Roles of sex hormones in mediating the causal effect of vitamin D on osteoporosis: A two-step Mendelian randomization study.

Background: Although 25-hydroxyvitamin D [25(OH)D] is a risk factor for osteoporosis, it is not clear whether sex hormones mediate this casual association. We aimed to explore how sex hormones affect the association between 25(OH)D and osteoporosis to provide meaningful insights on the underlying mechanisms from a genetic perspective. Methods: Genetic variations in 25(OH)D, total testosterone (TT), androstenedione (A4), estradiol (E2), and testosterone/17ß-estradiol (T/E2) were determined through summary statistics. Taking osteoporosis as the outcome (FinnGen biobank, 332,020 samples), we conducted a Mendelian randomization (MR) analysis to establish the association between 25(OH)D and these sex hormones. The two-step MR analysis quantified the mediatory effects of sex hormones on osteoporosis. The results were further verified by pleiotropy and heterogeneity analyses. Results: MR results showed that 25(OH)D (OR= 1.27, p = 0.04) and TT (OR= 1.25, p = 0.04) had a causal effect on osteoporosis. No significant associations were observed between the other sex hormones (A4, E2, and T/E2) and osteoporosis (p>0.05). Sensitivity analysis (p>0.05) confirmed the robustness of the MR results. The two-step MR analysis provided evidence that the mediatory effect of TT was 0.014 (the percentage of TT mediation was 5.91%). Moreover, the direct effect of 25(OH)D on osteoporosis was 0.221. A4, E2, and T/E2 were not considered as potential mediators of the role of 25(OH)D as a risk factor for OP. Conclusion: This study, through MR analysis, showed that TT mediates the causal effect of 25(OH)D on osteoporosis. Interventions targeting TT, therefore, have the potential to substantially reduce the burden of osteoporosis attributable to high 25(OH)D.

[Effect of moxibustion with deqi on Aß-receptor mediated transport and enzymatic degradation in hippocampus in rats with Alzheimer's disease].

OBJECTIVE: To observe the clinical effect of moxibustion with deqi on Alzheimer's disease (AD) rats, and evaluate its effect on ß-amyloid (Aß) transport and enzymatic degradation proteins, to explore its molecular mechanism for improving cognitive function. METHODS: Sixty SPF-grade male SD rats were randomly divided into a blank group (8 rats), a sham-operation group (8 rats) and a model establishment group (44 rats). The rats in the model establishment group were injected with Aß1-42 at bilateral ventricles to establish AD model. Among the 38 rats with successful model establishment, 8 rats were randomly selected as the model group, and the remaining rats were treated with mild moxibustion at "Dazhui" (GV 14), once a day, 40 min each time, for 28 days. According to whether deqi appeared and the occurrence time of deqi, the rats were divided into a deqi group (12 rats), a delayed deqi group (10 rats) and a non-deqi group (8 rats). After the intervention, the Morris water maze test was applied to evaluate the cognitive function; the HE staining was applied to observe the brain morphology; the Western blot method was applied to measure the protein expression of Aß and its receptor mediated transport [low-density lipoprotein receptor-related protein (LRP) 1, receptor for advanced glycation end products (RAGE), apolipoprotein E (ApoE)] and enzymatic degradation [neprilysin (NEP), insulin degrading enzyme (IDE), endothelin converting enzyme (ECE)-1 and angiotensin converting enzyme (ACE) 2]. RESULTS: Compared with the sham-operation group, in the model group, the escape latency was prolonged (P<0.01), and the times of platform crossing and the ratio of platform quadrant to total time were reduced (P<0.01); the brain tissue was seriously damaged; the expression of hippocampal Aß and RAGE was increased (P<0.01), and the expression of hippocampal LRP1, ApoE, NEP, IDE, ECE-1 and ACE2 was decreased (P<0.01). Compared with the model group, the escape latency was shortened in the deqi group (P<0.05, P<0.01), and the escape latency in the delayed deqi group and the non-deqi group was shortened from Day 2 to Day 5 (P<0.05, P<0.01), and the times of platform crossing and the ratio of platform quadrant to total time were increased in the deqi group and the delayed deqi group (P<0.01, P<0.05); the brain damage in each moxibustion group was reduced, which was smallest in the deqi group, followed by the delayed deqi group and the non-deqi group; the expression of Aß and RAGE was decreased (P<0.01, P<0.05) and the expression of LRP1 and IDE was increased in each moxibustion group (P<0.01, P<0.05); the expression of ApoE was increased in the deqi group and the delayed deqi group (P<0.01, P<0.05); the expression of NEP was increased in deqi group (P<0.05), and the expression of ECE-1 and ACE2 was increased in the deqi group and the delayed deqi group (P<0.05). Compared with the delayed deqi group and the non-deqi group, the escape latency in the deqi group was shortened from Day 3 to Day 5 (P<0.05), and the times of platform crossing and the ratio of platform quadrant to total time were increased (P<0.05, P<0.01). Compared with the non-deqi group, the expression of Aß was reduced (P<0.05), the expression of LRP1 and ApoE was increased in the deqi group (P<0.05). The expression of NEP in the deqi group was higher than that in the delayed deqi group and the non-deqi group (P<0.05). CONCLUSION: Compared with non-deqi, moxibustion with deqi could promote Aß transport and degradation, thereby reducing Aß level in the brain and improving cognitive function for AD rats.

[Development and initial evaluation of deqi sensation scale of heat-sensitive moxibustion].

