Arterial stiffness and progression of cerebral white matter hyperintensities in patients with type 2 diabetes and matched controls: a 5-year cohort study.

BACKGROUND: Stroke is a serious complication in patients with type 2 diabetes (T2DM). Arterial stiffness may improve stroke prediction. We investigated the association between carotid-femoral pulse wave velocity [PWV] and the progression of cerebral white matter hyperintensities (WMH), a marker of stroke risk, in patients with T2DM and controls. METHODS: In a 5-year cohort study, data from 45 patients and 59 non-diabetic controls were available for analysis. At baseline, participants had a mean (± SD) age of 59 ± 10 years and patients had a median (range) diabetes duration of 1.8 (0.8-3.2) years. PWV was obtained by tonometry and WMH volume by an automated segmentation algorithm based on cerebral T2-FLAIR and T1 MRI (corrected by intracranial volume, cWMH). High PWV was defined above 8.94 m/s (corresponding to the reference of high PWV above 10 m/s using the standardized path length method). RESULTS: Patients with T2DM had a higher PWV than controls (8.8 ± 2.2 vs. 7.9 ± 1.4 m/s, p < 0.01). WMH progression were similar in the two groups (p = 0.5). One m/s increase in baseline PWV was associated with a 16% [95% CI 1-32%], p < 0.05) increase in cWMH volume at 5 years follow-up after adjustment for age, sex, diabetes, pulse pressure and smoking. High PWV was associated with cWMH progression in the combined cohort (p < 0.05). We found no interaction between diabetes and PWV on cWMH progression. CONCLUSIONS: PWV is associated with cWMH progression in patients with type 2 diabetes and non-diabetic controls. Our results indicate that arterial stiffness may be involved early in the pathophysiology leading to cerebrovascular diseases.

A mortality analysis of septic shock, vasoplegic shock and cryptic shock classified by the third international consensus definitions (Sepsis-3).

INTRODUCTION: This study aimed to compare the 28-day mortality of patients with septic shock, defined by Sepsis-3 criteria and patients with vasoplegic or cryptic shock who are excluded from this new definition. OBJECTIVES: This retrospective observational study was performed using a tertiary emergency department's septic shock registry and investigated the records of patients managed between January 2010 and December 2015. In 2,138 total patients, 1004 (47.0%) had septic shock, 476 (22.2%) had vasoplegic shock and 655 (30.6%) had cryptic shock. RESULTS: There was significant variation in 28-day mortality among the three groups: 23.4% for septic shock, 8.8% for vasoplegic shock and 12.2% for cryptic shock (P < .001). In subgroup analysis of cryptic shock or septic shock according to lactate levels (2-3, 3-4 and >4 mmol/L), the mortality rate increased as lactate increased (cryptic shock: 9.5%, 14.8% and 18.0%; septic shock: 18.6%, 22.6% and 27.0%, respectively; P < .001). Multivariable analysis revealed odds ratios for mortality of 0.31 (95% CI 0.22-0.44; P < .001) for vasoplegic shock and 0.46 (95% CI 0.35-0.61; P < .001) for cryptic shock relative to septic shock. Survival curve analysis showed significant differences among patients with septic shock, vasoplegic shock and cryptic shock (Log rank test: P < .0001). CONCLUSION: The new septic shock definition may be useful for identifying high-risk patients requiring intensive care. However, cryptic shock-associated mortality increased to 18.0% as serum lactate increased, which suggests that some cryptic shock patients may also require intensive management.

Automatic calculation of myocardial external efficiency using a single 11C-acetate PET scan.

