Genetic rodent models of glaucoma in representing disease phenotype and insights into the pathogenesis

Genetic rodent models are widely used in glaucoma related research. With vast amount of information revealed by human studies about genetic correlations with glaucoma, use of these models is relevant and required. In this review, we discuss the glaucoma endophenotypes and importance of their representation in an experimental animal model. Mice and rats are the most popular animal species used as genetic models due to ease of genetic manipulations in these animal species as well as the availability of their genomic information. With technological advances, induction of glaucoma related genetic mutations commonly observed in human is possible to achieve in rodents in a desirable manner. This approach helps to study the pathobiology of the disease process with the background of genetic abnormalities, reveals potential therapeutic targets and gives an opportunity to test newer therapeutic options. Various genetic manipulation leading to appearance of human relevant endophenotypes in rodents indicate their relevance in glaucoma pathology and the utility of these rodent models for exploring various aspects of the disease related to targeted mutation. The molecular pathways involved in the pathophysiology of glaucoma leading to elevated intraocular pressure and the disease hallmark, apoptosis of retinal ganglion cells and optic nerve degeneration, have been extensively explored in genetic rodent models. In this review, we discuss the consequences of various genetic manipulations based on the primary site of pathology in the anterior or the posterior segment. We discuss how these genetic manipulations produce features in rodents that can be considered a close representation of disease phenotype in human. We also highlight several molecular mechanisms revealed by using genetic rodent models of glaucoma including those involved in increased aqueous outflow resistance, loss of retinal ganglion cells and optic neuropathy. Lastly, we discuss the limitations of the use of genetic rodent models in glaucoma related research.

Calculation of effective dose of phenylephrine bolus for treatment of post-spinal hypotension in pre-eclamptic patients undergoing caesarean section - a non-randomised controlled trial

BACKGROUND

Patients with pre-eclampsia require smaller vasopressor doses compared with those with normotension for management of post-spinal hypotension during caesarean section. However, the literature has little evidence as to the phenylephrine dose required for patients with pre-eclampsia.

METHODS

Fifty patients, with either pre-eclampsia or normotension, and developing post-spinal hypotension during caesarean section under spinal anaesthesia, were studied. Women in both groups did not receive prophylactic vasopressors. The first patient in each group received phenylephrine 50 µg to treat the first episode of hypotension, defined as fall of systolic blood pressure ≥20% from baseline or an absolute value <100 mmHg. If hypotension was corrected within one minute it was considered a 'success'. The doses for the subsequent patients were determined by responses to all previous patients, according to a variation of Narayana's rule for the up-down sequential allocation method.

RESULTS

The 95% effective dose (ED95) and 50% effective dose (ED50) of phenylephrine was 41.7 µg (95% CI 33.8 to 49.6 µg) and 29.1 µg (95% CI 26.0 to 32.2 µg) respectively in the pre-eclampsia group, and 64.9 µg (95% CI 54.1 to 75.7 µg) and 47.3 µg (95% CI 39.7 to 54.9 µg) respectively in the normotensive group. The proportionate reduction in phenylephrine dose ranged from 33% (95% CI 18 to 44%) to 40% (95% CI 19 to 52%).

CONCLUSION

Patients with pre-eclampsia may need a 33% to 40% reduction in the first phenylephrine bolus dose, compared with patients with normotension, for the treatment of the first episode of post-spinal hypotension.

Diabetic retinopathy: a comprehensive update on in vivo, in vitro and ex vivo experimental models

Diabetic retinopathy (DR), one of the leading causes of visual impairment and blindness worldwide, is one of the major microvascular complications in diabetes mellitus (DM). Globally, DR prevalence among DM patients is 25%, and 6% have vision-threatening problems among them. With the higher incidence of DM globally, more DR cases are expected to be seen in the future. In order to comprehend the pathophysiological mechanism of DR in humans and discover potential novel substances for the treatment of DR, investigations are typically conducted using various experimental models. Among the experimental models, in vivo models have contributed significantly to understanding DR pathogenesis. There are several types of in vivo models for DR research, which include chemical-induced, surgical-induced, diet-induced, and genetic models. Similarly, for the in vitro models, there are several cell types that are utilised in DR research, such as retinal endothelial cells, Müller cells, and glial cells. With the advancement of DR research, it is essential to have a comprehensive update on the various experimental models utilised to mimic DR environment. This review provides the update on the in vitro, in vivo, and ex vivo models used in DR research, focusing on their features, advantages, and limitations.

Connective tissue growth factor: Role in trabecular meshwork remodeling and intraocular pressure lowering

Connective tissue growth factor (CTGF) is a distinct signaling molecule modulating many physiological and pathophysiological processes. This protein is upregulated in numerous fibrotic diseases that involve extracellular matrix (ECM) remodeling. It mediates the downstream effects of transforming growth factor beta (TGF-β) and is regulated via TGF-β SMAD-dependent and SMAD-independent signaling routes. Targeting CTGF instead of its upstream regulator TGF-β avoids the consequences of interfering with the pleotropic effects of TGF-β. Both CTGF and its upstream mediator, TGF-β, have been linked with the pathophysiology of glaucomatous optic neuropathy due to their involvement in the regulation of ECM homeostasis. The excessive expression of these growth factors is associated with glaucoma pathogenesis via elevation of the intraocular pressure (IOP), the most important risk factor for glaucoma. The raised in the IOP is due to dysregulation of ECM turnover resulting in excessive ECM deposition at the site of aqueous humor outflow. It is therefore believed that CTGF could be a potential therapeutic target in glaucoma therapy. This review highlights the CTGF biology and structure, its regulation and signaling, its association with the pathophysiology of glaucoma, and its potential role as a therapeutic target in glaucoma management.

Advances in targeting the extracellular matrix for glaucoma therapy: current updates

INTRODUCTION

Elevated intraocular pressure (IOP) is a well-recognized risk factor for development of primary open angle glaucoma (POAG), a leading cause of irreversible blindness. Ocular hypertension is associated with excessive extracellular matrix (ECM) deposition in trabecular meshwork (TM) resulting in increased aqueous outflow resistance and elevated IOP. Hence, therapeutic options targeting ECM remodeling in TM to lower IOP in glaucomatous eyes are of considerable importance.

AREAS COVERED

This paper discusses the complex process of ECM regulation in TM and explores promising therapeutic targets. The role of Transforming Growth Factor-β as a central player in ECM deposition in TM is discussed. We elaborate the key regulatory processes involved in its activation, release, signaling, and cross talk with other signaling pathways including Rho GTPase, Wnt, integrin, cytokines, and renin-angiotensin-aldosterone. Further, we summarize the therapeutic agents that have been explored to target ECM dysregulation in TM.

