Target Organ Injury Research Articles

Should African Americans with hypertension be treated differently than non-African Americans?

African Americans have a higher burden of hypertension, more severe blood pressure (BP) elevations, more concurrent risk-enhancing co-morbidities (e.g., diabetes), sub-clinical vascular injury at lower non-hypertensive BP levels, lower BP control rates, and significantly greater risk for adverse pressure-related clinical complications (e.g., stroke, heart failure) than whites. Randomized prospective data from hypertension endpoint trials show a virtually identical percentage reduction in CVD risk for a given magnitude of BP lowering, irrespective of the presence or absence of pre-treatment CVD across a broad range of BP down to pre-treatment BP levels of 110/70mm Hg. These data, mostly emanating from white populations, do not necessarily inform practitioners as to the level below which BP should be lowered in those with established, long-standing hypertension; however, these data do provide support for initiating hypertension treatment at lower than conventional BP thresholds. A Mendelian randomized study examining the impact of life-long lower SBP levels showed that lifelong exposure to 10mm Hg lower SBP was associated with an 82% lesser rate of SBP rise per decade and a 58% lower CHD risk that was much greater than the 22% reduction in CHD reported for the same magnitude of SBP reduction in clinical trials. Arguably, it is the hypertension treatment paradigm that merits reexamination. Earlier hypertension treatment in all populations prior to the onset of significant pressure-related target organ injury might conceivably prevent, or at least significantly attenuate, the well documented age-related rise in BP seen in most Western societies. In addition, this treatment paradigm might also reduce the significant residual CVD risk observed under the current recommended approach to hypertension treatment. This new approach to therapy would likely have substantial clinical and public health benefits in the high-risk, under-treated African American population that suffers outsized devastating consequences from inadequate control of BP.

Contribution of RhoA/Rho-kinase/MEK1/ERK1/2/iNOS pathway to ischemia/reperfusion-induced oxidative/nitrosative stress and inflammation leading to distant and target organ injury in rats

The small G protein RhoA and its downstream effector Rho-kinase play an important role in various physiopathological processes including ischemia/reperfusion (I/R) injury. Reactive oxygen and nitrogen species produced by iNOS and NADPH oxidase are important mediators of inflammation and organ injury following an initial localized I/R event. The aim of this study was to determine whether RhoA/Rho-kinase signaling pathway increases the expression and activity of MEK1, ERK1/2, iNOS, gp91phox, and p47phox, and peroxynitrite formation which result in oxidative/nitrosative stress and inflammation leading to hindlimb I/R-induced injury in kidney as a distant organ and gastrocnemius muscle as a target organ. I/R-induced distant and target organ injury was performed by using the rat hindlimb tourniquet model. I/R caused an increase in the expression and/or activity of RhoA, MEK1, ERK1/2, iNOS, gp91phox, p47phox, and 3-nitrotyrosine and nitrotyrosine levels in the tissues. Although Rho-kinase activity was increased by I/R in the kidney, its activity was decreased in the muscle. Serum and tissue MDA levels and MPO activity were increased following I/R. I/R also caused an increase in SOD and catalase activities associated with decreased GSH levels in the tissues. Y-27632, a selective Rho-kinase inhibitor, (100µg/kg, i.p.; 1h before reperfusion) prevented the I/R-induced changes except Rho-kinase activity in the muscle. These results suggest that activation of RhoA/Rho-kinase/MEK1/ERK1/2/iNOS pathway associated with oxidative/nitrosative stress and inflammation contributes to hindlimb I/R-induced distant organ injury in rats. It also seems that hindlimb I/R induces target organ injury via upregulation of RhoA/MEK1/ERK1/2/iNOS pathway associated with decreased Rho-kinase activity.

Current insights and new perspectives on the roles of hyperglucagonemia in non-insulin-dependent type 2 diabetes.