BACKGROUND: Myocardial external efficiency (MEE) is defined as the ratio of kinetic energy associated with cardiac work [forward cardiac output (FCO)*mean systemic pressure] and the chemical energy from oxygen consumed (MVO2) by the left ventricular mass (LVM). We developed a fully automated method for estimating MEE based on a single 11C-acetate PET scan without ECG-gating. METHODS AND RESULTS: Ten healthy controls, 34 patients with aortic valve stenosis (AVS), and 20 patients with mitral valve regurgitation (MVR) were recruited in a dual-center study. MVO2 was calculated using washout of 11C -acetate activity. FCO and LVM were calculated automatically using dynamic PET and parametric image formation. FCO and LVM were also obtained using cardiac magnetic resonance (CMR) in all subjects. The correlation between MEEPET-CMR and MEEPET was high (r = 0.85, P < 0.001) without significant bias. MEEPET was 23.6 ± 4.2% for controls and was lowered in AVS (17.2 ± 4.3%, P < 0.001) and in MVR (18.0 ± 5.2%, P = 0.004). MEEPET was strongly associated with both NYHA class (P < 0.001) and the magnitude of valvular dysfunction (mean aortic gradient: P < 0.001, regurgitant fraction: P = 0.009). CONCLUSION: A single 11C-acetate PET yields accurate and automated MEE results on different scanners. MEE might provide an unbiased measurement of the phenotypic response to valvular disease.

The IGF system in patients with type 2 diabetes: associations with markers of cardiovascular target organ damage.

OBJECTIVE: Perturbations in the insulin-like growth factor (IGF) system may contribute to the accelerated cardiovascular disease (CVD) that occurs in patients with type 2 diabetes (T2D). However, it remains unknown whether the IGF system is also involved in the development of early, subclinical CVD. We characterised the IGF system in T2D patients and matched controls and examined the associations with markers of subclinical target organ damage. METHODS: The study included 99 patients with recently diagnosed T2D and 99 age- and sex-matched controls. IGF-1 and IGFBP-1 to -4 were measured by immunoassays, as were pregnancy-associated plasma protein-A (PAPP-A) and the PAPP-A-generated N-terminal (NT) and C-terminal (CT) IGFBP-4 fragments, which are novel CVD risk markers. Arterial stiffness was evaluated by carotid-femoral pulse wave velocity (PWV). Cerebral white matter lesions (WMLs) and carotid artery remodelling were determined by MRI. RESULTS: After multivariate adjustments, patients with T2D had lower concentrations of IGFBP-2, IGFBP-4, NT- and CT-IGFBP-4, when compared with controls. IGFBP-2 was inversely correlated to PWV in all subjects in multivariate analysis (P < 0.05), and IGFBP-3 was inversely associated with severity of WMLs (P < 0.05). The NT-IGFBP-4 fragment was associated with the degree of carotid artery remodelling among all subjects (regression coefficient (95% CI): 2.95 (0.70, 5.16), P = 0.011). Levels of NT- and CT-IGFBP-4 were reduced in T2D patients receiving metformin compared to those in controls and patients not receiving metformin. CONCLUSIONS: Even in recently diagnosed and well-controlled T2D patients, IGF protein levels are altered and associated with CVD risk factors.

Enhancing coronary Wave Intensity Analysis robustness by high order central finite differences.

BACKGROUND: Coronary Wave Intensity Analysis (cWIA) is a technique capable of separating the effects of proximal arterial haemodynamics from cardiac mechanics. Studies have identified WIA-derived indices that are closely correlated with several disease processes and predictive of functional recovery following myocardial infarction. The cWIA clinical application has, however, been limited by technical challenges including a lack of standardization across different studies and the derived indices' sensitivity to the processing parameters. Specifically, a critical step in WIA is the noise removal for evaluation of derivatives of the acquired signals, typically performed by applying a Savitzky-Golay filter, to reduce the high frequency acquisition noise. METHODS: The impact of the filter parameter selection on cWIA output, and on the derived clinical metrics (integral areas and peaks of the major waves), is first analysed. The sensitivity analysis is performed either by using the filter as a differentiator to calculate the signals' time derivative or by applying the filter to smooth the ensemble-averaged waveforms. Furthermore, the power-spectrum of the ensemble-averaged waveforms contains little high-frequency components, which motivated us to propose an alternative approach to compute the time derivatives of the acquired waveforms using a central finite difference scheme. RESULTS AND CONCLUSION: The cWIA output and consequently the derived clinical metrics are significantly affected by the filter parameters, irrespective of its use as a smoothing filter or a differentiator. The proposed approach is parameter-free and, when applied to the 10 in-vivo human datasets and the 50 in-vivo animal datasets, enhances the cWIA robustness by significantly reducing the outcome variability (by 60%).