EXPERT OPINION

Targeting molecular pathways to reduce ECM deposition and/or enhance its degradation are of considerable significance for IOP lowering. Challenges lie in pinpointing specific targets and designing drug delivery systems to precisely interact with pathologically active/inactive signaling. Recent advances in monoclonal antibodies, fusion molecules, and vectored nanotechnology offer potential solutions.

Exploring the current use of animal models in glaucoma drug discovery: where are we in 2023?

INTRODUCTION

Animal models are widely used in glaucoma-related research. Since the elevated intraocular pressure (IOP) is a major risk factor underlying the disease pathogenesis, animal models with high IOP are commonly used. However, models are also used to represent the clinical context of glaucomatous changes developing despite a normal IOP.

AREAS COVERED

Herein, the authors discuss the various factors that contribute to the quality of studies using animal models based on the evaluation of studies published in 2022. The factors affecting the quality of studies using animal models, such as the animal species, age, and sex, are discussed, along with various methods and outcomes of studies involving different animal models of glaucoma.

EXPERT OPINION

Translating animal research data to clinical applications remains challenging. Our observations in this review clearly indicate that many studies lack scientific robustness not only in their experiment conduct but also in data analysis, interpretation, and presentation. In this context, ensuring the internal validity of animal studies is the first step in quality assurance. External validity, however, is more challenging, and steps should be taken to satisfy external validity at least to some extent.

Tocotrienol-rich fraction reduces retinal inflammation and angiogenesis in rats with streptozotocin-induced diabetes

BACKGROUND

Diabetic retinopathy (DR) is the second commonest microvascular complication of diabetes mellitus. It is characterized by chronic inflammation and angiogenesis. Palm oil-derived tocotrienol-rich fraction (TRF), a substance with anti-inflammatory and anti-angiogenic properties, may provide protection against DR development. Therefore, in this study, we investigated the effect of TRF on retinal vascular and morphological changes in diabetic rats. The effects of TRF on the retinal expression of inflammatory and angiogenic markers were also studied in the streptozotocin (STZ)-induced diabetic rats.

METHODS

Male Sprague Dawley rats weighing 200-250 g were grouped into normal rats (N) and diabetic rats. Diabetes was induced by intraperitoneal injection of streptozotocin (55 mg/kg body weight) whereas N similarly received citrate buffer. STZ-injected rats with blood glucose of more than 20 mmol/L were considered diabetic and were divided into vehicle-treated (DV) and TRF-treated (DT) groups. N and DV received vehicle, whereas DT received TRF (100 mg/kg body weight) via oral gavage once daily for 12 weeks. Fundus images were captured at week 0 (baseline), week 6 and week 12 post-STZ induction to estimate vascular diameters. At the end of experimental period, rats were euthanized, and retinal tissues were collected for morphometric analysis and measurement of NFκB, phospho-NFκB (Ser536), HIF-1α using immunohistochemistry (IHC) and enzyme-linked immunosorbent assay (ELISA). Retinal inflammatory and angiogenic cytokines expression were measured by ELISA and real-time quantitative PCR.

RESULTS

TRF preserved the retinal layer thickness (GCL, IPL, INL and OR; p < 0.05) and retinal venous diameter (p < 0.001). TRF also lowered the retinal NFκB activation (p < 0.05) as well as expressions of IL-1β, IL-6, TNF-α, IFN-γ, iNOS and MCP-1 (p < 0.05) compared to vehicle-treated diabetic rats. Moreover, TRF also reduced retinal expression of VEGF (p < 0.001), IGF-1 (p < 0.001) and HIF-1α (p < 0.05) compared to vehicle-treated rats with diabetes.

CONCLUSION

Oral TRF provided protection against retinal inflammation and angiogenesis in rats with STZ-induced diabetes by suppressing the expression of the markers of retinal inflammation and angiogenesis.

Neuroprotection by trans-resveratrol in rats with N-methyl-D-aspartate (NMDA)-induced retinal injury: Insights into the role of adenosine A1 receptors

Adenosine A1 receptors (AA1R) have been shown to counteract N-methyl-D-aspartate (NMDA)-mediated glutamatergic excitotoxicity. In the present study, we investigated the role of AA1R in neuroprotection by trans-resveratrol (TR) against NMDA-induced retinal injury. In total, 48 rats were divided into the following four groups: normal rats pretreated with vehicle; rats that received NMDA (NMDA group); rats that received NMDA after pretreatment with TR; and rats that received NMDA after pretreatment with TR and 1,3-dipropyl-8-cyclopentylxanthine (DPCPX), an AA1R antagonist. Assessment of general and visual behaviour was performed using the open field test and two-chamber mirror test, respectively, on Days 5 and 6 post NMDA injection. Seven days after NMDA injection, animals were euthanized, and eyeballs and optic nerves were harvested for histological parameters, whereas retinae were isolated to determine the redox status and expression of pro- and anti-apoptotic proteins. In the present study, the retinal and optic nerve morphology in the TR group was protected from NMDA-induced excitotoxic damage. These effects were correlated with the lower retinal expression of proapoptotic markers, lipid peroxidation, and markers of nitrosative/oxidative stress. The general and visual behavioural parameters in the TR group showed less anxiety-related behaviour and better visual function than those in the NMDA group. All the findings observed in the TR group were abolished by administration of DPCPX.

The effect of palm oil-derived tocotrienol-rich fraction in preserving normal retinal vascular diameter in streptozotocin-induced diabetic rats

PURPOSE

Angiogenesis in diabetic retinopathy (DR) is associated with increased retinal expression of angiopoietin-2 (Ang-2) and protein kinase C (PKC). Tocotrienol-rich fraction (TRF) has been shown to reduce the expression vascular endothelial growth factor (VEGF) in several experimental models. However, its effect against other angiogenic markers such as Ang-2 and PKC in rat model of diabetes remains unknown. Therefore, we investigated the effect of TRF on the retinal vascular changes and Ang-2 and PKC expressions in rats with streptozotocin (STZ)-induced DR.

METHODS

Sprague-Dawley rats were divided into normal control rats (N) which received vehicle, and diabetic rats which either received vehicle (DV) or 100 mg/kg of TRF (DT). Diabetes was induced with intraperitoneal injection of STZ (60 mg/kg body weight). Treatments were given orally, once daily, for 12 weeks after confirmation of hyperglycaemia. Fundus photographs were captured at baseline, 6- and 12-week post-STZ injection and average diameter of retinal veins and arteries were measured. At 12-week post-STZ injection, rats were euthanised, and retinae were collected for measurement of Ang-2 and PKC gene and protein expressions.