Type 2 diabetes is well recognized as a noninsulin-dependent diabetic disease. Clinical evidence indicates that the level of circulating insulin may be normal, subnormal, and even elevated in type 2 diabetic patients. Unlike type 1 diabetes, the key problem for type 2 diabetes is not due to the absolute deficiency of insulin secretion, but because the body is no longer sensitive to insulin. Thus, insulin resistance is increased and the sensitivity to insulin is reset, so increasing levels of insulin are required to maintain body glucose and metabolic homeostasis. How insulin resistance is increased and what factors contribute to its development in type 2 diabetes remain incompletely understood. Overemphasis of insulin deficiency alone may be too simplistic for us to understand how type 2 diabetes is developed and should be treated, since glucose metabolism and homeostasis are tightly controlled by both insulin and glucagon. Insulin acts as a YIN factor to lower blood glucose level by increasing cellular glucose uptake, whereas glucagon acts as a YANG factor to counter the action of insulin by increasing glucose production. Furthermore, other humoral factors other than insulin and glucagon may also directly or indirectly contribute to increased insulin resistance and the development of hyperglycemia. The purpose of this article is to briefly review recently published animal and human studies in this field, and provide new insights and perspectives on recent debates as to whether hyperglucagonemia and/or glucagon receptors should be targeted to treat insulin resistance and target organ injury in type 2 diabetes.

The multiple chemokine-binding bovine herpesvirus 1 glycoprotein G (BHV1gG) inhibits polymorphonuclear cell but not monocyte migration into inflammatory sites.

Chemokines facilitate the recruitment of inflammatory cells into tissues, contributing to target organ injury in a wide range of inflammatory and autoimmune diseases. Targeting either single chemokines or chemokine receptors alters the progression of disease in animal models of rheumatoid arthritis and lupus with varying degrees of efficacy but clinical trials in humans have been less successful. Given the redundancy of chemokine-chemokine receptor interactions, targeting of more than one chemokine may be required to inhibit active inflammatory disease. To test the effects of multiple-chemokine blockade in inflammation, we generated an adenovirus expressing bovine herpesvirus 1 glycoprotein G (BHV1gG), a viral chemokine antagonist that binds to a wide spectrum of murine and human chemokines, fused to the Fc portion of murine IgG2a. Administration of the adenovirus significantly inhibited thioglycollate-induced migration of polymorphonuclear leukocytes into the peritoneal cavity of BALB/c mice and reduced both clinical severity and articular damage in K/BxN serum transfer-induced arthritis. However, treatment with BHV1gG-Ig fusion protein did not prevent monocyte infiltration into the peritoneum in the thioglycollate model and did not prevent renal monocyte infiltration or nephritis in lupus-prone NZB/W mice. These observations suggest that the simultaneous inhibition of multiple chemokines by BHV1gG has the potential to interfere with acute inflammatory responses mediated by polymorphonuclear leukocytes, but is less effective in chronic inflammatory disease mediated by macrophages.

Sodium Intake and Blood Pressure in Children

Elevation of blood pressure (BP) and the risk for progression to hypertension (HTN) is of increasing concern in children and adolescents. Indeed, it is increasingly recognized that target organ injury may begin with even low levels of BP elevation. Sodium intake has long been recognized as a modifiable risk factor for HTN. While it seems clear that sodium impacts BP in children, its effects may be enhanced by other factors including obesity and increasing age. Evidence from animal and human studies indicates that sodium may have adverse consequences on the cardiovascular system independent of HTN. Thus, moderation of sodium intake over a lifetime may reduce risk for cardiovascular morbidity in adulthood. An appetite for salt is acquired, and intake beyond our need is almost universal. Considering that eating habits in childhood have been shown to track into adulthood, modest sodium intake should be advocated as part of a healthy lifestyle.

Lithothamnion muelleri controls inflammatory responses, target organ injury and lethality associated with graft-versus-host disease in mice.

