No gender differences in the 24-month course of non-invasive liver fibrosis markers after DAA therapy in HCV-mono and HCV/HIV-coinfected patients.

Untreated HCV mono and HCV/HIV coinfected women have lower degrees of liver fibrosis (LF) compared to men. Direct acting antiviral (DAA) therapy attains viral eradication in > 90% of patients with progressive LF decline in parallel. Gender-related differences in LF regression in the long term assessed by non-invasive liver fibrosis markers (NILFM) in HCV mono and HCV/HIV coinfected after DAA treatment have not been explored so far. 374 HCV-infected adult patients, 214 of them HCV/HIV coinfected, were followed-up for 24 months after starting DAA therapy. LF was assessed by NILFM: transient elastometry (TE) and several biochemical indexes (APRI, Forns, FIB-4). Men had significantly more advanced LF at baseline than women assessed by NILFM. No LF differences at baseline in age, HIV coinfection course (CD4, HIV viral load), and HCV features (HCV viral load, genotype) were detected. No significant gender differences in LF decline after comparing 24-month and baseline LF values were observed. LF changes after DAA therapy were similar in HCV mono and HCV/HIV coinfected patients and in both sexes. Gender did not influence the course of LF decline after DAA assessed by NILFM: TE (P = 0.8), APRI (P = 0.9), Forns (P = 0.4) and FIB-4 (P = 0.7) by multivariate analysis. No gender differences in the 24 month LF decline after DAA with independence of having HCV mono or HCV/HIV coinfection were found.

IL-1 ß gene (+3954 C/T, exon 5, rs1143634) and NOS2 (exon 22) polymorphisms associate with early aseptic loosening of arthroplasties.

Aseptic prosthetic loosening (APL) and prosthetic joint infections (PJI) are frequent complications of hip and knee implants. Polymorphisms of cytokines and nitric oxide (NO), key inflammatory molecules in APL and PJI pathogenesis, could explain individual susceptibility to these complications. Three cytokines (IL-1-a, IL-1-ß, TNF-α) and two nitric oxide synthase (NOS2, NOS3) genes polymorphisms were genotyped in 77 APL and 117 PJI patients and 145 controls with aseptic hip or knee implants that were implanted for > 16 years. Plasma cytokines and nitrate-nitrite (NOx) levels also were measured. The TT genotype and T allele of (+3954 C/T, exon 5, rs1143634) IL-1ß polymorphism were more frequent in APL patients compared to controls (P = 0.03 and P = 0.02, respectively). No genotypic associations in PJI patients were observed. Plasma IL-6, TNF-α and NOx were significantly different between APL and controls (P < 0.0001). Plasma IL-1ß and IL-6 were significantly higher in APL T allele carriers vs. non-carriers (P < 0.03). Knee implant (HR 2.488, 95% CI 1.307-4.739, P = 0.005), male gender (HR 2.252, 95% CI 1.121-4.525, P = 0.023), carriages of the TT genotype of the (+3954 C/T) IL-1ß polymorphism (HR 3.704, 95% CI 1.274-10.753, P = 0.016) and AA genotype of the (exon 22) NOS2 polymorphism (HR 3.509, 95% CI 1.266-9.709, P = 0.016) were independently associated with a shorter implant survival by Cox regression. No genotypic associations in PJI patients were observed. Genotyping of IL-1ß (+3954 C/T, exon 5, rs1143634) and NOS2 (exon 22) polymorphisms could be useful as predictors of early hip or knee APL.

24-month decline of non-invasive liver fibrosis markers in HCV-mono and HCV/HIV coinfection after direct-acting antiviral therapy.

