HIV-1 matrix protein p17 binds to the IL-8 receptor CXCR1 and shows IL-8-like chemokine activity on monocytes through Rho/ROCK activation

Exogenous HIV-1 matrix protein p17 was found to deregulate biologic activities of many different immune cells that are directly or indirectly involved in AIDS pathogenesis after binding to unknown cellular receptor(s). In particular, p17 was found to induce a functional program in monocytes related to activation and inflammation. In the present study, we demonstrate that CXCR1 is the receptor molecule responsible for p17 chemokine-like activity on monocytes. After CXCR1 binding, p17 was capable of triggering rapid adhesion and chemotaxis of monocytes through a pathway that involved Rho/ROCK. Moreover, CXCR1-silenced primary monocytes lost responsiveness to p17 chemoattraction, whereas CXCR1-transfected Jurkat cells acquired responsiveness. Surface plasmon resonance studies confirmed the capacity of p17 to bind CXCR1 and showed that the p17/CXCR1 interaction occurred with a low affinity compared with that measured for IL-8, the physiologic CXCR1 ligand. In all of its activities, p17 mimicked IL-8, the natural high-affinity ligand of CXCR1. Recent studies have highlighted the role of IL-8 and CXCR1 in HIV-1 replication and AIDS pathogenesis. Our findings herein call for an exploration of the therapeutic potential of blocking the p17/IL-8/CXCR1 axis in HIV-1 infection.     

Sustained telomere length in hepatocytes and cholangiocytes with increasing age in normal liver

Telomeres, a validated biomarker of aging, comprise multiple nucleotide repeats capping chromosomes that shorten with each cell cycle until a critical length is achieved, precipitating cell senescence. Only two previous studies focused on the effect of aging in "normal" liver tissue, but these studies were compromised by small sample size, limited age range, tissue derived from individuals with an increased risk of senescence, and the use of liver homogenates. We developed a robust large-volume, four-color quantitative fluorescent in situ hybridization technique to measure telomere length in large numbers of hepatocytes, Kupffer cells, hepatic stellate cells, CD4-positive and CD8-positive lymphocytes, and cholangiocytes. Following validation against the gold standard (Southern blotting), the technique was applied to normal archived paraffin-embedded liver tissue obtained following reperfusion of implanted donor liver. We studied 73 highly selected donors aged 5-79 years with a short medical illness preceding death and no history of liver disease, reperfusion injury, or steatosis and normal graft function 1-year posttransplantation. Cholangiocytes had significantly longer telomeres compared with all other intrahepatic lineages over a wide age range (P < 0.05). Age-related telomere attrition was restricted to sinusoidal cells (i.e., Kupffer cells [P = 0.0054] and stellate cells [P = 0.0001]). Cholangiocytes and hepatocytes showed no age-related telomere shortening. Conclusion: In normal liver and over a broad age range, cholangiocytes have longer telomeres than all other intrahepatic lineages. Age-related telomere length decline is restricted to Kupffer cells and stellate cells. (HEPATOLOGY 2012).     

Left-handedness is statistically linked to lifetime experimentation with illicit drugs

Handedness has been linked to an enhanced risk of alcohol abuse, while less is known about other drugs. A convenience sample of 1004 male and female Italian participants (females=58%) from the general community (18 to 65 years old: average age = 30; standard deviation = 10, median = 25) was asked about: handedness (preference in writing); lifetime use of alcohol, tobacco, and illicit drugs; levels of psychological distress, as measured by the General Health Questionnaire (GHQ); and levels of delusion proneness, as measured by the Peters et al. Delusions Inventory (PDI). Overall, 92 individuals (9.2%) were classified as left-handed, with no significant difference reported among genders. Lifetime use of illicit drugs, primarily cannabis, was reported by 20% of the sample. In a multiple logistic regression analysis, after taking into account sex, age, and caseness on GHQ and PDI, left-handed people in the sample were statistically more likely to report lifetime experimentation with heroin, ecstasy/amphetamine, and, marginally, hallucinogens, but not alcohol or tobacco. Different mechanisms might contribute to an explanation of greater lifetime experimentation with some illicit drugs among left-handed people as compared to right-handed people. However, replications with clinical samples are necessary before any definitive statements can be made.     

