07.02.2023

Winter 2022

Original Articles

Complex Haploinsufficiency in Pluripotent Cells Yields Somatic Cells with DNA Methylation Abnormalities and Pluripotency Induction Defects

Rachel Lasry MSc, Noam Maoz PhD, Albert W. Cheng PhD, Nataly Yom Tov MSc, Elisabeth Kulenkampff PhD, Meir Azagury MSc, Hui Yang PhD, Cora Ople PhD, Styliani Markoulaki PhD, Dina A. Faddah PhD, Kirill Makedonski PhD, Ofra Sabag PhD, Rudolf Jaenisch PhD and Yosef Buganim PhD 6-15
Background: A complete knockout of a single key pluripotency gene may drastically affect embryonic stem cell function and epigenetic reprogramming. In contrast, the elimination of only one allele in a single pluripotency gene is mostly considered harmless to the cell.
Objectives: Here, we sought to understand whether complex haploinsufficiency exists in pluripotent cells and how it may affect the developmental potential of the cells and their cell’s derivatives
Methods: To induce complex haploinsufficiency, we simultaneously eliminated a single allele in different combinations of two pluripotency genes (i.e. Nanog+/-;Sall4+/-, Nanog+/-;Utf1+/-, Nanog+/-;Esr- rb+/- and Sox2+/-;Sall4+/-) in different pluripotent systems.
Results: Interestingly, although these double heterozygous lines maintain their stemness and contribute to chimeras equally to their parental control cells, fibroblasts derived from these systems show a significant reduction in their capability to induce pluripotency either by Oct4, Sox2, Klf4, and Myc (OSKM) or by nuclear transfer. Tracing the expression at early phases of reprogramming of Sall4 and Nanog, as representative key pluripotency targeted genes, could not explain the observed delay/blockage. Further exploration identified an abnormal methylation landscape around pluripotent and developmental genes in the double heterozygous fibroblasts. Accordingly, treatment with 5-azacytidine two days prior to transgene induction rescued the reprogramming defects.
Conclusions: This study emphasizes the importance of maintaining two intact alleles for pluripotency induction and suggests that insufficient levels of key pluripotency genes lead to DNA methylation abnormalities in the derived-somatic cells later on in development.

A Sub-Chronic Pharmacological Mouse Model For Schizophrenia Based On N-Methyl-D-Aspartate Receptor Hypo-function

Olga Konyukh BSc, Gilly Wolf PhD, Tzuri Lifschytz PhD, Hagar Ben-Ari MSc and Amit Lotan MD 16-21
Background: Schizophrenia is a severe psychiatric disorder, the precise underlying mechanisms of which are unknown. Many studies have shown that one of the abnormalities that play an important role in the etiology of schizophrenia is N-methyl-D-aspartate receptor (NMDAR) hypofunction. These observations prompted the development of the NMDAR hypo- function rat model of schizophrenia produced by daily injections of the receptor antagonist MK-801.
Objectives: Based on previous studies, it was decided to establish a sub-chronic (14 days) pharmacological mouse model of schizophrenia by administering the noncompetitive NMDA receptor antagonist MK-801 via mini-pumps.
Methods: Twenty-four male C-57BL/6 mice aged 5 weeks at the beginning of the protocol were used in this study. The mice were treated with MK-801 (0.5 mg/kg) or saline for two weeks. During post-natal weeks (PNW) 9-13, the mice underwent a four-week battery of behavioral and cognitive tests. To estimate the cognitive and motor functioning of mice, y-maze (on PNW 9 and 11) and elevated plus maze (on PNW 9) or open field test (on PNW 11) were performed. On PNW 13, an additional y-maze was performed after an acute injection of MK-801 (0.03 mg/kg). The mice were sacrificed at the end of the experiment.
Results: Two-week treatment with MK-801 impaired the working memory of mice. The observable behavioral effects dissipated over time, but the acute challenge with MK-801 made them reappear in the treated mice, but not in the healthy controls, presumably due to permanent damage as a result of the two-week treatment with MK-801. The drug also contributes to the appearance of positive schizophrenia symptoms (hyper locomotion).
Conclusions: The current study provides significant additions to schizophrenia research. However, further investigation of the subject is needed.

