cells while increasing the number of drugs tested to 40.

• It takes approximately 2–3 h for sample preparation and processing and a 1.5-hour imaging time.

Graphical overview

BM: bone marrow; PB: peripheral blood; ALL: acute lymphoblastic leukemia; MNCs: mononuclear cells, which include leukemia cells when present; MSCs: mesenchymal stromal cells; LC50: drug concentration that kills 50% of the leukemia cells

Cardiovascular diseases are the leading cause of death and morbidity worldwide. Patient mortality has been successfully reduced by nearly half in the last four decades, mainly due to advances in minimally invasive surgery techniques and interventional cardiology methods. However, a major hurdle is still the translational gap between preclinical findings and the conversion into effective therapies, which is partly due to the use of model systems that fail to recapitulate key aspects of human physiology and disease. Large animal models such as pigs and non-human primates are highly valuable because they closely resemble humans but are costly and time intensive. Here, we provide a method for long-term ex vivo culture of non-human primate (NHP) myocardial tissue that offers a powerful alternative for a wide range of applications including electrophysiology studies, drug screening, and gene function analyses.

Graphical overview

The nematode Haemonchus placei is a pathogenic parasite, the most seriously affecting ruminant’s health and being responsible for enormous economic losses all over the world. The present protocol describes different in vitro techniques to select potential candidate antigens with immune-protective activity from excretory and secretory products (ESP) from H. placei transitory infective larvae (xL₃). ESP from xL₃ were obtained from the in vitro infective larvae (L₃) maintained in Hank’s medium at 37 °C with 5% CO₂ for 48 h. Then, the presence of ESP proteins was confirmed by SDS-PAGE to be used in an in vitro proliferation assay with bovine peripheral blood mononuclear cells (PBMCs). The ESP were exposed to the PBMCs during two different periods (24 and 48 h). Genes associated with immune response against the nematode were analyzed using relative gene expression and bioinformatic tools. These are simple, economic, and helpful tools to identify potential immune-protective molecules under in vitro conditions for confirming the efficacy of future in vivo assays.

Graphical overview