Long term liver fibrosis (LF) changes and their best -monitoring non-invasive markers (NILFM) after effective anti-HCV DAA therapy are little- known. Matrix-metalloproteases (MMPs) and their tissue-inhibitors (TIMPs) are pivotal in liver inflammation repair. Their plasma levels might assess long-term LF changes after therapy. Overall 374 HCV-infected adult patients, 214 HCV-HIV coinfected, were followed-up for 24 months after starting DAA. LF was assessed by transient elastometry (TE), biochemical indexes (APRI, Forns, FIB-4) and, in 61 individuals, by MMPs and TIMP-1 plasma levels. Several MMPs and TIMP-1 SNPs were genotyped in 319 patients. TE was better than biochemical indexes for early and long-term LF monitoring. MMPs-2,-8,-9 and-TIMP-1 levels and TE displayed parallel declining curves although only TIMP-1 correlated with TE (P = 0.006) and biochemical indexes (P < 0.02). HCV monoinfected had significantly higher baseline NILFM and TIMP-1 plasma values, but lower MMPs levels than coinfected patients. No differences in NILFM course were observed between mono-and coinfected or between different DAA regimens. Only the MMP-2 (-1306 C/T) variant TT genotype associated with higher values of NILFM NILFM decline extends 24 months after therapy. TE and TIMP1 are reliable LF-monitoring tools. NILFM courses were similar in mono-and coinfected patients, DAA regimens type did not influence NILFM course.

The TNF-α (-238 G/A) polymorphism could protect against development of severe sepsis.

Primary responses in sepsis-mediated inflammation are regulated by pro-inflammatory cytokines. Variations in the cytokine genes might modify their transcription or expression, plasma cytokines levels and response to sepsis. Activation protein-1 (AP-1) and NF-κB regulate cytokines gene expression in sepsis. A total of 90 severely septic and 91 non-infected patients were prospectively studied. IL-1α (-889 C/T), IL-1ß (+3954 C/T), IL-6 (-174 G/C), TNF-α (-238 G/A), TNF-α (-308G/A), IL-8 (-251A/T) and IL-10 (-1082 G/A) SNPs, plasma IL-1ß, IL-4, IL-6, IL-8, IL-10, IL-13, IFN-γ, TNF-α and monocyte chemoattractant protein 1 (MCP-1) levels, and AP-1 and NF-κB gene expression by neutrophils were assessed. A allele carriers of TNF-α (-238 G/A) SNP were less frequent among septic patients. IL-6, IL-8, IL-10, TNF-α and MCP-1 levels were higher, and AP-1 and NF-κB gene expressions lower in septic patients. Sepsis was independently associated with higher fibrinogen, neutrophils counts and IL-8 levels, lower prothrombin, absence of the variant A allele of the TNF-α (-238 G/A) SNP, and haemodynamic failure. Death was independently associated with a higher APACHE II score, higher IL-8 levels, and the diagnosis of sepsis. TNF-a (-238 G/A) SNP could protect against sepsis development. Higher IL-8 levels are predictive of sepsis and mortality.

The N125S polymorphism in the cathepsin G gene (rs45567233) is associated with susceptibility to osteomyelitis in a Spanish population.

BACKGROUND: Osteomyelitis is a bone infection, most often caused by Staphylococcus aureus, in which neutrophils play a key role. Cathepsin G (CTSG) is a bactericidal serine protease stored in the neutrophil azurophilic granules. CTSG regulates inflammation, activating matrix metalloproteinases (MMPs), and coagulation. Lactoferrin (LF), a neutrophil glycoprotein, increases CTSG catalytic activity and induces inflammation. The aim of this study was to analyze a potential association between a CTSG gene polymorphism (Asn125Ser or N125S, rs45567233), that modifies CTSG activity, and could affect susceptibility to, or outcome of, bacterial osteomyelitis. METHODS: CTSG N125S polymorphism was genotyped in 329 osteomyelitis patients and 415 controls), Blood coagulation parameters, serum CTSG activity, LF, MMP-1, MMP-13, and soluble receptor activator for nuclear factor κ B ligand (sRANKL) levels were assessed in carriers of the different CTSG genotypes. RESULTS: CTSG N125S (AG) genotype was significantly more frequent among osteomyelitis patients than controls (15.5% vs. 9.4%, p = 0.014). CTSG N125S variant G allele (AG +GG) was also more frequent among osteomyelitis patients (8.1% vs. 4.7%, p = 0.01). Serum CTSG activity and LF levels were significantly higher in osteomyelitis patients carrying the G allele compared to those with the AA genotype, (p<0.04). Serum MMP-1 was lower in the G allele carriers (p = 0.01). There was no association between these genotypes and clinical characteristics of osteomyelitis, or coagulation parameters, MMP-13, and sRANKL serum levels. CONCLUSIONS: Differences in the CTSG gene might enhance osteomyelitis susceptibility by increasing CTSG activity and LF levels.

