A comprehensive review of animal models for cancer cachexia: Implications for translational research.

Cancer cachexia is a multifactorial syndrome characterized by progressive weight loss and a disease process that nutritional support cannot reverse. Although progress has been made in preclinical research, there is still a long way to go in translating research findings into clinical practice. One of the main reasons for this is that existing preclinical models do not fully replicate the conditions seen in clinical patients. Therefore, it is important to understand the characteristics of existing preclinical models of cancer cachexia and pay close attention to the latest developments in preclinical models. The main models of cancer cachexia used in current research are allogeneic and xenograft models, genetically engineered mouse models, chemotherapy drug-induced models, Chinese medicine spleen deficiency models, zebrafish and Drosophila models, and cellular models. This review aims to revisit and summarize the commonly used animal models of cancer cachexia by evaluating existing preclinical models, to provide tools and support for translational medicine research.

In vivo CAR T cell therapy against angioimmunoblastic T cell lymphoma.

BACKGROUND: For angioimmunoblastic T cell lymphoma (AITL), a rare cancer, no specific treatments are available and survival outcome is poor. We previously developed a murine model for AITL that mimics closely human disease and allows to evaluate new treatments. As in human AITL, the murine CD4+ follicular helper T (Tfh) cells are drivers of the malignancy. Therefore, chimeric antigen receptor (CAR) T cell therapy might represent a new therapeutic option. METHODS: To prevent fratricide among CAR T cells when delivering an CD4-specific CAR, we used a lentiviral vector (LV) encoding an anti-CD4 CAR, allowing exclusive entry into CD8 T cells. RESULTS: These anti-CD4CAR CD8-targeted LVs achieved in murine AITL biopsies high CAR-expression levels in CD8 T cells. Malignant CD4 Tfh cells were eliminated from the mAITL lymphoma, while the CAR + CD8 T cells expanded upon encounter with the CD4 receptor and were shaped into functional cytotoxic cells. Finally, in vivo injection of the CAR + CD8-LVs into our preclinical AITL mouse model carrying lymphomas, significantly prolonged mice survival. Moreover, the in vivo generated functional CAR + CD8 T cells efficiently reduced neoplastic T cell numbers in the mAITL tumors. CONCLUSION: This is the first description of in vivo generated CAR T cells for therapy of a T cell lymphoma. The strategy described offers a new therapeutic concept for patients suffering from CD4-driven T cell lymphomas.

Characterization of an Advanced Blast Simulator for Investigation of Large Scale Blast Traumatic Brain Injury Studies.

Blast traumatic brain injury (bTBI) is a prominent military health concern. The pervasiveness and long-term impacts of this injury highlight the need for investigation of the physiological outcomes of bTBI. Preclinical models allow for the evaluation of behavioral and neuropathological sequelae associated with bTBI. Studies have implemented rodent models to investigate bTBI due to the relative small size and low cost; however, a large animal model with similar neuroanatomical structure to humans is essential for clinical translation. Small blast simulators are used to induce bTBI in rodents, but a large animal model demands a larger device. This study describes a large advanced blast simulator (ABS4) that is a gas-detonation-driven system consisting of 5 sections totaling 40 ft in length with a cross-section of 4 × 4 ft at the test section. It is highly suitable for large animals and human surrogate investigations. This work characterized the ABS4 in preparation of large-scale bTBI testing. An array of tests were conducted with target overpressures in the test section ranging from 10 to 50 psi, and the pressure-time profiles clearly illustrate the essential characteristics of a free-field blast wave, specifically a sharp peak pressure and a defined negative phase. Multiple blast tests conducted at the same target pressure produced very similar pressure profiles, exhibiting the reproducibility of the ABS4 system. With its extensive range of pressures and substantial size, the ABS4 will permit military-relevant translational blast testing.

Preclinical Female Model of Urogenital Dysfunction and Pathophysiological Changes After Pelvic Radiation Therapy.