The Use of Point-of-Care Ultrasound in Teaching Medical Students Cardio-Vascular Physiology

Danna Krupik MD, Sheral Ohayon MD, Batsheva Tzadok MD, Ron Piran PhD, Majdi Halabi MD, Zeitun Teuta MD, Peter Gilbey MD, Daniel Glikman MD, Yair Blumberg PhD 22-26
Background: Teaching cardio-vascular physiology is a part of the basic training of a medical student. Learning and teaching physiology are perceived as challenging by both students and faculty. Ultrasound (US) is a foundational test in the evaluation of the function of the cardiovascular system. During the past two decades, US has been used increasingly in the instruction of medical students. Early exposure of medical students to this technology improves clinical decision-making and enhances the understanding of anatomy and physiology. The Bar-Ilan University Azrieli Faculty of Medicine in Safed has developed a pre-clinical physiology teaching module using US.
Objectives: To describe an innovative pre-clinical physiology teaching module using US and employing the flipped classroom approach.
Methods: Throughout the course, students were allocated self-study time, during which they were required to learn the course material. At the end of the self-study period, the students' knowledge was tested, and then students were divided into faculty-guided small groups, for practical application of the learned material. During the academic years 2019-20 and 2020-21, students received two practical US workshops: the cardiac cycle and cardiopulmonary interaction. Upon completion of the course, students filled in an evaluation questionnaire and were asked to rate their satisfaction with the US workshops.
Results: Students stated that the US laboratory helped in better understanding the subject matter in general, and specifically, greatly helped in the understanding of the cardiac cycle; 84% of the students felt that the exposure to US contributed to their understanding of the relevance of cardio-vascular physiology to their training as physicians. Students also stated that US helped in the transition from theory to practice.
Conclusions: The teaching of cardio-vascular physiology using US was found to be well-accepted by medical students. Further research is required in order to evaluate the efficacy of this teaching approach.

Sexual Dysfunction Among Cancer Patients Treated With Antineoplastic Therapy

Dina Punchik BSc, Hadar Barazani BSc, Vlada Bouki MD, Sharon Peleg Nesher RN, Emmanuel Waller RN , Eliya Shachar MD, Ido Wolf MD 27-31
Background: One of the essential components of quality of life (QOL) is a sexual function, which might be affected following treatment in cancer patients, either due to the disease or the treatment regimen itself. Long-term sexual dysfunction includes changes in body image, intimacy, sexual response, sexual satisfaction, and stability of relationships. The repercussions of oncology treatment necessitate sexual rehabilitation that will give patients awareness, knowledge, and guidance regarding sexual activity.
Objectives: The aim of this work was to assess sexual dysfunction and satisfaction reported by patients during chemotherapy, immunotherapy, and targeted treatments.
Methods: Patients treated with active anti-neoplastic therapy were asked to complete an anonymous questionnaire, assess- ing sexual function in relation to their sexual activity prior to treatment. The questionnaire was distributed to patients treated at the Oncology Division of Tel Aviv Sourasky Medical Center (TASMC) in August-September 2022. We evaluated the degree of healthcare support (oncologist, sexual therapist, therapist, support group) offered to cancer patients, and assessed whether the subject is sufficiently addressed to guide patients' needs.
Results: The survey was distributed to 75 patients, and 41 (55%) respondents participated. The majority of the patients (76%) reported that they were not offered information addressing sexual dysfunction during or after cancer treatment administration. 85% of the women reported a decline in the frequency of sexual desire, whereas 63% of men experienced a decline.
Conclusions: Our findings indicate, as was predicted, that cancer patients’ sexual activity is compromised during therapy, regardless of gender, age, and education level. Continued eval- uation to define optimal counseling and education strategies during antineoplastic treatment, are necessary to better main- tain sexual function among cancer patients. Further work is necessary to address the treatment-dependent effects and better define interventions that may improve patient QOL.

Review Articles

Glioblastoma, and its Supramaximal Resection

Rotem Bohbot, BSc, Tehila Kaisman-Elbaz, MD, PhD, BPT 32-41
Background: Glioblastoma is the most common primary malignant brain tumor in adults. It is an incurable, devastating disease, with a 5-year survival rate of less than 7%. The acceptable treatment protocol for glioblastoma includes resection followed by radiation and chemotherapy. Maximal safe resection of the contrast-enhancing area of the tumor has been correlated with improving patients' survival, but glioblastoma typically extends beyond the contrast-enhancing borders. Recently, a supramaximal resection (SMR) approach has been suggested, to increase tumor removal rates and possibly improve patients' survival even further.
Objectives: To thoroughly review the existing literature regarding glioblastoma's diagnosis, advances in molecular classification, prognosis, and available oncological treatments. In addition, to review the surgical approach currently applied to treat the disease and compare it with SMR and its associated benefits, if any, to the patient's survival and other oncological parameters.
Methods: A comprehensive literature search of the available papers was conducted. The studies' main outcomes were critically reviewed, compared, and summarized. Emphasis was placed on comparing oncological outcomes, such as progression-free survival (PFS) and overall survival (OS) data among patients that underwent acceptable gross total resection (GTR) to patients who underwent SMR in addition.
Results: SMR was found to significantly improve patients' PFS, and OS compared to GTR, in an extent-dependent manner. Median PFS and OS increased to 11 months and 29 months, respectively. Notably, the complication rate was low and recovery length was comparable, which enabled patients to receive complementary oncological treatment and to be included in clinical trials.
Conclusions: SMR is safe and the accumulating evidence indicates its significant benefit as regards extending PFS and OS. Nevertheless, most studies are retrospective, therefore, it is not yet certain whether SMR should be offered for all glioblastoma patients undergoing tumor resection. Future prospective studies should determine this.

