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Purpose: We evaluated demographic, financial and support predictors of distress for parents of young children with disorders of sex development including atypical genital development, and characterized early parental experiences. This work extends our previous findings to identify those parents at risk for distress., Materials and Methods: Participants included mothers (76) and fathers (63) of a child (78) diagnosed with disorders of sex development characterized by moderate to severe genital atypia. Parents completed a demographic questionnaire, measures of anxious and depressive symptoms, quality of life, illness uncertainty and posttraumatic stress symptoms, and rated their satisfaction with the appearance of their child's genitalia., Results: Depressive and posttraumatic stress symptoms of caregivers were comparable to standardized norms while levels of anxious symptoms were below norms. A subset of parents reported clinically elevated symptoms. Overall 26% of parents reported anxious symptoms, 24% reported depressive symptoms and 17% reported posttraumatic stress symptoms. Levels of illness uncertainty were lower than those of parents of children with other chronic illnesses. Differences by parent sex emerged, with mothers reporting greater distress. Lower income, increased medical care and travel expenses, and having no other children were related to increased psychosocial distress., Conclusions: Early psychosocial screening is recommended for parents of children with disorders of sex development. Clinicians should be aware that financial burden and lack of previous parenting experience are risk factors for distress.

Objective: The purpose of this study was to assess clinical practice patterns with regard to diagnosis and management of testicular regression syndrome (TRS), a condition in 46,XY males with male phenotypic genitalia and bilateral absence of testes. Methods: A retrospective review was conducted at two large pediatric academic centers to examine diagnostic and management approaches for TRS. Results: Records of 57 patients were reviewed. Diagnostic methods varied widely between patients and included hormonal testing, karyotype, imaging, and surgical exploration, with multiple diagnostic methods frequently used in each patient. Of the 30 subjects that had reached adolescence at the time of the study, 17 (57%) had gaps in care of more than 5 years during childhood. Thirty subjects had received testosterone replacement therapy at a mean age of 12.1 ± 1.0 years. Forty-seven percent had a documented discussion of infertility. Eighty-two percent discussed prosthesis placement, with 35% having prostheses placed. Twenty-three percent were seen by a psychosocial provider. The between-site differences were age at fertility discussion, age at and number of prostheses placed, and type/age of testosterone initiation. Conclusion: Our findings highlight the wide variation in diagnostic approaches, follow-up frequency, testosterone initiation, fertility counseling, and psychosocial support for patients with TRS. Developing evidence-based guidelines for the evaluation and management of TRS would help reduce inconsistencies in care and unnecessary testing. Ongoing follow-up and coordination of care, even during the years when no hormonal treatment is being administered, could lead to opportunities for psychosocial support and improved interdisciplinary approach to care. Abbreviations: AMH = antimüllerian hormone; CAH = congenital adrenal hyperplasia; DSD = differences/disorders of sex development; hCG = human chorionic gonadotropin; TRS = testicular regression syndrome.

