Reprogramming Primary Amniotic Fluid and Membrane Cells to Pluripotency in Xeno-free Conditions

Autologous cell-based therapies got a step closer to reality with the introduction of induced pluripotent stem cells. Fetal stem cells, such as amniotic ...

University of South Alabama

Candida parapsilosis is an extremely rare cause of meningitis. We report the case of a neonate born at 26+4 weeks of gestation who was admitted to the neonatal intensive care unit at our institution due to respiratory immaturity. During the course of a 3-month hospitalization, the neonate developed fever and lethargy. A lumbar puncture revealed milky-white, turbid cerebrospinal fluid which contained many nucleated cells, mostly neutrophils. Microscopic examination of the cerebrospinal fluid revealed marked acute inflammation and fungal yeast forms, and cultures of the cerebrospinal fluid and peripheral blood yielded C. parapsilosis. Imaging studies subsequently revealed a subdural empyema related to epidural migration of a central venous catheter (CVL). The neonate received extended therapy with amphotericin B and fluconazole. He responded favorably to therapy and was discharged 3 months after birth. This case underscores the clinical importance of the recognition and treatment of a potentially lethal fungal pathogen of the central nervous system and the need for awareness of complications resulting from CVL malposition.

Neonatal Candida parapsilosis meningitis and empyema related to epidural migration of a central venous catheter.

In pediatric patients, Kluyvera spp. has emerged as a cause of disease ranging from soft tissue infections to sepsis with multiorgan failure. Successful treatment options include third-generation cephalosporins, tetracycline, aminoglycosides, and fluoroquinolones, but resistance to first- and second-generation cephalosporins persists. Clinicians should be aware of the spectrum of disease and increasing clinical importance associated with this emerging pathogen.

Kluyvera infections in the pediatric population.

Gastrointestinal tract involvement by neurofibromatous lesions is rare and occurs most frequently as one of the systemic manifestations of generalized neurofibromatosis type 1 (NF1). In this setting, the lesions may manifest as focal scattered neurofibromas or as an extensive diffuse neural hyperplasia designated ganglioneuromatosis. Occasionally, such lesions may be the initial sign of NF1 in patients without any other clinical manifestations of the disease. Rarely, cases of isolated neurofibromatosis of the large bowel with no prior or subsequent evidence of generalized neurofibromatosis have been documented. We present the case of a 52 year-old female with abdominal pain and alternating bowel habits. Colonoscopic evaluation revealed multiple small polyps in the cecum and the presence of nodular mucosa in the colon and rectum. Pathologic evaluation of the biopsies from the cecum, descending colon, sigmoid colon, and rectum revealed tangled fascicles of spindle cells expanding the lamina propia leading to separation of the intestinal crypts. Immunohistochemical stains helped confirm the diagnosis of diffuse intestinal neurofibromatosis. A thorough clinical evaluation failed to reveal any stigmata of generalized neurofibromatosis. This case represents a rare presentation of isolated intestinal neurofibromatosis in a patient without classic systemic manifestations of generalized neurofibromatosis and highlights the need in such cases for close clinical follow-up to exclude neurofibromatosis type I or multiple endocrine neoplasia type II.

Isolated intestinal neurofibromatous proliferations in the absence of associated systemic syndromes.

We report a case of native valve and pacemaker endocarditis in a 78-year-old male with diabetes mellitus who died after cardiac surgery. At autopsy, tricuspid valve vegetations and lung abscesses containing thick, hyaline, septate, and branching hyphae were present. The culture identified Scedosporium apiospermum, an infrequent cause of opportunistic infections in immunocompromised hosts.

Tricuspid valve and pacemaker endocarditis due to Pseudallescheria boydii (Scedosporium apiospermum).

Gastrointestinal stromal tumors are mesenchymal neoplasms with a spectrum of histologic appearances and biologic activity. The morphologic classification of these lesions has evolved over time, and molecular analysis has led to a better understanding of their nature. The histologic differential diagnosis for these lesions is broad and includes many spindle cell lesions of the gastrointestinal tract, including neoplasms of true smooth muscle and neural origin, proliferating fibrous lesions, metastatic neoplasms, and primary sarcomas of vascular and adipose origin. Immunohistochemical studies that include CD117 have become invaluable in the classification of mesenchymal lesions arising in the gastrointestinal tract. Treatment of gastrointestinal stromal tumors has historically been involved surgery, but the use of the chemotherapeutic agent imatinib mesylate for advanced disease has made accurate classification even more important. The molecular features have not only allowed us to understand the pathogenesis of these tumors but also have proven to be associated with response to kinase inhibitors.

Gastrointestinal stromal tumors: a review of the literature.

Rosai-Dorfman disease (RDD), also known as "sinus histiocytosis with massive lymphadenopathy," only rarely involves the gastrointestinal (GI) tract. Therefore, this unusual site of presentation can be challenging for the pathologist. We present a case of RDD manifesting as a rectal submucosal mass associated with rectal bleeding in a 54 year old woman. The diagnosis was made on cytologic preparations obtained through endoscopic ultrasound guided fine needle aspiration (EUS-FNA) and subsequently confirmed by biopsy. To our knowledge, this is the first time extranodal RDD of the GI tract has been diagnosed by EUS-FNA. A review of previously published cases of GI RDD is presented to increase awareness of this exceptional presentation.

