Neonatal Myocardial Ischemia-Reperfusion Injury: A Proposed Pathogenic Sequence in the Context of Maternal/Fetal Vascular Malperfusion and Paradoxical Embolism.

BACKGROUND: Neonatal myocardial infarction (MI) in a structurally normal heart is frequently an obscure event that remains undiagnosed until autopsy. Causal attributions usually cite underlying maternal or fetal conditions. Refinement in understanding of pathogenic mechanisms underlying neonatal MI is key to advancements in diagnosis, prevention, treatments and prognosis. OBJECTIVE: This study presents a 36-week gestational age female with perinatal asphyxia, congenital hemolytic anemia and umbilical vein thrombosis who sustained catastrophic MI with reperfusion injury; and it reviews pertinent literature. RESULTS: We propose a pathogenic sequence that links maternal vascular malperfusion, fetal vascular malperfusion, hemolytic anemia, umbilical venous thrombosis, and paradoxical thromboemboli. CONCLUSION: This case highlights the importance of placental examination in connecting complex neonatal events with adverse maternal/placental conditions. A high index of suspicion is essential for early diagnosis of neonatal MI.

Congenital granular cell epulis: 24 new cases with more differences than similarities to granular cell tumor.

Congenital granular cell epulis (CGCE) is a rare tumor of gingiva that is exclusive to newborns, has marked female predominance, and is rarely associated with other abnormalities. Although benign in behavior, CGCE can be lethal by obstruction of respiration and/or deglutition and can require a multidisciplinary team of specialist at birth for survival of an otherwise normal infant. Histologically, CGCE resembles granular cell tumor (GCT), but unlike GCT, which is Schwannian-derived, derivation of CGCE remains an enigma, largely because of its low prevalence. This study presents 24 new cases of CGCE, the largest series since the original description 150 years ago and permits detailed study of homogeneity of cases diagnosed as CGCE as well as detailed comparisons of CGCE with GCT by clinical, morphological, immunohistochemical, and ultrastructural studies. The data show homogeneity within the CGCE cases, more differences than similarities between CGCE and GCT, and no immunohistochemical staining for common placental proteins/hormones in CGCE. The findings support a primitive mesenchymal cell origin, and a progressive degenerative process in CGCE, rather than neoplasia. Prenatal detection of this lesion is important to facilitate adequate preparations for support of these infants during labor and delivery.

Biphasic Postnatal Umbilical Cord Shortening.

INTRODUCTION: Variations in postnatal length of refrigerated, unfixed umbilical cords were studied over time to elucidate natural changes and times of stability. METHODS: Length was measured in 132 cords following severance, repeated at varying timed intervals and studied by analysis of variance and regression analysis. RESULTS: Data show immediate rapid initial phase shortening (mean 4.2+/-3.9 cm SD); an interval of lengthening; stable length at hours 3-4 following severance, a slower second phase shortening (mean 1.5+/-0.7 cm SD) beginning at 5 hours and peaking at 12 hours; and gradual lengthening to stable length after 23 hours. Overall, there was a significant net mean decrease of 3.49+/-2.29 cm SD. Shortening was greatest for intact long cord segments (p=0.0001), as much as 11 cm. Two highly significant models for predicting umbilical cord length at delivery (OL) were determined using the post-delivery lengths (Length) measured at different times following delivery (Hours), as follows:At ≤ 3 hours following delivery: OL=1.02xLength cm+1.11xHoursAt >3 hours following delivery: OL=1.07xLength+0.44xHours-0.01x(Hours)2. CONCLUSION: Cord lengths stabilized between hours 3-4 and after 23 hours following severance. Phase one shortening resembles vasoconstriction; phase two resembles rigor mortis. The models allow prediction of the original umbilical cord length at delivery, regardless of the time of measurement.

Sustained treatment of sickle cell mice with haptoglobin increases HO-1 and H-ferritin expression and decreases iron deposition in the kidney without improvement in kidney function.