RESULTS

Retinal venous and arterial diameters were significantly greater in DV compared to DT at week 12 post-STZ injection (p < 0.001 and < 0.05, respectively). The vessel diameter measurements in DT were comparable to N and this effect of TRF was associated with significantly lower Ang-2 and PKC gene and protein expressions compared to DV.

CONCLUSION

Oral TRF reduces the expression of retinal angiogenic markers and preserves the retinal vascular diameter of rats with STZ-induced DR.

Neuroprotective effects of exogenous brain-derived neurotrophic factor on amyloid-beta 1–40-induced retinal degeneration

Amyloid-beta (Aβ)-related alterations, similar to those found in the brains of patients with Alzheimer’s disease, have been observed in the retina of patients with glaucoma. Decreased levels of brain-derived neurotrophic factor (BDNF) are believed to be associated with the neurotoxic effects of Aβ peptide. To investigate the mechanism underlying the neuroprotective effects of BDNF on Aβ_1–40-induced retinal injury in Sprague-Dawley rats, we treated rats by intravitreal administration of phosphate-buffered saline (control), Aβ_1–40 (5 nM), or Aβ_1–40 (5 nM) combined with BDNF (1 µg/mL). We found that intravitreal administration of Aβ_1–40 induced retinal ganglion cell apoptosis. Fluoro-Gold staining showed a significantly lower number of retinal ganglion cells in the Aβ_1–40 group than in the control and BDNF groups. In the Aβ_1–40 group, low number of RGCs was associated with increased caspase-3 expression and reduced TrkB and ERK1/2 expression. BDNF abolished Aβ_1–40-induced increase in the expression of caspase-3 at the gene and protein levels in the retina and upregulated TrkB and ERK1/2 expression. These findings suggest that treatment with BDNF prevents RGC apoptosis induced by Aβ_1–40 by activating the BDNF-TrkB signaling pathway in rats.

Managing panic buying-related instabilities in supply chains: A COVID-19 pandemic perspective

Global supply chains (SCs) have been severely impacted by the COVID-19 pandemic on several levels. For example, SCs suffered from panic buying-related instabilities and multiple disruptions of supply, demand, and capacity during the pandemic. This study developed an agent-based model (ABM) to predict the effects of panic buying-related instabilities in SCs and offered strategies to improve them. The ABM model includes a simulation and optimization model of a typical SC of an essential product manufacturer (i.e., toilet paper SC) for the analysis of scenarios and strategies to observe improvements in SCs. Among the four strategies identified, the findings suggest boosting production capacity to the maximum and ensuring optimal reorder points, order sizes, and trucks helped the essential product manufacturers reduce panic buying-related instabilities in their SCs.

In patients with type 2 diabetes chronic kidney disease is a modifiable cardiovascular risk factor

Background/Introduction

Chronic kidney disease (CKD) in patients with type 2 diabetes (T2D) is associated with an increased risk of cardiovascular (CV) events. The modifiability of CKD-associated CV risk in patients with T2D across a spectrum of CKD stages remains unknown.

Purpose

To test whether CKD, as defined jointly by estimated glomerular filtration rate (eGFR) and albuminuria (urine albumin-to-creatinine ratio [UACR]), is a modifiable CV risk factor in patients with T2D. Furthermore, to estimate the population-wide reduction in first CV events in the US if all eligible patients were treated with finerenone.

Methods

We estimated the incidence rates of CV events (composite of CV death, non-fatal stroke, non-fatal myocardial infarction, or hospitalisation for heart failure) over a median follow-up of 3.0 years in 13,026 patients with CKD and T2D, treated with finerenone or placebo, in a joint analysis by eGFR and UACR categories. Patients were from FIDELITY, a prespecified pooled analysis of two phase III trials, and had an eGFR ≥25 ml/min/1.73 m2 and UACR 30–5000 mg/g at screening.The potential impact of finerenone treatment on the US population was evaluated by simulating the number of first CV events that could be prevented per year with finerenone, using incidence rates from FIDELITY and prevalence rates of CKD in patients with T2D from the National Health and Nutrition Examination Survey (NHANES).

Results

Lower eGFR and higher UACR categories were associated with higher incidences of CV events in finerenone and placebo recipients (Figure). Finerenone reduced CV risk versus placebo (hazard ratio 0.86; 95% CI 0.78–0.95; p=0.0018) without evidence of moderation of risk reduction by combined eGFR and UACR categories (p interaction = 0.66; Figure 1). Using NHANES, a total of 6.4 million treatment-eligible individuals with CKD and T2D were identified; 75% had CKD with an eGFR ≥60 ml/min/1.73 m2 and 25% had CKD with an eGFR &lt;60 ml/min/1.73 m2. Simulations using this NHANES population projected that 1 year of finerenone treatment could prevent 38,359 CV events in US patients with CKD and T2D, with 66% of events prevented in patients with eGFR ≥60 ml/min/1.73 m2.

Conclusions

Higher albuminuria and lower eGFR are associated with increased CV risk in patients with T2D. Across a range of eGFR and albuminuria categories, CV risk is modifiable. Therefore, CKD is a modifiable CV risk factor in part mediated by mineralocorticoid receptor overactivation. UACR screening to identify patients with T2D and albuminuria with an eGFR ≥60 ml/min/1.73 m2 is likely to provide a significant opportunity for population benefits.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Bayer AG

Relationship between serum and tear levels of tissue plasminogen activator and plasminogen activator inhibitor-1 in diabetic retinopathy

Background

Diabetic retinopathy (DR) is a serious complication of longstanding type 2 diabetes mellitus (T2DM), a leading cause of blindness and visual disability in the world. The aim of this study is to compare the activity of tissue plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1) in tears and serum of patients with DR and those without DR.

Method

Among the T2DM patients enrolled in this study, 26 patients had DR (n = 26) while 29 were without DR (n = 29). The blood and tear samples were obtained from all participants. The level of PAI-1 and tPA were measured in both the serum and tears. Anthropometric measurements, HbA1c, renal and lipid profile were also obtained.

Results

Patients with DR had significantly longer disease duration and higher systolic blood pressure compared to those without DR. Serum PAI-1 level was significantly higher in patients with DR compared to those without DR, 32.72 (IQR 32.52) vs 21.37 (IQR 14.93) ng/mL, respectively (p < 0.05). However, tear PAI-1 were comparable in both groups. Serum and tear tPA levels in both groups were also comparable (p > 0.05). Among patients with DR, there were no significant correlations between tear and serum of both biomarkers. Patients without DR showed a moderate positive correlation between serum and tear tPA levels with a coefficient of 0.363, albeit no statistical significance. Patients with DR demonstrated a significant positive correlation between levels of tears PAI-1 and BMI (r = 0.555, p = 0.026). In the group without DR, there was a statistically significant positive correlation between serum level of PAI-1 with urine albumin creatinine ratio (UACR) (r = 0.501, p = 0.013).

