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Biology subjects

Mousavi, M.

Publications and source records attributed to Mousavi, M..

3 recordsLinked to original sources
bioRxiv2025

Administration of short-chain fatty acids reduces bacterial translocation to peripheral organs and the brain, preserves gut barrier integrity, and mitigates brain injury following stroke

Ischemic stroke leads to neuronal death, neuroinflammation, blood-brain barrier breakdown, and disruption of the brain-immune-gut (BIG) axis. Despite improvements in recanalization treatments, stroke remains the second leading cause of death globally. Post-stroke infections (PSIs) are the main life-threatening complication (30-45% of all patients and 20% of mortality) after stroke. Traditionally attributed to nosocomial infections /associated medical procedures, ground-breaking research has revealed that PSIs primarily originate from bacterial translocation (BT) following gut barrier disruption after stroke. Despite the high mortality associated with PSIs, current treatments, including antibiotic prophylaxis, are largely ineffective, underscoring the urgent need for a better understanding of their aetiology. Short-chain fatty acids (SCFAs), microbiota-derived metabolites produced by bacterial fermentation of fibres, are key regulators of the BIG axis. SCFAs exert neuroprotective, anti-inflammatory, and antimicrobial effects across models of neurodegenerative and infectious diseases. Using a preclinical stroke model (transient middle cerebral artery occlusion, MCAO) in 12-week-old male mice, we evaluated the effects of SCFA administration starting 24 h after stroke until sacrifice at day 4 on BT, gut integrity, and brain injury. Our findings confirmed that stroke induces BT to several organs (e.g., liver, heart, spleen) and, for the first time, demonstrated bacterial presence in the brainstem and the ischemic core of the injured brain. Importantly, we also showed that SCFA treatment significantly reduced BT to several organs. In addition, SCFAs modulated gut barrier integrity, reduced brain lesion size, and improved functional recovery. These findings highlight the crucial role of SCFAs in the BIG axis following stroke and their potential to mitigate not only gut barrier disruption and brain injury, but also infection-related complications, offering a promising therapeutic strategy for one of the least understood yet most lethal complications of stroke.

physiology↗
bioRxiv2025

A Geometrically Transient Material for Bioelectronic Implants

The outstanding barrier properties of skin make it difficult to obtain reliable physiological information (especially chemical) without the use of implantable bioelectronic sensing devices to directly access the internal biology. The clinical utility of bioelectronic implants however, hinges on a key geometrical optimization problem: devices must scale-down in size to reduce surgical invasiveness while also creating enough space to integrate electronics for wireless power delivery, data exchange, and electrical/electrochemical monitoring. Here, we present a minimally invasive bioelectronic implant with a transient geometry that can be inserted subcutaneously and measures important markers, such as pH, temperature, cardiac and respiratory activity, and levels of lithium, an important element for medical applications. To produce this new class of minimally invasive and foldable implantable sensors, we developed a fabrication method that works with highly flexible substrates to enable multiple-fold miniaturization during implantation. After implantation, the implant autonomously unfolds back to its planar form for continuous wireless operation. We demonstrate the key concepts concerning implantation, operation, and removal through extensive in vitro, ex vivo, and in vivo animal experiments. Our approach allows for robust multiplexed monitoring using quick and suture-free insertion procedures and may provide a unique advantage in the transition towards personalized health profiles.

bioengineering↗
bioRxiv2022

Comparative study of the effect of neutrons emitted from neutron source 241Am-Be and curcumin on MCF-7 breast cancer cells in 3D culture medium

IntroductionCancer is one of the major medical problems threatening human health. Breast cancer is the most prevalent type of cancer in women. Reports indicate that treatments such as surgery, chemotherapy, biotherapy, and radiotherapy play a limited but important role in treating the disease. For more efficient treatment, new treatment strategies have been evolved based on combination therapy in which two or more different methods are exploited for this aim. In the present study, a combination therapy based on radiotherapy (using neutron radiation emitted from a 241Am-Be neutron source) and biotherapy (using curcumin) is applied to investigate the treatment efficiency of MCF-7 breast cancer in a three-dimensional culture medium. materials and methodsThe neutron dose rate in the 241Am-Be source was measured using BF3 detection and MCNPX simulation methods, and then the results of both methods were compared. MTT, neutral red uptake assay, nitric oxide, glutathione assay, catalase, cytochrome c, comet assay, and caspase-3 were used to determine the effect and type of mortality due to neutron effect as well as the combined effect of neutron and curcumin in cancer cells. ResultsCalculating the fast neutron flux around the source with two methods of simulation with MCNPX and detection with BF3 showed that with increasing distance from the source, the fast neutron flux decreased exponentially. The results of neutron dose rate measurement in the 241Am-Be source also showed that if the test cells in the vial are located at a distance of 22 cm from the inlet of the collimator and are exposed to neutron radiation for 5, 10, 15, and 20 hours, the neutron dose received by breast cancer cells will be 3, 6, 9, and 12 mGy/h, respectively. The results of cytotoxicity due to neutron irradiation as well as the combined effect of neutron and curcumin (80 M concentration) showed that neutron irradiation with or without curcumin at 5, 10, 15, and 20 hours reduced the survival of tumor cells. According to the results, the rate of apoptosis due to the neutron effect at irradiation times has increased with increasing time. Statistical analysis also showed that the rate of apoptosis due to the combined effect of neutrons and curcumin was not significant compared to the effect of neutrons only. The results of studying the effect of neutrons and the combination of neutrons and curcumin on the production of nitric oxide, catalase, and GSH also showed that curcumin has an antioxidant effect by reducing the amount of nitric oxide and increasing the production of catalase and glutathione in cells. However, neutrons, alone, lacked this effect. ConclusionOverall, this study showed that the neutron source 241Am-Be with the applied doses was able to destroy the c-o, and c-h bonds of curcumin, resulting in cell death and apoptosis induction in breast cancer cells. It was caused by neutron radiation. On the other hand, according to the results of the comet assay and caspase-3 experiments, although neutrons induced apoptosis in breast cancer cells, the death rate due to necrosis was much higher than apoptosis. Due to the significant anti-cancer effect of curcumin in 3D culture, the use of this molecule before or after neutron therapy is recommended. HighlightsO_LIThe results of neutron dose rate measurement in the 241Am-Be source showed that if the test cells in the vial are located at a distance of 22 cm from the inlet of the collimator and are exposed to neutron radiation for 5, 10, 15, and 20 hours, the neutron dose received by breast cancer cells will be 3, 6, 9, and 12 mGy/h, respectively. C_LIO_LIThe results of cytotoxicity due to neutron irradiation as well as the combined effect of neutron and curcumin (80 M concentration) showed that neutron irradiation with or without curcumin at 5, 10, 15, and 20 hours reduced the survival of tumor cells. C_LIO_LIAccording to the results, the rate of apoptosis due to the neutron effect at irradiation times has increased with increasing time. The results of studying the effect of neutrons and the combination of neutrons and curcumin on the production of nitric oxide, catalase, and GSH also showed that curcumin has an antioxidant effect by reducing the amount of nitric oxide and increasing the production of catalase and glutathione in cells. However, neutrons, alone, lacked this effect. C_LIO_LIthis study showed that the neutron source 241Am-Be with the applied doses was able to destroy the c-o, and c-h bonds of curcumin, resulting in cell death and apoptosis induction in breast cancer cells. It was caused by neutron radiation. C_LIO_LIaccording to the results of the comet assay and caspase-3 experiments, although neutrons induced apoptosis in breast cancer cells, the death rate due to necrosis was much higher than apoptosis. C_LI

biophysics↗