The Interplay of Hypoxia Signaling and B Cells Drives Bone Remodeling

Gal Kojukhov BSc 42-52
Background: Osteoimmunology is a well-characterized area of research that focuses on the interactions between the immune system and bone cells. Physiological bone turnover relies primarily on the balance between osteoblast-mediated bone formation and osteoclast-driven bone destruction, mediated through the RANK-RANKL-OPG pathway. Although compact bone makes up 80% of the human skeleton, the main regulators of bone mass and density reside primarily within bone marrow niches. Increasing evidence suggests that bone marrow-residing immune cells are significant mediators of this regulation. Furthermore, the bone marrow is characterized by a constant change in oxygen gradient, which leads to the formation of transient hypoxic niches. Hypoxia-induced transcription factors (HIFs) and erythropoietin (EPO) synthesis are characteristic features of the hypoxic response. HIFs are key regulators of the intracellular hypoxic response, whereas EPO is considered the hallmark extracellular cytokine/hormone that mediates the tissue-level response. The most well-known EPO effect is driving erythropoiesis; however, a plethora of evidence suggests that it also induces far-reaching changes in the immune system, particularly in B cells.
Objectives: This review aims to summarize leading ideas on the regulation of osteoclastogenesis and bone remodeling by B lineage cells, especially under hypoxic conditions.
Methods: Up-to-date information and results were collected on the subject of osteoimmunology from both experimental and clinical data. Particular focus was given to the effects of both B cells and hypoxia signals on physiological changes in bone.
Results: This review examines recent insights in the field of osteoimmunology, focusing on B cell-related bone remodeling and hypoxia signaling perturbations. The attention given to immune-related effects on bone turnover is constantly rising. Elucidation of more parts of the complex mechanisms involved in bone-immune regulation gives rise to new perspectives on pathological mechanisms and possible treatments.
Conclusions: A multitude of papers, applying different methodologies and aiming to verify distinct hypotheses, have given rise to many controversies. Here I address some of the unanswered questions and provide explanations.

Astrocyte-Glioblastoma Crosstalk

Yair Roth BMSc 52-58
Background: Glioblastoma multiforme (GBM) is the most aggressive malignant primary tumor arising in the brain. It ac- counts for thousands of deaths worldwide and has a very poor prognosis despite available therapies. The GBM relies on the tumor microenvironment (TME) in order to enhance invasion and support tumor progression. Astrocytes account for about 50% of brain cells, playing crucial roles in brain homeostasis. In brain pathologies, astrocytes become reactive through a process called “gliosis”. In GBM astrocytes are recruited and activated to support GBM invasiveness and progression. Tumor-associated astrocytes (TAAs) therefore help the GBM progression by providing an immunosuppressive phenotype and thus leading to inhibition of the immune response, chemoresistance, and upregulation of tumor-supporting genes. Furthermore, astrocytes modulate the TME by downregulating the blood-brain barrier and helping in the degradation of the extracellular matrix. Further understanding of the mechanisms by which TAAs support GBM progression could open innovative therapeutic approaches for the narrow and low efficacy therapies available.
Objectives: This review focuses on presenting the main pathways by which astrocytes enhance GBM proliferation, invasion, and tumor progression.
Methods: Selection criteria for articles included in the review involved a thorough search in the free search engine PUBMED for original articles published in peer-reviewed journals. Search terms included “Glioblastoma Multiforme AND Astrocytes”.
Results:
Conclusions: Astrocytes play an important role in modulating the TME and the immune system in a way that supports GBM proliferation and progression. Further research is required to fully elucidate the important role of astrocytes in TME. Furthermore, a clear understanding of the pathways in which astrocytes support GBM may provide the background needed to develop more effective innovative therapies than the conventional treatment of GBM.

Letters To The Editor

How Do We Detect Cancer? Some New and Exciting Techniques That Will Save Lives

Anne Krinsky 59-60
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Neurodiversity in the Workplace: Integration of Employees on the Autistic Spectrum into High-Tech Companies

Orr Erlich 61-62
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Can AI Achieve Its Potential in Healthcare? Only if Medical Schools Teach Students About Its Shortcomings

Guy Melamed, BMSc 63-64
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When Capitalism Kills: The Cautionary Story of the Sackler Family

Nica Shkolnik, BA 65-66
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Epiphany

שחיקת מפרקים

נריה יעקב 68
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