Sperm contributions to oocyte activation: more that meets the eye

It is well known that for successful fertilization, oocyte activation is required, which involves a signal transduction cascade leading to the conversion of the oocyte to a diploid embryo. During oocyte activation, intracellular calcium levels oscillate repetitively causing exocytosis of cortical granules, the enzymes which the latter contain are released into the perivitelline space, leading to modifications of the zona pellucida (ZP), which prevent the penetration of the ZP by further spermatozoa. Τhe necessary element that initiates oocyte activation is apparently the release of intracellular calcium (Ca²⁺) stored in the endoplasmic reticulum (ER). The exact mechanism via which Ca²⁺ is released within the oocyte has not been yet clarified, and has been a matter of an ongoing debate. Today, the sperm factor hypothesis has gained general acceptance, according to which a sperm molecule, either phospholipase C (PLCζ) or a post-acrosomal sheath WW domain-binding protein (PAWP), diffuses into the ooplasm initiating a molecular cascade involving mainly the phosphoinositide pathway. Mounting evidence now indicates that these calcium oscillations are caused by a testis-specific PLC termed PLCζ, released into the oocyte following gamete fusion. Also, recently, PAWP has been proposed as an alternative sperm factor candidate. These different sperm candidates have led to a significant debate. This raises important questions as regards to the relative importance of these two proteins as diagnostic tools in reproductive medicine with therapeutic potential, indicating the need for further research. In the present mini review, the phenomenon of oocyte activation during fertilization as well as the existing controversy will be highlighted and the possible mechanisms that are involved in this process will be discussed. Finally, an explanation of the existing debate will be attempted.     

Biomarkers in sarcoidosis

Introduction: Numerous biomarkers have been evaluated for the diagnosis, assessment of disease activity, prognosis, and response to treatment in sarcoidosis. In this report, we discuss the clinical and research utility of several biomarkers used to evaluate sarcoidosis.

Areas covered: The sarcoidosis biomarkers discussed include serologic tests, imaging studies, identification of inflammatory cells and genetic analyses. Literature was obtained from medical databases including PubMed and Web of Science.

Expert commentary: Most of the biomarkers examined in sarcoidosis are not adequately specific or sensitive to be used in isolation to make clinical decisions. However, several sarcoidosis biomarkers have an important role in the clinical management of sarcoidosis when they are coupled with clinical data including the results of other biomarkers.     

Focus on HPV Infection and the Molecular Mechanisms of Oral Carcinogenesis

This study is focused on the epidemiological characteristics and biomolecular mechanisms that lead to the development of precancerous and cancerous conditions of oral lesions related to Human Papilloma Virus (HPV) infections. Current evidence from the literature demonstrates the role of HPV in potentially malignant oral disorders. Therefore, the underlying biomolecular processes can give arise, or contribute to, benign lesions as well as to oral carcinogenesis.     

Predictors and Outcomes of Renal Replacement Therapy After Left Ventricular Assist Device Implantation

