Perioperative Management of Antiplatelet Therapy in Ophthalmic Surgery

Many patients undergoing ophthalmic surgery are elderly with comorbidities requiring antiplatelet therapy to prevent thromboembolic or atherothrombotic events. The use of antiplatelet therapy has expanded over the years, predisposing these patients to hemorrhagic complications perioperatively. The risk of hemorrhagic complications must be weighed against the risk of thromboembolic events with cessation of antiplatelet therapy. The decision to continue or interrupt antiplatelet therapy in the setting of ophthalmic surgery is based upon various factors, including the type of surgery and each patient’s comorbidities. This review examines the risks of thrombotic complications versus hemorrhagic complications in different types of ophthalmic surgeries with the use of antiplatelet medications and provides evidence-based recommendations regarding perioperative management of antiplatelet therapy

Proliferative Vitreoretinopathy: A Review

Proliferative vitreoretinopathy (PVR) is the most common cause for failure of rhegmatogenous retinal detachment repair and is characterized by the growth and contraction of cellular membranes within the vitreous cavity and on both sides of the retinal surface as well as intraretinal fibrosis. Currently, PVR is thought to be an abnormal wound healing response that is primarily driven by inflammatory, retinal, and RPE cells. At this time, surgery is the only management option for PVR as there is no proven pharmacologic agent for the treatment or prevention of PVR. Laboratory research to better understand PVR pathophysiology and clinical trials of various agents to prevent PVR formation are ongoing.

Cancer Treatment-Induced Bone Loss in Women With Breast Cancer and Men With Prostate Cancer

Cancer and cancer therapies can have a negative impact on bone health. Because cancer is a common diagnosis, survivorship concerns for osteoporosis and fragility fractures are an important component of care. This review addresses management of bone health in nonmetastatic cancer survivorship with a focus on breast cancer and prostate cancer.

Unusual cause of severe diabetic ketoacidosis precipitated by Streptococcus bovis/equinus (SBSEC) bacteremia: Case report and review of literature

Diabetic ketoacidosis is a feared complication in patients with diabetes mellitus and poses high risk of mortality and morbidity unless treated in timely manner. Infection is one of the most common precipitating factors for the development of diabetic ketoacidosis. Bacteremia with Group A and Group B beta hemolytic streptococcal strains are well known, however nonenterococcal Group D strains such as the Streptococcus bovis/Streptococcus equinus complex (SBSEC) still remains an understudied entity. Here we present a case of a 35-year-old Type I diabetic female presenting with severe diabetic ketoacidosis with overlapping features of hyperosmolar hyperglycemia, precipitated by Streptococcus alactolyticus bacteremia, successfully treated with four-week course of parenteral ceftriaxone. This case report emphasizes the potential importance of SBSEC as an emerging pathologic strain and culprit for triggering diabetic ketoacidosis which requires prompt diagnosis and targeted therapy.

Biomechanical Responses of Lamina Cribrosa to Intraocular Pressure Change Assessed by Optical Coherence Tomography in Glaucoma Eyes

Purpose

The purpose of this study was to measure change in anterior lamina cribrosa depth (ALD) globally and regionally in glaucoma eyes at different intraocular pressures (IOP).

Methods

Twenty-seven glaucoma patients were imaged before and after IOP-lowering procedures using optical coherence tomography. The anterior lamina was marked in approximately 25 locations in each of six radial scans to obtain global and regional estimates of ALD. ALD and its change with IOP were compared with optic disc damage, nerve fiber layer thickness, and visual field loss.

Results

Variables associated with deeper baseline ALD included larger cup/disc ratio, thinner rim area, larger cup volume, thinner central corneal thickness, and male sex (all P ≤ 0.02). When IOP was lowered, ALD position became more anterior, more posterior, or was unchanged. The mean ALD change after lowering was 27 ± 142 μm (P = 0.3). The mean absolute value of ALD change was 112 ± 90 μm (P = 0.002). Change in ALD was greater in eyes with lower IOP in paired comparisons (P = 0.006) but was not associated with the magnitude of IOP lowering between imaging sessions (P = 0.94). Eyes with no significant change in ALD tended to have more visual field loss than those with significant anterior ALD displacement (P = 0.07). Areas within each optic nerve head that corresponded to zones with thicker nerve fiber layer had greater ALD positional change (P = 0.0007).

Conclusions

The lamina can move either anteriorly or posteriorly with IOP decrease, with greater displacement at lower IOP. Glaucoma eyes and regions within glaucoma eyes associated with greater glaucoma damage exhibited smaller responses.