Conclusion

The present study demonstrated a significantly greater serum PAI-1 levels in patients with DR compared to those without DR. No significant correlations between tears and serum PAI-1 and tPA were observed. Thus, the role of tear biomarkers remains relevant for further investigations.

Neuroprotection by Trans-Resveratrol in Rats With Intracerebral Hemorrhage: Insights into the Role of Adenosine A1 Receptors

Given the neuroprotective effects of trans-resveratrol (RV), this study aimed to investigate the involvement of the adenosine A1 receptor (A1R) in RV-mediated neuroprotection in a rat intracerebral hemorrhage (ICH) model induced by intrastriatal injection of collagenase. Rats were divided into 5 groups: (1) control, (2) sham-operated, (3) ICH pretreated with vehicle, (4) ICH pretreated with RV, and (5) ICH pretreated with RV and the A1R antagonist DPCPX. At 48 hours after ICH, the rats were subjected to neurological testing. Brain tissues were assessed for neuronal density and morphological features using routine and immunohistochemical staining. Expression of tumor necrosis factor-α (TNF-α), caspase-3, and RIPK3 proteins was examined using ELISA. A1R, MAPK P38, Hsp90, TrkB, and BDNF genes were examined using RT-qPCR. RV protected against neurological deficits and neuronal depletion, restored the expression of TNF-α, CASP3, RIPK3, A1R, and Hsp90, and increased BDNF/TrkB. DPCPX abolished the effects of RV on neurological outcomes, neuronal density, CASP3, RIPK3, A1R, Hsp90, and BDNF. These data indicate that the neuroprotection by RV involves A1R and inhibits CASP3-dependent apoptosis and RIPK3-dependent necroptosis in the perihematoma region; this is likely to be mediated by crosstalk between A1R and the BDNF/TrkB pathway.

P-696 Serum androgen levels and risk of endometrial hyperplasia and malignancy in patients with polycystic ovarian syndrome: a cross-sectional analysis

Study question

In patients with polycystic ovarian syndrome (PCOS), are serum androgen levels (total and free testosterone) associated with the risk of endometrial hyperplasia or cancer?

Summary answer

Patients with PCOS diagnosed with endometrial hyperplasia or cancer had statistically significantly lower serum levels of androgens compared to PCOS patients with a normal endometrium.

What is known already

PCOS affects as many as 12% of women of reproductive age. Women with PCOS are almost three times as likely to develop endometrial cancer as women without PCOS, and endometrial hyperplasia precedes cancer in 36% of cases. Known risk factors of endometrial hyperplasia include anovulation, obesity, and resultant unopposed estrogen stimulation of the endometrium. A hallmark of PCOS is hyperandrogenism, however the effect of androgens on the endometrium is unclear.

Study design, size, duration

This was a cross-sectional, retrospective study of patients aged 18-40, being evaluated for oligomenorrhea and/or PCOS in the Reproductive Endocrinology Clinic at Los Angeles County Hospital, California, USA. All patients underwent an endometrial biopsy and serum measurement of free and total testosterone, estradiol, and hemoglobin A1c. Patients diagnosed with PCOS and with an endometrial biopsy diagnosis were included in the study. Patients on any hormonal therapy were excluded.

Participants/materials, setting, methods

In all patients included in the study, serum androgen levels (free and total testosterone) were measured by mass spectrometry. All endometrial biopsies were analyzed by an experienced histopathology, and all diagnoses of endometrial hyperplasia or cancer were confirmed by histologic studies.

Main results and the role of chance

Using the Rotterdam criteria, a total of 232 patients were diagnosed with PCOS during the study period. Of these patients, 161 patients (70%) had a normal endometrium, 19 (8%) were diagnosed with endometrial hyperplasia (EH) without atypia, 38 (16%) were diagnosed with EH with atypia, and 14 (6%) were diagnosed with endometrial cancer. Patients with a normal endometrium had a mean total testosterone of 60.9 ng/dL and mean free testosterone of 9.3 ng/dL. Relatively, patients with EH without atypia, EH with atypia, and endometrial cancer had lower mean total testosterone levels of 50.1 ng/dL, 45.5 ng/dL, and 30.1 ng/dL, respectively (p-values 0.04, 0.02, 0.001, respectively), as well as lower mean free testosterone levels of 8.2 pg/mL, 6.7 pg/mL, and 5.5 pg/mL, respectively (p-values 0.04, 0.03, and 0.01, respectively). There was no significant difference in age, parity, BMI, estradiol levels, or hemoglobin A1c between the four groups.

Limitations, reasons for caution

Limitations of our study include its retrospective nature. Furthermore, hormone levels were only measured in the serum, and not in the endometrial tissue directly, which would give the most insight into their actions on the endometrium.

Wider implications of the findings

Our findings suggest that androgens have a protective effect on the endometrium against endometrial hyperplasia and cancer. Further studies are needed to evaluate the therapeutic potential role of androgens in the prevention or treatment of these conditions.

Trial registration number

not applicable

Patient perspectives on nipple-areola complex micropigmentation during the COVID-19 pandemic

Background

Micropigmentation is a well-recognised option for nipple-areola complex reconstruction, as part of the breast reconstruction pathway for patients following mastectomy. As a part of delayed breast reconstruction, this treatment was put on hold during the COVID-19 pandemic.

Aims

To assess the views of patients regarding micropigmentation in response to the COVID-19 pandemic, and whether their attitudes to seeking out this part of the reconstructive journey had been altered.

Methods

A questionnaire undertaken with 53 patients between August & September 2020 attending the Micropigmentation clinic.

Findings

81.1% of patients reported COVID-19 had not impacted their decision, with a similar proportion happy to proceed with the treatment at the time of questioning.

Conclusions

The results highlight the importance of nipple-areola complex to our patients’ reconstructive journey.

