Reduction in augmentation index after successful renal transplantation

Background

Patients of end stage renal disease (ESRD) have an increased risk of cardiovascular events. Arterial stiffness is an established independent predictor of cardiovascular morbidity and mortality in ESRD patients. Carotid femoral pulse wave velocity (c-f PWV) and augmentation index (AI) are the indices which are used for the noninvasive assessment of arterial stiffness. Renal transplantation (RT) as a treatment modality in ESRD patients is associated with improvement in cardiovascular survival. Whether this improvement is due to attenuation of arterial stiffness has been inadequately investigated. The present study was conducted in ESRD patients before and 3 months after RT to assess the reversibility of the abnormalities of vascular compliance that are known to be associated with adverse outcome.

Methods

Arterial stiffness indices (c-f PWV and AI) were measured using the principle of applanation tonometry with a SphygmoCor^® CvMS system (Atcor Medicals, Australia) in 23 ESRD patients (age: 35.9 ± 9.3 years) before and 3 months after successful RT.

Results

After transplantation, augmentation index values reduced significantly as compared to their pre-transplant values (27.7 ± 11.3 % vs. 17.1 ± 9.0 %; P < 0.0001), while the carotid femoral pulse wave velocity values did not differ significantly (8.7 ± 2.0 vs. 8.6 ± 3.2 m/s). The augmentation index was correlated with the biochemical parameters of serum creatinine (Pearson r = 0.3628; P = 0.0128) and calcium phosphate product (Pearson r = 0.3868; P = 0.0079).

Conclusions

Restoration of renal function following successful RT is associated with differential effects on the two indices of arterial stiffness. The salient finding of our study is that 3 months after transplantation, functional changes in vasculature lead to a significant reduction in the augmentation index, while the pulse wave velocity may take longer to show an improvement.     

Transplant allograft vasculopathy: Role of multimodality imaging in surveillance and diagnosis

Cardiac allograft vasculopathy (CAV) is a challenging long-term complication of cardiac transplantation and remains a leading long-term cause of graft failure, re-transplantation, and death. CAV is an inflammatory vasculopathy distinct from traditional atherosclerotic coronary artery disease. Historically, the surveillance and diagnosis of CAV has been dependent on serial invasive coronary angiography with intravascular imaging. Although commonly practiced, angiography is not without significant limitations. Technological advances have provided sophisticated imaging techniques for CAV assessment. It is now possible to assess the vascular lumen, vessel wall characteristics, absolute blood flow, perfusion reserve, myocardial contractile function, and myocardial metabolism and injury in a noninvasive, expeditious manner with little risk. The current article will review key imaging modalities for the surveillance, diagnosis, and prognosis of CAV and discuss coronary physiology of transplanted hearts with emphasis on the clinical implications for provocative and vasodilator stress testing.     

Zonal differences in meniscus MR relaxation times in response to in vivo static loading in knee osteoarthritis

This study assessed the effects of static loading on MRI relaxation times of menisci in individuals with and without radiographic knee OA. High‐resolution fast spin‐echo (FSE) and T_1ρ/T₂ relaxation time MR sequences were obtained with and without loading at 50% body weight in 124 subjects. T_1ρ/T₂ relaxation times were calculated in menisci, and meniscus lesions were assessed through clinical grading. Student's t‐test compared OA and control unloaded relaxation times as well as within‐group changes with loading, Generalized Linear Models evaluated zonal variation, and ANCOVA compared loading response between groups. Unloaded T_1ρ and T₂ in the middle and inner zones of the lateral anterior horn and outer zone of the medial posterior horn were significantly higher in OA and suggest that meniscal OA change occurs unevenly. Zonal T_1ρ and T₂ showed differing patterns between anterior and posterior horns, suggesting differences in macromolecular organization. Significant increases with loading were seen largely in the T₂ of controls and less frequently in subjects with OA. In the medial posterior horn, T_1ρ and T₂ decreased with loading in OA but changed negligibly in controls; these significantly different loading responses between groups may indicate load transmission failure in OA menisci. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:249–261, 2016.     

Melioidosis: a review of orthopedic manifestations, clinical features, diagnosis and management

Melioidosis is an infectious disease caused by gram-negative soil-dwelling bacillus Burkholderia pseudomallei. Musculoskeletal melioidosis mimics other infections both clinically and radiologically. An extensive literature review has been performed over musculoskeletal melioidosis through various search engines such as Pubmed, Embase, Medscape, Altavista and Google. Diagnosis requires a high index of clinical suspicion and is dependent on microbiological confirmation. Prompt treatment with long-term combination antibiotics in high dosages and surgical drainage of abscesses improves survival.     

Antiapoptotic and immunomodulatory effects of chlorophyllin

Chlorophyllin (CHL) was earlier shown to reduce the level of intracellular ROS and apoptosis induced by ionizing radiation and 2,2'-azobis(2-propionimidinedihydrochloride) (AAPH). In the present studies, the effect of CHL on radiation-induced immunosuppression and modulation of immune responses in mice was examined. Chlorophyllin inhibited the in vitro lymphocyte proliferation induced by concanavalin A (Con A) in a dose dependent manner at doses>or=50 microM. At lower doses (10 microM) CHL significantly inhibited activation induced cell death (AICD) in Con A stimulated spleen cells. Spleen cells obtained from CHL treated mice showed an inhibition of response to Con A depending on dose of CHL and the time after its administration. Spleen cells obtained from CHL treated mice (24 h) showed lower inhibition of response to Con A following in vitro (5 Gy) as well as whole body irradiation (2 Gy). The expression of antiapoptotic genes bcl-2 and bcl-xL was up-regulated in these cells. Chlorophyllin treatment of mice led to splenomegaly and increase in the number of peritoneal exudate cells (PEC). The numbers of T cells, B cells and macrophages in the spleen were also increased. Increased phagocytic activity was seen in PEC obtained from CHL treated mice. Most importantly, CHL administration to mice immunized with sheep red blood cells (SRBC) augmented both humoral and cell-mediated immune responses.