Truncating plakophilin-2 mutations in arrhythmogenic cardiomyopathy are associated with protein haploinsufficiency in both myocardium and epidermis.

BACKGROUND: Arrhythmogenic cardiomyopathy (AC) is a hereditary cardiac condition associated with ventricular arrhythmias, heart failure, and sudden death. The disease is most often caused by mutations in the desmosomal gene for plakophilin-2 (PKP2), which is expressed in both myocardial and epidermal tissue. This study aimed to investigate protein expression in myocardial tissue of patients with AC carrying PKP2 mutations and elucidate whether keratinocytes of the same individuals exhibited a similar pattern of protein expression. METHODS AND RESULTS: Direct sequencing of 5 AC genes in 71 unrelated patients with AC identified 10 different PKP2 mutations in 12 index patients. One patient, heterozygous for a PKP2 nonsense mutation, developed severe heart failure and underwent cardiac transplantation. Western blotting and immunohistochemistry of the explanted heart showed a significant decrease in PKP2 protein expression without detectable amounts of truncated PKP2 protein. Cultured keratinocytes of the patient showed a similar reduction in PKP2 protein expression. Nine additional PKP2 mutations were investigated in both cultured keratinocytes and endomyocardial biopsies from affected individuals. It was evident that PKP2 mutations introducing a premature termination codon in the reading frame were associated with PKP2 transcript and protein levels reduced to ≈50%, whereas a missense variant did not seem to affect the amount of PKP2 protein. CONCLUSIONS: The results of this study showed that truncating PKP2 mutations in AC are associated with low expression of the mutant allele and that the myocardial protein expression of PKP2 is mirrored in keratinocytes. These findings indicate that PKP2 haploinsufficiency contributes to pathogenesis in AC.

Cardiac magnetic resonance and electroanatomical mapping of acute and chronic atrial ablation injury: a histological validation study.

AIMS: To provide a comprehensive histopathological validation of cardiac magnetic resonance (CMR) and endocardial voltage mapping of acute and chronic atrial ablation injury. METHODS AND RESULTS: 16 pigs underwent pre-ablation T2-weighted (T2W) and late gadolinium enhancement (LGE) CMR and high-density voltage mapping of the right atrium (RA) and both were repeated after intercaval linear radiofrequency ablation. Eight pigs were sacrificed following the procedure for pathological examination. A further eight pigs were recovered for 8 weeks, before chronic CMR, repeat RA voltage mapping and pathological examination. Signal intensity (SI) thresholds from 0 to 15 SD above a reference SI were used to segment the RA in CMR images and segmentations compared with real lesion volumes. The SI thresholds that best approximated histological volumes were 2.3 SD for LGE post-ablation, 14.5 SD for T2W post-ablation and 3.3 SD for LGE chronically. T2-weighted chronically always underestimated lesion volume. Acute histology showed transmural injury with coagulative necrosis. Chronic histology showed transmural fibrous scar. The mean voltage at the centre of the ablation line was 3.3 mV pre-ablation, 0.6 mV immediately post-ablation, and 0.3 mV chronically. CONCLUSION: This study presents the first histopathological validation of CMR and endocardial voltage mapping to define acute and chronic atrial ablation injury, including SI thresholds that best match histological lesion volumes. An understanding of these thresholds may allow a more informed assessment of the underlying atrial substrate immediately after ablation and before repeat catheter ablation for atrial arrhythmias.

Mutated desmoglein-2 proteins are incorporated into desmosomes and exhibit dominant-negative effects in arrhythmogenic right ventricular cardiomyopathy.

