Elizabeth H. Hammond

Infection With Chlamydia pneumoniae Accelerates the Development of Atherosclerosis and Treatment With Azithromycin Prevents It in a Rabbit Model

BACKGROUND Chlamydia pneumoniae infection has been associated with atherosclerosis by serological studies and detection of bacterial antigen within plaque. We sought to evaluate a possible causal role in an animal model. METHODS AND RESULTS Thirty New Zealand White rabbits were given three separate intranasal inoculations of either C pneumoniae (n = 20) or saline (n = 10) at 3-week intervals and fed chow enriched with a small amount (0.25%) of cholesterol. Immediately after the final inoculation, infected and control rabbits were randomized and begun on a 7-week course of azithromycin or no therapy. Three months after the final inoculation, rabbits were euthanatized and sections of thoracic aortas were blindly evaluated microscopically for maximal intimal thickness (MIT), percentage of luminal circumference involved (PLCI), and plaque area index (PAI) of atherosclerosis. Vascular chlamydial antigen was assessed by direct immunofluorescence. MIT differed among treatment groups (P=.009), showing an increase in infected rabbits (0.55 mm; SE = 0.15 mm) compared with uninfected controls (0.16 mm; SE = 0.06 mm) and with infected rabbits receiving antibiotics (0.20 mm; SE = 0.03 mm) (both P<.025), whereas MIT in infected/treated versus control rabbits did not differ. PLCI also tended to differ (P<.1) and PAI differed significantly (P<.01) among groups with a similar pattern. Chlamydial antigen was detected in 2 untreated, 3 treated, and 0 control animals. CONCLUSIONS Intranasal C pneumoniae infection accelerates intimal thickening in rabbits given a modestly cholesterol-enhanced diet. In addition, weekly treatment with azithromycin after infectious exposure prevents accelerated intimal thickening. These findings strengthen the etiologic link between C pneumoniae and atherosclerosis and should stimulate additional animal and human studies, including clinical antibiotic trials.

Increased incidence of Chlamydia species within the coronary arteries of patients with symptomatic atherosclerotic versus other forms of cardiovascular disease.

OBJECTIVES The objectives of this study were to test prospectively for an association between Chlamydia and atherosclerosis by comparing the incidence of the pathogen found within atherosclerotic plaques in patients undergoing directional coronary atherectomy with a variety of control specimens and comparing the clinical features between the groups. BACKGROUND Previous work has suggested an association between Chlamydia pneumoniae infection and coronary atherosclerosis, based on the demonstration of increased serologic titers and the detection of bacteria within atherosclerotic tissue, but this association has not yet been regarded as established. METHODS Coronary specimens from 90 symptomatic patients undergoing coronary atherectomy were tested for the presence of Chlamydia species using direct immunofluorescence. Control specimens from 24 subjects without atherosclerosis (12 normal coronary specimens and 12 coronary specimens from cardiac transplant recipients with subsequent transplant-induced coronary disease) were also examined. RESULTS Coronary atherectomy specimens were definitely positive in 66 (73%) and equivocally positive in 5 (6%), resulting in 79% of specimens showing evidence for the presence of Chlamydia species within the atherosclerotic tissue. In contrast, only 1 (4%) of 24 nonatherosclerotic coronary specimens showed any evidence of Chlamydia. The statistical significance of this difference is a p value < 0.001. Transmission electron microscopy was used to confirm the presence of appropriate organisms in three of five positive specimens. No clinical factors except the presence of a primary nonrestenotic lesion (odds ratio 3.0, p = 0.057) predicted the presence of Chlamydia. CONCLUSIONS This high incidence of Chlamydia only in coronary arteries diseased by atherosclerosis suggests an etiologic role for Chlamydia infection in the development of coronary atherosclerosis that should be further studied.