There is growing evidence that extracellular haemoglobin and haem mediate inflammatory and oxidative damage in sickle cell disease. Haptoglobin (Hp), the scavenger for free haemoglobin, is depleted in most patients with sickle cell disease due to chronic haemolysis. Although single infusions of Hp can ameliorate vaso-occlusion in mouse models of sickle cell disease, prior studies have not examined the therapeutic benefits of more chronic Hp dosing on sickle cell disease manifestations. In the present study, we explored the effect of Hp treatment over a 3-month period in sickle mice at two dosing regimens: the first at a moderate dose of 200 mg/kg thrice weekly and the second at a higher dose of 400 mg/kg thrice weekly. We found that only the higher dosing regimen resulted in increased haem-oxygenase-1 and heavy chain ferritin (H-ferritin) expression and decreased iron deposition in the kidney. Despite the decreased kidney iron deposition following Hp treatment, there was no significant improvement in kidney function. However, there was a nearly significant trend towards decreased liver infarction.

Pediatric Tenosynovial Giant Cell Tumor of the Flexor Hallucis Longus Tendon Sheath: A Case Report.

CASE: An otherwise healthy 13-year-old girl presented with a firm nodule on the plantar right forefoot that was tender after cheerleading. Initial workup was unremarkable, but magnetic resonance imaging revealed a multilobulated mass surrounding the flexor hallucis longus tendon. Surgical resection revealed a tenosynovial mass without tendon infiltration. Pathologic examination was consistent with tenosynovial giant cell tumor. The patient resumed cheerleading and remained asymptomatic after 1 year. CONCLUSION: As far as we know, this is the first report of a tenosynovial giant cell tumor of the flexor hallucis longus in a pediatric patient; it illustrates the importance of considering this lesion when diagnosing a pediatric plantar mass.

Distal Tibial Chondroblastoma With Intra-articular Penetration Treated With Gelatin Foam Sponge and Bone Grafting.

A 14-year-old boy presented with sharp left ankle pain for 1.5 years. Evaluation showed an irregular lytic lesion with surrounding sclerosis (diameter, 1.3×1.2×1.1 cm) in the central part of the distal tibial epiphysis, extending from the physis to the plafond with articular penetration. Treatment included intralesional curettage and bone grafting through a mid-anterior epiphyseal bone tunnel with fluoroscopic guidance and use of a gelatin foam sponge to help contain the bone graft within the epiphyseal cavity. Microscopic examination of the excised tissue was consistent with chondroblastoma. Ankle arthroscopy 11 months later showed that the tibial plafond articular surface was fully healed. Two years postoperatively, the patient was asymptomatic and had no recurrence. This case shows that intralesional curettage and bone grafting, with a gelatin foam sponge to prevent graft extrusion, may be used successfully in treating distal tibial epiphyseal chondroblastoma that penetrates the ankle joint. [Orthopedics. 2019; 42(4):e391-e394.].

Case series: Five pediatric germ cell/sex cord stroma tumors.

•This report consists of five pediatric tumors of ovarian cell lineage.•These unusual, interesting tumors challenge both surgeon and oncologist.•Some appear malignant, seemingly require chemotherapy, but behave with benignity. Some are easily resected; others demand the utmost skill.•Complexity perplexes; elucidation is by selection - ignoring some things, attending to others.•Case studies illustrate - for good or ill - the process whereby clinical conundrums are resolved.

Morphological and functional platelet abnormalities in Berkeley sickle cell mice.

Berkeley sickle cell mice are used as animal models of human sickle cell disease but there are no reports of platelet studies in this model. Since humans with sickle cell disease have platelet abnormalities, we studied platelet morphology and function in Berkeley mice (SS). We observed elevated mean platelet forward angle light scatter (FSC) values (an indirect measure of platelet volume) in SS compared to wild type (WT) (37+/-3.2 vs. 27+/-1.4, mean+/-SD; p<0.001), in association with moderate thrombocytopenia (505+/-49 x 10(3)/microl vs. 1151+/-162 x 10(3)/microl; p<0.001). Despite having marked splenomegaly, SS mice had elevated levels of Howell-Jolly bodies and "pocked" erythrocytes (p<0.001 for both) suggesting splenic dysfunction. SS mice also had elevated numbers of thiazole orange positive platelets (5+/-1% vs. 1+/-1%; p<0.001), normal to low plasma thrombopoietin levels, normal plasma glycocalicin levels, normal levels of platelet recovery, and near normal platelet life spans. Platelets from SS mice bound more fibrinogen and antibody to P-selectin following activation with a threshold concentration of a protease activated receptor (PAR)-4 peptide compared to WT mice. Enlarged platelets are associated with a predisposition to arterial thrombosis in humans and some humans with SCD have been reported to have large platelets. Thus, additional studies are needed to assess whether large platelets contribute either to pulmonary hypertension or the large vessel arterial occlusion that produces stroke in some children with sickle cell disease.