Introduction: Prior studies of outcomes following genitoplasty have reported high rates of surgical complications among children with atypical genitalia. Few studies have prospectively assessed outcomes after contemporary surgical approaches., Objective: The current study reported the occurrence of early postoperative complications and of cosmetic outcomes (as rated by surgeons and parents) at 12 months following contemporary genitoplasty procedures in children born with atypical genitalia., Study Design: This 11-site, prospective study included children aged ≤2 years, with Prader 3-5 or Quigley 3-6 external genitalia, with no prior genitoplasty and non-urogenital malformations at the time of enrollment. Genital appearance was rated on a 4-point Likert scale. Paired t-tests evaluated differences in cosmesis ratings., Results: Out of 27 children, 10 were 46,XY patients with the following diagnoses: gonadal dysgenesis, PAIS or testosterone biosynthetic defect, severe hypospadias and microphallus, who were reared male. Sixteen 46,XX congenital adrenal hyperplasia patients were reared female and one child with sex chromosome mosaicism was reared male. Eleven children had masculinizing genitoplasty for penoscrotal or perineal hypospadias (one-stage, three; two-stage, eight). Among one-stage surgeries, one child had meatal stenosis (minor) and one developed both urinary retention (minor) and urethrocutaneous fistula (major) (Summary Figure). Among two-stage surgeries, three children developed a major complication: penoscrotal fistula, glans dehiscence or urethral dehiscence. Among 16 children who had feminizing genitoplasty, vaginoplasty was performed in all, clitoroplasty in nine, external genitoplasty in 13, urethroplasty in four, perineoplasty in five, and total urogenital sinus mobilization in two. Two children had minor complications: one had a UTI, and one had both a mucosal skin tag and vaginal mucosal polyp. Two additional children developed a major complication: vaginal stenosis. Cosmesis scores revealed sustained improvements from 6 months post-genitoplasty, as previously reported, with all scores reported as good or satisfied., Discussion: In these preliminary data from a multi-site, observational study, parents and surgeons were equally satisfied with the cosmetic outcomes 12 months after genitoplasty. A small number of patients had major complications in both feminizing and masculinizing surgeries; two-stage hypospadias repair had the most major complications. Long-term follow-up of patients at post-puberty will provide a better assessment of outcomes in this population., Conclusion: In this cohort of children with moderate to severe atypical genitalia, preliminary data on both surgical and cosmetic outcomes were presented. Findings from this study, and from following these children in long-term studies, will help guide practitioners in their discussions with families about surgical management., (Copyright © 2018 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.)

Background: Bifid scrotum and hypospadias can be signs of undervirilization, yet boys presenting with these findings often do not undergo genetic evaluation. In some cases, identifying an underlying genetic diagnosis can help to optimize clinical care and improve guidance given to patients and families., Objectives: The aim of this study was to characterize current practice for genetic evaluation of patients with bifid scrotum, and to identify approaches with a good diagnostic yield., Methods: A retrospective study of the Boston Children's Hospital electronic medical records (1993-2015) was conducted using the search term "bifid scrotum" and clinical data were extracted. Data were abstracted into a REDCap database for analysis. Statistical analysis was performed using SPSS, SAS, and Excel software., Results: The search identified 110 subjects evaluated in the Urology and/or Endocrinology clinics for bifid scrotum. Genetic testing (including karyotype, microarray, or targeted testing) was performed on 64% of the subjects with bifid scrotum; of those tested, 23% (15% of the total cohort of 110 subjects) received a confirmed genetic diagnosis. Karyotype analysis, when performed, led to a diagnosis in 17% of patients. Of the ten instances when androgen receptor gene sequencing was performed, a pathogenic mutation was identified 20% of the time., Conclusion: This study demonstrated that the majority of individuals with moderate undervirilization resulting in bifid scrotum do not receive a genetic diagnosis. Over a third of the analyzed subjects did not have any genetic testing, even though karyotype analysis and androgen receptor (AR) sequencing were both relatively high yield for identifying a genetic etiology. Increased utilization of traditional genetic approaches could significantly improve the ability to find a genetic diagnosis., (Copyright © 2017 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.)