Lithothamnion muelleri (Hapalidiaceae) is a marine red alga, which is a member of a group of algae with anti-inflammatory, antitumor, and immunomodulatory properties. The present study evaluated the effects of treatment with Lithothamnion muelleri extract (LM) in a model of acute graft-versus-host disease (GVHD), using a model of adoptive splenocyte transfer from C57BL/6 donors into B6D2F1 recipient mice. Mice treated with LM showed reduced clinical signs of disease and mortality when compared with untreated mice. LM-treated mice had reduced tissue injury, less bacterial translocation, and decreased levels of proinflammatory cytokines and chemokines (interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), chemokine (C-C motif) ligand 2 (CCL2), chemokine (C-C motif) ligand 3 (CCL3) and chemokine (C-C motif) ligand 5 (CCL5)). The polysaccharide-rich fraction derived from LM could inhibit leukocyte rolling and adhesion in intestinal venules, as assessed by intravital microscopy. LM treatment did not impair the beneficial effects of graft-versus-leukaemia (GVL). Altogether, our studies suggest that treatment with Lithothamnion muelleri has a potential therapeutic application in GVHD treatment.

Potential Role of Rho Kinase Inhibitors in Combating Diabetes-Related Complications Including Diabetic Neuropathy-A Review

The worldwide epidemic scale of diabetes mellitus has been underestimated for a long time. Currently every 10 seconds one patient dies of diabetes-related pathologies. Given the high risk and prevalence of secondary complications as well as individual predisposition to target organ injury, diabetes is one of the major risk factors for various organ and tissue dysfunctions including nerves. The present review outlines the role of Rho Kinase (ROCK) in various diabetic indications: diabetic neuropathy, erectile dysfunction, cardiomyopathy, sexual dysfunction, nephropathy, cardiomyopathy, retinopathy, cerebro-vascular disease and cystopathy. We found that ROCK is involved in various pathophysiological mechanisms, leading to a number of unique diabetic complications. Recent studies have indicated an increasing interest in the use of ROCK inhibitors like Y-27632, H1152 and fasudil not only for the treatment of diabetic neuropathy, but also for the treatment of sexual dysfunction, cardiomyopathy and other diabetic complications. The pathophysiological mechanism has been extensively analyzed and the current status of ROCK inhibitors has been discussed in the review.

The Multiple Chemokine-Binding Bovine Herpesvirus 1 Glycoprotein G (BHV1gG) Inhibits Polymorphonuclear Cell but Not Monocyte Migration into Inflammatory Sites

AbstractChemokines facilitate the recruitment of inflammatory cells into tissues, contributing to target organ injury in a wide range of inflammatory and autoimmune diseases. Targeting either single chemokines or chemokine receptors alters the progression of disease in animal models of rheumatoid arthritis and lupus with varying degrees of efficacy, but clinical trials in humans have been less successful. Given the redundancy of chemokine-chemokine receptor interactions, targeting of more than one chemokine may be required to inhibit active inflammatory disease. To test the effects of multiple chemokine blockade in inflammation, we generated an adenovirus expressing bovine herpesvirus 1 glycoprotein G (BHV1gG), a viral chemokine antagonist that binds to a wide spectrum of murine and human chemokines, fused to the fragment crystallizable (Fc) portion of murine immunoglobulin (IgG)2a. Administration of the adenovirus significantly inhibited thioglycollate-induced migration of polymorphonuclear leukocytes into the peritoneal cavity of BALB/c mice and reduced both clinical severity and articular damage in K/BxN serum transfer-induced arthritis. However, treatment with BHV1gG-Ig fusion protein did not prevent monocyte infiltration into the peritoneum in the thioglycollate model and did not prevent renal monocyte infiltration or nephritis in lupus-prone NZB/W mice. These observations suggest that the simultaneous inhibition of multiple chemokines by BHV1gG has the potential to interfere with acute inflammatory responses mediated by polymorphonuclear leukocytes, but is less effective in chronic inflammatory disease mediated by macrophages.

