Ultraviolet light exposure and its penetrance through the eye in a porcine model

Thermo-sensitive Poloxamer based antibacterial anti-inflammatory and photothermal conductive multifunctional hydrogel as injectable, in situ curable and adjustable intraocular lens

Cataract patients look forwards to fewer postoperative complications and higher vision quality after surgery. However, the current intraocular lens (IOL) implanted after cataract surgery neither can adjust focal length in response to ciliary muscle contraction as natural lens nor have the ability to prevent postoperative complications. Herein, a thermosensitve Poloxamer based hybrid hydrogel with antibacterial anti-inflammatory and photothermal functional elements doping was designed and used as injectable, in situ curable, and adjustable IOL (FHTAB IOL). The FHTAB IOL was composed of thermosensitve triblock-polymer F127DA and a small amount of HAMA, combined with BP NS, TA, and Ag NPs. FHTAB IOL can be injected into the empty lens capsule after cataract surgery via an injectable thermos-gel under NIR illumination and then be rapidly cured to form a full-size IOL under short-time blue light irradiation. The designed injectable FHTAB IOL possesses high transparency and transmittance, with a refractive index similar to the natural lens and adjustable properties. It was stabilized as a refractive medium without any leakage in the eye. In addition, the TA and Ag NPs loaded in the FHTAB IOL displayed significant antibacterial and anti-inflammatory effects in vitro and vivo. This study presents a potentially effective new strategy for the development of multifunctional adjustable IOLs.

Dynamic and Energetic Aspects of Carotenoids In-and-Around Model Lipid Membranes Revealed in Molecular Modelling

In contrast to plants, humans are unable to synthesise carotenoids and have to obtain them from diet. Carotenoids fulfil several crucial biological functions in the organism; however, due to poor solubility in water, their bioavailability from plant-based food is low. The processes of carotenoid absorption and availability in the human body have been intensively studied. The recent experimental findings concerning these processes are briefly presented in the introductory part of this review, together with a summary of such topics as carotenoid carriers, body transport and tissue delivery, to finally report on molecular-level studies of carotenoid binding by membrane receptors. The main message of the review is contained in the section describing computational investigations of carotenoid intercalation and dynamic behaviour in lipid bilayers. The relevance of these computational studies lies in showing the direct link between the microscopic behaviour of molecules and the characteristics of their macroscopic ensembles. Furthermore, studying the interactions between carotenoids and lipid bilayers, and certainly proteins, on the molecular- and atomic-level using computational methods facilitates the interpretation and explanation of their macroscopic properties and, hopefully, helps to better understand the biological functions of carotenoids.

Design and Biocompatibility of a Novel, Flexible Artificial Cornea

Purpose

We sought to introduce the materials, design, and biocompatibility of a flexible and suturable artificial corneal device.

Methods

Single-piece, fully synthetic, optic-skirt design devices were made from compact perfluoroalkoxy alkane. The skirt and the optic wall surfaces were lined with a porous tissue ingrowth material using expanded polytetrafluoroethylene. Full-thickness macroapertures around the skirt perimeter were placed to facilitate nutrition of the recipient cornea. Material properties including the skirt's modulus of elasticity and bending stiffness, optic light transmission, wetting behavior, topical drug penetrance, and degradation profile were evaluated.

Results

The final prototype suitable for human use has a transparent optic with a diameter of 4.60 mm anteriorly, 4.28 mm posteriorly, and a skirt outer diameter of 6.8 mm. The biomechanical and optical properties of the device closely align with the native human cornea with an average normalized device skirt-bending stiffness of 4.7 kPa·mm4 and light transmission in the visible spectrum ranging between 92% and 96%. No optical damage was seen in the 36 devices tested in fouling experiments. No significant difference was observed in topical drug penetrance into the anterior chamber of the device implanted eye compared with the naïve rabbit eye.

Conclusions

The flexibility and biocompatibility of our artificial cornea device may offer enhanced tissue integration and decreased inflammation, leading to improved retention compared with rigid keratoprosthesis designs.