Induced pluripotent stem cells derived from human amnion in chemically defined conditions.

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.

Original Research: Diametric effects of hypoxia on pathophysiology of sickle cell disease in a murine model.

Hypoxia causes erythrocyte sickling in vitro; however, its role in the pathophysiology of sickle cell disease is poorly understood. We report that hypoxia rapidly decreased oxygen saturation in transgenic sickle cell disease mice, but this effect was immediately buffered by a robust ventilatory response. The initial hypoxemia improved steadily throughout the duration of hypoxia without any detectable acute pulmonary adverse effect. Furthermore, the mice suffered acute anemia that ironically was associated with lowering of both plasma hemoglobin and heme. These results were corroborated by increased plasma haptoglobin and hemopexin levels. Markers of ischemic tissue injury increased spatiotemporally following repeated hypoxia exposures. This variation was supported by organ-specific induction of hypoxia-responsive genes. Our results show that hypoxia exerts diametric effects on sickle cell disease by promoting ischemic injury while enhancing the expression of hemolysis scavenger molecules. This phenomenon may help to understand the disparate clinical syndromes associated with hemolysis and vaso-occlusion in sickle cell disease.

Lumbosacral ectopic nephrogenic rest unassociated with spinal dysraphism.

Nephrogenic rests (NRs) are thought to originate from persistent nephrogenic blastema and are considered precursor lesions of Wilms' tumor (WT). These rests usually occur as perilobar and intralobar lesions in the kidney and, rarely, in ectopic sites. We report a midline lumbosacral ectopic NR in a healthy full-term newborn male with no family history of WT or WT-associated syndromes. The NR presented as a soft polypoid mass covered by normal skin. An MRI study revealed no lumbosacral spine abnormalities and no communication with the vertebral canal. The resected mass measured 3 cm and contained fat and had a central 1.2-cm solid nodule. The nodule was composed of blastema, epithelial elements (mature tubules and nephrons), and abundant stroma. No other somatic tissue elements were identified after complete microscopic examination. There are 4 cases of NRs reported in the lumbosacral area associated with spinal dysraphism, and only 2 cases, in addition to our report, unassociated with spinal abnormalities. The pathogenesis of heterotopic immature nephrogenic tissue remains a source of conjecture and speculation. If these lesions are heterotopic rests, their potential for neoplastic progression is probably quite limited, but if a monodermal teratoma, then more scrupulous clinical follow-up is warranted.

High protein diet attenuates histopathologic organ damage and vascular leakage in transgenic murine model of sickle cell anemia.

Previous reports have shown that a high protein diet improves weight gain and decreases expression of inflammatory markers in weanling Berkeley transgenic sickle cell mice. The effect of this diet on the underlying histopathology, however, has not been studied. Age-matched, male C57BL/6 controls (n = 24), Berkley sickle mice (n = 31) and Townes sickle mice (n = 14) were randomized in a terminal experiment at weaning to isoenergetic diets, with either normal (20%) or high (35%) amount of energy from protein, by replacing dextrin. Tissue sampling for blinded histologic study and scoring of changes at baseline and after 3 months of feedings showed progressive siderosis and infarcts in spleen, kidney, and liver in all sickle groups, and no significant changes in age- and sex-matched normal controls. High-protein (35%) fed Berkeley sickle mice had significantly fewer (p < 0.01) infarcts in spleen (35.7% less), liver (12.5% less), and kidney (28.6% less) and lower histopathologic scores (p < 0.01) for chronic tissue injury in liver and spleen than matched normal-protein (20%) fed Berkeley sickle mice. In addition, high-protein fed Townes sickle mice had less vascular leakage (∼36%) in the heart, lungs, and brain and a better survival rate (21%) than matched normal-protein Townes sickle mice. This is the first report of histopathologic evidence that a high protein:calorie diet attenuates sickle cell related chronic organ injury in transgenic sickle cell mouse models.

Hemolysis in sickle cell mice causes pulmonary hypertension due to global impairment in nitric oxide bioavailability.

