Alteration of free radical development by ophthalmic viscosurgical devices in phacoemulsification

Avenoso

J of Applied Toxicology

et al. 2007

Oxidative stress, inflammation and apoptosis play a critical role in the onset and progression of cellular damage. It was previously reported that hyaluronan (HA) and chondroitin-4-sulphate (C4S) were able to protect human skin fibroblasts from oxidative stress. This antioxidant activity is due to the chelation of transition metal ions. Nuclear factor kB (NF-kB), complexed with the inhibitory protein IkB alpha, is an ubiquitous response transcription factor involved in inflammatory reactions and acts by inducing cytokine expression, chemokines and cell adhesion molecules. Caspases are specific proteases responsible for the regulation and the execution of apoptotic cell death. The damage caused by free radicals may be amplified greatly by the activation of these factors. The study investigated whether the ability of these glycosaminoglycans (GAGs) to reduce oxidative damage in fibroblast cultures involves NF-kB and caspases modulation. The treatment of fibroblasts with both HA and C4S limited the cell damage induced by FeSO(4) plus ascorbate. An interesting aspect of this treatment was that these GAGs significantly inhibited NF-kB DNA binding, as confirmed by the normalization of IkB alpha protein, and reduced caspase activation at both mRNA and protein level. A possible explanation for these results, since lipid peroxidation intermediates may induce NF-kB and caspase activation, is that HA and C4S indirectly blocked NF-kB DNA binding and apoptosis by inhibiting reactive oxygen species (ROS) production. These data suggest that, during oxidative stress, HA and C4S may reduce cell damage by inhibiting NF-kB and apoptosis activation as well as protecting cells from free radical attack. According to these finding the use of HA and C4S could be positive both as tool to clarify the exact mechanism of GAGs/ROS interaction, and also as drug therapy to reduce oxidative stress during inflammation.

“…• radical (Takahashi et al, 2002(Takahashi et al, , 2006. If so, the antioxidant effect of HA and C4S would have been independent from NF-kB and caspases activation.…”

Section: Discussionmentioning

confidence: 98%

NF‐kB and caspases are involved in the hyaluronan and chondroitin‐4‐sulphate‐exerted antioxidant effect in fibroblast cultures exposed to oxidative stress

Avenoso

J of Applied Toxicology

et al. 2007

Clinical and Experimental Optometry

“…48 A lesser known benefit of ophthalmic viscosurgical devices is their role in inhibiting free-radicals generated during phacoemulsification. 49 Higher viscosity agents are difficult to remove completely at the end of surgery and incomplete removal leads to increased IOP in the early postoperative period.…”

Section: Ophthalmic Visco-surgical Devicesmentioning

confidence: 99%

Advances in cataract surgery

Ashwin

Shah

Wolffsohn

2009

Cataract surgery is a technique described since recorded history, yet it has greatly evolved only in the latter half of the past century. The development of the intraocular lens and phacoemulsification as a technique for cataract removal could be considered as the two most significant strides that have been made in this surgical field. This review takes a comprehensive look at all aspects of cataract surgery, starting from patient selection through the process of consent, anaesthesia, biometry, lens power calculation, refractive targeting, phacoemulsification, choice of intraocular lens and management of complications, such as posterior capsular opacification, as well as future developments. As the most common ophthalmic surgery and with the expanding range of intraocular lens options, optometrists have an important and growing role in managing patients with cataract.

Journal of Cataract and Refractive Surgery

“…[1][2][3][4][5][6] One subject that has been under considerable investigation is hydroxyl radical generation during phacoemulsification and the damage these radicals might cause to endothelial tissue. [7][8][9][10][11][12][13][14][15] Purportedly, hydroxyl radicals can be created at locations where aqueous solutions are energized with sufficient heat or pressure. Because of the high pressures and temperatures that they release on implosion, cavitation bubbles, generated by a phacoemulsification tip oscillating at ultrasonic frequencies, are thought to release enough energy to create hydroxyl radicals.…”

mentioning

confidence: 99%

“…Recent studies have shown that the addition of organic chemicals to the irrigating solution can compete for reaction with the hydroxyl radical during phacoemulsification, thereby reducing the potential for free radical-induced damage to endothelial tissue. 12 Other studies show that new technologies, such as the Ozil Compatible Alcon Infiniti Vision System with the Ozil handpiece, torsional modality, and torsional-specific tips, substantially reduce the formation of hydroxyl radicals 15 without compromising other intraoperative and postoperative benefits. [16][17][18] The effectiveness of these techniques in reducing exposure to hydroxyl radicals has been based on the assumption that all radicals are generated exterior to the tip, within the anterior chamber of the eye and accessible to eye tissue.…”

mentioning

confidence: 99%

Determining the local origin of hydroxyl radical generation during phacoemulsification

Aust¹,

Terry²,

Hebdon³

et al. 2011