Rectal extranodal Rosai-Dorfman disease diagnosed by EUS-FNA: a case report and review of the literature.

Amniotic fluid stem cells (AFSC) represent an attractive potential cell source for fetal and pediatric cell-based therapies. However, upgrading them to pluripotency confers refractoriness toward senescence, higher proliferation rate and unlimited differentiation potential. AFSC were observed to rapidly and efficiently reacquire pluripotency which together with their easy recovery makes them an attractive cell source for reprogramming. The reprogramming process as well as the resulting iPSC epigenome could potentially benefit from the unspecialized nature of AFSC. iPSC derived from AFSC also have potential in disease modeling, such as Down syndrome or β-thalassemia. Previous experiments involving AFSC reprogramming have largely relied on integrative vector transgene delivery and undefined serum-containing, feeder-dependent culture. Here, we describe non-integrative oriP/EBNA-1 episomal plasmid-based reprogramming of AFSC into iPSC and culture in fully chemically defined xeno-free conditions represented by vitronectin coating and E8 medium, a system that we found uniquely suited for this purpose. The derived AF-iPSC lines uniformly expressed a set of pluripotency markers Oct3/4, Nanog, Sox2, SSEA-1, SSEA-4, TRA-1-60, TRA-1-81 in a pattern typical for human primed PSC. Additionally, the cells formed teratomas, and were deemed pluripotent by PluriTest, a global expression microarray-based in-silico pluripotency assay. However, we found that the PluriTest scores were borderline, indicating a unique pluripotent signature in the defined condition. In the light of potential future clinical translation of iPSC technology, non-integrating reprogramming and chemically defined culture are more acceptable.

Non-integrating episomal plasmid-based reprogramming of human amniotic fluid stem cells into induced pluripotent stem cells in chemically defined conditions.

Smooth muscle myosin heavy chain (SMMHC) is a major structural component of the contractile apparatus in smooth muscle cells. Even though it is considered a relatively specific marker for terminal smooth muscle cell differentiation, expression in other cell types such as follicular dendritic cells (FDCs) has rarely been reported. To determine whether SMMHC represents an effective FDC marker in lymphoid tissues, we compared the immunohistochemical results for SMMHC with those of the traditional FDC markers podoplanin (D2-40) and CD21. Paraffin sections of 44 lymphoid tissues were analyzed, including 31 cases of follicular hyperplasia, 6 cases of follicular lymphoma, 2 cases of peripheral T-cell lymphoma, 3 cases of diffuse large B-cell lymphoma arising in follicular lymphoma, 1 case of nodular sclerosis classical Hodgkin lymphoma, and 1 case of small lymphocytic lymphoma. There was no statistically significant difference between the number of SMMHC-positive and D2-40-positive or CD21 lymph nodes (P>0.05). The extent and intensity of SMMHC-positive FDCs were similar to those of D2-40-positive FDCs (P=0.127 and 0.733, respectively), but significantly lower compared with those of CD21 cells (P=0.009 and 0.00002, respectively). However, in contrast to CD21 which was also positive in some germinal center B cells, SMMHC expression was restricted to FDCs. Our results indicate that SMMHC is an excellent marker for FDCs and can be particularly helpful in demonstrating the underlying architecture in lymphoid processes.

Use of Smooth Muscle Myosin Heavy Chain as an Effective Marker of Follicular Dendritic Cells.

Exosomes are important mediators in intercellular communications and play a role in cancer progression and metastasis. Exosomal membranes are enriched in endosome-specific tetraspanins (CD9 and CD63). Here, we explored the expression of CD63 and CD9 utilizing immunohistochemistry in malignant and nonmalignant cells in 29 resected pancreatic specimens (RPSs) of mixed racial background.

Exosomal Markers (CD63 and CD9) Expression Pattern Using Immunohistochemistry in Resected Malignant and Nonmalignant Pancreatic Specimens.

Fetal stem cells are a unique type of adult stem cells that have been suggested to be broadly multipotent with some features of pluripotency. Their clinical potential has been documented but their upgrade to full pluripotency could open up a wide range of cell-based therapies particularly suited for pediatric tissue engineering, longitudinal studies or disease modeling. Here we describe episomal reprogramming of mesenchymal stem cells from the human amnion to pluripotency (AM-iPSC) in chemically defined conditions. The AM-iPSC expressed markers of embryonic stem cells, readily formed teratomas with tissues of all three germ layers present and had a normal karyotype after around 40 passages in culture. We employed novel computational methods to determine the degree of pluripotency from microarray and RNA sequencing data in these novel lines alongside an iPSC and ESC control and found that all lines were deemed pluripotent, however, with variable scores. Differential expression analysis then identified several groups of genes that potentially regulate this variability in lines within the boundaries of pluripotency, including metallothionein proteins. By further studying this variability, characteristics relevant to cell-based therapies, like differentiation propensity, could be uncovered and predicted in the pluripotent stage.

Javier Laurini

College of Medicine

University of South Alabama

Reprogramming Primary Amniotic Fluid and Membrane Cells to Pluripotency in Xeno-free Conditions

Javier Laurini

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University of South Alabama

Reprogramming Primary Amniotic Fluid and Membrane Cells to Pluripotency in Xeno-free Conditions

College of Medicine