Remote myocardial injury: the protective role of fluoxetine

Fluoxetine ameliorates Alzheimer's disease progression and prevents the exacerbation of cardiovascular dysfunction of socially isolated depressed rats through activation of Nrf2/HO-1 and hindering TLR4/NLRP3 inflammasome signaling pathway

Depression is a risk factor for Alzheimer's (AD) and cardiovascular diseases (CVD). Therefore, depression treatment restricts its deteriorating effects on mood, memory and CV system. Fluoxetine is the most widely used antidepressant drug, it has neuroprotective effect through its antioxidant/anti-inflammatory properties. The current study investigated for the first-time the cross link between depression, AD and CVD besides, role of fluoxetine in mitigating such disorders. Depression was induced in rats by social isolation (SI) for 12 weeks, AlCL3 (70 mg/kg/day, i.p.) was used to induce AD which was administered either in SI or normal control (NC) grouped rats starting at 8th week till the end of the experiment, fluoxetine (10 mg/kg/day, p.o) treatment also was started at 8th week. SI and AD showed a statistically significant deteriorated effect on behavioral, neurochemical and histopathological analysis which was exaggerated when two disorder combined than each alone. Fluoxetine treatment showed protective effect against SI, AD and prevents exacerbation of CVD. Fluoxetine improved animals' behavior, increased brain monoamines, BDNF besides increased antioxidant defense mechanism of SOD, TAC contents and increased protein expression of Nrf2/HO-1 with significant decrease of AChE activity, β-amyloid, Tau protein, MDA, TNF-α, IL1β contents as well as decreased protein expression of NF-kB, TLR4, NLRP3 and caspase1. It also showed cardioprotective effects as it improved lipid profile with pronounced decrease of cardiac enzymes of CK-MB, troponin and MEF2. In conclusion, fluoxetine represents as a promising drug against central and peripheral disorders through its anti-inflammatory/antioxidant effects via targeting antioxidant Nrf2/HO-1 and hindering TLR4/NLRP3 inflammasome signaling pathways.

Opportunities for Drug Repurposing of Serotonin Reuptake Inhibitors: Potential Uses in Inflammation, Infection, Cancer, Neuroprotection, and Alzheimer's Disease Prevention

Serotonin reuptake inhibitors (SRIs) are safe and widely used for a variety of indications including depressive disorders, anxiety, and chronic pain. Besides inhibiting the serotonin transporter, these medications have broad-spectrum properties in many systems. Their roles have been studied in cancer, Alzheimer's disease, and infectious processes. The COVID-19 pandemic highlighted the importance of drug repurposing of medications already in use. We conducted a narrative review of current evidence and ongoing research on drug repurposing of SRIs, with a focus on immunomodulatory, antiproliferative, and neuroprotective activity. SRIs may have clinical use as repurposed agents for a wide variety of conditions including but not limited to COVID-19, Alzheimer's disease, and neoplastic processes. Further research, particularly randomized controlled trials, will be necessary to confirm the utility of SRIs for new indications.

β-arrestin 2 is essential for fluoxetine-mediated promotion of hippocampal neurogenesis in a mouse model of depression

Over the last decade, the roles of β-arrestins in the treatment of neuropsychological diseases have become increasingly appreciated. Fluoxetine is the first selective serotonin reuptake inhibitor developed and is approved for the clinical treatment of depression. Emerging evidence suggests that fluoxetine can directly combine with the 5-HT receptor, which is a member of the G protein-coupled receptor (GPCR) family, in addition to suppressing the serotonin transporter. In this study, we prepared a chronic mild stress (CMS)-induced depression model with β-arrestin2-/- mice and cultured adult neural stem cells (ANSCs) to investigate the involvement of the 5-HT receptor-β-arrestin axis in the pathogenesis of depression and in the therapeutic effect of fluoxetine. We found that β-arrestin2 deletion abolished the fluoxetine-mediated improvement in depression-like behaviors and monoamine neurotransmitter levels, although β-arrestin2 knockout did not aggravate CMS-induced changes in mouse behaviors and neurotransmitters. Notably, the β-arrestin2-/- mice had a shortened dendritic length and reduced dendritic spine density, as well as decreased neural precursor cells, compared to the WT mice under both basal and CMS conditions. We further found that β-arrestin2 knockout decreased the number of proliferating cells in the hippocampal dentate gyrus and suppressed the proliferative capability of ANSCs in vitro. Moreover, β-arrestin2 knockout aggravated the impairment of cell proliferation induced by corticosterone and further blocked the fluoxetine-mediated promotion of mouse hippocampal neurogenesis. Mechanistically, we found that the 5-HT2BR-β-arrestin2-PI3K/Akt axis is essential to maintain the modulation of hippocampal neurogenesis in depressed mice. Our study may provide a promising target for the development of new antidepressant drugs.