Matrix metalloproteases and their tissue inhibitors in non-alcoholic liver fibrosis of human immunodeficiency virus-infected patients.

AIM: To investigate the relationships among diverse metalloproteases (MMPs) and their tissue inhibitors (TIMPs) and non-alcoholic liver fibrosis in human immunodeficiency virus (HIV)-infected patients. METHODS: Single nucleotide polymorphisms (SNPs) in MMPs, TNF-α and CCR5 genes, and serum levels of MMPs and TIMPs were determined in HIV-infected individuals with/out hepatitis C virus (HCV) coinfection. A total of 158 patients were included, 57 of whom were HCV-coinfected. All patients drank < 50 g ethanol/day. Diverse SNPs (MMP-1 -1607 1G/2G, MMP-8 -799C/T, MMP-9 -1562 C/T, MMP-13 -77A/G, TNF-α -308 G/A, CCR5-∆32), and serum levels of MMPs (2, 3, 8, 9 and 10) and TIMPs (1, 2 and 4) were assessed. Liver fibrosis was determined by transient elastometry, although other non-invasive markers of fibrosis were also considered. Significant liver fibrosis (F ≥ 2) was defined by a transient elastometry value ≥ 7.1 kPa. RESULTS: A total of 34 patients (21.5%) had liver fibrosis ≥ F2. MMP-2 and TIMP-2 serum levels were higher in patients with liver fibrosis ≥ F2 (P = 0.02 and P = 0.03, respectively) and correlated positively with transient elastometry values (P = 0.02 and P = 0.0009, respectively), whereas MMP-9 values were negatively correlated with transient elastometry measurements (P = 0.01). Multivariate analyses showed that high levels of MMP-2 (OR = 2.397; 95%CI: 1.191-4.827, P = 0.014) were independently associated with liver fibrosis ≥ F2 in the patients as a whole. MMP-2 (OR = 7.179; 95%CI: 1.210-42.581, P = 0.03) and male gender (OR = 10.040; 95%CI: 1.621-62.11, P = 0.013) were also independent predictors of fibrosis ≥ F2 in the HCV-infected subgroup. Likewise, MMP-2, TIMP-2 and MMP-9 were independently associated with transient elastometry values and other non-invasive markers of liver fibrosis. None of the six SNPs evaluated had any significant association with liver fibrosis ≥ F2. CONCLUSION: Certain MMPs and TIMPs, particularly MMP-2, seems to be associated with non-alcoholic liver fibrosis in HIV-infected patients with/without HCV coinfection.

Can antiretroviral therapy be tailored to each human immunodeficiency virus-infected individual? Role of pharmacogenomics.

Pharmacogenetics refers to the effect of single nucleotide polymorphisms (SNPs) within human genes on drug therapy outcome. Its study might help clinicians to increase the efficacy of antiretroviral drugs by improving their pharmacokinetics and pharmacodynamics and by decreasing their side effects. HLAB*5701 genotyping to avoid the abacavir-associated hypersensitivity reaction (HSR) is a cost-effective diagnostic tool, with a 100% of negative predictive value, and, therefore, it has been included in the guidelines for treatment of human immunodeficiency virus (HIV) infection. HALDRB*0101 associates with nevirapine-induced HSR. CYP2B6 SNPs modify efavirenz plasma levels and their genotyping help decreasing its central nervous system, hepatic and HSR toxicities. Cytokines SNPs might influence the development of drug-associated lipodystrophy. APOA5, APOB, APOC3 and APOE SNPs modify lipids plasma levels and might influence the coronary artery disease risk of HIV-infected individuals receiving antiretroviral therapy. UGT1A1*28 and ABCB1 (MDR1) 3435C > T SNPs modify atazanavir plasma levels and enhance hyperbilirubinemia. Much more effort needs to be still devoted to complete large prospective studies with multiple SNPs genotyping in order to reveal more clues about the role played by host genetics in antiretroviral drug efficacy and toxicity.