Disorders of sex development are challenging to evaluate and diagnose in the newborn. As pediatric urologists, our goals are to (1) identify patients who should be evaluated; (2) rule out life-threatening syndromes; and (3) involve a multidisciplinary team for evaluation, diagnosis, and gender assignment. This review briefly goes over the newborn differential diagnosis in disorders of sex development, highlights the important laboratory and imaging data needed, and discusses the multidisciplinary approach to gender assignment and care of these patients. Early involvement of the family in decision-making with the multidisciplinary team is paramount to a timely evaluation and diagnosis in these patients., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Introduction: Little data exist about the surgical interventions taking place for children with disorders of sex development (DSD). Most studies that have evaluated cosmetic outcomes after genitoplasty have included retrospective ratings by a physician at a single center., Objective: The present study aimed to: 1) describe frequency of sex assignment, and types of surgery performed in a cohort of patients with moderate-to-severe genital ambiguity; and 2) prospectively determine cosmesis ratings by parents and surgeons before and after genital surgery., Study Design: This prospective, observational study included children aged <2 years of age, with no prior genitoplasty at the time of enrollment, moderate-to-severe genital atypia, and being treated at one of 11 children's hospitals in the United States of America (USA). Clinical information was collected, including type of surgery performed. Parents and the local pediatric urologist rated the cosmetic appearance of the child's genitalia prior to and 6 months after genitoplasty., Results: Of the 37 children meeting eligibility criteria, 20 (54%) had a 46,XX karyotype, 15 (40%) had a 46,XY karyotype, and two (5%) had sex chromosome mosaicism. The most common diagnosis overall was congenital adrenal hyperplasia (54%). Thirty-five children had surgery; 21 received feminizing genitoplasty, and 14 had masculinizing genitoplasty. Two families decided against surgery. At baseline, 22 mothers (63%), 14 fathers (48%), and 35 surgeons (100%) stated that they were dissatisfied or very dissatisfied with the appearance of the child's genitalia. Surgeons rated the appearance of the genitalia significantly worse than mothers (P < 0.001) and fathers (P ≤ 0.001) at baseline. At the 6-month postoperative visit, cosmesis ratings improved significantly for all groups (P < 0.001 for all groups). Thirty-two mothers (94%), 26 fathers (92%), and 31 surgeons (88%) reported either a good outcome, or they were satisfied (see Summary Figure); there were no significant between-group differences in ratings., Discussion: This multicenter, observational study showed surgical interventions being performed at DSD centers in the USA. While parent and surgeon ratings were discordant pre-operatively, they were generally concordant postoperatively. Satisfaction with postoperative cosmesis does not necessarily equate with satisfaction with the functional outcome later in life., Conclusion: In this cohort of children with genital atypia, the majority had surgery. Parents and surgeons all rated the appearance of the genitalia unfavorably before surgery, with surgeons giving worse ratings than parents. Cosmesis ratings improved significantly after surgery, with no between-group differences., (Copyright © 2016 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.)

Purpose of Review: Disorders of sex development (DSD) are a diverse group of conditions affecting gonadal development, sexual differentiation, or chromosomal sex. In this review, we will discuss recent literature on the genetic causes of DSD, with a focus on novel genetic sequencing technologies, new phenotypes associated with known DSD genes, and increasing recognition of the role of genetic regulatory elements in DSD., Recent Findings: We performed a comprehensive search of PubMed through August 2016 to identify important peer-reviewed publications from 2015 to 2016 on the topic of DSD genetics., Summary: Whole-exome sequencing was used to successfully identify genetic causes of DSD in 35% of a cohort of 46,XY patients who had not previously received a genetic diagnosis. A novel mutation in NR5A1 has been identified as a cause of 46,XX testicular and ovotesticular DSD, demonstrating a previously unappreciated role of NR5A1 in preventing testicular differentiation in 46,XX individuals. Genetic regulatory elements of SOX9 have been identified as causes of 46,XX and 46,XY DSD.