Pseudopalisades in Glioblastoma Are Hypoxic, Express Extracellular Matrix Proteases, and Are Formed by an Actively Migrating Cell Population

Necrosis and vascular proliferation are the pathologic features that distinguish the most malignant infiltrative astrocytoma, glioblastoma (GBM), from those of lower grades. In GBM, hypercellular zones called pseudopalisades typically surround necrotic foci. Although these cells are known to secrete high levels of proangiogenic factors that promote tumor growth, their origins are ill defined. We propose that pseudopalisades represent differing stages and histologic samplings of astrocytoma cells migrating away from a hypoxic/anoxic focus, often triggered by a central vaso-occlusive event. This proposition is based on our findings that pseudopalisading cells are 5–50% less proliferative and 6–20 times more apoptotic than adjacent astrocytoma, indicating that cell accumulation does not result from increased proliferation or resistance to apoptosis. Coexisting inflammatory cells account for <2% of pseudopalisading cells and cannot account for hypercellularity. Pseudopalisading cells show nuclear expression of hypoxia-inducible factor 1α, consistent with their hypoxic nature, and hypoxia induces a 20–60% increase in glioma cell migration in vitro. Hypoxic cells in vitro and pseudopalisades in GBM specimens show enhanced gelatinase activity, typical of an invasive phenotype. These results suggest that pseudopalisading cells are migrating at the periphery of a hypoxic center. To uncover a potential source of hypoxia and sequence of structural events leading to pseudopalisade formation, we performed a morphometric analysis of 234 pseudopalisades from 85 pretreatment GBMs. We found distorted, degenerating, or thrombosed blood vessels within the center of more than half the pseudopalisades, suggesting that at least a subset of pseudopalisades are two-dimensional histologic representations of tumor cells migrating away from a vaso-occlusive event.

Immunoglobulin G fractions from patients with antiphospholipid antibodies cause fetal death in BALB/c mice: A model for autoimmune fetal loss

We determined whether purified immunoglobulin G from patients with antiphospholipid antibodies causes fetal loss in pregnant mice. Sera were obtained from nonpregnant parous women (group 1) and nonpregnant women with antiphospholipid antibodies and a history of fetal loss (group 2). Pregnant BALB/c mice were given an intraperitoneal injection of 15 mg of IgG on day 8 of pregnancy. Typically, mice treated with IgG from antiphospholipid antibodies aborted within 48 hours. When animals were sacrificed on days 9 to 15, the uterus of each animal was inspected for the presence of live, dead, or resorbing fetuses. In contrast to mice injected with control IgG or saline solution, each mouse injected with IgG from antiphospholipid antibodies aborted and no live fetuses were found (p less than 0.05). Histologic examination of the uteroplacental interface showed decidual necrosis in the mice treated with IgG containing antiphospholipid antibodies, and immunofluorescent studies also showed prominent intravascular decidual IgG and fibrin deposition. We conclude that IgG from antiphospholipid antibodies of women with fetal loss causes fetal loss in BALB/c mice. It appears that the fetal loss is mediated by IgG binding in the maternal decidual vasculature.

Clinical Use of the Total Artificial Heart

We report here our first experience with the use of a total artificial heart in a human being. The heart was developed at the University of Utah, and the patient was a 61-year-old man with chronic congestive heart failure due to primary cardiomyopathy, who also had chronic obstructive pulmonary disease. Except for dysfunction of the prosthetic mitral valve, which required replacement of the left-heart prosthesis on the 13th postoperative day, the artificial heart functioned well for the entire postoperative course of 112 days. The mean blood pressure was 84 +/- 8 mm Hg, and cardiac output was generally maintained at 6.7 +/- 0.8 liters per minute for the right heart and 7.5 +/- 0.8 for the left, resulting in postoperative diuresis and relief of congestive failure. The postoperative course was complicated by recurrent pulmonary insufficiency, several episodes of acute renal failure, episodes of fever of unidentified cause (necessitating multiple courses of antibiotics), hemorrhagic complications of anticoagulation, and one generalized seizure of uncertain cause. On the 92nd postoperative day, the patient had diarrhea and vomiting, leading to aspiration pneumonia and sepsis. Death occurred on the 112th day, preceded by progressive renal failure and refractory hypotension, despite maintenance of cardiac output. Autopsy revealed extensive pseudomembranous colitis, acute tubular necrosis, peritoneal and pleural effusion, centrilobular emphysema, and chronic bronchitis with fibrosis and bronchiectasis. The artificial heart system was intact and uninvolved by thrombosis or infectious processes. This experience should encourage further clinical trials with the artificial heart, but we emphasize that the procedure is still highly experimental. Further experience, development, and discussion will be required before more general application of the device can be recommended.

