Increased circulating concentrations of the counteradhesive proteins SPARC and thrombospondin-1 in systemic sclerosis (scleroderma). Relationship to platelet and endothelial cell activation

OBJECTIVE: To determine whether circulating concentrations of the counteradhesive proteins SPARC (secreted protein acidic and rich in cysteine) and thrombospondin-1 (TSP-1) are elevated in scleroderma (systemic sclerosis, SSc). The relationship of these counteradhesive proteins to measures of platelet and endothelial cell activation was examined. METHODS: Plasma from 45 patients with SSc (26 limited form, 19 diffuse) and 22 age and sex matched controls was assayed for SPARC, TSP-1, beta-thromboglobulin (betaTG), and platelet factor 4 (PF4), 2 distinct platelet a-granule products, and soluble E-selectin, a marker of endothelial cell activation. RESULTS: The mean (+/- SE) SPARC concentration was greater in patients with limited SSc (124.0 +/- 9.6 ng/ml) compared to controls (66.8 +/- 8.0 ng/ml) (p = 0.0005), whereas in patients with diffuse SSc (74.1 +/- 7.9 ng/ml) it was not. Elevated SPARC concentrations in the limited SSc group could not be ascribed to either platelet or endothelial cell activation. TSP-1 concentrations were also increased in SSc patients (n = 29) compared to controls (n = 11) (2.98 +/- 0.12 vs 2.4 +/- 0.21 log transformed ng/ml; p < 0.02). Unlike SPARC, TSP-1 concentrations correlated with both betaTG (r = 0.57, p = 0.0014) and PF4 (r = 0.41, p = 0.026) levels, indicating that increased TSP-1 could, in part, be explained through elevated platelet a-granule release in SSc patients. Plasma levels of betaTG, PF4, and E-selectin were each similarly elevated (p < 0.003) in patients with both limited and diffuse SSc compared to controls. CONCLUSION: That circulating SPARC and TSP-1 are elevated in patients with SSc raises the possibility that counteradhesive proteins, which regulate vascular organization and remodeling, might contribute to the pathogenesis of SSc vasculopathy.     

Diverse injurious stimuli reduce protein tyrosine phosphatase-μ expression and enhance epidermal growth factor receptor signaling in human airway epithelia

In response to injury, airway epithelia utilize an epidermal growth factor (EGF) receptor (EGFR) signaling program to institute repair and restitution. Protein tyrosine phosphatases (PTPs) counterregulate EGFR autophosphorylation and downstream signaling. PTPμ is highly expressed in lung epithelia and can be localized to intercellular junctions where its ectodomain homophilically interacts with PTPμ ectodomain expressed on neighboring cells. We asked whether PTPμ expression might be altered in response to epithelial injury and whether altered PTPμ expression might influence EGFR signaling. In A549 cells, diverse injurious stimuli dramatically reduced PTPμ protein expression. Under basal conditions, small interfering RNA (siRNA)-induced silencing of PTPμ increased EGFR Y992 and Y1068 phosphorylation. In the presence of EGF, PTPμ knockdown increased EGFR Y845, Y992, Y1045, Y1068, Y1086, and Y1173 but not Y1148 phosphorylation. Reduced PTPμ expression increased EGF-stimulated phosphorylation of Y992, a docking site for phospholipase C (PLC)γ(1), activation of PLCγ(1) itself, and increased cell migration in both wounding and chemotaxis assays. In contrast, overexpression of PTPμ decreased EGF-stimulated EGFR Y992 and Y1068 phosphorylation. Therefore, airway epithelial injury profoundly reduces PTPμ expression, and PTPμ depletion selectively increases phosphorylation of specific EGFR tyrosine residues, PLCγ(1) activation, and cell migration, providing a novel mechanism through which epithelial integrity may be restored.     

PD 404,182 is a virocidal small molecule that disrupts hepatitis C virus and human immunodeficiency virus

We describe a virucidal small molecule, PD 404,182, that is effective against hepatitis C virus (HCV) and human immunodeficiency virus (HIV). The median 50% inhibitory concentrations (IC(50)s) for the antiviral effect of PD 404,182 against HCV and HIV in cell culture are 11 and 1 μM, respectively. The antiviral activity of PD 404,182 is due to the physical disruption of virions that is accompanied to various degrees (depending on the virus and exposure temperature/time) by the release of viral nucleic acids into the surrounding medium. PD 404,182 does not directly lyse liposomal membranes even after extended exposure, and it shows no attenuation in antiviral activity when preincubated with liposomes of various lipid compositions, suggesting that the compound inactivates viruses through interaction with a nonlipid structural component of the virus. The virucidal activity of PD 404,182 appears to be virus specific, as little to no viral inactivation was detected with the enveloped Dengue and Sindbis viruses. PD 404,182 effectively inactivates a broad range of primary isolates of HIV-1 as well as HIV-2 and simian immunodeficiency virus (SIV), and it does not exhibit significant cytotoxicity with multiple human cell lines in vitro (50% cytotoxic concentration, >300 μM). The compound is fully active in cervical fluids, although it exhibits decreased potency in the presence of human serum, retains its full antiviral potency for 8 h when in contact with cells, and is effective against both cell-free and cell-associated HIV. These qualities make PD 404,182 an attractive candidate anti-HIV microbicide for the prevention of HIV transmission through sexual intercourse.     