Endothelial (NOS3 E298D) and inducible (NOS2 exon 22) nitric oxide synthase polymorphisms, as well as plasma NOx, influence sepsis development.

INTRODUCTION: Nitric oxide (NO) influences susceptibility to infection and hemodynamic failure (HF) in sepsis. NOS3 and NOS2 SNPs might modify plasma nitrite/nitrate (NOx) levels, sepsis development, hemodynamics and survival. METHODS: 90 severely septic and 91 non-infected ICU patients were prospectively studied. NOS3 (E298D), NOS3 (-786 T/C), NOS3 (27 bp-VNTR), and NOS2A (exon 22) SNPs and plasma NOx levels were assessed. RESULTS: 21 patients (11.6%) died, 7 with sepsis. TT homozygotes and T allele carriers of NOS3 (E298D) and AG carriers of the NOS2A (exon 22) SNPs were more frequent among septic compared to non-infected ICU patients (p < 0.05). Plasma NOx was higher in septic, especially in septic with hemodynamic failure (HF) or fatal outcome (p < 0.006). Plasma NOx was higher in carriers of the T allele of the NOS3 (E298D) SNP (p = 0.006). Sepsis independently associated with HF, increased NOx, peripheral neutrophils, and fibrinogen levels, decreased prothrombin and the presence of the NOS3 (E298D) and NOS2A (exon 22) SNPs. A low APACHE II score was the only variable associated with sepsis survival. NOx was independently associated with sepsis, HF, decreased neutrophils and higher APACHE. CONCLUSIONS: NOS3 (E298D) and NOS2A (exon 22) SNPs, individually and in combination, and plasma NOx, associated with sepsis development. NOx associated with HF and fatal outcome.

Role of plasma matrix-metalloproteases (MMPs) and their polymorphisms (SNPs) in sepsis development and outcome in ICU patients.

Matrix-metalloproteases (MMPs) and their tissue-inhibitors (TIMPs), modulated by different single nucleotide polymorphisms (SNPs), are critical in sepsis development. Ninety ICU severely septic and 91 ICU uninfected patients were prospectively studied. MMP-1 (-1607 1G/2G), MMP-3 (-1612 5A/6A), MMP-8 (-799 C/T), MMP-9 (-1562 C/T), and MMP-13 (-77A/G) SNPs were genotyped. Plasma MMPs (-1, -2, -3, -8, -9, -10, -13) and TIMPs (-1,-2,-4) were measured. AA homozygotes and A allele carriers of MMP-13 (-77 A/G) and 1G2G carriers of the MMP-1 (-1607 1G/2G) SNPs frequencies were different between septic and uninfected patients (p < 0.05), as well as plasma MMP-3, -8, -9 -10 and TIMP-2 levels (p < 0.04). No differences in MMPs levels among MMP-13 or MMP-1 SNPs genotypes carriers were observed. The area under the ROC curve for MMP-8 in the diagnosis of sepsis was 0.87 (95% CI 0.82-0.92), and that of CRP was 0.98 (0.94-0.998), whereas the area of MMP-9 in the detection of non-septic state was 0.73 (0.65-0.80), p < 0.0001 for all curves. Sepsis associated with increased MMP-8 and decreased MMP-9 levels in multivariate analysis (p < 0.0002). We report for the first time an association between MMP-13 and MMP-1 SNPs and sepsis. An independent association of MMP-8 and MMP-9 levels with sepsis was also observed.

Involvement of the LPS-LPB-CD14-MD2-TLR4 inflammation pathway in HIV-1/HAART-associated lipodystrophy syndrome (HALS).

