Stem Cells: In Sickness and in Health

Stem cells are undifferentiated cells with the ability to proliferate and convert to different types of differentiated cells that make up the various tissues and organs in the body. They exist both in embryos as pluripotent stem cells that can differentiate into the three germ layers and as multipotent or unipotent stem cells in adult tissues to aid in repair and homeostasis. Perturbations in these cells' normal functions can give rise to a wide variety of diseases. In this review, we discuss the origin of different stem cell types, their properties and characteristics, their role in tissue homeostasis, current research, and their potential applications in various life-threatening diseases. We focus on neural stem cells, their role in neurogenesis and how they can be exploited to treat diseases of the brain including neurodegenerative diseases and cancer. Next, we explore current research in Induced Pluripotent Stem Cells (iPSC) techniques and their clinical applications in regenerative and personalized medicine. Lastly, we tackle a special type of stem cells called Cancer Stem Cells (CSCs) and how they can be responsible for therapy resistance and tumor recurrence and explore ways to target them.

PTSD in the COVID-19 Era

Background

In December 2019, Wuhan City in Hubei Province, China witnessed an outbreak of a novel type of coronavirus (COVID-19), named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The sharp rise in the number of infected cases and the surge spike in fatalities worldwide prompted the World Health Organization (WHO) to declare this rapid outbreak a global pandemic in March 2020. The economic, health, and social ramifications of COVID-19 induced fear and anxiety all over the world.

Objective

The purpose of this review is to discuss how precautionary measures and restrictions imposed by governments, such as quarantines, lockdowns, and social distancing, have not only caused economic losses, but also a rise in mental health problems specifically post-traumatic stress disorder (PTSD).

Methods

A deep comprehensive review of the relevant literature regarding the pandemic and its debilitating consequences on the psychological status of the public was performed.

Results

This review illustrates that the pandemic had a traumatic impact on the psychological functioning of the public, particularly COVID-19 survivors, older adults, and healthcare workers, due to difficulties in coping with new realities and uncertainties.

Conclusion

In this review, we have discussed the psychological implications of this pandemic and we have provided an extensive background for understanding options regarding PTSD management in healthy individuals and those with preexisting conditions.

Long-term stimulation of the anteromedial thalamus increases hippocampal neurogenesis and spatial reference memory in adult rats

Deep brain stimulation (DBS) has shown positive clinical results in neurodegenerative diseases. Previous work from our group showed that a single session of DBS to the anteromedial thalamic nucleus (AMN) in awake rats, increased proliferation of stem/progenitor cells in the dentate gyrus (DG) of the hippocampus. We thought to examine the effect of single versus multiple sessions of DBS to the AMN in modulating adult hippocampal neurogenesis. Rats received unilateral single session, multiple sessions or no electrical stimulation (sham) in the right AMN. Rats received 5'-bromo-2'-deoxyuridine (BrdU) injections and were followed over a period of 1 week or 4 weeks. Single session of electrical stimulation induced a 1.9-fold increase in the number of proliferating BrdU positive cells after one week from stimulation and a 1.8-fold increase at four weeks post stimulation, both in the ipsilateral DG. As for multiple sessions of stimulation, they induced a 3- fold increase that extended to the contralateral DG after 4 weeks from stimulation. Spatial reference memory was tested in the Y-maze test by examining novel arm exploration. Both single and multiple sessions of stimulation prompted an increase in novel arm exploration at week 4, while only the multiple sessions of stimulation had this effect starting from week 1. This study demonstrates that sustained activation of the AMN boosts neurogenesis and improves spatial reference memory.

Role of MicroRNAs in Anesthesia-Induced Neurotoxicity in Animal Models and Neuronal Cultures: a Systematic Review

Exposure to anesthetic agents in early childhood or late intrauterine life might be associated with neurotoxicity and long-term neurocognitive decline in adulthood. This could be attributed to induction of neuroapoptosis and inhibition of neurogenesis by several mechanisms, with a pivotal role of microRNAs in this milieu. MicroRNAs are critical regulators of gene expression that are differentially expressed in response to internal and external environmental stimuli, including general anesthetics. Through this systematic review, we aimed at summarizing the current knowledge apropos of the roles and implications of deregulated microRNAs pertaining to anesthesia-induced neurotoxicity in animal models and derived neuronal cultures. OVID/Medline and PubMed databases were lastly searched on April 1st, 2019, using the Medical Subject Heading (MeSH) or Title/Abstract words ("microRNA" and "anesthesia"), to identify all published research studies on microRNAs and anesthesia. During the review process, data abstraction and methodological assessment was done by independent groups of reviewers. In total, 29 studies were recognized to be eligible and were thus involved in this systematic review. Anesthetic agents studied included sevoflurane, isoflurane, propofol, bupivacaine, and ketamine. More than 40 microRNAs were identified to have regulatory roles in anesthesia-induced neurotoxicity. This field of study still comprises several gaps that should be filled by conducting basic, clinical, and translational research in the future to decipher the exact role of microRNAs and their functions in the context of anesthesia-induced neurotoxicity.