Downregulation of beta-microglobulin to diminish T-lymphocyte lysis of non-syngeneic cell sources of engineered heart tissue constructs

The presence of non-autologous major histocompatibility complex class I (MHC-I) molecules on the surface of the grafted cells is one of the main reasons for their rejection in non-syngeneic hosts. We present a straightforward strategy to decrease the presence of MHC-I by shRNA inhibition of beta-2-microglobulin (B2M), a conservative light chain of MHC-I, on the surface of two main cell types that are used to engineer heart tissue constructs. Engineered heart tissue constructs can be generated by combining mouse WT19 fibroblasts and mouse embryonic stem cell-derived cardiac myocytes (mESC-CM). WT19 fibroblasts were stably transduced with an anti-B2M shRNA, which yielded a cell line with dramatically reduced B2M expression levels (16 ± 11% of mock treated control cell line). Interferon gamma treatment increased the levels of B2M expression by >3-fold in both control and transduced fibroblasts; yet, B2M expression levels still remained very low in the transduced cells. When compared with their unmodified counterparts, transduced fibroblasts caused 5.7-fold lesser activation of cognate T-cells. B2M depletion in mESC-CM was achieved by 72 h transduction with anti-B2M shRNA lentiviral particles. Transduced mESC-CM exhibited regular beating and expressed classical cardiac markers. When compared with their unmodified counterparts, transduced mESC-CM caused 2.5-fold lesser activation of cognate T-cells. In vivo assessment of B2M downregulation was performed by analyzing the preferential survival of B2M-downregulated cells in the intraperitoneal cavity of allogeneic mice. Both B2M-downregulated fibroblasts and B2M-downregulated myocytes survived significantly better when compared to their unmodified counterparts (2.01 ± 0.4 and 5.07 ± 1.6 fold increase in survival, respectively). In contrast, when modified WT19 fibroblasts were injected into the intraperitoneal cavity of syngeneic C57Bl/6 mice, no significant survival advantage was observed. Notably, the preferential survival of B2M-downregulated cells persisted in allogeneic hosts with normal levels of natural killer cells, although the effect was lesser in magnitude. Use of shRNA against beta-2-microglobulin offers a simple and effective approach to minimize immunogenicity of the main cellular components of cardiac tissue constructs in non-syngeneic recipients.

In vivo function of the ER-Golgi transport protein LMAN1 in photoreceptor homeostasis

LMAN1 is a type I transmembrane protein that selectively transports its cargo proteins from ER to ER-Golgi intermediate compartment (ERGIC) and Golgi. Lman1 is a direct target of the transcription factor NRL in mouse retina. Therefore, we examined the in vivo function of LMAN1 in retina. Although Lman1 (- / -) mouse eyes did not show abnormality in histology and electroretinogram analysis at 3 months, Lman1 (- / -) retina at 6 months showed a decrease in cis-Golgi markers GM130 and GRASP65. We also observed abnormal level and location of Rhodopsin in these mice. Taken together, LMAN1 may play a role in photoreceptor gene transport and homeostasis.

Decreasing immunogenicity of ESC derived cardiomyocytes (73.1)

One of the major obstacles to repair damaged myocardium with embryonic stem cell derived cardiomyocytes (ESC-CM) is their rejection by non-syngeneic hosts. We aimed to reduce the immunogenicity of these cells by downregulation of MHC class I molecules (MHC-I) on their surface. Cardiomyocytes were derived from mouse ESC in which puromycin resistance gene is driven by a cardiac-specific promoter. They formed beating cardiomyocyte layers and expressed cardiac specific proteins. Interferon gamma treatment was used to mimic the effects of inflammatory stimuli on the expression of MHC-I. Transduction of ESC-CM with beta-2-microglobulin shRNA decreased expression of MHC-I in both interferon gamma-treated and untreated samples. When MHC-I downregulated ESC-CM were used as in vitro targets, activation of cognate T-lymphocytes was significantly reduced. Moreover, in vivo, MHC-I downregulated cells exhibited improved survival when injected i.p. into allogeneic, but not to syngeneic mice. To confirm that this strategy can be used for different cell types, the results were verified using W19 fibroblasts. In the past, ESC-CM have been shown to improve ischemic myocardium in syngeneic or immunocompromised animals. Inhibition of MHC-I via shRNA offers a simple approach to minimize the immunogenicity of these cells for use in allo- or xenogeneic recipients. Extension of this methodology to ESC of larger mammals can provide a source of less immunogenic cardiomyocytes for human heart repair.

The effect of opioids and their antagonists on the nocifensive response of Caenorhabditis elegans to noxious thermal stimuli

Opiates modulate nociception in vertebrates. This has also been demonstrated in a number of invertebrate models. Herein, the effect of the opiate morphine and opioid neuropeptides Endomorphin 1 and 2 on the thermal avoidance (Tav) behavior of Caenorhabditis elegans is explored. Adult wild-type C. elegans N2 were collected from NGM plates using M9 buffer and exposed to morphine and endomorphine 1 and 2 in concentrations between 10(-8) and 10(-4) M (2.5 pmol/mg to 25 nmol/mg) for 30 min and tested for Tav. The opioid receptor antagonists Naloxone and CTOP were tested in combination with the drugs. Forty-seven percentage of the morphine exposed worms exhibited a class I response versus 76% of the control group (P < 0.001). Endomorphin 1 and 2 also caused a statistically significant reduction in class I responses, 36 and 39%, respectively. These effects were reversed with Naloxone and CTOP. Thermonocifensive behavior in C. elegans is modulated by opioids.