OBJECTIVES: A relationship between obesity and intestinal bacterial translocation has been reported. Very little information is available with respect to the involvement of the bacterial translocation mechanistic pathway in HIV-1/highly active antiretroviral therapy (HAART)-associated lipodystrophy syndrome (HALS). We determined whether lipopolysaccharide (LPS)-binding protein (LBP), cluster of differentiation 14 (CD14), myeloid differentiation protein 2 (MD2) and toll-like receptor 4 (TLR4) single-nucleotide polymorphisms and LPS, LBP and soluble CD14 (sCD14) plasma levels are involved in HALS. PATIENTS AND METHODS: This cross-sectional multicentre study involved 558 treated HIV-1-infected patients, 240 with overt HALS and 318 without HALS. Anthropometric, clinical, immunovirological and metabolic variables were determined. Polymorphisms were assessed by genotyping. Plasma levels were determined by ELISA in 163 patients (81 with HALS and 82 without HALS) whose stored plasma samples were available. Student's t-test, one-way ANOVA, two-way repeated measures ANOVA, the χ(2) test and Pearson and Spearman correlation analyses were carried out for statistical analysis. RESULTS: LBP rs2232582 T→C polymorphism was significantly associated with HALS (P = 0.01 and P = 0.048 for genotype and allele analyses, respectively). Plasma levels of LPS (P = 0.009) and LBP (P < 0.001) were significantly higher and sCD14 significantly lower (P < 0.001) in patients with HALS compared with subjects without HALS. LPS levels were independently predicted by triglycerides (P < 0.001) and hepatitis C virus (P = 0.038), LBP levels by HALS (P < 0.001) and sCD14 levels by age (P = 0.008), current HIV-1 viral load (P = 0.001) and protease inhibitor use (P = 0.018). CONCLUSIONS: HALS is associated with LBP polymorphism and with higher bacterial translocation.

tPA Alu (I/D) polymorphism associates with bacterial osteomyelitis.

BACKGROUND: Coagulation and fibrinolysis are important in infections and systemic inflammatory response syndrome. Polymorphisms in plasminogen activator inhibitor-1 (PAI-1, SERPINE1) and tissue plasminogen activator (tPA, PLAT), such as PAI-1 (-675 4G/5G deletion/insertion) and tPA (Alu insertion/deletion [I/D]), are associated with strokes, myocardial infarctions, bacterial infections and septic shock severity, and trauma. Osteomyelitis is a mostly posttraumatic, Staphylococcal bone infection. PATIENTS AND METHODS: tPA Alu (I/D) (rs4646972) and PAI-1 (4G/5G) (rs1799889) polymorphisms were studied by DNA amplification with polymerase chain reaction in 261 patients with osteomyelitis and in 299 matched blood donors. Plasma PAI-1/tPA complex was assessed by enzyme-linked immuosorbent assay. RESULTS: II homozygotes (37.9% vs 19.1%) and I allele carriers (56.3% vs 46.3%) for the tPA Alu (I/D) polymorphism were significantly more frequent in osteomyelitis patients compared to controls (P < .001). II genotype carrier osteomyelitis patients had lower PAI-1/tPA complex levels compared to those with the D allele (P ≤ .04). There was no association between these genotypes and chronicity of osteomyelitis, post-traumatic etiology, or with a specific bacterial etiology. PAI-1 (4G/4G) homozygotes were not significantly different between osteomyelitis patients and controls (P = .1). CONCLUSIONS: We report for the first time to our knowledge an association between the tPA Alu (I/D) polymorphism and susceptibility to bacterial osteomyelitis, perhaps by fibrinolysis dysfunction.

The MMP1 (-16071G/2G) single nucleotide polymorphism associates with the HAART-related lipodystrophic syndrome.