Intranigral Injection of Endotoxin Suppresses Proliferation of Hippocampal Progenitor Cells

Brain inflammation can result in functional disorders observed in several neurodegenerative diseases and that can be also associated with reduced neurogenesis. In this study, we investigate the effect of mild inflammation, induced by unilateral injection of Endotoxin (ET) in the substantia nigra (SN)/Ventral Tegmental Area, on the proliferation and survival of stem/progenitor cells in the dentate gyrus (DG) of the hippocampus. Adult female rats received unilateral injection of ET (2 μg/2 μl saline) or sterile saline (2 μl) in the right SN followed by 5′-Bromo-2′-deoxyuridine (BrdU) injections (66 mg/kg/injection). Intranigral ET injection induced bilateral decrease in the number of newly born BrdU positive cells in the DG. This effect was paralleled by a significant decrease in the exploratory behavior of rats, as assessed by the Y-maze novel arm exploration task. ET also induced a transient decrease in the number of tyrosine hydroxylase-positive cells in the injected SN, impaired motor behavior, and caused microglial activation in the SN. This study provides an experimental simulation of the remote effects of moderate and reversible neuroinflammation resulting in impaired communication between midbrain dopaminergic neurons and the hippocampus.

Combined laparoscopic and cystoscopic approach in large deep infiltrating endometriosis of the bladder

Resection of endometriosis nodules infiltrating the bladder is routinely performed by laparoscopy. However, laparoscopic resection may lead to inadvertent loss of healthy bladder tissue. Conversely, when bladder nodules are treated by cystoscopy alone, resection may be incomplete. A combined laparoscopic-cystoscopic approach allows safe and controlled resection. The video reports the procedure performed in a 33 year-old primipara who presented with a 40mm bladder nodule. The laparoscopic step is carried out by the gynecologist, who separates the bladder from the uterus and opens the vesico-vaginal space. Concomitantly, the urologist identifies and circumscribes the nodule's limits by cystoscopy. Then, the gynecologist identifies the circular incision previously performed, and completes the resection. The bladder defect is sutured. Early and mid-term postoperative outcomes were uneventful. In patients with large nodules of the bladder, combined laparoscopic-cystoscopic approach allows complete resection of endometriosis lesion, preserves healthy bladder tissue and avoids inadvertent injury of ureters.

Modeling Human Neurological and Neurodegenerative Diseases: From Induced Pluripotent Stem Cells to Neuronal Differentiation and Its Applications in Neurotrauma

With the help of several inducing factors, somatic cells can be reprogrammed to become induced pluripotent stem cell (iPSCs) lines. The success is in obtaining iPSCs almost identical to embryonic stem cells (ESCs), therefore various approaches have been tested and ultimately several ones have succeeded. The importance of these cells is in how they serve as models to unveil the molecular pathways and mechanisms underlying several human diseases, and also in its potential roles in the development of regenerative medicine. They further aid in the development of regenerative medicine, autologous cell therapy and drug or toxicity screening. Here, we provide a comprehensive overview of the recent development in the field of iPSCs research, specifically for modeling human neurological and neurodegenerative diseases, and its applications in neurotrauma. These are mainly characterized by progressive functional or structural neuronal loss rendering them extremely challenging to manage. Many of these diseases, including Parkinson's disease (PD), Huntington's disease (HD), Amyotrophic lateral sclerosis (ALS) and Alzheimer's disease (AD) have been explored in vitro. The main purpose is to generate patient-specific iPS cell lines from the somatic cells that carry mutations or genetic instabilities for the aim of studying their differentiation potential and behavior. This new technology will pave the way for future development in the field of stem cell research anticipating its use in clinical settings and in regenerative medicine in order to treat various human diseases, including neurological and neurodegenerative diseases.

Stoma obstruction after laparoscopic adjustable gastric banding for morbid obesity: report of two cases and treatment options

Laparoscopic adjustable gastric band is one of the surgical options available for morbid obesity in the current century. Its popularity is gained by its proven efficacy with a reported low incidence of the intraoperative as well as the postoperative complications. Stomal obstruction post-laparoscopic adjustable gastric band (LAGB) has been under reported in the English literature. We report this complication in two patients and discuss two different simple modalities of treatment. Post-LAGB complications are numerous, dealing with their complications have a steeping curve. Educating the patients postoperatively in regard to food ingestion manner is a must and should prevent such complication.

Desmoplastic infantile ganglioglioma/astrocytoma with cerebrospinal metastasis

Desmoplastic infantile ganglioglioma and astrocytoma (DIG/DIA) are rare intracranial tumours of early childhood that involve superficial cerebral cortex and leptomeninges. Despite the large size of the tumour and the presence of poorly differentiated cells, it is believed that the prognosis of DIG/DIA is excellent. We report two patients with DIG/DIA who developed multiple cerebrospinal metastases. To our knowledge only two similar cases have been reported in the literature. It appears that not all tumours with histological features of DIG/DIA behave in a benign way. It is possible that what is called DIG/DIA may be a heterogenous group of tumours with variable biological behaviour.

