Marco M. Hefti

Mesenchymal lineage precursor cells induce vascular network formation in ischemic myocardium.

Mesenchymal lineage precursors can be reproducibly isolated from adult mammalian bone marrow and grown in culture. Immunoselection with monoclonal antibodies against STRO-1 and vascular-cell-adhesion molecule 1 (VCAM1/CD106) prior to expansion results in a 1,000-fold enrichment of mesenchymal precursors compared to standard isolation techniques. Intramyocardial injection of human STRO-1-selected precursors in an athymic rat model of acute myocardial infarction results in induction of vascular network formation and arteriogenesis coupled with global functional cardiac recovery.

Estrogen receptor negative/progesterone receptor positive breast cancer is not a reproducible subtype

IntroductionEstrogen receptor (ER) and progesterone receptor (PR) testing are performed in the evaluation of breast cancer. While the clinical utility of ER as a predictive biomarker to identify patients likely to benefit from hormonal therapy is well-established, the added value of PR is less well-defined. The primary goals of our study were to assess the distribution, inter-assay reproducibility, and prognostic significance of breast cancer subtypes defined by patterns of ER and PR expression.MethodsWe integrated gene expression microarray (GEM) and clinico-pathologic data from 20 published studies to determine the frequency (n = 4,111) and inter-assay reproducibility (n = 1,752) of ER/PR subtypes (ER+/PR+, ER+/PR-, ER-/PR-, ER-/PR+). To extend our findings, we utilized a cohort of patients from the Nurses’ Health Study (NHS) with ER/PR data recorded in the medical record and assessed on tissue microarrays (n = 2,011). In both datasets, we assessed the association of ER and PR expression with survival.ResultsIn a genome-wide analysis, progesterone receptor was among the least variable genes in ER- breast cancer. The ER-/PR+ subtype was rare (approximately 1 to 4%) and showed no significant reproducibility (Kappa = 0.02 and 0.06, in the GEM and NHS datasets, respectively). The vast majority of patients classified as ER-/PR+ in the medical record (97% and 94%, in the GEM and NHS datasets) were re-classified by a second method. In the GEM dataset (n = 2,731), progesterone receptor mRNA expression was associated with prognosis in ER+ breast cancer (adjusted P <0.001), but not in ER- breast cancer (adjusted P = 0.21). PR protein expression did not contribute significant prognostic information to multivariate models considering ER and other standard clinico-pathologic features in the GEM or NHS datasets.ConclusionER-/PR+ breast cancer is not a reproducible subtype. PR expression is not associated with prognosis in ER- breast cancer, and PR does not contribute significant independent prognostic information to multivariate models considering ER and other standard clinico-pathologic factors. Given that PR provides no clinically actionable information in ER+ breast cancer, these findings question the utility of routine PR testing in breast cancer.

Severity of inflammation as a predictor of colectomy in patients with chronic ulcerative colitis.

PURPOSE: We evaluated a large cohort of patients with longstanding ulcerative colitis in a colonoscopic surveillance program to determine predictors of colectomy. METHODS: We queried a retrospective database of patients who had symptoms of ulcerative colitis for seven years or more. Histologic inflammation in biopsies was graded on a validated four-point scale: absent, mild, moderate, severe. We performed a multivariate analysis of the inflammation scores and other variables to determine predictive factors for colectomy. Patients who underwent colectomy for neoplasia were censored at the time of surgery; those who did not undergo colectomy were censored at the time of last contact. RESULTS: A total of 561 patients were evaluated, with a median follow-up of 21.4 years since disease onset. A total of 97 patients (17.3 percent) underwent surgery; 25 (4.5 percent) for reasons other than dysplasia. These 25 constitute events for this analysis. For univariate analysis, mean inflammation (P < 0.001) and steroid use (P = 0.01) were predictors of colectomy. For multivariable proportional hazards analysis, mean inflammation (P < 0.001) and steroid use (P = 0.03) were predictors of colectomy, whereas salicylate use (P = 0.007) was protective. CONCLUSIONS: Higher median inflammation scores and corticosteroid use were predictors of colectomy in this patient population. The overall rate of colectomy during a long period of follow-up was low (<1 percent per year).

Significance analysis of prognostic signatures.

