Soybean Meal-Dependent Intestinal Inflammation Induces Different Patterns of Bone-Loss in Adult Zebrafish Scale

Chronic social isolation affects feeding behavior of juvenile zebrafish (Danio rerio)

Many organisms exhibit social behaviors and are part of some scheme of social structure. Zebrafish are highly social, shoaling fish and therefore, social isolation may have notable impacts on their physiology and behavior. The objective of this study was to evaluate the effects of social isolation on feed intake, monoaminergic system related gene expression, and intestinal health of juvenile zebrafish fed a high-inclusion soybean meal based diet. At 20 days post-fertilization zebrafish were randomly assigned to chronic isolation (1 fish per 1.5 L tank) or social housing (6 fish per 9 L tank) with 18 tanks per treatment group (n = 18). Dividers were placed between all tanks to prevent visual cues between fish. Zebrafish were fed a commercial fishmeal based diet until 35 days post-fertilization and then fed the experimental high-inclusion soybean meal based diet until 50 days post-fertilization. At the end of the experiment (51 days post-fertilization), the mean total length, weight, and weight gain were not significantly different between treatment groups. Feed intake and feed conversion ratio were significantly higher in chronic isolation fish than in social housing fish. Expression of monoaminergic and appetite-related genes were not significantly different between groups. The chronic isolation group showed higher expression of the inflammatory gene il-1b, however, average intestinal villi width was significantly smaller and average length-to-width ratio was significantly higher in chronic isolation fish, suggesting morphological signs of inflammation were not present at the time of sampling. These results indicate that chronic isolation positively affects feed intake of juvenile zebrafish and suggest that isolation may be useful in promoting feed intake of less-palatable diets such as those based on soybean meal.

Effects of Oregano (Origanum vulgare) Essential Oil Supplementation on Growth Performance of Zebrafish (Danio rerio) Fed a High-Inclusion Soybean Meal Diet

Soybean meal (SBM) has become a common dietary replacement for fish meal (FM) in aquafeed. However, at high inclusions, SBM has been shown to have negative impacts presenting as reduced feed intake and intestinal inflammation. Medicinal plant extracts, namely essential oils, have been used to promote growth performance and immune response. The objective of this study was to investigate the potential therapeutic effects of oregano (Origanum vulgare) essential oil (OEO) inclusion on utilization of a high-inclusion SBM diet using zebrafish as a model. Five diets were used in this study: reference-FM-based diet, control-55.7% inclusion SBM diet, and three experimental SBM-based diets OEO1, OEO2, and OEO3 that were supplemented with 1%, 2%, or 3% of oregano oil, respectively. The FM group had overall better growth performance when compared with the other treatment groups; however, the OEO3 mean weight and feed conversion ratio were not significantly different from the FM group (p > 0.05) and were significantly improved compared with the SBM group (p < 0.05). Similarly, OEO2 total length was not significantly different from FM (p > 0.05) but significantly higher than the SBM group (p < 0.05). Expression of inflammation-related genes did not significantly differ between the OEO groups and the SBM-only group. However, the OEO2 and OEO3 groups displayed improved growth performance compared with the SBM group, suggesting that inclusion of OEO at or above 2% inclusion may help to alleviate common symptoms induced by a high-inclusion SBM diet.

Advancements in the impact of human microbiota and probiotics on leukemia

The human gut microbiota is a complex ecosystem that plays a crucial role in promoting the interaction between the body and its environment. It has been increasingly recognized that the gut microbiota has diverse physiological functions. Recent studies have shown a close association between the gut microbiota and the development of certain tumors, including leukemia. Leukemia is a malignant clonal disease characterized by the uncontrolled growth of one or more types of blood cells, which is the most common cancer in children. The imbalance of gut microbiota is linked to the pathological mechanisms of leukemia. Probiotics, which are beneficial microorganisms that help maintain the balance of the host microbiome, play a role in regulating gut microbiota. Probiotics have the potential to assist in the treatment of leukemia and improve the clinical prognosis of leukemia patients. This study reviews the relationship between gut microbiota, probiotics, and the progression of leukemia based on current research. In addition, utilizing zebrafish leukemia models in future studies might reveal the specific mechanisms of their interactions, thereby providing new insights into the clinical treatment of leukemia. In conclusion, further investigation is still needed to fully understand the accurate role of microbes in leukemia.