Introduction Radiation therapy (RT) is the gold standard for many pelvic cancers and improves overall patient survival. However, pelvic RT is associated with increased sexual dysfunction and urinary incontinence. Although the side effects of pelvic RT are well-documented, the pathological mechanisms leading to pelvic organ dysfunction are unknown, and a preclinical model has not been established. This study characterized the impact of pelvic RT at early and late timepoints on female rat bladder, vaginal, and urethral physiology and morphology. Methods Adult female Sprague-Dawley rats were divided into three groups (n = 8/group): (I) Sham, (II) four weeks RT (4wk RT), and (III) nine weeks RT (9wk RT). The RT groups received a single dose of 20 Gy external beam radiation, and experiments were conducted at 4wk and 9wk post-RT. Nerve-mediated vaginal blood flow was measured via laser Doppler. Tissue bath studies assessed vaginal contractility to electric field stimulation (EFS), adrenergic and cholinergic agonists, and relaxation to a nitric oxide donor. Bladder and urethral sphincters were evaluated for cholinergic, caffeine, and EFS-mediated contractility. Quantitative polymerase chain reaction (qPCR) measured gene expression of markers of oxidative stress. Vaginal, bladder, and urethral fibrosis were assessed with Masson's trichrome staining. Results At 4wk post-RT, total vaginal blood flow decreased, and at 9wk post-RT, returned to baseline levels. At 9wk post-RT, vaginal neurogenic and adrenergic-mediated contractile responses increased significantly. Vaginal epithelial thickness decreased post-RT and correlated with an acute rise in vaginal inflammatory gene expression. At 4wk post-RT, bladder neurogenic contractions decreased and remained lowered. Internal urethral contractions increased at 4wk post-RT and returned to Sham levels after 9wk post-RT. Pelvic RT increased external urethral neurogenic contractions, which remained elevated. Conclusion This novel preclinical model provides valuable insights into the temporal pathophysiology of pelvic RT-induced sexual and urinary dysfunction. The establishment of this model is crucial for understanding the underlying mechanisms involved in RT-induced pelvic injury. A reliable, clinically relevant model will allow for the testing of therapeutic strategies to prevent adverse effects with RT in pelvic cancer survivors.

Toxicity in the era of immune checkpoint inhibitor therapy.

Immune checkpoint inhibitors (ICIs) reinvigorate anti-tumor immune responses by disrupting co-inhibitory immune checkpoint molecules such as programmed cell death 1 (PD-1) and cytotoxic T lymphocyte antigen 4 (CTLA-4). Although ICIs have had unprecedented success and have become the standard of care for many cancers, they are often accompanied by off-target inflammation that can occur in any organ system. These immune related adverse events (irAEs) often require steroid use and/or cessation of ICI therapy, which can both lead to cancer progression. Although irAEs are common, the detailed molecular and immune mechanisms underlying their development are still elusive. To further our understanding of irAEs and develop effective treatment options, there is pressing need for preclinical models recapitulating the clinical settings. In this review, we describe current preclinical models and immune implications of ICI-induced skin toxicities, colitis, neurological and endocrine toxicities, pneumonitis, arthritis, and myocarditis along with their management.

Evaluation of Clobetasol and Tacrolimus Treatments in an Imiquimod-Induced Psoriasis Rat Model.