Based on heat-sensitive moxibustion (HSM) theory, a widely applicable scale was developed to reflect the deqi (arrival of qi) sensation of HSM. By documentary method and interviewing method, the items of describing deqi sensation of HSM were collected to establish the pool of candidate items. With expert questionnaire, patient questionnaire and core expert discussion, the items were screened and quantified by method of subjective evaluation to develop the initial draft of the scale. A total of 121 patients were pre-surveyed with the initial draft, and the structural validity of the scale was examined by exploratory factor analysis (principal component) and its internal consistency was assessed by Cronbach's coefficient. As a result, the items in the scale was reduced from 36 to 9; 110 effective questionnaires were reclaimed for statistical analysis. Finally, the scale (Version 1.0) contained 9 items and 4 dimensions, of which, 3 items highlighted the comfort emotional experience, 3 items highlighted autonomic response, 2 items highlighted heat sensation, and 1 item highlighted non-heat sensation. In conclusion, the deqi sensation scale of HSM containes 9 items, which has fair content and structure validity. It is in line with the current clinical understanding of deqi sensation of HSM and has strong clinical operability and wide adaptability.

The Characterization of Deqi during Moxibustion in Stroke Rats.

The efficacy of acupuncture and moxibustion is closely related to Deqi phenomenons, which are some subjective feelings. However, no one has reported the objective characterization of Deqi. Our preliminary research has found a phenomenon of tail temperature increasing (TTI) obviously in some stroke rats by suspended moxibustion at the acupoint dà zhui (DU 14), which is similar to one characterization of Deqi during moxibustion that moxibustion heat is transferred from the original moxibustion acupoint to the other areas of the body. We wonder whether TTI is the objective indicator of Deqi characterization in animals. The present study showed that the stroke rat's recovery was also associated with TTI phenomenon. This suggests that TTI phenomenon is one objective characterization of the Deqi in stroke rats. Application of the TTI phenomenon contributes to explore the physiological mechanism of Deqi.

Efficacy of suspended moxibustion in stroke rats is associated with a change in tail temperature.

Suspended moxibustion-produced heat can transfer from the acupoint to other sites of the body. The suspended moxibustion should be terminated when clinical propagated sensation disappears, because this implies that the quantity of moxibustion is sufficient. We wanted to investigate if this phenomenon also occurs in experimental animals. In the present study, a rat model of stroke was established and treated with suspended moxibustion at Dazhui (DU14) for 60 minutes. Results showed that the increase in tail temperature began at 15 minutes after suspended moxibustion and decreased gradually at 40 minutes. In addition, neurological function was significantly improved in stroke rats with tail temperature increase following suspended moxibustion, and this effect was associated with significantly reduced tumor necrosis factor α and interleukin 1ß mRNA. However, there was no significant difference between 40- and 60-minute suspended moxibustion. The findings indicate that elevated tail temperature began to decrease at 40 minutes after suspended moxibustion, and further suspended moxibustion was not useful in the recovery of stroke rats.

Infrared thermography fails to visualize stimulation-induced meridian-like structures: comment by Rixin Chen and Zhimai Lv and reply from Gerhard Litscher.

A comment on G. Litscher: Infrared thermography fails to visualize stimulation-induced meridian-like structures. Biomed. Eng. OnLine 2005, 4:38 (15 June 2005), with a response by the author.

Stroke treatment in rats with tail temperature increase by 40-min moxibustion.

The distant heat induced by suspended moxibustion (SM) for 40 min is confirmed to have a favorable effect in treating diseases such as ischemic brain injury in the clinical setting, but its precise mechanism remains to be explained. Since a similar reaction to the phenomenon of distant heat is found in some transient middle cerebral artery occlusion (tMCAO) rats treated by a 40-min SM session with tail temperature increase (TTI), we hereby study its mechanism by comparing the neuroprotective effect of 40 min's SM with TTI to those without. The experimental results show that 40 min's SM with TTI can significantly reduce the infarct volume and neurological deficit score in tMCAO rats. Western blot demonstrates that a reduction in the levels of cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS) expression in tMCAO rats with TTI is more striking than that of the rats without TTI. The expression of caspase-3 protein is inhibited in tMCAO rats with TTI. The results suggest that the efficacy of SM for 40 min with TTI is higher than that without. Although neuroprotective effects present in tMCAO rats with and without TTI, those with TTI revealed a higher level of anti-inflammation effect and exhibited an anti-apoptosis effect.

Altered expression of Abeta metabolism-associated molecules from D-galactose/AlCl(3) induced mouse brain.

Cerebral deposition of amyloid-beta peptide (Abeta) is a critical feature of Alzheimer's disease (AD). Either aluminium trichloride (Al) or D-galactose (D-gal) induces Abeta overproduction in rat or mouse brain and has been used to produce models of aging and AD. Here it is shown that mice treated with Al plus D-gal represent a good model of AD with altered expression of Abeta metabolism-associated molecules. The work shows that Al/D-gal causes memory impairment and high Abeta levels in the cortex (Co) and hippocampus (Hi). Then, we found that beta-site APP cleavage enzyme 1 (BACE1) was increased in mouse Co and Hi. Al or Al plus D-gal suppressed mRNA of the low-density lipoprotein receptor-related protein 1(LRP1). D-gal also decreased the LRP expression in Hi, but not in Co. However, Al/D-gal did not affect the receptor for advanced glycation end products (RAGE) expression in mouse brains. Furthermore, Al/D-gal reduced the expression of neprilysin (NEP), but not the insulin degrading enzyme (IDE). This study indicates that Al/D-gal affects the expression of Abeta metabolism-associated molecules that are responsible for Abeta deposition during AD, suggesting that this mouse model can be a useful model for studying the mechanisms and biomarkers of AD and for drug screening.