Brain-Derived Neurotrophic Factor-Mediated Neuroprotection in Glaucoma: A Review of Current State of the Art

Retinal ganglion cells (RGCs) are neurons of the visual system that are responsible for transmitting signals from the retina to the brain via the optic nerve. Glaucoma is an optic neuropathy characterized by apoptotic loss of RGCs and degeneration of optic nerve fibers. Risk factors such as elevated intraocular pressure and vascular dysregulation trigger the injury that culminates in RGC apoptosis. In the event of injury, the survival of RGCs is facilitated by neurotrophic factors (NTFs), the most widely studied of which is brain-derived neurotrophic factor (BDNF). Its production is regulated locally in the retina, but transport of BDNF retrogradely from the brain to retina is also crucial. Not only that the interruption of this retrograde transport has been detected in the early stages of glaucoma, but significantly low levels of BDNF have also been detected in the sera and ocular fluids of glaucoma patients, supporting the notion that neurotrophic deprivation is a likely mechanism of glaucomatous optic neuropathy. Moreover, exogenous NTF including BDNF administration was shown reduce neuronal loss in animal models of various neurodegenerative diseases, indicating the possibility that exogenous BDNF may be a treatment option in glaucoma. Current literature provides an extensive insight not only into the sources, transport, and target sites of BDNF but also the intracellular signaling pathways, other pathways that influence BDNF signaling and a wide range of its functions. In this review, the authors discuss the neuroprotective role of BDNF in promoting the survival of RGCs and its possible application as a therapeutic tool to meet the challenges in glaucoma management. We also highlight the possibility of using BDNF as a biomarker in neurodegenerative disease such as glaucoma. Further we discuss the challenges and future strategies to explore the utility of BDNF in the management of glaucoma.

The association between neutrophil to lymphocyte ratio and echocardiographic parameters in hospitalised adults with COVID-19 - a retrospective analysis

Funding Acknowledgements

Type of funding sources: None.

Background

The neutrophil to lymphocyte ratio (NLR) is an inflammatory biomarker with prognostic value in several cardiovascular conditions. Hyperinflammation contributes to severe coronavirus disease 2019 (COVID-19), which is characterized by a multi-organ dysfunction. Cardiovascular complications of COVID-19 include arrhythmias, myocardial damage, acute heart failure, and acute coronary syndrome. Transthoracic echocardiography (TTE) can be used to assess cardiovascular structure and function non-invasively.

Purpose

To investigate the association between NLR at admission and TTE abnormalities in hospitalised adults with COVID-19.

Methods

This single-centre retrospective study was conducted at a COVID-19 referral hospital in Indonesia. All consecutive hospitalised adults with confirmed COVID-19 who underwent TTE assessments between 3 April 2020 to 6 April 2021 were included. Comprehensive data including NLR at admission, demographics, co-morbidities, peak severity of COVID-19, and TTE parameters were extracted from electronic medical records. A receiver operating characteristic (ROC) curve analysis was conducted to determine the optimal NLR cut-off for prediction of severe-critical COVID-19. Patients with high and low NLR were compared using the chi-square test and odds ratios (OR), with a confidence level of 95%.

Results

A total of 487 patients were included in this study. From ROC curve analysis, the area under curve was 0.80 (95% CI: 0.76 – 0.84). The optimal NLR cut-off was determined as 4.42, which predicted severe-critical COVID-19 with a sensitivity of 74.5% and a specificity of 74.6%. Based on this, the low NLR and high NLR groups had 223 and 264 patients, respectively.  Male sex, diabetes, and chronic kidney disease occurred more frequently in the high NLR group (P &lt; 0.05). On TTE assessment, the high NLR group had higher odds of left ventricular (LV) systolic dysfunction (OR: 2.49; 95% CI: 1.14 – 5.45), LV wall motion abnormalities (OR: 2.62; 95% CI: 1.41 – 4.87), valve abnormalities (OR: 2.04; 95% CI: 1.35 – 3.07), and right ventricular (RV) dysfunction (OR: 10.55; 95% CI: 2.46 – 45.25).

Conclusions

COVID-19 patients with a high NLR at admission had higher odds of abnormal TTE findings, including LV systolic dysfunction, LV wall motion abnormalities, valve abnormalities, and RV dysfunction. This indicates a possible link between inflammation and cardiovascular dysfunction in COVID-19, which must be confirmed in larger prospective studies. Abstract Figure. ROC Curve Analysis  Abstract Figure. Odds Ratios for TTE Abnormalities

The association between transthoracic echocardiographic parameters and severity of COVID-19 in hospitalised adults - a retrospective analysis

Funding Acknowledgements

Type of funding sources: None.

Background

The coronavirus disease 2019 (COVID-19) is an ongoing global pandemic with more than 220 million cases and 4.5 million deaths reported worldwide. Its clinical spectrum varies widely, and non-invasive prognostic markers are valuable as they can guide efficient resource allocation.  Cardiovascular complications of COVID-19 include myocardial injury, acute heart failure, and arrhythmias. Both de novo cardiovascular complications and pre-existing cardiovascular co-morbidities are associated with a poor prognosis. Transthoracic echocardiography (TTE) can be used to assess cardiovascular structure and function non-invasively.

Purpose

To investigate the association between TTE parameters and severity of disease in hospitalised adults with confirmed COVID-19

Methods

This single-centre retrospective analysis was conducted at a COVID-19 referral hospital in Indonesia. All consecutive adults hospitalised with confirmed COVID-19 who underwent TTE assessment between 3 April 2020 to 6 April 2021 were included. Comprehensive data including demographics, peak COVID-19 severity, pre-existing co-morbidities, and TTE findings were extracted from electronic medical records. Patients with mild-moderate and severe-critical disease were compared using the chi-square test and odds ratios (OR), with a confidence level of 95%.

Results

A total of 488 patients were included in this study; 202 with mild-moderate disease and 286 with severe-critical disease. Frequency of old age (>60 years), obesity, diabetes, chronic kidney disease, and congestive heart failure were higher in the severe-critical group (P < 0.05). On TTE assessment, Patients with severe-critical disease had higher odds of left ventricular hypertrophy (LVH) (OR: 2.20; CI: 1.49 – 3.24), LV wall motion abnormality (OR: 3.33; CI: 1.68 – 6.60), diastolic dysfunction (OR: 1.46; CI: 1.02 – 2.11), valve abnormality (OR: 1.93; CI: 1.27 – 2.92), and right ventricular (RV) dysfunction (OR: 5.53; CI: 1.63 – 18.73). After matching for age, obesity, and diabetes, patients with severe-critical COVID-19 continued to have higher odds of LVH (OR: 1.91; CI: 1.21 – 3.02), LV wall motion abnormality (OR: 2.76; CI: 1.28 – 5.96), diastolic dysfunction (OR: 1.55; CI: 1.00 – 2.38), and RV dysfunction (OR: 3.86; CI: 1.06 – 14.08).

Conclusions

The presence of LVH, LV wall motion abnormality, diastolic dysfunction, and RV dysfunction on TTE assessment were associated with severe-critical disease in hospitalised adults with COVID-19. These findings must be validated in a larger prospective study.

