Fisetin provides antidepressant effects by activating the tropomyosin receptor kinase B signal pathway in mice.

Depression has been associated with a low-grade chronic inflammatory state, suggesting a potential therapeutic role for anti-inflammatory agents. Fisetin is a naturally occurring flavonoid in strawberries that has anti-inflammatory activities, but whether fisetin has antidepressant effects is unknown. In this study, we exposed mice to spatial restraint for 2 weeks with or without treatment with fisetin. Immobility time in the forced swimming and tail suspension test after this restraint increased in the untreated group, but this increase did not occur in the fisetin group. We administered fisetin to Abelson helper integration site-1 (Ahi1) knockout mice, which have depressive phenotypes. We found that fisetin attenuated the depressive phenotype of these Ahi1 knockout mice. We further investigated the potential mechanism of fisetin's antidepressant effects. Because TrkB is a critical signaling pathway in the mechanisms of depression, we examined whether phosphorylated TrkB was involved in the antidepressant effects of fisetin. We found that fisetin increased phosphorylated TrkB level without altering total TrkB; this increase was attenuated by K252a, a specific TrkB inhibitor. Taken together, our results demonstrated that fisetin may have therapeutic potential for treating depression and that this antidepressant effect may be mediated by the activation of the TrkB signaling pathway.

Exogenous Adipokine Peptide Resistin Protects Against Focal Cerebral Ischemia/Reperfusion Injury in Mice.

Previous studies have demonstrated that plasma resistin levels were increased in patients with acute ischemic stroke. However, the role of resistin after ischemic brain injury is still unclear. In this study, we investigated the protective effects of resistin on cerebral ischemia/reperfusion injury in a middle cerebral artery occlusion mouse model. We found that resistin (i.c.v.) significantly reduced infarct volume and improved neurological deficits after 45 min of ischemia and 24 h of reperfusion. Furthermore, our data demonstrate that intraperitoneal administration of resistin (10 µg/kg body weight) also had protective effects on infarct volume, indicating the crossing of resistin through the impaired BBB after ischemia injury. Resistin treatment reduced cleaved protein level of Poly(ADP-ribose)polymerase-1 (PARP-1), a marker of cellular apoptosis, showing the anti-apoptotic activity of resistin. Resistin increased the level of phosphorylated Akt after ischemic brain injury. The neuroprotective effect of resistin was partially reversed by a PI3K inhibitor wortmannin, demonstrating that the PI3K/Akt signal pathway is involved in the anti-apoptotic mechanisms of resistin. Finally, we found that resistin treatment improved neurological function recovery at 14 days after treatment, including balance ability and muscle strength. Given these findings, resistin may have therapeutic potential for the treatment of stroke.

Increased oligodendrogenesis by humanin promotes axonal remyelination and neurological recovery in hypoxic/ischemic brains.

Oligodendrocytes are the predominant cell type in white matter and are highly vulnerable to ischemic injury. The role of oligodendrocyte dysfunction in ischemic brain injury is unknown. In this study, we used a 24-amino acid peptide S14G-Humanin (HNG) to examine oligodendrogenesis and neurological functional recovery in a hypoxic/ischemic (H/I) neonatal model. Intraperitoneal HNG pre-treatment decreased infarct volume following H/I injury. Delayed HNG treatment 24 h after H/I injury did not reduce infarct volume but did decrease neurological deficits and brain atrophy. Delayed HNG treatment did not attenuate axonal demyelination at 48 h after H/I injury. However, at 14 d after H/I injury, delayed HNG treatment increased axonal remyelination, the thickness of corpus callosum at the midline, the number of Olig2(+) /BrdU(+) cells, and levels of brain-derived neurotrophic factor (BDNF). Our results suggest that targeting oligodendrogenesis via delayed HNG treatment may represent a promising approach for the treatment of stroke.

Diagnostic thresholds in osteoporosis: how are they used in clinical trials?

Clinical trials are used to determine the efficacy and safety of a medication prior to approval for commercial use and to influence the prescribing habits of clinicians. The lack of uniformity in the diagnostic thresholds used in clinical trials on osteoporosis makes it difficult to compare the results of these trials. The use of placebo, different anatomical sites, T-score cutoff points, and risk factors precludes any meaningful comparison being made between the outcomes of clinical trials. Finally, the lack of uniform reporting format makes it difficult to retrieve important information to compare one medication to another. Because the diagnostic thresholds used affect the outcomes of these trials, health care providers need to be aware of these criteria to determine whether the results of a particular clinical trial can be applied to a particular patient.

Fracture risk assessment in postmenopausal women.

Patients with osteoporosis have an increased risk of sustaining fractures because of the low bone mineral density (BMD) and altered bone micro-architecture which are characteristic features of the disease. Although a good correlation exists between BMD and fracture risks, many other factors influence this relationship. While there is consensus that patients with osteoporosis should be investigated and treated, the issue is much less clear for patients with osteopenia. Because osteopenia is so prevalent, it would be unrealistic to treat all patients with this condition. Therefore, there is a need to identify those patients who are at risk of sustaining a fracture and would benefit most from the available therapy. Providing treatment to the appropriate risk group would not only reduce the number of fractures, but could also reduce the adverse effects associated with treatment, as treating patients earlier could shorten the treatment time. The availability of tools to select patients at risk of fracture should change the impact of the disease.