Emerging polyfluorinated compound Nafion by-product 2 disturbs intestinal homeostasis in zebrafish (Danio rerio)

Nafion by-product 2 (Nafion BP2), an emerging fluorinated sulfonic acid commonly used in polymer electrolyte membrane technologies, has been detected in various environmental and human matrices. To date, however, few studies have explored its toxicity. In this study, zebrafish embryos were exposed to Nafion BP2 at concentrations of 20, 40, 60, 80, 100, 120, 140, and 160 mg/L from fertilization to 120 post-fertilization (hpf), and multiple developmental parameters (survival rate, hatching rate, and malformation rate) were then determined. Results showed that Nafion BP2 exposure led to a significant decrease in survival and hatching rates and an increase in malformations. The half maximal effective concentration (EC₅₀) of Nafion BP2 for malformation at 120 hpf was 55 mg/L, which is higher than the globally important contaminant perfluorooctane sulfonate (PFOS, 6 mg/L). Furthermore, exposure to Nafion BP2 resulted in additional types of malformations compared to PFOS exposure. Pathologically, Nafion BP2 caused abnormal early foregut development, with exfoliation of intestinal mucosa, damage to lamina propria, and aberrant proliferation of lamina propria cells. Nitric oxide content also decreased markedly. In addition, embryos showed an inflammatory response following Nafion BP2 exposure, with significantly increased levels of pro-inflammatory factors C4 and IL-6. Acidic mucin in the hindgut increased more than two-fold. 16 S rRNA sequencing revealed a marked increase in the pathogen Pseudomonas otitidis. Furthermore, pathways involved in intestinal protein digestion and absorption, inflammatory response, and immune response were significantly altered. Our findings suggest that the intestine is a crucial toxicity target of Nafion BP2 in zebrafish, thus highlighting the need to evaluate its health risks.

Propionate and butyrate attenuate macrophage pyroptosis and osteoclastogenesis induced by CoCrMo alloy particles

BACKGROUND

Wear particles-induced osteolysis is a major long-term complication after total joint arthroplasty. Up to now, there is no effective treatment for wear particles-induced osteolysis except for the revision surgery, which is a heavy psychological and economic burden to patients. A metabolite of gut microbiota, short chain fatty acids (SCFAs), has been reported to be beneficial for many chronic inflammatory diseases. This study aimed to investigate the therapeutic effect of SCFAs on osteolysis.

METHODS

A model of inflammatory osteolysis was established by applying CoCrMo alloy particles to mouse calvarium. After two weeks of intervention, the anti-inflammatory effects of SCFAs on wear particle-induced osteolysis were evaluated by Micro-CT analysis and immunohistochemistry staining. In vitro study, lipopolysaccharide (LPS) primed bone marrow-derived macrophages (BMDMs) and Tohoku Hospital Pediatrics-1 (THP-1) macrophages were stimulated with CoCrMo particles to activate inflammasome in the presence of acetate (C2), propionate (C3), and butyrate (C4). Western blotting, Enzyme-linked immunosorbent assay, and immunofluorescence were used to detect the activation of NLRP3 inflammasome. The effects of SCFAs on osteoclasts were evaluate by qRT-PCR, Western blotting, immunofluorescence, and tartrate-resistant acid phosphatase (TRAP) staining. Additionally, histone deacetylase (HDAC) inhibitors, agonists of GPR41, GPR43, and GPR109A were applied to confirm the underlying mechanism of SCFAs on the inflammasome activation of macrophages and osteoclastogenesis.