Pulmonary hypertension is a highly prevalent complication of sickle cell disease and is a strong risk factor for early mortality. However, the pathophysiologic mechanisms leading to pulmonary vasculopathy remain unclear. Transgenic mice provide opportunities for mechanistic studies of vascular pathophysiology in an animal model. By microcardiac catheterization, all mice expressing exclusively human sickle hemoglobin had pulmonary hypertension, profound pulmonary and systemic endothelial dysfunction, and vascular instability characterized by diminished responses to authentic nitric oxide (NO), NO donors, and endothelium-dependent vasodilators and enhanced responses to vasoconstrictors. However, endothelium-independent vasodilation in sickle mice was normal. Mechanisms of vasculopathy in sickle mice involve global dysregulation of the NO axis: impaired constitutive nitric oxide synthase activity (NOS) with loss of endothelial NOS (eNOS) dimerization, increased NO scavenging by plasma hemoglobin and superoxide, increased arginase activity, and depleted intravascular nitrite reserves. Light microscopy and computed tomography revealed no plexogenic arterial remodeling or thrombi/ emboli. Transplanting sickle marrow into wild-type mice conferred the same phenotype, and similar pathobiology was observed in a nonsickle mouse model of acute alloimmune hemolysis. Although the time course is shorter than typical pulmonary hypertension in human sickle cell disease, these results demonstrate that hemolytic anemia is sufficient to produce endothelial dysfunction and global dysregulation of NO.

Pathology of Berkeley sickle cell mice: similarities and differences with human sickle cell disease.

Because Berkeley sickle cell mice are used as an animal model for human sickle cell disease, we investigated the progression of the histopathology in these animals over 6 months and compared these findings to those published in humans with sickle cell disease. The murine study groups were composed of wild-type mixed C57Bl/6-SV129 (control) mice and sickle cell (SS) mice (alpha-/-, beta-/-, transgene +) of both sexes and between 1 and 6 months of age. SS mice were similar to humans with sickle cell disease in having erythrocytic sickling, vascular ectasia, intravascular hemolysis, exuberant hematopoiesis, cardiomegaly, glomerulosclerosis, visceral congestion, hemorrhages, multiorgan infarcts, pyknotic neurons, and progressive siderosis. Cerebral perfusion studies demonstrated increased blood-brain barrier permeability in SS mice. SS mice differed from humans with sickle cell disease in having splenomegaly, splenic hematopoiesis, more severe hepatic infarcts, less severe pulmonary manifestations, no significant vascular intimal hyperplasia, and only a trend toward vascular medial hypertrophy. Early retinal degeneration caused by a homozygous mutation (rd1) independent from that causing sickle hemoglobin was an incidental finding in some Berkeley mice. While our study reinforces the fundamental strength of this model, the notable differences warrant careful consideration when drawing parallels to human sickle cell disease.

Cardiofaciocutaneous syndrome (CFC) with congenital peripheral neuropathy and nonorganic malnutrition: an autopsy study.

Many phenotypic manifestations have been reported in cardiofaciocutaneous (CFC) syndrome, but none, to date, are pathognomonic or obligatory. Previous histopathological studies reported findings in skin and hair; no autopsy studies have been published. We report the clinical and autopsy findings of a 7-year-old boy with severe CFC syndrome and malnutrition of psychosocial origin. Manifestations of CFC, reported previously, included macrocephaly and macrosomia at birth; short stature; hypotonia; global developmental delays; dry, sparse thin curly hair; sparse eyebrows and eyelashes; dilated cerebral ventricles; high cranial vault; bitemporal constriction; supraorbital ridge hypoplasia; hypertelorism; ptosis; exophthalmos; depressed nasal bridge; anteverted nostrils; low-set, posteriorly-rotated, large, thick ears; decayed, dysplastic teeth; strabismus; hyperelastic skin; wrinkled palms; keratosis pilaris atrophicans faciei; ulerythema ophryogenes; hyperkeratosis; gastroesophageal reflux; and tracheobronchomalacia. Additional findings, not previously reported, include islet cell hyperplasia, lymphoid depletion, thymic atrophy and congenital hypertrophy of peripheral nerves with onion bulb formations. Although the islet cell hyperplasia, lymphoid depletion, and thymic atrophy are nonspecific findings that may be associated with either CFC or malnutrition, the onion bulb hypertrophy is specific for a demyelinating-remyelinating neuropathy. These findings implicate congenital peripheral neuropathy in the pathogenesis of the developmental delays, feeding difficulties, respiratory difficulties, ptosis and short stature in this case. Additional studies of other cases of CFC are needed.

Perivascular fibrosis in the bone marrow in sickle cell disease.

