Anastassios Philippou | National and Kapodistrian University of Athens (original) (raw)

Papers by Anastassios Philippou

Cureus

Endometriosis, defined as the development of endometrial tissue outside of the uterine cavity, is... more Endometriosis, defined as the development of endometrial tissue outside of the uterine cavity, is a common gynecological disorder. The prevalence of pelvic endometriosis approaches 6%-10% in the general female population, and in women with pain, infertility, or both, the frequency is 35%-50%. The gold standard recommended process for diagnosing endometriosis is laparoscopy, an invasive surgical procedure, with or without histologic verification. The currently available nonsurgical treatments include oral contraceptives (estrogen-progestogen preparations), progestogen preparations (containing progesterone derivatives), androgenic hormones (danazol), and gonadotropin-releasing hormone (GnRH) agonists and antagonists. Two GnRH types have been discovered in mammals, GnRH I and GnRH II. In particular, GnRH I is released by the hypothalamus; however, it can be present in various tissues and organs of the body, including neural tissue, where it exerts neuroendocrine, autocrine, and paracrine actions in the peripheral and central nervous system (CNS). Interestingly, another GnRH isoform, GnRH III, has been identified, which has 60% similarity with GnRH I from which it varies by four amino acids. This peptide has been shown to have a significant role in reproduction, specifically in gametogenesis and steroidogenesis. Further research is needed to identify innovative treatment options for endometriosis, such as the therapeutic exogenous administration of GnRH II or antagonists of the GnRH I receptor. In this review, we examined the role of GnRH in endometriosis, outlining the specific actions of GnRH and GnRH receptors (GnRHRs). The innovative use of GnRH analogs and antagonists in the treatment of endometriosis is also discussed.

Cells

Mitochondria are cellular organelles that play an essential role in generating the chemical energ... more Mitochondria are cellular organelles that play an essential role in generating the chemical energy needed for the biochemical reactions in cells. Mitochondrial biogenesis, i.e., de novo mitochondria formation, results in enhanced cellular respiration, metabolic processes, and ATP generation, while autophagic clearance of mitochondria (mitophagy) is required to remove damaged or useless mitochondria. The balance between the opposing processes of mitochondrial biogenesis and mitophagy is highly regulated and crucial for the maintenance of the number and function of mitochondria as well as for the cellular homeostasis and adaptations to metabolic demands and extracellular stimuli. In skeletal muscle, mitochondria are essential for maintaining energy homeostasis, and the mitochondrial network exhibits complex behaviors and undergoes dynamic remodeling in response to various conditions and pathologies characterized by changes in muscle cell structure and metabolism, such as exercise, mus...

Medicine and Science in Sports and Exercise, Sep 1, 2022

Medicine & Science in Sports & Exercise

Public Health and Toxicology, May 27, 2022

Journal of clinical medicine, Feb 6, 2024

Biomolecules, Dec 19, 2023

Metabolites, Oct 12, 2023

Journal of Clinical Medicine

Sarcopenic obesity (SO) constitutes the coexistence of skeletal muscle mass loss (sarcopenia) and... more Sarcopenic obesity (SO) constitutes the coexistence of skeletal muscle mass loss (sarcopenia) and excess adiposity (obesity). It is mainly considered as a condition in the elderly with health-threatening impacts ranging from frailty to mortality. Mitochondrial dysfunction consists one of the basic pathophysiological mechanisms leading to the development of SO and its consequences. Indirect indicators of mitochondrial function, such as VO2max and exercise capacity, have been demonstrated to be negatively affected in individuals with SO, while the positive effect of exercise on mitochondrial function has been widely proved; thus, in this review, we aimed at investigating the effects of endurance, resistance, and concurrent exercise training on indexes of mitochondrial dysfunction in SO patients. The results of the clinical trials evaluated reveal positive effects of chronic exercise on VO2max and physical capacity, as well as mitochondrial biogenesis and activity. It has been conclude...

Purpose CHCHD2 is an anti-apoptotic mitochondrial protein acting through the BCL2/BAX pathway in ... more Purpose CHCHD2 is an anti-apoptotic mitochondrial protein acting through the BCL2/BAX pathway in various cancers. However, data on the regulatory role of CHCHD2 in adrenal tumourigenesis are scarce. Methods We studied the expression of CHCHD2, BCL2 and BAX in human adrenocortical tissues and SW-13 cells. mRNA and protein levels were analysed through qPCR and immunoblotting respectively in 16 benign adrenocortical neoplasms (BANs) and 10 adrenocortical carcinomas (ACCs) along with the adjacent normal adrenal tissues (controls). BCL2/BAX mRNA expression was also analyzed in SW-13 cells after CHCHD2 silencing. MTS, flow cytometry and scratch assays were performed to assess cell viability, apoptosis and invasion respectively. Results BCL2 and CHCHCD2 mRNA and protein expression was increased in BANs compared with normal adrenal tissues whereas BAX was decreased. BAX and CHCHD2 mRNA and protein levels were significantly down-regulated and up-regulated respectively in ACCs compared to eit...

