Faculty of Applied Sciences & Biotechnology, Shoolini University, Solan, 173229, India.
BMC Complement Med Ther. 2023 Oct 13;23(1):362. doi: 10.1186/s12906-023-04193-4.
Sterile fecal filtrate (SFF) is being considered a safer alternative to fecal microbiota transplantation (FMT) therapy; however, its bioactive potency is very little understood. The present study thus assessed the age-dependent immunostimulatory and immunomodulatory attributes of murine SFF in vitro.
SFF from young (Y-SFF) and old (O-SFF) Swiss albino mice were prepared. Immunostimulatory and immunomodulatory effects of SFF were evaluated in resting and lipopolysaccharide (LPS) stimulated macrophage cells by measuring intracellular reactive oxygen species (ROS), nitric oxide (NO) production, inflammatory cytokines profile, as well as gene expression of oxidative and inflammatory transcription factors. SFF were also evaluated for native antioxidant capacity by measuring DPPH and ABTS free radical scavenging activity. Bioactive components present in SFF were also determined by GC/MS analysis.
Both Y-SFF and O-SFF induced potent immunostimulatory effects characterized by changes in cell morphology, a significant increase in NO production, ROS levels, and an increased ratio of pro-inflammatory (IL-6, TNF-α, IL-1β) to anti-inflammatory (IL-10) secretory proteins although no significant aggravation in the transcription of NF-κB and Nrf-2 could be observed. Application of LPS to cells significantly augmented a pro-oxidative and pro-inflammatory response which was much higher in comparison to Y-SFF or O-SFF application alone and mediated by strong suppression of Nrf-2 gene expression. Pre-treatment of macrophages with both Y-SFF and O-SFF robustly attenuated cellular hyperresponsiveness to LPS characterized by significantly decreased levels of NO, ROS, and inflammatory cytokines while a concomitant increase in anti-inflammatory protein (IL-10) was observed. Further, both Y-SFF and O-SFF strongly resisted LPS-induced downregulation of Nrf-2 expression although O-SFF appeared to protect cells slightly better from the overall LPS threat. Neat SFF samples exhibited moderate antioxidant capacity and GC/MS analysis of SFF revealed diverse volatile organic compounds characterized by alkanes, organosulphur compounds, furans, amides, amino acids, and antimicrobial elements.
Our results indicate that SFF is a potent stimulant of macrophages and confers strong anti-inflammatory effects regardless of donor age thereby suggesting its therapeutic efficacy in lieu of FMT therapy.
无菌粪便滤液（SFF）被认为是粪便微生物群移植（FMT）治疗的更安全替代品；然而，其生物活性强度还知之甚少。本研究因此评估了体外鼠 SFF 的年龄依赖性免疫刺激和免疫调节特性。
从小鼠（Y-SFF）和老年（O-SFF）瑞士白化鼠中制备 SFF。通过测量细胞内活性氧（ROS）、一氧化氮（NO）的产生、炎症细胞因子谱以及氧化和炎症转录因子的基因表达，评估 SFF 对静止和脂多糖（LPS）刺激的巨噬细胞的免疫刺激和免疫调节作用。还通过测量 DPPH 和 ABTS 自由基清除活性来评估 SFF 的天然抗氧化能力。通过 GC/MS 分析确定 SFF 中的生物活性成分。
Y-SFF 和 O-SFF 均诱导出强烈的免疫刺激作用，其特征在于细胞形态发生变化，NO 产生、ROS 水平显著增加，促炎（IL-6、TNF-α、IL-1β）与抗炎（IL-10）分泌蛋白的比值增加，尽管未观察到 NF-κB 和 Nrf-2 的转录明显加重。LPS 对细胞的应用显著增强了促氧化和促炎反应，与 Y-SFF 或 O-SFF 单独应用相比，这种反应更高，并且受到 Nrf-2 基因表达的强烈抑制。巨噬细胞用 Y-SFF 和 O-SFF 预处理可显著减弱细胞对 LPS 的过度反应，其特征是 NO、ROS 和炎症细胞因子水平显著降低，同时抗炎蛋白（IL-10）增加。此外，Y-SFF 和 O-SFF 均可强烈抵抗 LPS 诱导的 Nrf-2 表达下调，尽管 O-SFF 似乎能使细胞更好地免受 LPS 的整体威胁。未稀释的 SFF 样品具有中等的抗氧化能力，SFF 的 GC/MS 分析显示了多种挥发性有机化合物，其特征是烷烃、有机硫化合物、呋喃、酰胺、氨基酸和抗菌元素。
我们的结果表明，SFF 是巨噬细胞的有力刺激物，并赋予强烈的抗炎作用，无论供体年龄如何，这表明其在 FMT 治疗中的治疗功效。