Prevalence of Dry Eye Disease in Glass Industry Workers of Firozabad, Uttar Pradesh, India: A Cross-sectional Observational Study

Introduction: Dry eye disease is a rising occupational hazard in India. Firozabad, is known for its glass manufacturing work worldwide. As there is limited evidence available on dry eye prevalence in glass industry workers, the present study was undertaken. Aim: To find out the prevalence and severity of Dry Eye Disease (DED) in glass industry workers of Firozabad, Uttar Pradesh, India. Materials and Methods: The cross-sectional observational study was conducted in Department of Ophthalmology at Sarojini Naidu Medical College, Agra, Uttar Pradesh, India, from March 2020 to September 2021 among the glass industry workers at Firozabad. It was a field survey, conducted in the factories only. Ocular Surface Disease Index (OSDI) Questionnaire was presented to 500 randomly selected glass industry workers to screen for dry eye disease. Based on subject’s response to OSDI questionnaire, score was calculated and then evaluated with an OSDI chart to assess the magnitude of dry eye symptoms. The final diagnosis and grading of dry eye was done on the basis of Schirmer’s test. Chi-square test was used to detect the association between variables. Statistical Package for Social Sciences (SPSS) software (version 28.0) was used for analysis. A p-value <0.05 was regarded as significant. Results : In the present study, the overall dry eye prevalence in glass industry workers was 28%. Mild dry eye was present in 3.2% of workers, moderate dry eye in 16.8%, and severe dry eye was present in 8% of glass workers. There was significant association between dry eye and working hours (per day) in two different study groups (<8 hrs and >8 hrs) (χ2 =20.9, p-value <0.001). There was also a significant association between the prevalence of dry eye and the years of exposure (in years) in the glass industry (χ2 =51.4, p-value <0.001). Conclusion: Prevalence of dry eye in glass industry workers is significantly high. Glass industry workers should undergo regular eye checkups to pick up DED as the earliest.

Neuroprotection Against NMDA-Induced Retinal Damage by Philanthotoxin-343 Involves Reduced Nitrosative Stress

N-methyl-D-aspartate receptor (NMDAR) overstimulation is known to mediate neurodegeneration, and hence represents a relevant therapeutic target for neurodegenerative disorders including glaucoma. This study examined the neuroprotective effects of philanthotoxin (PhTX)-343 against NMDA-induced retinal injury in rats. Male Sprague Dawley rats were divided into three groups; group 1 received phosphate buffer saline as the negative control, group 2 was injected with NMDA (160 nM) to induce retinal excitotoxic injury, and group 3 was pre-treated with PhTX-343 (160 nM) 24 h before NMDA exposure. All treatments were given intravitreally and bilaterally. Seven days post-treatment, rats were subjected to visual behaviour assessments using open field and colour recognition tests. Rats were then euthanized, and the retinas were harvested and subjected to haematoxylin and eosin (H&E) staining for morphometric analysis and 3-nitrotyrosine (3-NT) ELISA protocol as the nitrosative stress biomarker. PhTX-343 treatment prior to NMDA exposure improved the ability of rats to recognize visual cues and preserved visual functions (i.e., recognition of objects with different colours). Morphological examination of retinal tissues showed that the fractional ganglion cell layer thickness within the inner retina (IR) in the PhTX-343 treated group was greater by 1.28-fold as compared to NMDA-treated rats (p < 0.05) and was comparable to control rats (p > 0.05). Additionally, the number of retinal cell nuclei/100 μm² in IR for the PhTX-343-treated group was greater by 1.82-fold compared to NMDA-treated rats (p < 0.05) and was comparable to control group (p > 0.05). PhTX-343 also reduced the retinal 3-NT levels by 1.74-fold compared to NMDA-treated rats (p < 0.05). In conclusion, PhTX-343 pretreatment protects against NMDA-induced retinal morphological changes and visual impairment by suppressing nitrosative stress as reflected by the reduced retinal 3-NT level.

Neonatal outcomes following phenylephrine or norepinephrine for treatment of spinal anaesthesia-induced hypotension at emergency caesarean section in women with fetal compromise - a randomised controlled study

BACKGROUND

Norepinephrine is as effective as phenylephrine for management of spinal anaesthesia-induced hypotension. Most of the studies comparing these vasopressors have been conducted in healthy pregnant women undergoing elective caesarean section. In the current study, we tested the null hypothesis that there is no difference in neonatal outcome when phenylephrine or norepinephrine is used to treat spinal anaesthesia-induced hypotension in women undergoing emergency caesarean section for fetal compromise.

METHODS

Patients undergoing caesarean section for fetal compromise who developed spinal anaesthesia-induced hypotension were randomised to receive phenylephrine 100 μg or norepinephrine 8 μg for treatment of each hypotensive episode, defined as systolic blood pressure <100 mmHg. Umbilical cord arterial and venous blood samples were obtained for blood gas analysis. The primary outcome measure was umbilical artery pH.

RESULTS

One hundred patients (50 in each group) were studied. There was no significant difference in umbilical artery pH between the two groups (mean difference 0.001; 95% CI -0.032 to 0.034). The number of hypotensive episodes, vasopressor boluses required, the incidence of bradycardia, heart rate and blood pressure trends following vasopressor administration, and the incidence of nausea/vomiting were not significantly different between groups.

CONCLUSION

Phenylephrine 100 μg and norepinephrine 8 μg were not significantly different in terms of neonatal outcome when administered as intravenous boluses for treatment of spinal anaesthesia-induced hypotension in parturients undergoing emergency caesarean sections for fetal compromise.

Stepwise interventions for improving hand hygiene compliance in a level 3 academic neonatal intensive care unit in north India

OBJECTIVE

We evaluated effect of sequentially introducing four WHO-recommended interventions to promote hand-hygiene compliance in tertiary-care NICU.

STUDY DESIGN

Four dedicated research nurses directly observed doctors and nurses to record success in hand-hygiene opportunities at randomly selected NICU beds and randomly sampled time-slots in four phases (of 4-weeks each): I-Baseline, II-Self-directed learning; III-Participatory learning; IV-Closed-Circuit Television (CCTV); and V-CCTV-plus (with feedback).

FINDINGS

Hand-hygiene compliance changed from 61.8% (baseline) to 77% (end) with overall relative change: 24.6% (95% CI 18, 32; p value= 0.003); compared with preceding phase, relative changes of 21% (15, 28; <0.001), 4% (0, 8; 0.008), -10% (-13, -6; <0.001), and 10% (5, 15; <0.001) during phases II, III, IV, and V, respectively were observed. Rise in hand-hygiene compliance was higher for after-WHO-moments (12.7%; upto 2.5-folds for moment 5, <0.001) compared to before-WHO-moments (5.2%). Educational interventions, feedback and monitoring WHO moments can improve hand-hygiene compliance significantly among health-care providers in NICU.