The 2013 International Society for Heart and Lung Transplantation Working Formulation for the standardization of nomenclature in the pathologic diagnosis of antibody-mediated rejection in heart transplantation

During the last 25 years, antibody-mediated rejection of the cardiac allograft has evolved from a relatively obscure concept to a recognized clinical complication in the management of heart transplant patients. Herein we report the consensus findings from a series of meetings held between 2010-2012 to develop a Working Formulation for the pathologic diagnosis, grading, and reporting of cardiac antibody-mediated rejection. The diagnostic criteria for its morphologic and immunopathologic components are enumerated, illustrated, and described in detail. Numerous challenges and unresolved clinical, immunologic, and pathologic questions remain to which a Working Formulation may facilitate answers.

The ISHLT working formulation for pathologic diagnosis of antibody-mediated rejection in heart transplantation: Evolution and current status (2005-2011)

From the Department of Pathology, Stanford University, Stanford, California; Universita of Padua Medical School, Padua, Italy; Royal Brompton and Harefield NHS Trust, London, United Kingdom; Hopital Europeen Georges Pompidou, Paris, France; David Geffen School of Medicine at the University of California-Los Angeles, Los Angeles, California; Intermountain Medical Center, Salt Lake City, Utah; Queen Elizabeth Hospital, Birmingham, United Kingdom; University of Utah, Salt Lake City, Utah; Cleveland Clinic, Cleveland, Ohio; Papworth Hospital, Papworth, United Kingdom; Brigham & Women’s Hospital, Boston, Massachusetts; Cedars Sinai Heart Institute, Los Angeles, California; University of Maryland School of Medicine, Baltimore, Maryland.

The intermediate layer: A morphologic study of the elastin and hyaluronic acid constituents of normal human vocal folds*

The lamina propria of vocal folds are important in voice production. We evaluated the morphologic features of elastin and hyaluronic acid, two important constituents of the lamina propria. Thirty normal human vocal folds were obtained from patients dying of traumatic causes without vocal fold injury. These tissues were immediately prepared for histologic and ultrastructural examination by standard methods. For specific study of the ultrastructure of the layers of the lamina propria, six vocal folds were divided horizontally through the midplane of the lamina propria. We found that the elastin composition of the vocal folds is variable, the largest amount being seen in the midportion on elastin-van Gieson (EVG) staining and ultrastructural evaluation. The superficial layer of the lamina propria contains fewer large elastin fibers. In this region, we found that elastin was predominantly composed of elaunin and oxytalan, which stain poorly with EVG. Using computer-assisted image analysis, we quantified the differences in elastin composition between the layers. The amount of elastin varied between men and women, and these differences could not be accurately measured by the methods employed. Hyaluronic acid was abundant especially in the midportion of the lamina propria and was significantly more abundant in men than women on quantification. The significance of these observations in normal vocal folds is discussed.

Preliminary report on hormone receptors in the human vocal fold

UNLABELLED There has been an ongoing effort to describe the physiologic factors associated with perceived and/or measured human voice changes that occur with age. In our study we focused on possible endocrine involvement on voice by using immunohistochemical staining to observe hormone receptor presence in vocal folds from 42 deceased subjects (fresh cadavers), male and female, ranging in age from 2 months to 82 years (average 37.7 years). On statistical analysis, age and gender were found to be associated with progesterone receptor staining of the glandular nuclei (young>old P = 0.013; male>female, P = 0.060). Gender was associated with androgen receptor staining in glandular cytoplasm (male>female, P = 0.014) and progesterone receptor staining in the epithelial cytoplasm (male>female, P = 0.039). No statistical significance was noted in other categories. CONCLUSION Hormone receptors are found in the nucleus and cytoplasm of cells in the vocal fold with statistically significant differences in age and gender distribution.

Benign Pathologic Responses of the Larynx

Benign laryngeal lesions were examined for patterns of injury indicated by deposition of fibronectin and collagen type iv. An immunoperoxidase technique was used to compare 33 fresh or paraffin-embedded tissues with regard to their staining of monoclonal antibodies directed against fibronectin and collagen type iv. Two types of patterns were recognized. One pattern showed intense fibronectin deposition in the superficial layer of the lamina propria, often coupled with basement membrane zone injury, indicated by thick collagen type IV bands. The other pattern showed rare basement membrane zone injury and very little fibronectin deposition. The first pattern correlated more with nodules, the second pattern more with Reinkes edema and some polyps. A better understanding of the effects of excessive deposition of structural glycoproteins such as fibronectin and of abnormal proteoglycan deposition may lead to a better characterization of vocal fold disease and its causation and, ultimately, better treatment.