Background: A variant in steroidogenic factor-1 (SF-1, encoded by the gene NR5A1), p.Arg92Trp, has recently been reported in multiple families with 46,XX ovotesticular or testicular disorders of sex development (DSD). This amino acid change impacts the DNA-binding domain and perturbs gonadal differentiation pathways., Methods: Whole-exome sequencing was performed on a 46,XX subject with ovotesticular DSD., Results: Exome results identified a heterozygous NR5A1 variant, p.Arg92Gln, in the 46,XX ovotesticular DSD proband. This arginine-to-glutamine change has been previously reported in the homozygous state in a 46,XY patient with gonadal and adrenal dysgenesis, though 46,XY and 46,XX heterozygous carriers of this variant have not been previously reported to have any clinical phenotype., Conclusions: The NR5A1 p.Arg92Gln variant, which has thus far only been seen in a family with 46,XY DSD, most likely contributes to the ovotesticular DSD in this case. In light of the recent reports of unrelated 46,XX subjects with testicular or ovotesticular DSD with the NR5A1 variant p.Arg92Trp, it appears that other mutations in the DNA binding domain have the potential to impact the factors determining testicular and ovarian differentiation. This case demonstrates the variability of phenotypes with the same genotype and broadens our understanding of the role of SF-1 in gonadal differentiation., (© 2016 S. Karger AG, Basel.)

Background: Undervirilized 46,XY males with bifid scrotum often pose a diagnostic challenge, and the majority of cases typically do not receive a genetic diagnosis. NR5A1 mutations can be seen in 10-20% of the cases and are a relatively common cause of undervirilization., Methods: Whole-exome sequencing was utilized to study 10 undervirilized 46,XY subjects with bifid scrotum., Results: Exome sequencing identified novel NR5A1 variants, both affecting exon 7, in 2 of the 10 subjects with bifid scrotum. Subject 1 had a heterozygous frameshift variant, c.1150delC, p.Leu384fsTer1, within the ligand-binding domain inherited from his unaffected father. Subject 2 had a novel splice-site variant c.1139-2T>C, affecting the canonical splice acceptor site for exon 7 and also disrupting the ligand-binding domain. Both subjects had serum testosterone levels within the normal range as infants., Conclusions: We describe two novel NR5A1 variants, demonstrating mutations in this gene as a common cause of milder cases of 46,XY undervirilization. Whole-exome sequencing results yielded the diagnosis in 2 out of 10 cases without a previous diagnosis, supporting the value of this approach. Significant genotype-phenotype variability was also noted with Subject 1's paternal inheritance from his unaffected father., (© 2016 S. Karger AG, Basel.)

Erosion, sediment production, and routing on a tectonically active continental margin reflect both tectonic and climatic processes; partitioning the relative importance of these processes remains controversial. Gulf of Alaska contains a preserved sedimentary record of the Yakutat Terrane collision with North America. Because tectonic convergence in the coastal St. Elias orogen has been roughly constant for 6 My, variations in its eroded sediments preserved in the offshore Surveyor Fan constrain a budget of tectonic material influx, erosion, and sediment output. Seismically imaged sediment volumes calibrated with chronologies derived from Integrated Ocean Drilling Program boreholes show that erosion accelerated in response to Northern Hemisphere glacial intensification (∼ 2.7 Ma) and that the 900-km-long Surveyor Channel inception appears to correlate with this event. However, tectonic influx exceeded integrated sediment efflux over the interval 2.8-1.2 Ma. Volumetric erosion accelerated following the onset of quasi-periodic (∼ 100-ky) glacial cycles in the mid-Pleistocene climate transition (1.2-0.7 Ma). Since then, erosion and transport of material out of the orogen has outpaced tectonic influx by 50-80%. Such a rapid net mass loss explains apparent increases in exhumation rates inferred onshore from exposure dates and mapped out-of-sequence fault patterns. The 1.2-My mass budget imbalance must relax back toward equilibrium in balance with tectonic influx over the timescale of orogenic wedge response (millions of years). The St. Elias Range provides a key example of how active orogenic systems respond to transient mass fluxes, and of the possible influence of climate-driven erosive processes that diverge from equilibrium on the million-year scale.