Psoriasis is a chronic inflammatory skin disorder characterized by keratinocyte hyperproliferation, inflammation, and aberrant differentiation. Imiquimod-induced psoriasis in rodent models has been widely used to study the pathogenesis of the disease and evaluate potential therapeutic interventions. In this study, we investigated the efficacy of two commonly used treatments, Clobetasol and Tacrolimus, in ameliorating psoriatic symptoms in an Imiquimod-induced psoriasis Wistar rat model. Interestingly, rat models are poorly evaluated in the literature despite rats displaying several advantages in evaluating pharmacological substances. Psoriasis-like skin lesions were induced by topical application of Imiquimod cream on shaved dorsal skin for seven consecutive days. Following induction, rats in the treatment groups received either a Clobetasol or Tacrolimus ointment once daily for one week, while the control group did not receive any application. Disease severity was assessed using clinical scoring, histological examination, and measurement of proinflammatory cytokine levels. Both Clobetasol and Tacrolimus treatments significantly reduced psoriatic lesion severity compared to the control group. Clinical scoring revealed a decrease in erythema, scaling, transepidermal water loss, and thickness of skin lesions in both treatment groups with a more marked effect with Clobetasol. Histological analysis demonstrated reduced epidermal hyperplasia in treated animals compared to controls. Furthermore, Clobetasol led to a significant reduction in the expression levels of the interleukin-17 (IL-17a and IL-17f) proinflammatory cytokines in lesioned skin. Overall, our findings demonstrated the therapeutic efficacy of both Clobetasol and, in a modest manner, Tacrolimus in attenuating Imiquimod-induced psoriasis-like symptoms in a rat model. These results support the clinical use of these agents in the management of psoriasis and mitigating psoriatic inflammation. They also provide insights into the use of rats as a relevant species for the Imiquimod-induced psoriasis model.

Comparison of mouse models of heart failure with reduced ejection fraction.

AIMS: Heart failure with reduced ejection fraction (HFrEF) is a leading cause of death worldwide; thus, therapeutic improvements are needed. In vivo preclinical models are essential to identify molecular drug targets for future therapies. Transverse aortic constriction (TAC) is a well-established model of HFrEF; however, highly experienced personnel are needed for the surgery, and several weeks of follow-up are necessary to develop HFrEF. To this end, we aimed (i) to develop an easy-to-perform mouse model of HFrEF by treating Balb/c mice with angiotensin-II (Ang-II) for 2 weeks by minipump and (ii) to compare its cardiac phenotype and transcriptome to the well-established TAC model of HFrEF in C57BL/6J mice. METHODS: Mortality and gross pathological data, cardiac structural and functional characteristics assessed by echocardiography and immunohistochemistry and differential gene expression obtained by RNA-sequencing and gene-ontology analyses were used to characterize and compare the two models. To achieve statistical comparability between the two models, changes in treatment groups related to the corresponding control were compared (ΔTAC vs. ΔAng-II). RESULTS: Compared with the well-established TAC model, chronic Ang-II treatment of Balb/c mice shares similarities in cardiac systolic functional decline (left ventricular ejection fraction: -57.25 ± 7.17% vs. -43.68 ± 5.31% in ΔTAC vs. ΔAng-II; P = 0.1794) but shows a lesser degree of left ventricular dilation (left ventricular end-systolic volume: 190.81 ± 44.13 vs. 57.37 ± 10.18 mL in ΔTAC vs. ΔAng-II; P = 0.0252) and hypertrophy (cell surface area: 58.44 ± 6.1 vs. 10.24 ± 2.87 µm2 in ΔTAC vs. ΔAng-II; P < 0.001); nevertheless, transcriptomic changes in the two HFrEF models show strong correlation (Spearman's r = 0.727; P < 0.001). In return, Ang-II treatment in Balb/c mice needs significantly less procedural time [38 min, interquartile range (IQR): 31-46 min in TAC vs. 6 min, IQR: 6-7 min in Ang-II; P < 0.001] and surgical expertise, is less of an object for peri-procedural mortality (15.8% in TAC vs. 0% in Ang-II; P = 0.105) and needs significantly shorter follow-up for developing HFrEF. CONCLUSIONS: Here, we demonstrate for the first time that chronic Ang-II treatment of Balb/c mice is also a relevant, reliable but significantly easier-to-perform preclinical model to identify novel pathomechanisms and targets in future HFrEF research.

Effects of xylazine on naloxone-precipitated fentanyl withdrawal in male and female rats.