OBJECTIVE: Matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) are involved in extracellular matrix remodelling and adipocyte differentiation and are inhibited by antiretrovirals. MMPs and TIMPs and their single nucleotide polymorphisms (SNPs) might contribute to the HAART-related lipodystrophic syndrome pathogenesis. DESIGN AND SETTING: Cross-sectional study in a university-based outpatient clinic. PATIENTS AND METHODS: Two hundred and sixteen HIV-infected patients on extended HAART were studied. Serum MMPs (1, 2, 3, 8, 9, 10, 13) and TIMPs (1, 2, 4) were measured by ELISA microarrays. MMP1 (-16071G/2G) SNP was also genotyped. Lipodystrophic syndrome was diagnosed by a clinical scale validated by fat dual energy X-ray absorptiometry. RESULTS: Eighty-two patients (38.0%) showed lipodystrophic syndrome, mostly lipoatrophy. The 2G/2G MMP1 SNP genotype was more frequent among lipodystrophic syndrome patients (41.3 vs. 20.5%, odds ratio, 2.73; 95% confidence interval, 1.41-5.29; χ² = 9.62, P = 0.002 for HIV-infected patients with and without lipodystrophic syndrome respectively). Carriers of this genotype had higher serum levels of MMP1 compared with those with the 1G/1G (P = 0.02). Higher MMP1 (P = 0.022) and lower TIMP4 (P = 0.038) serum levels were observed while comparing HIV patients with and without lipodystrophic syndrome. MMP1 2G carriage (P = 0.0008), TIMP4 lower serum levels (P = 0.02), treatment with stavudine (P < 0.0001), treatment with zidovudine (P = 0.006) and absence of hepatitis C virus coinfection (P = 0.002) were associated with lipodystrophic syndrome by logistic regression. CONCLUSION: MMP1 SNP, which induced increased serum levels of this protein, was associated with lipodystrophic syndrome.

A functional polymorphism in MMP1 could influence osteomyelitis development.

Osteomyelitis (OM) is a bone infection characterized by necrosis and new formation of bone. Because matrix metalloproteases (MMPs) play an important role in bone extracellular matrix remodeling, we investigated the role of some MMP polymorphisms in OM patients. A total of 118 OM patients and 300 blood donors were genotyped for the polymorphisms of MMP1 (-1607 1G/2G) and MMP13 (-77A/G). Levels of MMPs (-1, -2, -3, -8, -9, -10, and -13) and tissue inhibitors of metaloproteases (TIMP-1, -2, and -4) in serum and in human osteoblasts obtained from OM biopsies also were determined. The MMP1 (-1607 2G/2G) genotype was significantly more frequent among OM patients compared with controls [65.3% versus 33.7%, chi(2) = 26.85, odds ratio (OR) = 3.24, 95% confidence interval (CI) 2.03-5.2, p < .0001]. The MMP1 2G allele also was more frequent in OM patients (73.3% versus 57.2%, chi(2) = 37.76, OR = 2.75, 95% CI 1.96-3.85, p < .0001). Carriers of the 2G allele had significantly higher osteoblast MMP1 mRNA and MMP-1 serum levels than noncarriers (p < .04). Interleukin 1alpha (IL-1alpha) increased MMP-1 and -13 protein secretion and Ets1 mRNA expression by OM patients' osteoblasts. No association of the MMP13 (-77 A/G) polymorphism with OM was observed. The MMP1 (-1607 1G/2G) polymorphism might contribute to OM pathogenesis. This could be due to increased expression of MMP-1 by osteoblasts and is regulated by IL-1alpha.

IL-1beta (+3954C/T) polymorphism could protect human immunodeficiency virus (HIV)-infected patients on highly active antiretroviral treatment (HAART) against lipodystrophic syndrome.