Translational Relevance

We have developed a fully synthetic, flexible, suturable, optic-skirt design prototype artificial cornea that is ready to be tested in early human feasibility studies.

Evaluation of corneal backward light scattering in type 2 diabetes mellitus

AIM

To compare the corneal backward light scattering values in type 2 diabetes mellitus (DM) patients with those of age and sex-matched healthy controls.

METHODS

The study included 30 patients (30 eyes) with type 2 DM and 30 control subjects (30 eyes). Duration of diabetes, most recent hemoglobin A1c levels, along with the status of diabetic retinopathy, and existing medical treatment of all subjects were recorded. All subjects underwent a complete ophthalmologic examination. In addition, backward light scattering (densitometry) was measured to assess changes in corneal transparency using tomography (Pentacam HR).

RESULTS

The type 2 DM patients included 12 males and 18 females and control subjects included 16 males and 14 females. The age was 50.40±7.80y (range: 40-68y) of the diabetic group and 49.30±9.50y (rang: 40-73y) of control group. The diabetic group demonstrated significantly higher mean densitometry values of the anterior (6-10 mm) zone (P=0.047), the total anterior layer (P=0.036) and the total cornea (P=0.043) than control group. The corneal densitometry of the diabetic eyes demonstrated no significant correlation with hemoglobin A1c levels and DM duration.

CONCLUSION

Diabetic group has higher densitometry in anterior corneal (6-10 mm) zone, total anterior cornea, and total cornea and with no correlation with hemoglobin A1c levels and DM duration.

Toxic External Exposure Leading to Ocular Surface Injury

The surface of the eye is directly exposed to the external environment, protected only by a thin tear film, and may therefore be damaged by contact with ambient particulate matter, liquids, aerosols, or vapors. In the workplace or home, the eye is subject to accidental or incidental exposure to cleaning products and pesticides. Organic matter may enter the eye and cause infection. Ocular surface damage can trigger a range of symptoms such as itch, discharge, hyperemia, photophobia, blurred vision, and foreign body sensation. Toxin exposure can be assessed clinically in multiple ways, including via measurement of tear production, slit-lamp examination, corneal staining, and conjunctival staining. At the cellular level, environmental toxins can cause oxidative damage, apoptosis of corneal and conjunctival cells, cell senescence, and impaired motility. Outcomes range from transient and reversible with complete healing to severe and sight-compromising structural changes. Classically, evaluation of tolerance and safety was carried out using live animal testing; however, new in vitro and computer-based, in silico modes are superseding the gold standard Draize test. This review examines how environmental features such as pollutants, temperature, and seasonality affect the ocular surface. Chemical burns to the eye are considered, and approaches to protect the ocular surface are detailed.

Crosstalk between the endocannabinoid and mid-brain dopaminergic systems: Implication in dopamine dysregulation

Endocannabinoids (eCBs) and the expanded endocannabinoid system (ECS)-"endocannabinoidome", consists of the endogenous ligands, eCBs, their canonical and non-canonical receptor subtypes, and their synthesizing and metabolizing enzymes. This system modulates a wide range of body functions and acts as a retrograde signaling system within the central nervous system (CNS) by inhibition of classical transmitters, and plays a vital modulatory function on dopamine, a major neurotransmitter in the CNS. Dopamine is involved in different behavioral processes and contributes to different brain disorders-including Parkinson's disease, schizophrenia, and drug addiction. After synthesis in the neuronal cytosol, dopamine is packaged into synaptic vesicles until released by extracellular signals. Calcium dependent neuronal activation results in the vesicular release of dopamine and interacts with different neurotransmitter systems. The ECS, among others, is involved in the regulation of dopamine release and the interaction occurs either through direct or indirect mechanisms. The cross-talk between the ECS and the dopaminergic system has important influence in various dopamine-related neurobiological and pathologic conditions and investigating this interaction might help identify therapeutic targets and options in disorders of the CNS associated with dopamine dysregulation.