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a hereditary cardiac condition associated with ventricular arrhythmias, heart failure, and sudden death. The most frequent ARVC genes encode desmosomal proteins of which mutations in desmoglein-2 (DSG2), account for 10%-20% of cases. This study aimed to investigate how DSG2 mutations contribute to the pathogenesis of ARVC. Initial mutation analysis of DSG2 in 71 probands identified the first family reported with recessively inherited ARVC due to a missense mutation. In addition, three recognized DSG2 mutations were identified in 12 families. These results and further mutation analyses of four additional desmosomal genes indicated that ARVC caused by DSG2 mutations is often transmitted by recessive or digenic inheritance. Because desmosomal proteins are also expressed in skin tissue, keratinocytes served as a cell model to investigate DSG2 protein expression by Western blotting, 2D-PAGE, and liquid chromatography-mass spectrometry. The results showed that heterozygous mutation carriers expressed both mutated and wild-type DSG2 proteins. These findings were consistent with the results obtained by immunohistochemistry of endomyocardial biopsies and epidermal tissue of mutation carriers, which indicated a normal cellular distribution of DSG2. The results suggested a dominant-negative effect of the mutated DSG2 proteins because they were incorporated into the desmosomes.

Factors promoting the prolonged shedding of the pandemic (H1N1) 2009 influenza virus in patients treated with oseltamivir for 5 days.

BACKGROUND: The duration of viral shedding is an important determinant of infectivity and transmissibility and provides vital information for effective infection prevention and control. However, few studies have evaluated viral shedding in patients admitted to hospital with 2009 H1N1 influenza and treated with oseltamivir. OBJECTIVE: To determine the incidence of prolonged 2009 H1N1 influenza viral shedding in patients treated for 5 days with oseltamivir and to identify factors that promote prolonged viral shedding. METHODS: This was a prospective, observational cohort study of 173 patients infected with 2009 H1N1 influenza (confirmed by RT-PCR) who were admitted to isolation rooms in the emergency department of our hospital between August 25, 2009 and December 31, 2009. All of the patients were treated according to institutional protocols and received routine follow-up RT-PCR testing after 5 days of oseltamivir therapy. Prolonged viral shedding was defined as a positive follow-up RT-PCR result. RESULT: Of the 173 patients in our cohort, 88 (50.8%) showed persistent viral shedding after oseltamivir treatment. Viral shedding was significantly prolonged if antiviral therapy was started ≥ 2 days after symptom onset (OR 2.74, 95% CI 1.29-5.82), if there were major comorbidities (OR 3.07, 95% CI 1.29-7.32), and/or if respiratory symptoms were still present on the day 5 of antiviral treatment (OR 4.13, 95% CI 2.10-8.11). CONCLUSIONS: The presence of major comorbidities, a delay in initiating antiviral treatment, and continuing respiratory symptoms after 5 days of antiviral treatment are associated with prolonged shedding of the 2009 H1N1 influenza virus.

Carotid-femoral pulse wave velocity is associated with cerebral white matter lesions in type 2 diabetes.

OBJECTIVE: Patients with type 2 diabetes have a high incidence of cardiovascular events including stroke. Increased arterial stiffness (AS) predicts cardiovascular events in the general population. Cerebral white matter lesions (WMLs) are associated with an increased risk of stroke. It is unknown whether AS in patients with type 2 diabetes is associated with WMLs. RESEARCH DESIGN AND METHODS: We examined 89 patients recently diagnosed with type 2 diabetes (<5 years) and 89 sex- and age-matched controls. AS was assessed with carotid-femoral pulse wave velocity (PWV). WMLs were identified using magnetic resonance imaging and graded qualitatively with the Breteler scale (no/slight changes = 0, moderate changes = 1, severe changes = 2) and semiquantitatively. RESULTS: The diabetic population had excellent glycemic control (HbA(1c), 6.5% [6.2-6.8]; median [interquartile range {IQR}]) and had, compared with the controls, lower office blood pressure (BP) (127 ± 12/79 ± 8 vs. 132 ± 14/84 ± 10 mmHg) and total cholesterol (4.3[3.9-4.7] vs. 5.6 [5.1-6.4]; mmol/L; median [IQR]), (P < 0.01 for all). Despite this, PWV was higher in the patients with diabetes compared with controls (9.3 ± 2.0 vs. 8.0 ± 1.6 m/s; P < 0.0001). PWV was associated with Breteler score (OR 1.36 [95% CI 1.17-1.58]; P < 0.001) and WML volume (OR 1.32 [95% CI 1.16-1.51]; P < 0.001) per 1 m/s increase in PWV. These associations remained significant when adjusted for age, sex, diabetes, 24-h mean arterial BP, BMI, heart rate, and use of antihypertensives and statins (Breteler score: OR 1.28 [95% CI 1.03-1.60]; P < 0.05 and WML volume: OR 1.30 [95% CI 1.06-1.58]; P < 0.05). CONCLUSIONS: PWV was higher among patients with well-controlled type 2 diabetes compared with controls and was independently associated with WMLs. PWV may represent a clinically relevant parameter in the evaluation of cerebrovascular disease risk in type 2 diabetes.