PURPOSE: The combination of fentanyl and xylazine (i.e., "tranq-dope") was recently declared an emerging national health threat in the United States. Given the recency of this development, very little is known regarding the behavioral pharmacology of fentanyl-xylazine combinations. The purpose of this study was to characterize the somatic and affective withdrawal symptoms of this drug combination. METHODS: Male and female Long Evans rats were given twice daily (08:00 and 20:00) subcutaneous injections of fentanyl, xylazine, or combined fentanyl-xylazine for five days. On the sixth (testing) day, rats were given a final injection at 08:00. Four hours later, rats were injected intraperitoneally with either saline or a naloxone challenge before behavioral observation. Somatic withdrawal was examined using the Gellert-Holtzman scale and anxiety-like behavior was examined using the elevated plus maze. RESULTS: Naloxone administration did not induce somatic or affective symptoms in rats treated with fentanyl alone, a low dose of xylazine alone, or a high dose of xylazine alone. Naloxone induced somatic but not affective withdrawal symptoms in rats treated with both fentanyl and xylazine. CONCLUSION: Chronic co-exposure to fentanyl and xylazine produces an opioid-like somatic withdrawal syndrome at doses that are not apparent with either drug alone. These results corroborate clinical reports that xylazine worsens fentanyl withdrawal and suggest that novel interventions may be required to treat withdrawal from fentanyl-xylazine combinations in humans.

Diverse Engraftment Capability of Neuroblastoma Cell Lines in Zebrafish Larvae.

Xenotransplantation of neuroblastoma cells into larval zebrafish allows the characterization of their in vivo tumorigenic abilities and high-throughput treatment screening. This established preclinical model traditionally relies on microinjection into the yolk or perivitelline space, leaving the engraftment ability of cells at the hindbrain ventricle (HBV) and pericardial space (PCS), sites valuable for evaluating metastasis, angiogenesis, and the brain microenvironment, unknown. To address this gap in knowledge, Casper zebrafish at 48 h postfertilization were microinjected with approximately 200 Kelly, Be(2)-C, SK-N-AS, or SY5Y cells into either the HBV or PCS. Fish were imaged at 1, 3, and 6 days postinjection and tumor growth was monitored at each timepoint. We hypothesized that engraftment ability and location preference would be cell line dependent. Kelly and SK-N-AS cells were able to engraft at both the HBV and PCS, with a near doubling in size of tumor volume during the 6 days observation period, with cells appearing to grow better in the HBV. Be(2)-C tumors remained static while SY5Y tumors decreased in size, with almost complete loss of volume at both sites. Therefore, the capability of neuroblastoma cell engraftment in zebrafish larvae is cell line dependent with a location preference.

Natural Compounds That Activate the KEAP1/Nrf2 Signaling Pathway as Potential New Drugs in the Treatment of Idiopathic Parkinson's Disease.

Recently, a single-neuron degeneration model has been proposed to understand the development of idiopathic Parkinson's disease based on (i) the extremely slow development of the degenerative process before the onset of motor symptoms and during the progression of the disease and (ii) the fact that it is triggered by an endogenous neurotoxin that does not have an expansive character, limiting its neurotoxic effect to single neuromelanin-containing dopaminergic neurons. It has been proposed that aminochrome is the endogenous neurotoxin that triggers the neurodegenerative process in idiopathic Parkinson's disease by triggering mitochondrial dysfunction, oxidative stress, neuroinflammation, dysfunction of both lysosomal and proteasomal protein degradation, endoplasmic reticulum stress and formation of neurotoxic alpha-synuclein oligomers. Aminochrome is an endogenous neurotoxin that is rapidly reduced by flavoenzymes and/or forms adducts with proteins, which implies that it is impossible for it to have a propagative neurotoxic effect on neighboring neurons. Interestingly, the enzymes DT-diaphorase and glutathione transferase M2-2 prevent the neurotoxic effects of aminochrome. Natural compounds present in fruits, vegetables and other plant products have been shown to activate the KEAP1/Nrf2 signaling pathway by increasing the expression of antioxidant enzymes including DT-diaphorase and glutathione transferase. This review analyzes the possibility of searching for natural compounds that increase the expression of DT-diaphorase and glutathione transferase through activation of the KEAP1/Nrf2 signaling pathway.