PubMed, Apr 8, 2011

Background/aim: The E peptide of the IGF-1Ec transcript has been documented to stimulate the grow... more Background/aim: The E peptide of the IGF-1Ec transcript has been documented to stimulate the growth of different cell lines, via a type I IGF-1 receptor (IGF-1R)-independent mechanism. The aim of the present study was to determine the implication of the IGF-1Ec isoform into the posterior capsule opacification process in human lens epithelium. Materials and methods: The expression of the IGF-1 system was characterized in human HLE-B3 lens epithelium cells and the mitogenic activity of IGF-1 and synthetic E peptide and the effects of growth hormone (GH) and dihydrotestosterone (DHT) were examined, using qualitative real-time PCR, RT-PCR, Western blot analysis and trypan blue exclusion assays in wild-type and IGF-1R knock-out HLE-B3 cells. Results: The data showed that HLE-B3 cells express only the IGF-1Ea and IGF-1R transcripts. GH increased the expression of IGF-1Ea and of the previously undetectable IGF-1Eb mRNA. Finally, IGF-1 did not present any activity in the knock-out cells. Conclusion: The IGF-1Ea isoform is the main source for the formation of mature IGF-1 in HLE-B3 cells. The effects of exogenous IGF-1 depend on the existence of IGF-1R. IGF-1 Ec is not expressed even in the presence of GH or DHT nor has it any effect on cell proliferation.

The insulin-like growth factor-I (IGF-I) is an important growth factor which regulates a variety ... more The insulin-like growth factor-I (IGF-I) is an important growth factor which regulates a variety of cellular responses and has important roles in multiple biological systems. IGF-I is produced by many tissues including the myocardium, indicating that a signifi cant component of its action is due to an autocrine and paracrine mode of function. Multiple transcripts of the Igf1 gene code for several precursor polypeptides (isoforms). IGF-I actions are mediated through its binding to several cell-membrane receptors, inducing cell proliferation, differentiation, migration and survival, and implicating this growth factor in mitogenic, myogenic and anti-apoptotic processes in cardiac muscle. In this chapter, focus has been driven on the signaling pathways that IGF-I triggers in the regulation of physiological and pathophysiological processes during cardiac hypertrophy, regeneration and remodeling. The concept of a potentially differential bioactivity and signaling of the different IGF-I peptides in the myocardium is also discussed.

Exercise affects many vital processes and biological functions in the human body, acting as a mul... more Exercise affects many vital processes and biological functions in the human body, acting as a multistressor for most of the organ systems and inducing their adaptive responses to exercise stress. Skeletal muscle is a paradigm of an organ on which exercise exerts multiple stress, e.g., metabolic and mechanical, and which exhibits a remarkable plasticity, possessing the ability to adapt to mechanical stimuli by changing its mass and overall contractile phenotype. The magnitude to which mechanical loading applied on the muscle can lead to its specific adaptations depends on the complex relationships between muscle shape, loading state, structural interactions, and metabolic status. When muscle tissue is subjected to mechanical deformation, mechanosensitive complexes (mechanosensors) situated in the muscle cell membrane sense mechanical alterations and activate intracellular signaling pathways (mechanotransduction), resulting in a plethora of acute molecular and cellular responses, as well as chronic adaptations. This chapter focuses mainly on the cellular and molecular mechanisms that mediate the transformation of mechanical loadinginduced muscle deformation into biochemical responses. KEY POINTS: ✓ Mechanotransduction describes the ability of a cell to sense, modify and translate a mechanical stimulus into biochemical signals. ✓ Mechanotransduction occurs at different components of the muscular system and includes the combined action of various elements of skeletal muscle, i.e., myofibers, myotendinous junction, tendons, muscle connective tissue and extracellular matrix. ✓ Isolated whole muscle ex vivo, and in vitro models have been developed to study the intracellular alterations that occur through mechanotransduction. ✓ Mechanotransduction, through specialized proteins, activates signaling pathways that contribute to the maintenance, regeneration, remodeling, and development of skeletal muscle.