Long term outcome in children with Moyamoya disease: experience with 16 patients

We present our experience with 16 children with Moyamoya disease/variant diagnosed at the Royal Alexandra Hospital for Children, Westmead, Sydney, Australia in the period between January 1982 and March 2004. Thirteen of these patients had one of the different revascularisation procedures. We reviewed the modes of presentation and the long-term outcome in these children. In our series the functional outcome was related to the functional status at presentation and was not related to the type of surgical procedure or age at presentation. We believe this is the largest reported series of Moyamoya disease/variant in Australia.

Third ventricular cavernous haemangioma

We report a case of a third ventricular cavernous haemangioma (cavernoma). Cavernomas rarely occur within the ventricular system. Only 47 well-documented cases have been reported in the literature, 21 of which were located in the third ventricle. Cavernomas should be considered in the differential diagnosis of third ventricular lesions. Ventriculoscopy is very useful in establishing the diagnosis.

Intraventricular meningioma with drop metastases and subgaleal metastatic nodule

We report a case of malignant intraventricular meningioma with CSF drop metastases and an implantation metastatic subgaleal nodule in a 53-year-old woman. Malignant intraventricular meningiomas are rare with only seven cases being reported in the literature. These tumours can be very aggressive and one should consider immediate postoperative radiotherapy.

Juvenile pilocytic astrocytoma `pilomyxoid variant' with spinal metastases

We report a case of juvenile pilocytic astrocytoma of the hypothalamic/chiasmatic region with cerebrospinal fluid dissemination in a 16-month old girl. The tumour in this case had unusual histological features including the abundance of myxoid background, the absence of Rosenthal fibres and the presence of an angiocentric pattern. These features are consistent with the recently described "variant" named pilomyxoid astrocytoma. It remains unclear whether pilomyxoid astrocytoma represents an aggressive variant of classical juvenile pilocytic astrocytoma, or an entirely distinct clinico-pathological entity. Larger series and new molecular techniques may answer this question in the future.

Intracranial and spinal tuberculosis requiring neurosurgical intervention. The Wellington Hospital experience 1998-2001

AIMS

To describe the Wellington Neurosurgical Unit's recent experience of managing tuberculosis between January 1998 and January 2001.

METHODS

Patients with microbiologically confirmed tuberculosis of the central nervous system and whose management included surgery are described. Personal recall and review of the hospital records were used to extract relevant data.

RESULTS

Five patients were identified. As well as involvement of the brain parenchyma, meninges, spinal cord or spinal column, all had evidence of tuberculosis elsewhere. All but one patient deteriorated neurologically after being started on antituberculous chemotherapy.

CONCLUSIONS

The number of patients presenting with neurotuberculosis appears to have increased recently in the Wellington region. The high proportion of paradoxical progression in our series is unusual. Neurosurgical intervention may be required for diagnosis, to treat hydrocephalus, or to relieve mass effect. Management is prolonged and often complex, and close co-operation is required between the neurosurgical team and a physician experienced in the management of tuberculosis.

Tumor lysis syndrome in small cell carcinoma and other solid tumors

OBJECTIVE

To review the risk factors and clinical findings associated with tumor lysis syndrome (TLS) in patients with small cell carcinomas and other solid tumors.

METHODS

Reports of TLS in the English-language literature were identified by searching MEDLINE and the bibliographies of relevant case reports, journal articles, and book chapters. All reports identified through these searches, including abstracts from national meetings, were reviewed and included in this analysis. Data regarding clinical and biochemical parameters relevant to the occurrence of TLS were extracted from each report.

RESULTS

Of the 25 reported solid tumor patients who developed TLS, 7 had small cell carcinoma, 5 breast cancer, and 4 neuroblastoma. TLS was associated with a variety of treatment regimens, including chemotherapy, immunotherapy, hormonal therapy, radiation therapy, and surgery. Common risk factors for TLS in this population included pretreatment renal insufficiency, elevated serum lactate dehydrogenase (LDH), and hyperuricemia. Among the typical biochemical findings of TLS, acute renal insufficiency and hyperuricemia were identified in nearly all patients and hyperkalemia, hyperphosphatemia, hypocalcemia, and increased serum LDH were reported in over 75% of patients. In addition, seven patients, including the current case, presented with profound metabolic acidosis. Nine of 25 patients died during the acute episode of TLS.

CONCLUSIONS

Although TLS occurs infrequently in patients with solid tumors, the risk factors and biochemical abnormalities associated with this potentially fatal complication of therapy must be recognized to allow for adequate monitoring and early initiation of appropriate therapeutic measures.