CMR assessment of endothelial damage and angiogenesis in porcine coronary arteries using gadofosveset.

BACKGROUND: Endothelial damage and angiogenesis are essential for atherosclerotic plaque development and destabilization. We sought to examine whether contrast enhanced cardiovascular magnetic resonance (CMR) using gadofosveset could show endothelial damage and neovessel formation in balloon injured porcine coronary arteries. METHODS AND RESULTS: Data were obtained from seven pigs that all underwent balloon injury of the left anterior descending coronary artery (LAD) to induce endothelial damage and angiogenesis. Between one - 12 days (average four) after balloon injury, in vivo and ex vivo T1-weighted coronary CMR was performed after intravenous injection of gadofosveset. Post contrast, CMR showed contrast enhancement of the coronary arteries with a selective and time-dependent average expansion of the injured LAD segment area of 45% (p = 0.04; CI95 = [15%-75%]), indicating local extravasation of gadofosveset. Vascular and perivascular extravasation of albumin (marker of endothelial leakiness) and gadofosveset was demonstrated with agreement between Evans blue staining and ex vivo CMR contrast enhancement (p = 0.026). Coronary MRI contrast enhancement and local microvessel density determined by microscopic examination correlated (ρ = 0.82, p < 0.001). CONCLUSION: Contrast enhanced coronary CMR with gadofosveset can detect experimentally induced endothelial damage and angiogenesis in the porcine coronary artery wall.

Zinc finger-containing glycine-rich RNA-binding protein in Oryza sativa has an RNA chaperone activity under cold stress conditions.

The rice (Oryza sativa) genome harbours three genes encoding CysCysHisCys (CCHC)-type zinc finger-containing glycine-rich RNA-binding proteins, designated OsRZ proteins, but their importance and physiological functions remain largely unknown. Here, the stress-responsive expression patterns of OsRZs were assessed, and the biological and cellular functions of OsRZs were evaluated under low temperature conditions. The expression levels of the three OsRZs were up-regulated by cold stress, whereas drought or high salt stress did not significantly alter its transcript level. OsRZ2 complemented the cold sensitivity of BX04 Escherichia coli cells under low temperatures, and had DNA-melting activity and transcription anti-termination activity, thereby indicating that OsRZ2 possesses an RNA chaperone activity. By contrast, neither OsRZ1 nor OsRZ3 harboured these activities. Ectopic expression of OsRZ2, but not OsRZ3, in cold-sensitive Arabidopsis grp7 knockout plants rescued the grp7 plants from cold and freezing damage, and OsRZ2 complemented the defect in mRNA export from the nucleus to the cytoplasm in grp7 mutant during cold stress. The present findings support the emerging idea that the regulation of mRNA export is one of the adaptive processes in plants under stress conditions, and RNA chaperone functions as a regulator in mRNA export under cold stress conditions.

Geometric determinants of chronic functional ischemic mitral regurgitation: insights from three-dimensional cardiac magnetic resonance imaging.