The angiotensin II type 1 receptor blocker olmesartan preferentially improves nocturnal hypertension and proteinuria in chronic kidney disease

Accumulated evidence suggests that an altered ambulatory blood pressure (BP) profile, particularly elevated nighttime BP, reflects target organ injury and is a better predictor of further cardiorenal risk than the clinic BP or daytime BP in hypertensive patients complicated by chronic kidney disease (CKD). In this study, we examined the beneficial effects of olmesartan, an angiotensin II type 1 receptor blocker (ARB), on ambulatory BP profiles and renal function in hypertensive CKD patients. Forty-six patients were randomly assigned to the olmesartan add-on group (n=23) or the non-ARB group (n=23). At baseline and after the 16-week treatment period, ambulatory BP monitoring was performed and renal function parameter measurements were collected. Although the baseline clinic BP levels and the after-treatment/baseline (A/B) ratios of clinic BP levels were similar in the olmesartan add-on and non-ARB groups, the A/B ratios of ambulatory 24-h and nighttime BP levels in the olmesartan add-on group were significantly lower. Furthermore, the A/B ratios of urinary protein, albumin and type IV collagen excretion in the olmesartan add-on group were significantly lower than those in the non-ARB group (urinary protein excretion, 0.72±0.41 vs. 1.45±1.48, P=0.030; urinary albumin excretion, 0.73±0.37 vs. 1.50±1.37, P=0.005; urinary type IV collagen excretion, 0.87±0.42 vs. 1.48±0.87, P=0.014) despite comparable A/B ratios for the estimated glomerular filtration rate in the two groups. These results indicate that in hypertensive patients with CKD, olmesartan add-on therapy improves the ambulatory BP profile via a preferential reduction in nighttime BP with concomitant renal injury inhibition.

Should African Americans Have a Lower Blood Pressure Goal than Other Ethnic Groups to Prevent Organ Damage?

African Americans manifest an inordinately high burden of hypertension, pressure-related target-organ injury (eg, left ventricular hypertrophy, stroke), and sub-optimal hypertension control rates to conventional levels (<140/90 mm Hg). A substantive proportion of the excessive premature mortality in African Americans relative to Whites is pressure-related. Randomized prospective pharmacologic hypertension end-point trials have shown invariable cardiovascular disease (CVD) risk reduction across a broad range of pre-treatment BP levels down to 110/70 mm Hg with the magnitude of CVD risk reduction across the 5 major antihypertensive drug classes being directly linked to degree of blood pressure (BP) lowering. Pooled endpoint data from pharmacologic hypertension trials in African Americans showed that CVD risk reduction was the same with major antihypertensive drug classes when similar levels of BP were achieved. A lower than conventional BP target for African Americans seems justified and prudent because attainment of lower BP should incrementally lower CVD risk in this high-risk population.

Advances of utilizing microRNAs as biomarkers

MicroRNAs (miRNAs) are a new class of endogenous, single-strand, noncoding small RNAs. MiRNAs play an important regulatory role in a variety of pathological and physiological process, such as cell proliferation and apoptosis, organ development and differentiation and tumorigenesis and so on. It has been found that circulating miRNAs are also stably and specially expressed in serum or plasma and other body fluids. Circulating miRNAs could be taken as noninvasive and new biomarkers for evaluating the drug-induced target organ injury, which may play a vital role in monitoring the drug toxicity at the early stage.