Magnesium acetyltaurate prevents retinal damage and visual impairment in rats through suppression of NMDA-induced upregulation of NF-κB, p53 and AP-1 (c-Jun/c-Fos)

Magnesium acetyltaurate (MgAT) has been shown to have a protective effect against N-methyl-D-aspartate (NMDA)-induced retinal cell apoptosis. The current study investigated the involvement of nuclear factor kappa-B (NF-κB), p53 and AP-1 family members (c-Jun/c-Fos) in neuroprotection by MgAT against NMDA-induced retinal damage. In this study, Sprague-Dawley rats were randomized to undergo intravitreal injection of vehicle, NMDA or MgAT as pre-treatment to NMDA. Seven days after injections, retinal ganglion cells survival was detected using retrograde labelling with fluorogold and BRN3A immunostaining. Functional outcome of retinal damage was assessed using electroretinography, and the mechanisms underlying antiapoptotic effect of MgAT were investigated through assessment of retinal gene expression of NF-κB, p53 and AP-1 family members (c-Jun/c-Fos) using reverse transcription-polymerase chain reaction. Retinal phospho-NF-κB, phospho-p53 and AP-1 levels were evaluated using western blot assay. Rat visual functions were evaluated using visual object recognition tests. Both retrograde labelling and BRN3A immunostaining revealed a significant increase in the number of retinal ganglion cells in rats receiving intravitreal injection of MgAT compared with the rats receiving intravitreal injection of NMDA. Electroretinography indicated that pre-treatment with MgAT partially preserved the functional activity of NMDA-exposed retinas. MgAT abolished NMDA-induced increase of retinal phospho-NF-κB, phospho-p53 and AP-1 expression and suppressed NMDA-induced transcriptional activity of NF-κB, p53 and AP-1 family members (c-Jun/c-Fos). Visual object recognition tests showed that MgAT reduced difficulties in recognizing the visual cues (i.e. objects with different shapes) after NMDA exposure, suggesting that visual functions of rats were relatively preserved by pre-treatment with MgAT. In conclusion, pre-treatment with MgAT prevents NMDA induced retinal injury by inhibiting NMDA-induced neuronal apoptosis via downregulation of transcriptional activity of NF-κB, p53 and AP-1-mediated c-Jun/c-Fos. The experiments were approved by the Animal Ethics Committee of Universiti Teknologi MARA (UiTM), Malaysia, UiTM CARE No 118/2015 on December 4, 2015 and UiTM CARE No 220/7/2017 on December 8, 2017 and Ethics Committee of Belgorod State National Research University, Russia, No 02/20 on January 10, 2020.

Use of Elastic Stain Technique to Detect Histologically Occult Vascular Invasion in Resected Colorectal Carcinomas at Danbury Hospital

Introduction/Objective

Colorectal carcinoma (CRC) represents a leading cause of cancer related death in the western world and is by far the most common malignancy of the gastrointestinal tract. Vascular invasion (VI), in particular extramural VI by tumor is recognized as a feature of colorectal cancer progression, and the latter is an independent prognostic indicator of disease recurrence and survival in colorectal carcinoma. The purpose of this study is to detect VI in resected colorectal tumor samples and compare sensitivity of elastic staining to routine H&E staining at Danbury Hospital.

Methods/Case Report

A total of 50 colorectal cancer specimens from segmental colon resection or endoscopic polypectomy performed at Danbury Hospital over a 3-year period were included. Histologic sections of each tumor were assessed for the presence of VI by routine H&E staining. Superficial recuts of each tumor were subjected to elastic Von Giesen staining and reassessed for the presence of vascular invasion. Sensitivity of routine H&E staining for the detection of VI was calculated with elastic stain serving as the “gold standard”.

Results (if a Case Study enter NA)

In this study, VI by carcinoma was identified by H&E stain and/or elastic stain in 17 (34%) out of 50 cases. H&E stain and elastic stain detected VI in 12 (24%) and 16 (32%) out of 50 cases, respectively. There was a single case for which H&E stain showed vascular invasion that was not confirmed by elastic stain, representing a false negative for the H&E technique. Elastic staining detected VI in 5 cases for which the corresponding H&E stain was falsely negative for VI. Overall, vascular invasion status (absent or present) was concordant in 44 (88 %) of the 50 cases. With elastic stain deemed the “gold standard” for VI detection, the sensitivity, specificity, negative predictive value, and positive predictive value of H&E stain were found to be 68.7%, 97.0%, 86.8%, and 91.6%, respectively.

Conclusion

Although H & E staining of colorectal carcinoma tissue sections have a very good specificity and positive predictive value for the detection of VI, this technique suffers from a suboptimal sensitivity. For these reasons, we agree with previously published literature reports that the use of elastic stain as a supplement to H & E staining should be strongly considered for the proper evaluation and prognostication of colorectal carcinoma specimens.

Modulation of NFκB signalling pathway by tocotrienol: A systematic review

Tocotrienols have been reported to exert anticancer, anti-inflammatory, antioxidant, cardio-protective and boneprotective effects through modulation of NFκB signalling pathway. The objective of this systematic review is to evaluate available literature showing the effect of tocotrienols on NFκB signalling pathway and identify the potential mechanisms involved. A comprehensive search was conducted using PubMed and SCOPUS databases using the keywords "tocotrienol" and "NFκB" or "nuclear factor kappa b". Main inclusion criteria were English language original articles showing the effect of tocotrienol on NFκB signalling pathway. Fifty-nine articles were selected from the total of 117 articles initially retrieved from the literature search. Modulation of regulatory proteins and genes such as inhibition of farnesyl prenyl transferase were found to be the mechanisms underlying the tocotrienol-induced suppression of NFκB activation.

Knowledge assessment and outcomes of otolaryngology practice amidst the COVID-19 pandemic in a busy ENT department

INTRODUCTION

Otolaryngology health personnel are at high risk of acquiring COVID-19 disease and, hence, are likely to have high stress levels. This study was designed to evaluate the feedback of otolaryngology healthcare workers in ENT departments who are managing patients in the coronavirus pandemic.

METHODS

A questionnaire focused on all aspects of healthcare delivery was completed by otolaryngology healthcare workers.

RESULTS

The findings, based on statistical analyses, included high stress levels and inadequate disease-related information in these workers.

CONCLUSIONS

Healthcare authorities need to take care of issues related to mental health in healthcare professionals in addition to spreading awareness about safe practices. Further studies are needed to continuously monitor feedback from personnel as the coronavirus pandemic unravels in the future.

Tackling retinal ganglion cell apoptosis in glaucoma: role of adenosine receptors

INTRODUCTION

The role of adenosine receptors as therapeutic targets for neuroprotection is now widely recognized. Their role, however, in protection against retinal ganglion cell (RGC) apoptosis in glaucoma needs further investigation. Hence, in this review, we look into the possibility of adenosine receptors as potential therapeutic targets by exploring their role in modulating various pathophysiological mechanisms underlying glaucomatous RGC loss.