Background: Cockayne syndrome is an autosomal recessive, heterogeneous syndrome with classical features, including short stature, microcephaly, developmental delay, neuropathy, and photosensitivity. New genomic approaches offer improved molecular diagnostic potential., Methods: Whole-exome sequencing was employed to study a consanguineous extended family with severe short stature and variable presentations of peripheral neuropathy, lipoatrophy, photosensitivity, webbed neck, and hirsutism., Results: We identified a novel homozygous ERCC6 variant at the donor splice site of intron 9 (c.1992 + 3A>G), which was predicted to only slightly perturb splicing efficiencies. Assessment of primary fibroblast-derived mRNAs, however, revealed a dominant splicing species that utilized an unsuspected putative donor splice site within exon 9, resulting in predicted early protein termination (p.Arg637Serfs*34)., Conclusions: We describe a new splicing ERCC6 defect causal of Cockayne syndrome. The application of exome sequence analysis was integral to diagnosis, given the complexity of phenotypic presentation in the affected family members. The novel splicing defect, furthermore, illustrates how a seemingly minor change in the relative strength of a splice site can have significant biological consequences., (2014 S. Karger AG, Basel)

Problem: This study explores contribution of the orbital floor to mechanical outcomes of orbital decompressions., Method of Study: Endoscopic medial wall orbital decompressions with and without extensive medial orbital floor removal (OFR) were performed on opposite sides of ten thawed fresh-frozen cadaver heads Bone removal was compared on pre- and post-dissection CT scans and after orbital exenteration., Results: Bony removal in the anterior orbital apex was significantly better after OFR (117 vs 66, p < 0.0001). An average of 10.3% (range 0 - 45.5%) of the orbital floor directly under the globe was removed with the OFR technique. The orbital floor preservation (OFP) technique resulted in average bone removal of 3.6 cm2, whereas OFR decompression resulted in average of 5.7 cm2 (p = 0.0003). Post-operative recession of the globe was significant in both arms of the study relative to the unoperated state (OFP averaged 2.99 mm decompression, p = 0.001 and OFR averaged 4.25 mm decompression, p = 0.02)., Conclusions: Endoscopic removal of the medial orbital floor when performed in addition to medial wall decompression removes > 60% more orbital bone and an additional 51 of orbital apex bone. Extensive endoscopic removal of the mid-portion of the medial orbital floor results in bone loss beneath the globe itself.

A critical role for eosinophils in remodeling of allergic airways was observed in vivo upon disruption of the dblGATA enhancer that regulates expression of GATA-1, which resulted in an eosinophil-deficient phenotype in the DeltadblGATA mouse. We demonstrate here that bone marrow progenitors isolated from DeltadblGATA mice can differentiate into mature eosinophils when subjected to cytokine stimulation ex vivo. Cultured DeltadblGATA eosinophils contain cytoplasmic granules with immunoreactive major basic protein and they express surface Siglec F and transcripts encoding major basic protein, eosinophil peroxidase, and GATA-1, -2, and -3 to an extent indistinguishable from cultured wild-type eosinophils. Fibroblast coculture and bone marrow cross-transplant experiments indicate that the in vivo eosinophil deficit is an intrinsic progenitor defect, and remains unaffected by interactions with stromal cells. Interestingly, and in contrast to those from the wild type, a majority of the GATA-1 transcripts from cultured DeltadblGATA progenitors express a variant GATA-1 transcript that includes a first exon (1E(B)), located approximately 3700 bp downstream to the previously described first exon found in hemopoietic cells (1E(A)) and approximately 42 bp upstream to another variant first exon, 1E(C). These data suggest that cultured progenitors are able to circumvent the effects of the DeltadblGATA ablation by using a second, more proximal, promoter and use this mechanism to generate quantities of GATA-1 that will support eosinophil growth and differentiation.