RESULTS

C3 and C4 but not C2 could alleviate wear particles-induced osteolysis with fewer bone erosion pits (P < 0.001), higher level of bone volume to tissue volume (BV/TV, P < 0.001), bone mineral density (BMD, P < 0.001), and a lower total porosity (P < 0.001). C3 and C4 prevented CoCrMo alloy particles-induced ASC speck formation and nucleation-induced oligomerization, suppressing the cleavage of caspase-1 (P < 0.05) and IL-1β (P < 0.05) stimulated by CoCrMo alloy particles. C3 and C4 also inhibited the generation of Gasdermin D-N-terminal fragment (GSDMD-NT) to regulate pyroptosis. Besides, C3 and C4 have a negative impact on osteoclast differentiation (P < 0.05) and its function (P < 0.05), affecting the podosome arrangement and morphologically normal podosome belts formation.

CONCLUSION

Our work showed that C3 and C4 are qualified candidates for the treatment of wear particle-induced osteolysis.

Osteoporosis in Patients With Respiratory Diseases

Climate change, environmental pollution, and virus epidemics have sharply increased the number of patients suffering from respiratory diseases in recent years. Prolonged periods of illness and drug use increase the occurrence of complications in these patients. Osteoporosis is the common bone metabolism disease with respiratory disturbance, which affects prognosis and increases mortality of patients. The problem of osteoporosis in patients with respiratory diseases needs more attention. In this review, we concluded the characteristics of osteoporosis in some respiratory diseases including COPD, asthma, COVID-19, tuberculosis, and lung cancer. We revealed that hypoxia was the common pathogenesis of osteoporosis secondary to respiratory diseases, with malnutrition and corticosteroid abuse driving the progression of osteoporosis. Hypoxia-induced ROS accumulation and activated HIF-1α lead to attenuated osteogenesis and enhanced osteoclastogenesis in patients with respiratory diseases. Tuberculosis and cancer also invaded bone tissue and reduced bone strength by direct infiltration. For the treatment of osteoporosis in respiratory patients, oral-optimized bisphosphonates were the best treatment modality. Vitamin D was a necessary supplement, both for calcium absorption in osteogenesis and for improvement of respiratory lesions. Reasonable adjustment of the dose and course of corticosteroids according to the etiology and condition of patients is beneficial to prevent the occurrence and development of osteoporosis. Additionally, HIF-1α was a potential target for the treatment of osteoporosis in respiratory patients, which could be activated under hypoxia condition and involved in the process of bone remodeling.

Soybean Meal-Dependent Acute Intestinal Inflammation Delays Osteogenesis in Zebrafish Larvae

Foods are known to be modulators of inflammation and skeletal development. The intestine plays an essential role in the regulation of bone health mainly through the regulation of the absorption of vitamin D and calcium; in fact, inflammatory bowel diseases are often related to bone health issues such as low bone mineral density, high fracture risk, osteoporosis and osteopenia. Considering the complexity of the pathways involved, the use of a simple animal model can be highly useful to better elucidate the pathogenic mechanisms. Soybean flour with a high saponin content has been used in many studies to induce intestinal inflammation in zebrafish larvae. Using a 50% soybean meal (SBM), we analyzed the effects of this soy-induced inflammatory bowel disease on zebrafish larval osteogenesis. Soybean meal induces intestinal functional alterations and an inflammatory state, highlighted by neutral red staining, without altering the general development of the larvae. Our data show that the chondrogenesis as well as endochondral ossification of the head of zebrafish larvae are not affected by an SBM-diet, whereas intramembranous ossification was delayed both in the head, where the length of the ethmoid plate reduced by 17%, and in the trunk with a delayed vertebral mineralization of 47% of SBM larvae. These data highlight that diet-dependent bowel inflammation can differently modulate the different mechanisms of bone development in different zones of the skeleton of zebrafish larvae.