A major goal in translational cancer research is to identify biological signatures driving cancer progression and metastasis. A common technique applied in genomics research is to cluster patients using gene expression data from a candidate prognostic gene set, and if the resulting clusters show statistically significant outcome stratification, to associate the gene set with prognosis, suggesting its biological and clinical importance. Recent work has questioned the validity of this approach by showing in several breast cancer data sets that “random” gene sets tend to cluster patients into prognostically variable subgroups. This work suggests that new rigorous statistical methods are needed to identify biologically informative prognostic gene sets. To address this problem, we developed Significance Analysis of Prognostic Signatures (SAPS) which integrates standard prognostic tests with a new prognostic significance test based on stratifying patients into prognostic subtypes with random gene sets. SAPS ensures that a significant gene set is not only able to stratify patients into prognostically variable groups, but is also enriched for genes showing strong univariate associations with patient prognosis, and performs significantly better than random gene sets. We use SAPS to perform a large meta-analysis (the largest completed to date) of prognostic pathways in breast and ovarian cancer and their molecular subtypes. Our analyses show that only a small subset of the gene sets found statistically significant using standard measures achieve significance by SAPS. We identify new prognostic signatures in breast and ovarian cancer and their corresponding molecular subtypes, and we show that prognostic signatures in ER negative breast cancer are more similar to prognostic signatures in ovarian cancer than to prognostic signatures in ER positive breast cancer. SAPS is a powerful new method for deriving robust prognostic biological signatures from clinically annotated genomic datasets.

Hippocampal sclerosis and mesial temporal lobe epilepsy in chorea-acanthocytosis: a case with clinical, pathologic and genetic evaluation

Chorea-acanthocytosis (ChAc) is an autosomal recessive neurodegenerative disease associated with mutations in VPS13A that encodes the protein chorein. ChAc is characterized by progressive chorea, dystonia, and psychiatric symptoms, developing in young adulthood, often with acanthocytosis in peripheral blood. Tongue protrusion, or feeding dystonia, is common, as are seizures and neuropathy [1]. On neuropathology, there is basal ganglia atrophy, neuronal loss, and gliosis, especially in the caudate nucleus [2]. We report the case of a patient with ChAc with hippocampal sclerosis who had extensive longitudinal follow-up, including neuropathology and general autopsy. This article is protected by copyright. All rights reserved.

Identification of a novel RASD1 somatic mutation in a USP8-mutated corticotroph adenoma

Cushings disease (CD) is caused by pituitary corticotroph adenomas that secrete excess adrenocorticotropic hormone (ACTH). In these tumors, somatic mutations in the gene USP8 have been identified as recurrent and pathogenic and are the sole known molecular driver for CD. Although other somatic mutations were reported in these studies, their contribution to the pathogenesis of CD remains unexplored. No molecular drivers have been established for a large proportion of CD cases and tumor heterogeneity has not yet been investigated using genomics methods. Also, even in USP8-mutant tumors, a possibility may exist of additional contributing mutations, following a paradigm from other neoplasm types where multiple somatic alterations contribute to neoplastic transformation. The current study utilizes whole-exome discovery sequencing on the Illumina platform, followed by targeted amplicon-validation sequencing on the Pacific Biosciences platform, to interrogate the somatic mutation landscape in a corticotroph adenoma resected from a CD patient. In this USP8-mutated tumor, we identified an interesting somatic mutation in the gene RASD1, which is a component of the corticotropin-releasing hormone receptor signaling system. This finding may provide insight into a novel mechanism involving loss of feedback control to the corticotropin-releasing hormone receptor and subsequent deregulation of ACTH production in corticotroph tumors.

A Century of Germinal Matrix Intraventricular Hemorrhage in Autopsied Premature Infants: A Historical Account.

The care of premature infants in the 20th century is remarkable for technical advances that have dramatically improved survival, but little is known about temporal changes in the neuropathology of the premature infant over this time frame. We hypothesize that the autopsy rate of germinal matrix hemorrhage changed in the 20th century relative to combined influences of clinical interventions that were both harmful and helpful. We examined germinal matrix hemorrhage with intraventricular hemorrhage (GMH-IVH) in 345 premature infants (gestational age 25–36 weeks) autopsied at Boston Childrens Hospital from 1914 to 2015. There was a median of 19 cases/decade (range 7–68). Over the course of the study median gestational age decreased from 33 to 27 gestational weeks (P < 0.001), and median postnatal survival increased from 2 to 26 days (P = 0.02). The incidence of GMH-IVH increased from 4.7% before 1960 to 50.0% from 1975 to 1980, and then decreased to 12.5% after 2005 (P < 0.001). The incidence of GMH-IVH increased >3-fold around the time of the introduction of positive pressure ventilation into premature intensive care in the mid–1960s. The increased incidence of GMH-IVH in the 1970s–1980s likely reflects respiratory and hemodynamic imbalances complicating mechanical ventilation. We speculate that the subsequent decreased incidence of GMH-IVH likely reflects stabilization of respiratory function with improvements in ventilators and in ventilator management beginning in the 1970s and the use of surfactant and antenatal steroids in the 1980s.