PURPOSE: To evaluate the impact of acquired and inherited factors on the development of lipodystrophic syndrome in patients on highly active antiretroviral therapy. METHODS: Two hundred forty-three human immunodeficiency virus-infected Caucasians on highly active antiretroviral therapy were prospectively followed-up for 3 years. Eleven were naIve and 232 were on antiretrovirals (mean, 93.0 months +/- 43.8 months). Lipodystrophic syndrome was diagnosed clinically with a lipodystrophy severity grading scale. Polymorphisms of cytokines (IL-1beta, IL-6, TNF-alpha), TLR4, and NOS genes were genotyped. RESULTS: Ninety (37%) patients developed lipodystrophic syndrome. The polymorphic T allele of the (+3954C/T) polymorphism of IL-1beta was less frequent in patients with lipodystrophic syndrome compared with those without (17.8% vs. 27.0%, P = 0.03). Factors significantly associated with lipodystrophic syndrome were time on stavudine (P < 0.001), use of stavudine (P = 0.001), absence of the T allele of the (+3954C/T) IL-1beta polymorphism (P = 0.02), acquired immune deficiency syndrome diagnosis (P = 0.005), nadir levels of CD4 (P = 0.003), and time on highly active antiretroviral therapy (P = 0.003). Of these factors, only the time on stavudine (hazard ratio [95% confidence intervals] 1.007 [1.001-1.013]), use of stavudine (1.678 [1.048-2.68]), and absence of the T allele of the IL-1beta (+3954C/T) polymorphism (0.569 [0.347-0.931]) were significantly associated with lipodystrophic syndrome by Cox regression. CONCLUSIONS: Genotyping of the (+3954C/T) polymorphism of IL-1beta could be useful in patients starting highly active antiretroviral therapy, especially in potential users of stavudine, to predict their risk of developing lipodystrophic syndrome.

Autoregulation mechanism of human neutrophil apoptosis during bacterial infection.

Neutrophils (PMN), potent phagocytes, are the first line of the host immune defence against microorganisms, especially bacteria. Their half-life is very short and they are eliminated through apoptosis. Delayed neutrophil apoptosis is a characteristic feature of human osteomyelitis arising from Gram-negative or Gram-positive bacterial infection. The aim of this study was to investigate the modulation of apoptosis during infection of the human neutrophils by Staphylococcus aureus or Escherichia coli, the most common isolate in osteomyelitis. Analysis of host cells by flow cytometry using propidium iodide or annexin V labelling revealed an apoptosis inhibition after bacterial infection or treatment with LPS or LTA. We detected the secretion of cytokines such as IL-6, TNF-alpha and IL-1 beta by infected neutrophils. The addition of monoclonal antibodies to each cytokine abolished the protection against apoptosis. The anti-apoptotic Bcl-x(L) protein expression was increased and the pro-apoptotic Bax-alpha protein expression was decreased. These results identify a novel apoptotic effect in bacteria-infected cells that is mainly dependent on auto-production of cytokines and is correlated with Bax-alpha/Bcl-x(L) ratio. This may be a mechanism through which to resolve bacterial osteomyelitis infection.

Bax gene G(-248)A promoter polymorphism is associated with increased lifespan of the neutrophils of patients with osteomyelitis.

BACKGROUND: Patients with osteomyelitis have a decreased rate of spontaneous apoptosis of their peripheral blood neutrophils. The G(-248)A polymorphism in the promoter region of the bax gene is associated with prolonged peripheral blood neutrophil survival in leukemic patients and may play some role in osteomyelitis. METHODS: Bax G(-248)A promoter polymorphism was detected by DNA amplification using polymerase chain reaction, followed by restriction fragment length polymorphism analysis. Spontaneous apoptosis of peripheral blood neutrophils was measured by propidium iodide, annexin V, and flow cytometry, and Bax was quantified by Western blotting. RESULTS: The bax promoter polymorphism A allele was significantly more frequent in 80 patients with osteomyelitis than in 220 healthy donors (18.1% vs. 10.6%, chi=4.84, odds ratio=1.81, 95% confidence interval=1.06-3.07, P=.028). Carriers of the A allele had a lower apoptotic rate of their peripheral blood neutrophils compared with noncarriers (33.3+/-16.7 vs. 43.1+/-3.1, P=.036). Patients with the AA genotype showed a lower expression of the Bax protein compared with carriers of other genotypes (P=.038). CONCLUSIONS: Substitution of a nucleotide G-->A at position -248 in the bax gene was more frequent in patients with osteomyelitis and was associated with a longer lifespan of their peripheral blood neutrophils and lower Bax protein expression. These findings may play a role in the pathogenesis of osteomyelitis.