BACKGROUND AND AIM OF THE STUDY: The assessment of three-dimensional (3-D) mitral valve geometry in patients with chronic functional ischemic mitral valve regurgitation (FIMR) has been hampered by a lack of adequate imaging techniques. The study aim was to use a clinically applicable cardiac magnetic resonance imaging (MRI) technique to assess the 3-D mitral annular, leaflet and papillary muscle geometry in pigs with chronic FIMR. METHODS: Ten pigs with moderate chronic FIMR induced by catheter-based coiling of the circumflex artery, were examined using cardiac MRI. The reconstruction of 3-D data from two-dimensional cardiac MRI scans allowed the mitral annulus and leaflet geometries to be assessed. Using 3-D morphology scans, the spatial position of the posterior papillary muscle (PPM) relative to the anterior papillary muscle (APM), mitral annulus and anterior (A-trig) and posterior (P-trig) trigones was assessed. Using dedicated software for image analysis, data were transferred to a Cartesian coordinate system (x,y,z) for geometric analysis. Ten healthy pigs served as controls. RESULTS: Compared to controls, at end-systole in the chronic FIMR group the PPM was significantly displaced (p <0.05) from the APM (38 +/- 2 versus 23 +/- 1 mm), A-trig (48 +/- 2 versus 36 +/- 1 mm) and P-trig (41 +/-1 versus 33 +/- 1 mm). There was no significant apical PPM displacement (20 +/- 2 versus 20 +/- 1 mm). The annular area (1,240 +/- 90 versus 850 +/- 90 mm2), septolateral distance (36 +/- 2 versus 26 +/- 1 mm), commissure-to-commissure distance (38 +/- 2 versus 33 +/- 1 mm), mean tenting height (8 +/- 1 versus 5 +/- 0 mm), maximum tenting height (10 +/- 1 versus 7 +/- 0 mm), tenting volume (2,600 +/- 400 versus 1,500 +/- 200 mm3), and occlusional leaflet area (1,820 +/- 110 versus 1,120 +/- 70 mm2) were each significantly increased. CONCLUSION: This clinically applicable cardiac MRI modality permitted a detailed geometric insight to be made into the mitral annular, leaflet and PPM geometries that cause FIMR. Such a reliable tool for geometric mitral valve analysis has previously been demonstrated only by using invasive techniques. Hence, this approach holds promise for further clarifying the pathogenesis of chronic FIMR and improving preoperative surgical planning.

Blockade of the 4-1BB (CD137)/4-1BBL and/or CD28/CD80/CD86 costimulatory pathways promotes corneal allograft survival in mice.

To explore the roles of 4-1BB (CD137) and CD28 in corneal transplantation, we examined the effect of 4-1BB/4-1BB ligand (4-1BBL) and/or CD28/CD80/CD86 blockade on corneal allograft survival in mice. Allogeneic corneal transplantation was performed between two strains of wild-type (WT) mice, BALB/c and C57BL/6 (B6), and between BALB/c and B6 WT donors and various gene knockout (KO) recipients. Some of the WT graft recipients were treated intraperitoneally with agonistic anti-4-1BB or blocking anti-4-1BBL monoclonal antibody (mAb) on days 0, 2, 4 and 6 after transplantation. Transplanted eyes were observed over a 13-week period. Allogeneic grafts in control WT B6 and BALB/c mice treated with rat immunoglobulin G showed median survival times (MST) of 12 and 14 days, respectively. Allogeneic grafts in B6 WT recipients treated with anti-4-1BB mAb showed accelerated rejection, with an MST of 8 days. In contrast, allogeneic grafts in BALB/c 4-1BB/CD28 KO and B6 CD80/CD86 KO recipients had significantly prolonged graft survival times (MST, 52.5 days and 36 days, respectively). Treatment of WT recipients with anti-4-1BB mAb resulted in enhanced cellular proliferation in the mixed lymphocyte reaction and increased the numbers of CD4(+) CD8(+) T cells, and macrophages in the grafts, which correlated with decreased graft survival time, whereas transplant recipients with costimulatory receptor deletion showed longer graft survival times. These results suggest that the absence of receptors for the 4-1BB/4-1BBL and/or CD28/CD80/CD86 costimulatory pathways promotes corneal allograft survival, whereas triggering 4-1BB with an agonistic mAb enhances the rejection of corneal allografts.