Robot-assisted off-pump minimally invasive reoperative coronary artery bypass grafting: case report.

BACKGROUND Resternotomy for reoperative coronary artery bypass grafting (CABG) has become increasingly common with an aging patient population. Minimally invasive and robotic techniques permit us to perform these surgeries with reduced morbidity and mortality. CASE REPORT A 67-year-old woman was taken to the operating room for repeat CABG. A free right internal mammary graft was endoscopically harvested using the da Vinci robotic operating system. A small left thoracotomy was then used to perform an off-pump bypass from the descending aorta to the hood of a diseased saphenous vein graft. CONCLUSION Robotic and minimally invasive cardiac surgery undergoes continuous refinement. As the incidence of reoperative surgery in patients with multiple previous interventions rises, surgeons will have to become increasingly creative with their choice of conduits, incisions, and the use of hybrid open and endoscopic techniques.

Cerebral mitochondrial dysfunction associated with deep hypothermic circulatory arrest in neonatal swine

Abstract OBJECTIVES Controversy remains regarding the use of deep hypothermic circulatory arrest (DHCA) in neonatal cardiac surgery. Alterations in cerebral mitochondrial bioenergetics are thought to contribute to ischaemia–reperfusion injury in DHCA. The purpose of this study was to compare cerebral mitochondrial bioenergetics for DHCA with deep hypothermic continuous perfusion using a neonatal swine model. METHODS Twenty-four piglets (mean weight 3.8 kg) were placed on cardiopulmonary bypass (CPB): 10 underwent 40-min DHCA, following cooling to 18°C, 10 underwent 40 min DHCA and 10 remained at deep hypothermia for 40 min; animals were subsequently rewarmed to normothermia. 4 remained on normothermic CPB throughout. Fresh brain tissue was harvested while on CPB and assessed for mitochondrial respiration and reactive oxygen species generation. Cerebral microdialysis samples were collected throughout the analysis. RESULTS DHCA animals had significantly decreased mitochondrial complex I respiration, maximal oxidative phosphorylation, respiratory control ratio and significantly increased mitochondrial reactive oxygen species (P < 0.05 for all). DHCA animals also had significantly increased cerebral microdialysis indicators of cerebral ischaemia (lactate/pyruvate ratio) and neuronal death (glycerol) during and after rewarming. CONCLUSIONS DHCA is associated with disruption of mitochondrial bioenergetics compared with deep hypothermic continuous perfusion. Preserving mitochondrial health may mitigate brain injury in cardiac surgical patients. Further studies are needed to better understand the mechanisms of neurological injury in neonatal cardiac surgery and correlate mitochondrial dysfunction with neurological outcomes.

High-resolution temporal and regional mapping of MAPT expression and splicing in human brain development

The microtubule associated protein tau plays a critical role in the pathogenesis of neurodegenerative disease. Recent studies suggest that tau also plays a role in disorders of neuronal connectivity, including epilepsy and post-traumatic stress disorder. Animal studies have shown that the MAPT gene, which codes for the tau protein, undergoes complex pre-mRNA alternative splicing to produce multiple isoforms during brain development. Human data, particularly on temporal and regional variation in tau splicing during development are however lacking. In this study, we present the first detailed examination of the temporal and regional sequence of MAPT alternative splicing in the developing human brain. We used a novel computational analysis of large transcriptomic datasets (total n = 502 patients), quantitative polymerase chain reaction (qPCR) and western blotting to examine tau expression and splicing in post-mortem human fetal, pediatric and adult brains. We found that MAPT exons 2 and 10 undergo abrupt shifts in expression during the perinatal period that are unique in the canonical human microtubule-associated protein family, while exon 3 showed small but significant temporal variation. Tau isoform expression may be a marker of neuronal maturation, temporally correlated with the onset of axonal growth. Immature brain regions such as the ganglionic eminence and rhombic lip had very low tau expression, but within more mature regions, there was little variation in tau expression or splicing. We thus demonstrate an abrupt, evolutionarily conserved shift in tau isoform expression during the human perinatal period that may be due to tau expression in maturing neurons. Alternative splicing of the MAPT pre-mRNA may play a vital role in normal brain development across multiple species and provides a basis for future investigations into the developmental and pathological functions of the tau protein.