Systemic and Hepatic Thiol Redox Dysregulation in Graft Versus Host Disease

Graft-versus-host disease (GVHD) is mediated by a series of pathophysiological events that follow transplant conditioning and are amplified by cellular effectors and inflammatory pathways. In addition, GVHD increases oxidative stress and alters the redox environment. Whether redox dysregulation in itself potentiates the tissue injury of GVHD is unknown. We hypothesized that redox pertubation is a proximal event that precedes target organ injury in GVHD. To explore this, we applied mass-spectrometry based thiol redox metabolomics to analyze the plasma and hepatic sulfur amino acid (SAA) and thiol oxidation states in several well characterized murine models of GVHD (Allo) and compared to syngeneic (Syn) controls, at multiple time-points post-transplantation. Of the 38 amino-acid metabolites profiled, significant depletion of plasma glutathione (GSH) redox potential was noted in Allo (-127.3 ± 16 mV) compared to Syn [158.1±18 mV (p = 0.04)] mice as early as day +4 post- transplantation. This change in GSH redox state was not reflected in the cysteine (Cys/CySS) system, the principal redox couple in plasma. By day +14 post-transplantation, further decline in plasma GSH was noted in Allo mice while normalization of this metabolite was seen in Syn controls. The total hepatic GSH concentration in Allo (43.2 ± 13 nmol/mg proteins) declined by ∼33% (p = 0.05) relative to Syn group (68 ± 16 nmol/mg proteins), indicating impaired GSH synthesis. Additionally, a significant twofold (p = 0.0007) rise in hepatic homocysteine and ophthalmic acid levels were detected in Allo mice, linking both SAA and redox metabolic imbalance to GVHD. To investigate mechanism(s) of GSH redox loss in GVHD, hepatic mRNA and protein levels of gamma-glutamylcysteine ligase [GCLC (rate-limiting enzyme)], were quantified. The hepatic GCLC transcript and protein declined in Allo compared to Syn mice [GCLC fold change: day +4 = 0.4 vs 1.03±0.15; day +10 = 0.3± 0.05 vs 1.0± 0.05 (p = 0.0004), respectively]. Target organs like lungs and gut also revealed depletion of intracellular thiol in Allo mice that directly correlated with the degree of T cell infiltration. Together, these data show that the GSH synthetic pathway is specifically affected in GVHD. The tight transcriptional deregulation of GCLC with depletion of GSH reserve is an early event and precedes histopathological changes of GVHD. Identification of modifiers of GCLC/GSH/GSSG system may provide a novel target for treatment of GVHD.

Lack of Nocturnal Blood Pressure Fall in Elderly Bedridden Hypertensive Patients With Cerebrovascular Disease

To prevent recurrence of cerebrovascular disease (CVD), adequate control of blood pressure (BP) is extremely important for the treatment of hypertensive CVD patients. As absence of the nocturnal fall of BP by the expected 10–20% from daytime levels is reported to exaggerate target organ injury, 24-h ambulatory blood pressure monitoring (ABPM) was conducted, especially to obtain data during nighttime sleep. Forty-eight elderly bedridden chronic phase CVD hypertensive patients (assessed 1–3 mo after CVD accident) participated. As a group, nocturnal BP was higher than diurnal BP, whereas nocturnal pulse rate was lower than diurnal pulse rate. The nocturnal BP fall was blunted in most (∼90%) of the patients. These results suggest that to perform a rational drug treatment, it is essential to do 24-h ABPM before initiation of antihypertensive therapy in elderly bedridden hypertensive CVD patients. (Author correspondence: akiofuji@jichi.ac.jp)

The Emerging Role of Heme Oxygenase and Its Metabolites in the Regulation of Cardiovascular Function

The Emerging Role of Heme Oxygenase and Its Metabolites in the Regulation of Cardiovascular Function

Association of Filtered Sodium Load With Medullary Volumes and Medullary Hypoxia in Hypertensive African Americans as Compared With Whites

African Americans develop hypertension earlier with more target manifestations than whites despite having a higher glomerular filtration rate (GFR) for any level of serum creatinine. STUDY DESIGN & PARTICIPANTS: This study tested the hypothesis that increased GFR and sodium reabsorption in African Americans is associated with increased metabolic work and medullary hypoxia in 49 nondiabetic patients with essential hypertension (29 whites and 20 African Americans) following a constant-sodium diet (150 mEq/d) and renin-angiotensin system blockade. Ethnicity, age, measured GFR, sodium excretion, and body mass index. We examined cortical and medullary volumes and blood flows using multidetector computed tomography and intrarenal deoxyhemoglobin (R2*) using blood oxygen level-dependent magnetic resonance. Blood pressure and sodium excretion were similar, whereas African Americans were more obese and had higher iothalamate GFRs. Renal cortical volumes did not differ, but medullary volumes adjusted for body size and age were higher in African Americans (32.3 ± 11.2 vs 25.1 ± 7.4 cm(3)/m(2) body surface area; P < 0.001). Sodium reabsorption and blood flows were higher in African Americans. Basal cortical deoxyhemoglobin values were similar between ethnic groups, whereas medullary R2* was higher in African Americans (39.7 ± 5.1 vs 36.3 ± 6.5/s; P = 0.02), but decreased to levels similar to whites after furosemide treatment. Levels of the circulating isoprostane prostaglandin F(2α) were higher in African Americans and daily urinary prostaglandin F(2α) excretion in African Americans correlated directly with renal blood flow (R = 0.71; P < 0.01). Studies were limited to treated volunteers with normal kidney function without knowledge of prior nutrient intake. These data show for the first time that increased sodium reabsorption in obese African American patients with hypertension was associated with enlarged medullary volumes, functional hypoxia related to solute reabsorption, and a direct relationship between blood flows and urinary isoprostane levels. Our results support a model of increased oxygen consumption and oxidative stress in African Americans that may accelerate hypertension and target-organ injury compared with white patients with essential hypertension.

