Background: In the year 2020 we observe the world adapting to "new normal" due to the COVID-19 pandemic, ways of which include physical distancing, hand hygiene, and wearing a face mask. There is no conclusive evidence about ocular manifestations of the new coronavirus infection, but cases of conjunctivitis, keratitis, and episcleritis have been reported in infected individuals. Objective: Determining if wearing a face mask during COVID-19 pandemic causes a new onset or deterioration of previously existing dry eye disease (DED).Methods: A prospective cohort study included 203 participants, all using surgical facemasks daily due to new regulations during COVID-19 pandemic. Participants completed a survey, containing modified Ocular Surface Disease Index (OSDI) questionnaire. They were divided into groups according to: sex, age, duration of face mask-wear, and existence of prior DED history. Results: Our results indicate that women have a statistically higher OSDI score compared to men (14.4 (IQR = 2.4 -41.7) vs. 5.0 (IQR = 0.0 -24.4); P = .004). Age did not significantly affect OSDI median values. Group that used masks from 3 to 6 hours/ day demonstrated significantly higher OSDI scores compared to <3 hour/day group (15.3 (IQR = 8.3 -47.7) vs. 8.3 (IQR = 0.0 -35.1); P = .001). OSDI score was significantly greater in participants with prior DED history compared to those without it (36.1 (IQR = 14.1 -61.6) vs. 4.2 (IQR = 2.3 -8.3); P <.001). Participants with prior DED exhibited greater worsening of their disturbances during mask wearing period compared to the ones without previous DED (54.8% vs. 17.7%, Chi-Square 28.3 DF1; P <.001), regardless of daily mask wear duration. Conclusion: Our study confirmed the existence of mask-associated dry eye (MADE), most profoundly in females, subjects with a history of prior DED, and if wearing a face mask lasts longer than 3 hours per day. Ophthalmologists should advise their patients of the potential ocular surface health risks related to inadequately fitted facemasks.

Cerebral blood flow (CBF) is uniquely regulated by the anatomical design of the cerebral vasculature as well as through neurovascular coupling. The process of directing the CBF to meet the energy demands of neuronal activity is referred to as neurovascular coupling. Microvasculature in the brain constitutes the critical component of the neurovascular coupling. Mitochondria provide the majority of ATP to meet the high-energy demand of the brain. Impairment of mitochondrial function plays a central role in several age-related diseases such as hypertension, ischemic brain injury, Alzheimer's disease, and Parkinson disease. Interestingly, microvessels and small arteries of the brain have been the focus of the studies implicating the vascular mechanisms in several age-related neurological diseases. However, the role of microvascular mitochondrial dysfunction in age-related diseases remains unexplored. To date, high-throughput assay for measuring mitochondrial respiration in microvessels is lacking. The current study presents a novel method to measure mitochondrial respiratory parameters in freshly isolated microvessels from mouse brain ex vivo using Seahorse XFe24 Analyzer. We validated the method by demonstrating impairments of mitochondrial respiration in cerebral microvessels isolated from old mice compared to the young mice. Thus, application of mitochondrial respiration studies in microvessels will help identify novel vascular mechanisms underlying a variety of age-related neurological diseases.

Little is known about mitochondrial functioning in the cerebral vasculature during insulin resistance (IR). We examined mitochondrial respiration in isolated cerebral arteries of male Zucker obese (ZO) rats and phenotypically normal Zucker lean (ZL) rats using the Seahorse XFe24 analyzer. We investigated mitochondrial morphology in cerebral blood vessels as well as mitochondrial and nonmitochondrial protein expression levels in cerebral arteries and microvessels. We also measured reactive oxygen species (ROS) levels in cerebral microvessels. Under basal conditions, the mitochondrial respiration components (nonmitochondrial respiration, basal respiration, ATP production, proton leak, and spare respiratory capacity) showed similar levels among the ZL and ZO groups with the exception of maximal respiration, which was higher in the ZO group. We examined the role of nitric oxide by measuring mitochondrial respiration following inhibition of nitric oxide synthase with Nω-nitro-l-arginine methyl ester (l-NAME) and mitochondrial activation after administration of diazoxide (DZ). Both ZL and ZO groups showed similar responses to these stimuli with minor variations. l-NAME significantly increased the proton leak, and DZ decreased nonmitochondrial respiration in the ZL group. Other components were not affected. Mitochondrial morphology and distribution within vascular smooth muscle and endothelium as well as mitochondrial protein levels were similar in the arteries and microvessels of both groups. Endothelial nitric oxide synthase (eNOS) and ROS levels were increased in cerebral microvessels of the ZO. Our study suggests that mitochondrial function is not significantly altered in the cerebral vasculature of young ZO rats, but increased ROS production might be due to increased eNOS in the cerebral microcirculation during IR.

The underlying factors promoting increased mitochondrial proteins, mtDNA, and dilation to mitochondrial-specific agents in male rats following tMCAO are not fully elucidated. Our goal was to determine the morphological and functional effects of ischemia/reperfusion (I/R) on mitochondria using electron microscopy, Western blot, mitochondrial oxygen consumption rate (OCR), and Ca sparks activity measurements in middle cerebral arteries (MCAs) from male Sprague Dawley rats (Naïve, tMCAO, Sham). We found a greatly increased OCR in ipsilateral MCAs (IPSI) compared with contralateral (CONTRA), Sham, and Naïve MCAs. Consistent with our earlier findings, the expression of Mitofusin-2 and OPA-1 was significantly decreased in IPSI arteries compared with Sham and Naïve. Mitochondrial morphology was disrupted in vascular smooth muscle, but morphology with normal and perhaps greater numbers of mitochondria were observed in IPSI compared with CONTRA MCAs. Consistently, there were significantly fewer baseline Ca events in IPSI MCAs compared with CONTRA, Sham, and Naïve. Mitochondrial depolarization significantly increased Ca sparks activity in the IPSI, Sham, Naïve, but not in the CONTRA group. Our data indicate that altered mitochondrial structure and function occur in MCAs exposed to I/R and that these changes impact not only OCR but Ca sparks activity in both IPSI and CONTRA MCAs.