CD137-deficient mice have reduced NK/NKT cell numbers and function, are resistant to lipopolysaccharide-induced shock syndromes, and have lower IL-4 responses.

CD137, a member of the TNF superfamily, is involved in T cell and NK cell activation and cytokine production. To establish its in vivo role in systems dependent on NK and NKT cells, we studied the response of CD137-/- mice to LPS-induced shock, tumor killing, and their IL-4-controlled Th2 responses. In both high and low dose shock models, all the CD137-deficient mice, but none of the wild-type BALB/c mice, survived. After injection of LPS/2-amino-2-deoxy-D-galactose (D-gal), CD137-/- mice had reduced serum cytokine levels and substantially impaired liver IFN-gamma and TNF-alpha mRNA levels. Phenotypic analysis of mononuclear cells revealed fewer NK and NKT cells in the CD137-/- mice. The knockout mice did not generate a rapid IL-4 response after systemic T cell activation, or effective Ag-specific Th2 responses. In addition, both in vitro and in vivo NK-specific cytolytic activities were reduced. These findings suggest that CD137-directed NK/NKT cells play an important role in the inflammatory response leading to the production of proinflammatory cytokines, LPS-induced septic shock, and tumor killing, as well as IL-4-dependent Th2 responses.

Blocking 4-1BB/4-1BB ligand interactions prevents herpetic stromal keratitis.

Herpetic stromal keratitis (HSK) is a chronic inflammatory process in corneal stroma that results from recurrent HSV type 1 infection. We used the murine model of HSK to demonstrate the importance of the interaction between an inducible T cell costimulatory receptor, 4-1BB, and its ligand, 4-1BB ligand (4-1BBL), in the development of this disease. In BALB/c mice, HSK ordinarily induced by infection with the RE strain of herpes was prevented by blocking 4-1BB/4-1BBL interaction, either by deleting 4-1BB (in mutant 4-1BB(-/-) mice) or by introducing mAbs against 4-1BBL. The majority of T cells infiltrating the infected corneas were 4-1BB(+) activated effector cells that expressed cell surface markers CD44, CD25, and/or CD62L, as well as chemokine receptors CCR1, CCR2, and CCR5, and a limited number of TCR Vbeta chains (Vbeta8.1/8.2, Vbeta8.3, Vbeta10b, and Vbeta5.1/5.2, in order of abundance). Analysis of cell surface phenotypes showed that the failure to develop HSK in the 4-1BB(-/-) mice was associated with a reduced expression of CD62L at the time of T cell migration into the corneal stroma.

Effect of leukotactin-1 on the protection in vivo of myeloid progenitor cells against cytotoxic chemotherapeutics.

Leukotactin-1 (Lkn-1) is a human CC chemokine that induces chemotaxis of neutrophils, monocytes, eosinophils, and lymphocytes and suppresses colony formation of myeloid progenitor cells in vitro. Present studies evaluated the myeloprotective capabilities of Lkn-1 in vivo against Ara-C and 5-fluorouracil (5-FU). The effect of Lkn-1 on myelopoiesis was first assessed in vivo by injecting recombinant Lkn-1 in C3H/HeJ mice. Lkn-1 rapidly decreased cycling rates and absolute numbers of myeloid progenitor cells in marrow. Lkn-1 administration prior to and during the chemotherapeutics treatment resulted in increased progenitors for colony-forming units-granulocyte/macrophage (CFU-GM), colony-forming units-granulocyte/erythroid/megakaryocyte/macrophage (CFU-GEMM), and burst-forming units-erythroid (BFU-E) compared with a saline-treated group. The protective effects lasted until day 3 after the termination of Ara-C administration and until day 7 after the termination of 5-FU administration. The results indicate that Lkn-1 protects bone marrow myeloid progenitor cells when cytotoxic chemotherapeutics are used in a preclinical setting. These results may be of use in clinical treatment for myeloprotection.