Heme oxygenase, a novel target for the treatment of hypertension and obesity?

Heme oxygenase (HO) is the rate-limiting enzyme in the metabolism of heme-releasing bioactive molecules carbon monoxide (CO), biliverdin, and iron, each with beneficial cardiovascular actions. Biliverdin is rapidly reduced to bilirubin, a potent antioxidant, by the enzyme biliverdin reductase, and iron is rapidly sequestered by ferritin in the cell. Several studies have demonstrated that HO-1 induction can attenuate the development of hypertension as well as lower blood pressure in established hypertension in both genetic and experimental models. HO-1 induction can also reduce target organ injury and can be beneficial in cardiovascular diseases, such as heart attack and stroke. Recent studies have also identified a beneficial role for HO-1 in the regulation of body weight and metabolism in diabetes and obesity. Chronic HO-1 induction lowers body weight and corrects hyperglycemia and hyperinsulinemia. Chronic HO-1 induction also modifies the phenotype of adipocytes in obesity from one of large, cytokine producing to smaller, adiponectin producing. Finally, chronic induction of HO-1 increases oxygen consumption, CO(2), and heat production and activity in obese mice. This review will discuss the current understanding of the actions of the HO system to lower blood pressure and body weight and how HO or its metabolites may be ideal candidates for the development of drugs that can both reduce blood pressure and lower body weight.

Toxicogenomics and Metabolomics of Pentamethylchromanol (PMCol)-Induced Hepatotoxicity

Pentamethyl-6-chromanol (PMCol), a chromanol-type compound related to vitamin E, was proposed as an anticancer agent with activity against androgen-dependent cancers. In repeat dose-toxicity studies in rats and dogs, PMCol caused hepatotoxicity, nephrotoxicity, and hematological effects. The objectives of this study were to determine the mechanisms of the observed toxicity and identify sensitive early markers of target organ injury by integrating classical toxicology, toxicogenomics, and metabolomic approaches. PMCol was administered orally to male Sprague-Dawley rats at 200 and 2000 mg/kg daily for 7 or 28 days. Changes in clinical chemistry included elevated alanine aminotransferase, total bilirubin, cholesterol and triglycerides-indicative of liver toxicity that was confirmed by microscopic findings (periportal hepatocellular hydropic degeneration and cytomegaly) in treated rats. Metabolomic evaluations of liver revealed time- and dose-dependent changes, including depletion of total glutathione and glutathione conjugates, decreased methionine, and increased S-adenosylhomocysteine, cysteine, and cystine. PMCol treatment also decreased cofactor levels, namely, FAD and increased NAD(P)+. Microarray analysis of liver found that differentially expressed genes were enriched in the glutathione and cytochrome P450 pathways by PMCol treatment. Reverse transcription-polymerase chain reaction of six upregulated genes and one downregulated gene confirmed the microarray results. In conclusion, the use of metabolomics and toxicogenomics demonstrates that chronic exposure to high doses of PMCol induces liver damage and dysfunction, probably due to both direct inhibition of glutathione synthesis and modification of drug metabolism pathways. Depletion of glutathione due to PMCol exposure ultimately results in a maladaptive response, increasing the consumption of hepatic dietary antioxidants and resulting in elevated reactive oxygen species levels associated with hepatocellular damage and deficits in liver function.