Fluoxetine as an antidepressant medicine improves the effects of ionizing radiation for the treatment of glioma

Radiotherapy is a cancer treatment protocol which delivers high dose of ionizing radiation (IR) to tumor. Tumor resistance and side effects induced by IR still are the major challenges in radiotherapy. The purpose of this study was to evaluate the synergistic killing effect of fluoxetine (FL) with IR on glioma cancer cell (U-87 MG), as well as radioprotective effect of FL against cellular toxicity induced by IR on non-malignant human fibroblast cell (HFFF2). Firstly, the inhibitory effects of FL on cell proliferations were evaluated in U-87 MG and HFFF2 cells. The clonogenic and MTT assays were used to evaluate the radiosensitivity and radioprotective effects of FL on cancer and non-malignant cells. The frequencies of apoptotic cells were evaluated by flow cytometry on both cancer and normal cells. Results showed that FL exhibited anti-cancer effect on glioma cells, while cellular toxicity was low in HFFF2 cells treated with FL. FL decreased the viable colonies and enhanced apoptotic cells when U-87 cells were treated with FL prior irradiation. For comparison, FL exhibited radioprotective effect through increasing cellular proliferation rate and reducing apoptosis in HFFF2 cells against IR. The results showed that FL enhanced the IR-induced glioma cancer cell death and apoptosis, whereas it exhibited a radioprotective effect on normal fibroblast cells suggesting that FL administration may improve glioma radiotherapy.

The Protective Effects of Thymosin-β-4 in a Rat Model of Ischemic Acute Kidney Injury

BACKGROUND

Despite the progress in the treatment of acute kidney injury (AKI), current curative approaches fail to provide adequate treatment. In this study, we aimed to investigate the possible protective effects of thymosin-β-4(Tβ4) on an ischemic AKI model in rats.

METHODS

Rats were randomly assigned into four groups (n = 8/group): The control group (sham-operated), the ischemia-reperfusion (I/R) group; renal ischemia (90 min) by infrarenal abdominal aortic occlusion followed by reperfusion (3 h), the Tβ4 + I/R group; treated with Tβ4 before I/R, and the I/Tβ4/R group; treated with Tβ4 just before reperfusion. Besides renal function determination (creatinine (Cr) and blood urea nitrogen (BUN)); histological evaluation was also conducted. Renal tissue caspase-9, matrix metalloproteinase (MMP-9) activities, and hyaluronan levels were measured. Additionally, renal tissue oxidative stress (lipid hydroperoxide, malondialdehyde, superoxide dismutase, glutathione, pro-oxidant-antioxidant balance, ferric reducing antioxidant power, nitric oxide), inflammation (tumor necrosis factor-α, interleukin-1β, interleukin-6, nuclear factor-κβ) were evaluated.

RESULTS

I/R increased the level of caspase-9, MMP-9 activity, and hyaluronan (p < 0.001) and these were significantly decreased in both Tβ4 groups. Moreover, I/R led to increases in oxidative stress and inflammation parameters (p < 0.001) while the levels of antioxidants were decreased. Nevertheless, Tβ4 in both groups were able to restore oxidative stress and inflammation parameters. Furthermore, Tβ4 attenuated histologic injury caused by I/R (p < 0.01) and diminished serum urea-creatinine levels (p < 0.001).

CONCLUSION

These results suggest that Tβ4 has significant improving effects in ischemic acute kidney injury. This beneficial effect might be a result of the inhibition of extracellular matrix remodeling and apoptosis cascade via modulation in renal redox status and inflammation.