Decreased retinal capillary density as a beneficial response to 24-week high-speed circuit resistant training in healthy older adults.

PURPOSE: To determine the changes in retinal microvascular density after a 24-week high-speed circuit resistance training program (HSCT) in healthy older adults. METHODS: Thirty healthy older adults were recruited and randomly assigned to either a training group (HSCT) or a non-training (CON) group. Fifteen subjects (age 73.3 ± 7.76 yrs) in the HSCT group exercised three times per week on non-consecutive days for 24 weeks. Fifteen subjects in the CON group (age 72.2 ± 6.04 yrs) did not have formal physical training. Both eyes of each subject were imaged using optical coherence tomography angiography (OCTA) at baseline and at the 24-week follow-up. The vessel densities of the retinal vascular network (RVN), superficial vascular plexus (SVP), and deep vascular plexus (DVP) were measured. RESULTS: There were no demographic differences between the study groups. There were significant decreases in the retinal vessel densities of RVN, SVP and DVP in the HSCT group (P < 0.05). However, there were no significant changes in all three vascular measurements in the CON group (P > 0.05), although the changes showed a decreasing trend. The decreased vessel densities were doubled in the HSCT group in comparison to the CON group. However, the differences between groups did not reach a significant level (P > 0.05). CONCLUSIONS: This is the first study to reveal the decreased retinal vessel densities as a possible imaging marker for the beneficial effects of the 24-week HSCT program in older adults.

Impaired Retinal Capillary Function in Patients With Alzheimer Disease.

BACKGROUND: Extensive evidence indicates that vasculopathy, especially the level of microcirculation, contributes to neurodegeneration in Alzheimer disease (AD). However, it is not easy to directly monitor cerebral microcirculation. The retinal microvasculature has been proposed as a surrogate measure to study cerebral vascular changes. Indeed, decreased retinal microvascular network densities were reported in patients with AD. We sought to determine the retinal capillary function (RCF, the efficiency of blood flow transferring in the capillary network) in patients with AD. METHODS: Twenty patients (age 60-84 years, mean ± SD: 72.8 ± 7.7 years) with AD and 14 age-matched cognitively normal controls (CN, age 62-81 years, mean ± SD: 68.6 ± 6.7 years.) were recruited. There were no differences in vascular risk factors, including smoking, hypertension, hyperlipidemia, Type 2 diabetes, and cardiovascular disease, between the groups. One eye of each subject in both groups was imaged. Retinal blood flow (RBF) was measured using a retinal function imager, and retinal capillary density (RCD, expressed as fractal dimension Dbox) was measured using optical coherence tomography angiography. RCF was defined as the ratio of RBF to RCD. RESULTS: RCF was 1.62 ± 0.56 nl/s/Dbox (mean ± SD) in the AD group, which was significantly lower than that (2.56 ± 0.25 nl/s/Dbox, P < 0.01) in the CN group. The change of RCF in the AD group represented 28% lower than in the CN group. RCF was significantly and positively correlated with RBF in the AD group (r = 0.98, P < 0.05) and in the CN group (r = 0.65, P < 0.05). CONCLUSIONS: Our study is the first to demonstrate impaired retinal capillary function in patients with AD. The alteration of RCF was mainly due to decreased retinal blood flow, which is transferred by the capillary network. The RCF may be developed as a biomarker of impaired cerebral microcirculation in patients with AD.

A sensitive LC-MS assay using derivatization with boron trifluoride to quantify curcuminoids in biological samples.

A procedure is described to measure curcumin (C), demethoxycurcumin (DMC), bisdemethoxycurcumin (BDMC), tetrahydrocurcumim (TC) and their glucuronidated metabolites (CG, DMCG, and BDMCG) in plasma, brain, liver and tumor samples. The procedure involves converting the analytes to their boron difluoride derivatives and analyzing them by combined liquid chromatography coupled to an ion trap mass spectrometer operating in the negative ion MSn scan mode. The method has superb limits of detection of 0.01 nM for all curcuminoids and 0.5 nM for TC and the glucuroniated metabolites, and several representative chromatograms of biological samples containing these analytes are provided. In addition, the pharmacokinetic profile of these compounds in one human who daily consumed an over-the-counter curcuminoid product shows the peak and changes in circulating concentrations achieved by this mode of administration.