AREAS COVERED

This review presents a summary of the adenosine receptor distribution in retina and the cellular functions mediated by them. The major pathophysiological mechanisms such as excitotoxicity, vascular dysregulation, loss of neurotrophic signaling, and inflammatory responses involved in glaucomatous RGC loss are discussed. The literature showing the role of adenosine receptors in modulating these pathophysiological mechanisms is discussed. The literature search was conducted using Pubmed search engine using key words such as 'RGC apoptosis,' 'adenosine,' adenosine receptors' 'retina' 'excitotoxicity,' 'neurotrophins,' 'ischemia', and 'cytokines' individually and in various combinations.

EXPERT OPINION

Use of adenosine receptor agonists and antagonists, for preservation of the RGCs in glaucomatous eyes independent of the level of intraocular pressure seems a very useful strategy. Future application of this strategy would require appropriate designing of drug formulation for tissue and disease-specific receptor targeting. Furthermore, the modulation of physiological functions and potential adverse effects need further investigations.

An agent-based model for supply chain recovery in the wake of the COVID-19 pandemic

The current COVID-19 pandemic has hugely disrupted supply chains (SCs) in different sectors globally. The global demand for many essential items (e.g., facemasks, food products) has been phenomenal, resulting in supply failure. SCs could not keep up with the shortage of raw materials, and manufacturing firms could not ramp up their production capacity to meet these unparalleled demand levels. This study aimed to examine a set of congruent strategies and recovery plans to minimize the cost and maximize the availability of essential items to respond to global SC disruptions. We used facemask SCs as an example and simulated the current state of its supply and demand using the agent-based modeling method. We proposed two main recovery strategies relevant to building emergency supply and extra manufacturing capacity to mitigate SC disruptions. Our findings revealed that minimizing the risk response time and maximizing the production capacity helped essential item manufacturers meet consumers' skyrocketing demands and timely supply to consumers, reducing financial shocks to firms. Our study suggested that delayed implementation of the proposed recovery strategies could lead to supply, demand, and financial shocks for essential item manufacturers. This study scrutinized strategies to mitigate the demand-supply crisis of essential items. It further proposed congruent strategies and recovery plans to alleviate the problem in the exceptional disruptive event caused by COVID-19.

Quantification of bioactive compounds in guava at different ripening stages

Guava (Psidium guajava L.) is one of the most important tropical fruits belonging to the genus Psidium and the Myrtaceae family and claim to have phenolic compounds that have been reported to possess strong antioxidant activity. This study was aimed to evaluate the bioactive constituents in guava cultivars at different ripening stages by HPLC. The five guava cultivars were selected at different ripening stages and the bioactive components were analysed by high-pressure liquid chromatography. The quantification of bioactive compounds revealed that the highest amount of bioactive compounds was found in cultivar Safeda at the unripe stage, while a minimum amount was found in ripe Apple Colour guava cultivar. The six bioactive compounds were quantified in the range of gallic acid (9.46-63.08 mg/100 g), quercetin (0.11-2.51 mg/100 g), myrcetin (0.09-0.034 mg/100 g), ascorbic acid (7.45-75.07 mg/100 g), apegenin (0.01-0.032 mg/100 g) and lycopene (0.34-0.92 mg/100 g). The exploratory evaluation of guava samples was performed through Principal Component Analysis (PCA), the bioactive compounds, lycopene, myricetin, and quercetin are dominant variables on this PC1 (61.52%) (Scores better than 0.7), thereby causing greater variability among these samples. The second principal component (PC2) represents 16.54% of the total variance and the ascorbic acid, gallic acid and apeginin (score better than 0.7), are the dominant variables on this PC.

Glutathione (GSH) improves sperm quality and testicular morphology in streptozotocin-induced diabetic mice

Diabetes mellitus (DM) is known to cause reproductive impairment. In men, it has been linked to altered sperm quality and testicular damage. Oxidative stress (OS) plays a pivotal role in the development of DM complications. Glutathione (GSH) is a part of a nonenzymatic antioxidant defense system that protects lipid, protein, and nucleic acids from oxidative damage. However, the protective effects of exogenous GSH on the male reproductive system have not been comprehensively examined. This study determined the impact of GSH supplementation in ameliorating the adverse effect of type 1 DM on sperm quality and the seminiferous tubules of diabetic C57BL/6NTac mice. GSH at the doses of 15 mg kg⁻¹ and 30 mg kg⁻¹ was given intraperitoneally to mice weekly for 6 consecutive weeks. The mice were then weighed, euthanized, and had their reproductive organs excised. The diabetic (D Group) showed significant impairment of sperm quality and testicular histology compared with the nondiabetic (ND Group). Diameters of the seminiferous lumen in diabetic mice treated with 15 mg kg⁻¹ GSH (DGSH15) were decreased compared with the D Group. Sperm motility was also significantly increased in the DGSH15 Group. Improvement in testicular morphology might be an early indication of the protective roles played by the exogenous GSH in protecting sperm quality from effects of untreated type 1 DM or diabetic complications. Further investigation using different doses and different routes of GSH is necessary to confirm this suggestion.

New solutions for old challenges in glaucoma treatment: is taurine an option to consider?

Glaucoma is a range of progressive optic neuropathies characterized by progressive retinal ganglion cell loss and visual field defects. It is recognized as a leading cause of irreversible blindness affecting more than 70 million people worldwide. Currently, reduction of intraocular pressure, a widely recognized risk factor for glaucoma development, is the only pharmacological strategy for slowing down retinal ganglion cell loss and disease progression. However, retinal ganglion cell death and visual field loss have been observed in normotensive glaucoma, suggesting that the disease process is partially independent of intraocular pressure. Taurine is one of the agents that have attracted attention of researchers recently. Taurine has been shown to be involved in multiple cellular functions, including a central role as a neurotransmitter, as a trophic factor in the central nervous system development, as an osmolyte, as a neuromodulator, and as a neuroprotectant. It also plays a role in the maintenance of the structural integrity of the membranes and in the regulation of calcium transport and homeostasis. Taurine is known to prevent N-methyl-D-aspartic acid-induced excitotoxic injury to retinal ganglion cells. A recently published study clearly demonstrated that taurine prevents retinal neuronal apoptosis both in vivo and in vitro. Protective effect of taurine may be attributed to direct inhibition of apoptosis, an activation of brain derived neurotrophic factor-related neuroprotective mechanisms and reduction of retinal oxidative and nitrosative stresses. Further studies are needed to fully explore the potential of taurine as a neuroprotective agent, so that it can be applied in clinical practice, particularly for the treatment of glaucoma. The objective of current review was to summarize recent evidence on neuroprotective properties of taurine in glaucoma.