We explore the controversial issue of the role of eosinophils in host defense against helminthic parasites using the established Schistosoma mansoni infection model in 2 novel mouse models of eosinophil lineage ablation (DeltadblGATA and TgPHIL). No eosinophils were detected in bone marrow of infected DeltadblGATA or TgPHIL mice, despite the fact that serum IL-5 levels in these infected mice exceeded those in infected wild type by approximately 4-fold. Liver granulomata from infected DeltadblGATA and TgPHIL mice were likewise depleted of eosinophils compared with those from their respective wild types. No eosinophil-dependent differences in granuloma number, size, or fibrosis were detected at weeks 8 or 12 of infection, and differential accumulation of mast cells was observed among the DeltadblGATA mice only at week 12. Likewise, serum levels of liver transaminases, alanine aminotransferase (ALT), and aspartate aminotransferase (AST) increased in all mice in response to S mansoni infection, with no eosinophil-dependent differences in hepatocellular damage observed. Finally, eosinophil ablation had no effect on worm burden or on egg deposition. Overall, our data indicate that eosinophil ablation has no impact on traditional measures of disease in the S mansoni infection model in mice. However, eosinophils may have unexplored immunomodulatory contributions to this disease process.

Plasminogen activator inhibitor-2 (PAI-2) as a potential eosinophil protein was inferred from our gene microarray study of mouse eosinophilopoiesis. Here, we detect 47 kDa intracellular and approximately 60 kDa secretory forms of PAI-2 in purified human eosinophil extracts. PAI-2 is present at variable concentrations in eosinophil lysates, ranging from 30 to 444 ng/10(6) cells, with a mean of 182 ng/10(6) cells from 10 normal donors, which is the highest per-cell concentration among all leukocyte subtypes evaluated. Enzymatic assay confirmed that eosinophil-derived PAI-2 is biologically active and inhibits activation of its preferred substrate, urokinase. Immunohistochemical and immunogold staining demonstrated PAI-2 localization in eosinophil-specific granules. Immunoreactive PAI-2 was detected in extracellular deposits in and around the eosinophil-enriched granuloma tissue encapsulating the parasitic egg in livers of wild-type mice infected with the helminthic parasite Schistosoma mansoni. Among the possibilities, we consider a role for eosinophil-derived PAI-2 in inflammation and remodeling associated with parasitic infection as well as allergic airways disease, respiratory virus infection, and host responses to tumors and metastasis in vivo.

Purpose: The purpose of this study was to evaluate the influence of alloy surface microabrasion, silica coating, or microabrasion plus tin plating on the tensile bond strengths between a resin-modified glass-ionomer luting cement and a high-noble alloy. Bond strength between the microabraded alloy specimens and conventional glass-ionomer cement or resin cement were included for comparison., Materials and Methods: One hundred twenty uniform size, disk-shaped specimens were cast in a noble metal alloy and divided into 6 groups (n = 10 pairs/group). The metal surfaces of the specimens in each group were treated and cemented as follows. Group 1: No surface treatment (as cast, control), cemented with a resin-modified glass-ionomer cement. Group 2: Microabrasion with 50-microm aluminum oxide particles, resin-modified glass-ionomer cement. Group 3: A laboratory microabrasion and silica coating system, resin-modified glass-ionomer cement. Group 4: Microabrasion and tin-plating, resin-modified glass-ionomer cement. Group 5: Microabrasion only, conventional glass-ionomer cement. Group 6: Microabrasion and tin-plating, conventional resin cement. The uniaxial tensile bond strength for each specimen pair was determined using an Instron Universal Testing Machine (Instron Corp, Canton, MA). Results were analyzed using a one-way analysis of variance (alpha = 0.05) and a Tukey post-hoc analysis., Results: Mean bond strength: Group 1: 3.6 (+/- 1.5) MPa. Group 2: 4.2 (+/-0.5) MPa. Group 3: 6.7 (+/- 0.9) MPa. Group 4: 10.6 (+/- 1.8) MPa. Group 5: 1.1 (+/- 0.4) MPa. Group 6: 14.6 (+/- 2.3) MPa. Group 6 was significantly stronger than Group 4. The bond strength of specimens cemented with the resin-modified glass-ionomer cement using microabrasion and tin-plating (Group 4) was significantly stronger than all other groups except the resin cement with microabrasion and tin-plating (Group 6)., Conclusion: Microabraded and tin-plated alloy specimens luted with the resin-modified glass-ionomer cement resulted in the greatest mean tensile strengths for the resin-modified glass-ionomer cement groups. This strength was 73% of the mean tensile strength of microabraded specimens luted with resin cement.