Autoimmune Neuromuscular Disorders

Autoimmune neuromuscular disorders affecting peripheral nerves, neuromuscular junction or muscle have a wide clinical spectrum with diverse pathogenetic mechanisms. Peripheral nervous system may be targeted in the context of complex immune reactions involving different cytokines, antigen-presenting cells, B cells and different types of T cells. Various immunomodulating and cytotoxic treatments block proliferation or activation of immune cells by different mechanisms attempting to control the response of the immune system and limit target organ injury. Most treatment protocols for autoimmune neuromuscular disorders are based on the use of corticosteroids, intravenous immunoglobulins and plasmapheresis, with cytotoxic agents mostly used as steroid-sparing medications. More recently, development of specific monoclonal antibodies targeting individual cell types allowed a different approach targeting specific immune pathways, but these new treatments are also associated with various adverse effects and their long-term efficacy is still unknown.

Advances in medical decision support systems for diagnosis of acute graft-versus-host disease: molecular and computational intelligence joint approaches

Acute graft-versus-host disease (aGVHD) is a serious systemic complication of allogeneic hematopoietic stem cell transplantation (HSCT) causing considerable morbidity and mortality. Acute GVHD occurs when alloreactive donor-derived T cells recognize host-recipient antigens as foreign. These trigger a complex multiphase process that ultimately results in apoptotic injury in target organs. The early events leading to GVHD seem to occur very soon, presumably within hours from the graft infusion. Therefore, when the first signs of aGVHD clinically manifest, the disease has been ongoing for several days at the cellular level, and the inflammatory cytokine cascade is fully activated. So, it comes as no surprise that progress in treatment based on clinical diagnosis of aGVHD has been limited in the past 30 years. It is likely that a pre-emptive strategy using systemic high-dose corticosteroids as early as possible could improve the outcome of aGVHD. Due to the deleterious effects of such treatment particularly in terms of infection risk posed by systemic steroid administration in a population that is already immune-suppressed, it is critical to identify biomarker signatures for approaching this very complex task. Some research groups have begun addressing this issue through molecular and proteomic analyses, combining these approaches with computational intelligence techniques, with the specific aim of facilitating the identification of diagnostic biomarkers in aGVHD. In this review, we focus on the aGVHD scenario and on the more recent state-of-the-art. We also attempt to give an overview of the classical and novel techniques proposed as medical decision support system for the diagnosis of GVHD.

Immune activation and target organ damage are consequences of hydrodynamic treatment but not delivery of naked siRNAs in mice.

Short-interfering RNAs (siRNAs), key mediators of RNA interference comprise a promising therapeutic tool, although side effects such as interferon (IFN) response are still not perfectly understood. Further, delivery to target organs is a major challenge, possibly associated with side effects including immune activation or organ damage. We investigated whether immune activation as a consequence of double-stranded RNA induced IFN response (Jak/STAT pathway activation or cytokine production) or target organ damage is induced by in vivo low-volume (LV) or high-volume (HV) hydrodynamic delivery or treatment with naked siRNA. NMRI mice were injected with naked siRNAs or saline by hydrodynamic injection (HDI) and positive control mice received polyinosinic-polycytidilic acid (poly I:C). LV (1 mL/mouse) and HV (10% of body weight) HDI were compared. After LV HDI, STAT1 and OAS1 gene expression inflammatory cytokine plasma levels and target organ injury were assessed. LV HDI induced slight alanine aminotransferase elevation and mild hepatocyte injury, whereas HV HDI resulted in high ALAT level and extensive hepatocyte necrosis. STAT1 or OAS1 was not induced by LV siRNA; however, HV saline led to a time-dependent slight increase in gene expression. Inflammatory cytokine plasma level and organ histology and functional parameters demonstrated no damage following LV HDI with or without siRNA. Our data demonstrate that naked siRNAs may be harnessed, without the induction of IFN response or immune activation, and that LV HDI is preferable, because HV HDI may cause organ damage.