CONTEXT: Magnetic resonance imaging of bone marrow in homozygous sickle cell disease (hemoglobin [Hb] SS) shows nonhomogeneous, mottled signals that increase with age and number of crises. The pattern of these signals is reminiscent of the underlying vascular architecture, but histopathology of this tissue has not been adequately studied. OBJECTIVE: To elucidate the histopathology of blood vessels in the bone marrow in sickle cell disease. DESIGN: Retrospective histochemical morphometric study of bone marrow arteries by point counting in HbSS (13 cases) and sickle cell Hb C (HbSC) (8 cases) compared to nonanemic normal controls (HbAA) (10 cases). All patients were nondiabetic, normotensive, younger than 37 years, and matched for age group. RESULTS: The mean point count for perivascular fibrous tissue was significantly greater in the HbSS group (P <.001) in both small (P <.001) and medium-sized (P =.002) vessels, and in both age groups (pediatric, P <.001; adult, P =.005) compared with the HbAA group. Additional analysis showed the difference was significant in HbSS pediatric small vessels (P <.001) and in pediatric and adult medium vessels (P =.045 and P =.03, respectively). Ratios of fibrous tissue to muscle showed proportionately greater fibrous tissue in HbSS pediatric small (P <.001) and medium-sized vessels (P =.02), and in adult large vessels (P =.03). Mean point counts for muscle were significantly decreased in HbSS small vessels when all ages were compared as a group (P =.02), but when compared by age groups, counts were significantly increased in adult HbSS medium-sized vessels (P =.01). Overall mean point counts for muscle and fibrous tissue in the HbSC group were intermediate between those of the HbSS and HbAA groups, but were not significantly different from counts in the HbAA group (P =.78 and P =.35, respectively). CONCLUSION: In sickle cell disease, arterial vessels in the bone marrow show significantly increased fibrous connective tissue and changes in muscle that vary with age and vessel size.

Causes of death in sickle cell disease: an autopsy study.

More precise analysis of causes of death is needed to focus research efforts and improve morbidity and mortality in sickle cell disease. In this study, the morphological evidence of the cause of death was studied in 306 autopsies of sickle cell disease, which were accrued between 1929 and 1996. The most common cause of death for all sickle variants and for all age groups was infection (33-48%). The terminal infection was heralded by upper respiratory tract syndromes in 72.6% and by gastroenteritis in 13.7%. The most frequent portal of entry in children was the respiratory tract but, in adults, a site of severe chronic organ injury. Other causes of death included stroke 9.8%, therapy complications 7.0%, splenic sequestration 6.6%, pulmonary emboli/thrombi 4.9%, renal failure 4.1%, pulmonary hypertension 2.9%, hepatic failure 0.8%, massive haemolysis/red cell aplasia 0.4% and left ventricular failure 0.4%. Death was frequently sudden and unexpected (40.8%) or occurred within 24 h after presentation (28.4%), and was usually associated with acute events (63.3%). This study shows that the first 24 h after presentation for medical care is an especially perilous time for patients with sickle cell disease and an acute event. Close monitoring and prompt aggressive treatment are warranted.

Chimerism and cure: hematologic and pathologic correction of murine sickle cell disease.

Bone marrow transplantation (BMT) is the only curative therapy for sickle cell disease (SCD). However, the morbidity and mortality related to pretransplantation myeloablative chemotherapy often outweighs the morbidity of SCD itself, thus severely limiting the number of patients eligible for transplantation. Although nonmyeloablative transplantation is expected to reduce the risk of BMT, it will likely result in mixed-chimerism rather than complete replacement with donor stem cells. Clinical application of nonmyeloablative transplantation thus requires knowledge of the effect of mixed chimerism on SCD pathophysiology. We have, therefore, created a panel of transplanted SCD mice that received transplants displaying an array of red blood cell (RBC) and white blood cell (WBC) chimerism. A significant enrichment of RBC over WBC chimerism occurred in these mice, because of the dramatic survival advantage of donor over sickle RBCs in the peripheral blood. Increasing levels of RBC chimerism provided progressive correction of hematologic and pathologic abnormalities. However, sickle bone marrow and splenic hematopoiesis was not corrected until peripheral blood sickle RBCs were fully replaced with donor RBCs. These results have important and unexpected implications for nonmyeloablative BMT for SCD. As the critical hematopoietic organs were not corrected without full RBC replacement, 100% peripheral blood RBC chimerism becomes the most important benchmark for cure after nonmyeloablative BMT.