Chemokine receptors pivotal for human immunodeficiency virus type 1 (HIV-1) infection in lymphocytes and macrophages (CCR3, CCR5, and CXCR4) are expressed on neural cells (microglia, astrocytes, and/or neurons). It is these cells which are damaged during progressive HIV-1 infection of the central nervous system. We theorize that viral coreceptors could effect neural cell damage during HIV-1-associated dementia (HAD) without simultaneously affecting viral replication. To these ends, we studied the ability of diverse viral strains to affect intracellular signaling and apoptosis of neurons, astrocytes, and monocyte-derived macrophages. Inhibition of cyclic AMP, activation of inositol 1,4,5-trisphosphate, and apoptosis were induced by diverse HIV-1 strains, principally in neurons. Virions from T-cell-tropic (T-tropic) strains (MN, IIIB, and Lai) produced the most significant alterations in signaling of neurons and astrocytes. The HIV-1 envelope glycoprotein, gp120, induced markedly less neural damage than purified virions. Macrophage-tropic (M-tropic) strains (ADA, JR-FL, Bal, MS-CSF, and DJV) produced the least neural damage, while 89.6, a dual-tropic HIV-1 strain, elicited intermediate neural cell damage. All T-tropic strain-mediated neuronal impairments were blocked by the CXCR4 antibody, 12G5. In contrast, the M-tropic strains were only partially blocked by 12G5. CXCR4-mediated neuronal apoptosis was confirmed in pure populations of rat cerebellar granule neurons and was blocked by HA1004, an inhibitor of calcium/calmodulin-dependent protein kinase II, protein kinase A, and protein kinase C. Taken together, these results suggest that progeny HIV-1 virions can influence neuronal signal transduction and apoptosis. This process occurs, in part, through CXCR4 and is independent of CD4 binding. T-tropic viruses that traffic in and out of the brain during progressive HIV-1 disease may play an important role in HAD neuropathogenesis.

The mechanism(s) by which HIV-1 affects neural injury in HIV-1-associated dementia (HAD) remains unknown. To ascertain the role that cellular and viral macrophage products play in HAD neurotoxicity, we explored one potential route for neuronal demise, CXCR4. CXCR4, expressed on lymphocytes and neurons, is both a part of neural development and a co-receptor for HIV-1. Its ligand, stromal cell-derived factor-1alpha (SDF-1alpha), affects neuronal viability. GTP binding protein (G-protein) linked signaling after neuronal exposure to SDF-1alpha, virus-infected monocyte-derived macrophage (MDM) secretory products, and virus was determined. In both human and rat neurons, CXCR4 was expressed at high levels. SDF-1alpha/beta was detected predominantly in astrocytes and at low levels in MDM. SDF-1beta/beta was expressed in HAD brain tissue and upregulated in astrocytes exposed to virus infected and/or immune activated MDM conditioned media (fluids). HIV-1-infected MDM secretions, virus and SDF-1beta induced a G inhibitory (Gi) protein-linked decrease in cyclic AMP (cAMP) and increase inositol 1,4, 5-trisphosphate (IP3) and intracellular calcium. Such effects were partially blocked by antibodies to CXCR4 or removal of virus from MDM fluids. Changes in G-protein-coupled signaling correlated, but were not directly linked, to increased neuronal synaptic transmission, Caspase 3 activation and apoptosis. These data, taken together, suggest that CXCR4-mediated signal transduction may be a potential mechanism for neuronal dysfunction during HAD.