Hb Stara Zagora: a new hyper-unstable hemoglobin causing severe hemolytic anemia

We describe a new hyper-unstable beta chain variant (codons 137-139, -6 bp) in a 2-year-old Bulgarian boy. The abnormal hemoglobin (Hb) is associated with severe hemolytic anemia as a consequence of its hyper instability. The child was admitted to the Pediatric Clinic (Faculty of Medicine, Stara Zagora, Bulgaria) at the age of 2 months. Because of anemia (Hb 6.9 g/dL) and high serum iron level (58 microM/L) the child was transfused. However, a month later his Hb level had dropped to 7.5 g/dL, and since then he has been on a regular monthly blood transfusion regimen. Hemoglobin analysis of a blood sample collected 2 months after the last transfusion at the age of 2 years, revealed no abnormalities except for the presence of inclusion bodies after incubation of peripheral blood with brilliant cresyl blue. Sequencing of the beta-globin gene revealed heterozygosity for a 6 bp deletion (-TGGCTA) at codons 137 [the second and third base pair (bp)], 138 and 139 (the first bp), forming a new codon at position 137 (GAT). This event eliminates three amino acids (Val-Ala-Asn) and introduces a new residue (Asp). It creates a new restriction site for HphI. The parents and his dizygotic twin brother had no history of hemolysis. The paternity of the child was confirmed by DNA analysis.     

Hb Stara Zagora: A New Hyper-Unstable Hemoglobin Causing Severe Hemolytic Anemia

We describe a new hyper-unstable β chain variant (codons 137–139, ? 6 bp) in a 2-year-old Bulgarian boy. The abnormal hemoglobin (Hb) is associated with severe hemolytic anemia as a consequence of its hyper instability. The child was admitted to the Pediatric Clinic (Faculty of Medicine, Stara Zagora, Bulgaria) at the age of 2 months. Because of anemia (Hb 6.9 g/dL) and high serum iron level (58 μM/L) the child was transfused. However, a month later his Hb level had dropped to 7.5 g/dL, and since then he has been on a regular monthly blood transfusion regimen. Hemoglobin analysis of a blood sample collected 2 months after the last transfusion at the age of 2 years, revealed no abnormalities except for the presence of inclusion bodies after incubation of peripheral blood with brilliant cresyl blue. Sequencing of the β-globin gene revealed heterozygosity for a 6 bp deletion (–TGGCTA) at codons 137 [the second and third base pair (bp)], 138 and 139 (the first bp), forming a new codon at position 137 (GAT). This event eliminates three amino acids (Val-Ala-Asn) and introduces a new residue (Asp). It creates a new restriction site for HphI. The parents and his dizygotic twin brother had no history of hemolysis. The paternity of the child was confirmed by DNA analysis.     

Mapping frailty in people living with HIV: A nationwide study in Greece

Objectives

Frailty is known to affect people living with HIV prematurely, compared to the ageing seronegative population. In this cross-sectional study, we aimed to assess frailty prevalence in people living with HIV in Greece and find associations of frailty criteria with clinical data.

Methods

Demographic and clinical data were collected from 477 participants in six HIV clinics. Fried's frailty phenotype was used to assess frailty prevalence, and participants were classified as frail, pre-frail or robust. Associations of several factors with overall frailty phenotype, as well as with frailty criteria, were explored.

Results

The median age was 43 years old (IQR = 51.5) and 444/477 (93%) were men. Most of the participants (429/477, 93.5%) had an undetectable HIV viral load, and a CD4 cell count over 500 cells/μl (366/477, 76.7%). Frailty assessment classified 285/477 (62.1%) as robust, 155/477 (33.8%) as pre-frail and 19/477 (4.1%) as frail. Weakness in grip strength was the most prevalent criterion (128/477, 26.8%), followed by exhaustion (46/477, 9.6%). Lower CD4 cell count, history of AIDS diagnosis, CNS disorders, psychiatric diagnoses, and polypharmacy were strongly associated with frailty.

Conclusions

Although the prevalence of frailty in people living with HIV in Greece is uncommon, when combined with pre-frailty over a third of people are affected, which requires attention in clinical practice. The physical and psychological aspects of frailty highlight the need for a holistic approach to prevent or counteract it. The diverse associations of frailty criteria with HIV-related and non-HIV-related factors suggest a possible variation in people's different healthcare needs.