Pentoxifylline Enhances Antioxidative Capability and Promotes Mitochondrial Biogenesis in D-Galactose-Induced Aging Mice by Increasing Nrf2 and PGC-1α through the cAMP-CREB Pathway

Phosphodiesterase inhibitor ameliorates senescent changes of renal interstitial pericytes in aging kidney

Pericytes are mesenchymal cells that surround endothelial cells, playing a crucial role in angiogenesis and vessel maturation. Additionally, they are associated with interstitial fibrosis as a major contributor to renal myofibroblasts. In this study, we aim to investigate whether the phosphodiesterase inhibitor, pentoxifylline (PTX), can ameliorate aging-related functional and histological deterioration in the kidney. We subjected aging C57BL/6 mice, dividing into young, aging, and PTX-treated aging groups. Renal function, albuminuria, and histological changes were assessed. Interstitial pericytes were assessed by immunohistochemistry analysis. We examined changes in pericytes in elderly patients using human kidney tissue obtained from healthy kidney donors for kidney transplantation. In vitro experiments with human pericytes and endothelial cells were performed. Aging mice exhibited declined renal function, increased albuminuria, and aging-related histological changes including mesangial expansion and tubulointerstitial fibrosis. Notably, number of pericytes declined in aging kidneys, and myofibroblasts increased. PTX treatment ameliorated albuminuria, histological alterations, and microvascular rarefaction, as well as modulated angiopoietin expression. In vitro experiments showed PTX reduced cellular senescence and inflammation. Human kidney analysis confirmed similar pericyte changes in aging kidneys. The phosphodiesterase inhibitor, PTX preserved microvascular density and improved renal interstitial fibrosis and inflammation in aging mice kidneys. These protective effects were suggested to be associated with the amelioration of pericytes reduction and the transition to myofibroblasts. Additionally, the upregulation of angiopoietin-1 expression may exert potential impacts. To the best of our knowledge, this is the first report on the changes in renal interstitial pericytes in aging human kidneys.

Rutaecarpine Mitigates Cognitive Impairment by Balancing Mitochondrial Function Through Activation of the AMPK/PGC1α Pathway

Mitochondrial dysfunction plays a fundamental role in the pathogenesis of cognitive deficit. Rutaecarpine (Rut) is a natural alkaloid with anti-inflammatory and antioxidant properties. This study explored whether Rut treatment could enhance cognitive function by improving mitochondrial function and examined the potential mechanisms underlying this ameliorative effect. We used the Morris water maze and Y-maze tests to evaluate the behavioral effects of Rut in a mouse model of cognitive impairment induced by subcutaneous injection of D-galactose (D-gal). Furthermore, we assessed the effects of Rut on mitochondrial function using cell viability assays, flow cytometry, western blotting, biochemical analysis, and immunochemical techniques in vivo and in vitro. The results indicated Rut treatment attenuated cognitive deficits and mitochondrial dysfunction in the mouse model. Similarly, it maintained the balance of mitochondrial dynamics in neurocytes and reduced oxidative stress and mitochondrial apoptosis in the HT22 cell model. Moreover, we found that these protective effects were dependent on the activation of the AMP-activated protein kinase/proliferator-activated receptor gamma coactivator 1-alpha (AMPK/PGC1α) signaling pathway. Our data indicate that Rut treatment are sensitive to reversal cognitive deficits and mitochondrial dysfunction induced by D-gal; this suggests that Rut is a promising mitochondria-targeted therapeutic agent for treating cognitive impairment.

Use of Steaming Process to Improve Biochemical Activity of Polygonatum sibiricum Polysaccharides against D-Galactose-Induced Memory Impairment in Mice

Polysaccharide from Polygonatum sibiricum (PSP) possesses antioxidant, antiaging, and neuroprotective activities. However, whether and how the steaming process influences the biological activities of PSP, especially against aging-related memory impairment, is not yet known. In this study, Polygonatum sibiricum rhizome was subjected to a “nine steaming and nine drying” process, then PSPs with different steaming times were abstracted. Thereafter, the physicochemical properties were qualified; the antioxidant activities of PSPs were evaluated in a D-gal-induced HT-22 cell model, and the effects of PSPs (PSP0, PSP5 and PSP9) on memory was evaluated using D-gal-injured mice. Our results showed that while the steamed PSPs had a low pH value and a large negative charge, they shared similar main chains and substituents. Cellular experiments showed that the antioxidant activity of steamed PSPs increased. PSP0, PSP5, and PSP9 could significantly ameliorate the memory impairment of D-gal-injured mice, with PSP5 showing the optimal effect. Meanwhile, PSP5 demonstrated the best effect in terms of preventing cell death and synaptic injury in D-gal-injured mice. Additionally, the steamed PSPs increased anti-oxidative stress-related protein expression and decreased inflammation-related protein expression in D-gal-injured mice. Collectively, the steaming process improves the effects of PSPs against D-gal-induced memory impairment in mice, likely by increasing the antioxidant activity of PSPs.

Development and in vivo Evaluation of Hydroxy-α-Sanshool Intranasal Liposomes as a Potential Remedial Treatment for Alzheimer’s Disease

Purpose

Hydroxy-α-sanshool (HAS) improves cognitive dysfunction, but its structural instability has limited its clinical application. The present study was conducted to investigate the optimal formulation of hydroxy-α-sanshool liposomes (HAS-LPs) and its effect on ameliorating learning and memory disorders in an Alzheimer’s disease (AD) model.

Methods

In this study, HAS was prepared as HAS-LP using a thin film dispersion method. After selecting the optimal preparation conditions, HAS-LP was characterized using transmission electron microscopy (TEM) and by measuring the zeta potential, particle size, and in vitro drug release. Next, evaluated the effect of HAS-LP on the rat nasal mucosa and then applied it to AD mice. By performing behaviour experiments, pathological test and related pharmacokinetic parameters, we explored its effect on attenuating learning and memory impairment in mice.

Results

When the mass ratio of HAS:cholesterol:soybean lecithin was 1:4:16 and 15 mL of ultrapure water were added, the highest encapsulation efficiency and drug loading were obtained. HAS-LP had a particle size of 181.77 nm, a polydispersity index of 0.207 and a zeta potential of −53.8 mV, and it remained stable at 25 °C for 1 week and 4 °C for 8 weeks. Moreover, HAS-LP exhibited slow drug release and was highly consistent with the Higuchi release model. HAS-LP was not significantly toxic to the nasal mucosa and effectively alleviated D-galactose-induced learning memory deficits and protected mouse hippocampal neuronal cells. HAS-LP was highly enriched in plasma and brain tissue after administration via the nasal route and obtained some ability to target the brain.

Conclusion

HAS encapsulated in soybean lecithin and cholesterol was successfully developed, suggesting that treatment with the nanoparticles might reverse some AD symptoms. Therefore, these nanoparticles might be used as promising new candidates for the delivery of HAS to treat AD.