Adipose-derived stem cells and rabbit bone regeneration: histomorphometric, immunohistochemical and mechanical characterization

Background

In the last few years, several attempts have been made to treat large bone loss, including the use of tissue engineering with osteoinductive scaffolds and cells. This study highlights the role of mesenchymal stem cells from adipose tissue (ASCs; adipose-derived stem cells) in a rabbit bone regeneration model.

Methods

We compared the neoformed bone tissues achieved by treating critical tibial defects with either hydroxyapatite alone (HA, group I) or hydroxyapatite–autologous ASC constructs (ASCs-HA, group II), investigating their histomorphometric, immunohistochemical and biomechanical properties.

Results

After eight weeks of follow-up, we observed advanced maturation and a spatial distribution of new bone that was more homogeneous in the inner parts of the pores in group II, not just along the walls (as seen in group I). The new tissue expressed osteogenic markers, and biomechanical tests suggested that the newly formed bone in group II had a higher mineral content than that in group I. Although variability in differentiation was observed among the different cell populations in vitro, no differences in bone healing were observed in vivo; the variability seen in vitro was probably due to local microenvironment effects.

Conclusions

Tibial defects treated with rabbit ASCs-HA showed an improved healing process when compared to the process that occurred when only the scaffold was used. We suggest that implanted ASCs ameliorate the bone reparative process either directly or by recruiting resident progenitor cells.     

Reoperative Surgery After Repair of Postcholecystectomy Bile Duct Injuries: Is it Worthwhile?

Background

Repeat repair of bile duct injuries (BDIs) after cholecystectomy is technically challenging, and its success remains uncertain. We retrospectively evaluated the short- and long-term outcomes of patients requiring reoperative surgery for BDI at a major referral center for hepatobiliary surgery.

Methods

Between January 1991 and May 2011, we performed surgical BDI repairs in 46 patients. Among them, 22 patients had undergone a previous surgical repair elsewhere (group 1), and 24 patients had no previous repair (group 2). We compared the early and late outcomes in the two groups.

Results

The patients in group 1 were younger (48.6 vs. 54.8 years, p = 0.0001) and were referred after a longer interval (>1 month) from BDI (72.7 vs. 41.7 %, p = 0.042). Intraoperative diagnosis of BDI (59.1 vs. 12.5 %, p = 0.001), ongoing cholangitis (45.4 vs. 12.5 %; p = 0.02), and delay of repair after referral to our institution (116 ± 34 days vs. 23 ± 9 days; p = 0.001) were significantly more frequent in group 1 than in group 2. No significant differences were found for postoperative mortality, morbidity, or length of stay between the groups. Patients with associated vascular injuries had a higher postoperative morbidity rate (p = 0.01) and associated hepatectomy rate (p = 0.045). After a mean follow-up of 96.6 ± 9.7 months (range 5–237.2 months, median 96 months), the rate of recurrent cholangitis (6.5 %) was comparable in the two groups.

Conclusions

This study demonstrates that short- and long-term outcomes after surgical repair of BDI are comparable regardless of whether the patient requires reoperative surgery for a failed primary repair. Associated vascular injuries increase postoperative morbidity and the need for liver resection.     

Transplantation of Autologous Cultivated Conjunctival Epithelium for the Restoration of Defects in the Ocular Surface

Ocular surface disorders are often characterised by partial or complete loss of corneo-conjunctival epithelium, which causes dramatic functional and cosmetic problems. Depletion of stem cells and the scarcity of donor tissue available make large or bilateral defects challenging to reconstruct, and usually require the transplantation of heterotopic or allogeneic grafts. We investigated the feasibility of restoring severely damaged ocular surfaces with autologous cultivated conjunctival epithelium. Conjunctival cells were harvested from the healthy eyelid bed of four patients with oculopalpebral diseases. An epithelial sheet reproducing the original conjunctival epithelium was generated by serial cell culture. This was transplanted for the first time ever to our knowledge on to the ocular surface of the same patients. Take was excellent and the cultivated epithelium was stable, resulting in great improvement of patient's symptoms and cosmesis. Transplantation of cultivated conjunctival cells opens new perspectives in the treatment of severe ocular surface disorders.