Analysis of Retinol Binding Protein 4 and ABCA4 Gene Variation in Non-Neovascular Age-Related Macular Degeneration

Age-related macular degeneration (AMD) may be associated with ABCA4 variants and is characterized by the accumulation of visual cycle-byproduct lipofuscin. Reducing retinol-binding protein 4 (RBP4), a retinol transporter protein, may reduce lipofuscin production. This study aims to assess the associations between plasma RBP4, the ABCA4 variation, and AMD severity. Sixty-seven participants were grouped into healthy/mild AMD (n = 32) and severe AMD (n = 35) groups. The latter group was older than the former group and had higher levels of RBP4 (36.8 ± 8.3 vs. 30.4 ± 7.0 μg/mL, p = 0.0012). The ten participants with six ABCA4 linked-variants had higher RBP4 than those without (37.8 ± 7.7 vs. 32.4 ± 7.9 μg/mL; p = 0.026), and eight of them had severe AMD. Univariate analyses showed that severe AMD was related to older age (OR, 1.26; 95% CI, 1.13-1.40; p < 0.0001) and to higher RBP4 levels (OR, 1.12; 95% CI, 1.04-1.20; p = 0.003), whereas the linked ABCA4 variants had no associations. After adjustment, however, only age remained significantly associated with severe AMD. This pilot study shows a trend of higher plasma RBP4 levels in severe AMD or the ABCA4-linked variants, and further age-matched studies are warranted.

Therapeutic drug monitoring study on the switch from coformulated 600-mg efavirenz, tenofovir disoproxil fumarate, and emtricitabine to coformulated 400-mg efavirenz, tenofovir disoproxil fumarate, and lamivudine among HIV-positive patients with viral suppression

OBJECTIVES

This study evaluated the efavirenz (EFV) mid-dose plasma concentration (C12), clinical efficacy, and safety after the switch to a single-tablet regimen containing tenofovir disoproxil fumarate (TDF), lamivudine (3TC), and 400-mg EFV in virally suppressed HIV-positive Taiwanese who were receiving co-formulated TDF, emtricitabine (FTC), and 600-mg EFV.

METHODS

In this single-arm, open-label study, HIV-positive adults who had undetectable plasma HIV RNA load (<50 copies/ml) for 6 months or longer while receiving co-formulated TDF, FTC, and 600-mg EFV with EFV C12 of ≥1 mg/L were enrolled. The participants were switched to co-formulated TDF, 3TC, and 400-mg EFV and followed for 24 weeks. The primary endpoint was the proportion of participants with EFV C12 ≥ 1 mg/L at Week 4. The secondary endpoints included virologic response and change of CD4 lymphocyte count up to Week 24. Specific adverse effects associated with EFV were recorded before and after the switch.

RESULTS

From December 2018 to January 2019, 50 participants were enrolled. EFV C12 remained ≥1 mg/L in 48 (96.0%) participants with a median reduction of 38.9% (interquartile range 29.0-44.4) at Week 4 after switch. All participants had undetectable plasma HIV RNA by Week 12, whereas 96.0% of them remained so at Week 24. Significant increases of CD4 lymphocyte count were observed at Weeks 12 and 24. Thirty-three participants (66.0%) reported improvement of pre-existing adverse effects.

CONCLUSION

Switch to coformulated TDF, 3TC, and 400-mg EFV in virally suppressed HIV-positive Taiwanese maintained effective EFV concentration and viral suppression while the adverse effects were reduced.

Zhi-Long-Huo-Xue-Tong-Yu modulates mitochondrial fission through the ROCK1 pathway in mitochondrial dysfunction caused by streptozotocin-induced diabetic kidney injury

Zhi-Long-Huo-Xue-Tong-Yu (ZLHXTY) is a defined mixture of 5 herbs developed by Professor S.J. Yang according to the Buyang Huanwu decoction method, which has been recorded in the Yilingaicuo. This study investigated the renoprotective effects of ZLHXTY on mitochondrial dysfunction induced by diabetic kidney injury in a diabetic rat model. Diabetes was induced by a single intravenous injection of streptozotocin. Rats were daily fed either ZLHXTY or vehicle beginning in the 1st week after injection. Levels of mitofusin 2 (mfn2), dynamin-related protein 1 (Drp1), caspase-9, and rho-associated, coiled-coil-containing protein kinase 1 (ROCK1) were detected using Western blotting. Levels of intracellular calcium and adenosine triphosphate (ATP) were examined using an enzyme-linked immunosorbent assay. An electron microscopic examination of kidney tissue was performed. The levels of mfn2 and ATP in the diabetes and ZLHXTY groups decreased from the 4th week after modeling. The expression levels of Drp1, ROCK1, and caspase-9 increased in the diabetes group but decreased in the ZLHXTY group from the 4th week after modeling. Compared with the diabetes group, ZLHXTY treatment decreased the mesangial expansion index and proteinuria levels, and improved the pathological changes typical of diabetic kidney injury. Furthermore, ZLHXTY treatment inhibited the activation of ROCK1 and expression of Drp1 and caspase-9, but did not affect the expression of mfn2. This study indicates that ZLHXTY treatment could protect kidney tissue from diabetic injury through the ROCK1 pathway response to mitochondrial dysfunction induced by diabetes.