ObjectiveTo examine the frequency and outcomes of patients requiring renal replacement therapy (RRT) early after left ventricular assist device (LVAD) implantation.Patients and MethodsWe examined use of in-hospital RRT and outcomes in consecutive adults who underwent continuous-flow LVAD implantation from February 15, 2007, through August 8, 2017. Logistic regression was used to examine predictors of RRT. The associations of RRT with outcomes were examined using Cox proportional hazards regression.ResultsOf 354 patients who underwent LVAD implantation, 54 (15%) required in-hospital RRT. Patients receiving RRT had higher preoperative Charlson Comorbidity Index values (median, 5 vs 4; P=.03), Model for End-Stage Liver Disease scores (mean, 19.0 vs 14.5; P<.001), right atrial pressure (mean, 19.1 vs 13.4 mm Hg; P<.001), and estimated 24-hour urine protein levels (median, 357 vs 174 mg; P<.001) and lower preoperative estimated glomerular filtration rate (eGFR) (median, 43 vs 57 mL/min; P<.001) and measured GFR using ¹²⁵I-iothalamate clearance (median, 33 vs 51 mL/min; P=.001) than those who did not require RRT. Approximately 40% of patients with eGFR less than 45 mL/min/1.73 m² and 24-hour urine protein level greater than 400 mg required RRT vs 6% with eGFR greater than45 mL/min/1.73 m² and without significant proteinuria. Lower preoperative eGFR, higher estimated 24-hour urine protein level, higher right atrial pressure, and longer cardiopulmonary bypass time were independent predictors of RRT after LVAD implantation. Of patients requiring in-hospital RRT, 18 (33%) had renal recovery, 18 (33%) required outpatient hemodialysis, and 18 (33%) died before hospital discharge. After median (Q1, Q3) follow-up of 24.3 (8.9, 49.6) months, RRT was associated with increased risk of death (adjusted hazard ratio [HR], 2.86; 95% CI, 1.90-4.33; P<.001) and gastrointestinal bleeding (adjusted HR, 4.47; 95% CI, 2.57-7.75; P<.001).ConclusionIn-hospital RRT is associated with poor prognosis after LVAD. A detailed preoperative assessment of renal function before LVAD may be helpful in risk stratification and patient selection.     

Immune Modulation in Heart Failure: the Promise of Novel Biologics

Purpose of review

Immune system activation plays a central role in heart failure progression. Large-scale immune modulatory clinical trials targeting tumor necrosis factor-α and broad spectrum immune modulation have been negative. The objective of this review is to highlight past, present, and what is in the horizon for the immunomodulation in heart failure with a focus of biologics.

Recent findings

Strategies targeting interleukin-1 pathway are currently undergoing clinical evaluation and data from pilot studies are promising. The potential of cell therapy for immune modulation is increasingly recognized in clinical trials. Strategies targeting anti-cardiac antibodies such as immunoadsorption and intravenous immunoglobulin have been used in clinical practice with positive outcomes but large pragmatic clinical trials are lacking. The use of an aptamer to block anti-cardiac antibodies is undergoing phase 1 clinical evaluation. Promising targets include inflammasomes, toll-like receptors, chemokines, natural killer cells, and macrophages.

Summary

Large-scale immune modulatory clinical trials have been negative. Nevertheless, the experience gained from them along with increasing understanding of molecular mechanisms of immune pathophysiology in heart failure is leading to rapid recognition of new therapeutic targets and approaches.

     

Heart involvement in systemic sclerosis: a combined echocardiographic and scintigraphic study

The aim of this study is to investigate systemic sclerosis (SSc) patients without clinically evident heart disease for cardiac abnormalities. SSc patients and age- and sex-matched healthy controls from the hospital staff underwent transthoracic echocardiography for the assessment of the left ventricle (LV) morphology and function and estimation of the pulmonary artery systolic pressure (PASP). Patients further underwent stress-rest myocardial perfusion imaging (MPI) scintigraphy by single-photon emission computed tomography (SPECT). Thirty-seven patients were included (33 women, 19 with diffuse, and 18 with limited SSc). LV hypertrophy was more common in SSc patients than controls (24.3 vs 0 %, p?=?0.001). Impaired LV relaxation was found in 45.9 % of patients and 40.5 % controls (p?=?0.639). Excluding patients with arterial hypertension, LV hypertrophy was still found in 23.1 % and LV relaxation impairment in 38.5 %. PASP over 30 mmHg was found in 13 patients (35.1 %), 11 of whom had no history of pulmonary arterial hypertension (PAH). Of 35 patients who underwent SPECT, 21 patients (60 %) exhibited reversible LV perfusion defects. Their mean age was 51.8 years; four patients were younger than 40 years old and eight patients younger than 50 years. In all cases, ischemia was graded as mild or moderate and in a single case, graded as significant. Subclinical heart involvement is common in SSc patients even in the younger age groups. LV hypertrophy and impaired relaxation, raised PASP, and ischemia on MPI with SPECT are found in a significant proportion of SSc patients. Careful screening of SSc patients for potential heart involvement and consultation by a cardiologist may be of value.