Global risk stratification in primary hypertension: the role of the kidney

OBJECTIVE: Microalbuminuria and a reduction in creatinine clearance are well known, independent predictors of unfavourable cardiovascular prognosis. Our aim was to evaluate the impact of renal damage on global risk stratification in 459 non-diabetic, untreated hypertensive patients (64% men, mean age 47.3 years). METHODS: Renal damage was defined as creatinine clearance < 60 ml/min per 1.73 m2 (Cockcroft-Gault formula) or the presence of microalbuminuria (albumin to creatinine ratio). Cardiac and vascular organ damage was assessed by ultrasound scan. We evaluated the impact of renal damage, left ventricular hypertrophy and carotid atherosclerosis on risk stratification as recommended by the 2007 European Society of Hypertension-European Society of Cardiology Guidelines. RESULTS: The prevalence of renal damage, microalbuminuria and creatinine clearance < 60 ml/min per 1.73 m2 was 24, 12 and 13%, respectively. There was no correlation between albuminuria and estimated creatinine clearance, and only 0.9% of patients showed microalbuminuria and reduced creatinine clearance simultaneously. The presence of renal damage entailed a 3.3 times higher risk of having cardiovascular abnormalities. Based on routine work-up, 58% of our study patients were classified as high-very high risk. The simultaneous evaluation of albuminuria and creatinine clearance resulted in a significant change in risk stratification, since 68% of patients were classified in the high-very high risk class. The search for left ventricular hypertrophy or carotid atherosclerosis by ultrasonography did not improve risk stratification significantly as compared to the assessment of renal damage. CONCLUSIONS: Our findings support the assessment of renal abnormalities as the first step when evaluating target organ damage for cardiovascular risk assessment in hypertensive patients.     

Monocyte-derived tissue factor contributes to stent thrombosis in an in vitro system

OBJECTIVES: This study evaluated the role of circulating tissue factor (TF) in mediating thrombus formation on stents in an in vitro model of stent perfusion. BACKGROUND: The traditional view of coagulation has recently been challenged by the demonstration that TF is present in circulating blood. The potential contribution of this intravascular pool of TF to thrombus formation on stents is not known. METHODS: Coronary stents were placed in parallel silicone tubes connected to a roller pump that was set to pump blood at a flow rate of 10 ml/min. Stents were then exposed to heparinized blood from healthy volunteers for 120 min. RESULTS: The presence of the stent in the circuit caused a significant increase in monocyte TF expression, but only monocytes with attached platelets stained positive for TF. Thrombi formed on stents and the thrombi stained positive for TF. Pretreatment of blood with a monoclonal antibody against TF (cH36) caused a 56% reduction in (125)I-fibrin(ogen) deposition on stents compared with controls (p = 0.002). Monocyte depletion of blood reduced (125)I-fibrin(ogen) deposition by 45% (p = 0.01) and TF staining in the thrombus by 83% (p = 0.01). Pretreatment of blood with a monoclonal antibody against P-selectin reduced (125)I-fibrin(ogen) deposition by 24% (p = 0.04). Perfusion of stents with leukocyte-reduced platelet-rich plasma (PRP) produced small thrombi and treatment of PRP with cH36 reduced (125)I-fibrin(ogen) deposition by 43% (p = 0.01). CONCLUSIONS: Circulating TF plays a pivotal role in thrombus formation on stents. Monocytes appear to be the main, but not only, source of TF depositing in the thrombus.     

Age-related changes in cognitive domains. A population-based study

BACKGROUND AND AIMS: The aim of the present study is to describe the effects of aging on various cognitive domains (global cognitive function, executive function, motor speed) in a population sample of elderly men, and to describe how their age-related changes are influenced by education, depression, or prevalent cerebrovascular accidents (CEVD). METHODS: A cross-sectional observational study was conducted in a cohort of 334 men, 65 to 95 years old, living in rural communities, participating in the Italian cohort of two population studies--MATISS (Malattie cardiovascolari ATerosclerotiche Istituto Superiore di Sanità) and FINE (Finland, Italy, Netherlands, Elderly). Global cognitive function was measured by the Mini-Mental State Examination (MMSE), executive function by the Stroop test, motor speed by the Purdue Pegboard test, and depression by the CES-D test. Prevalence of cerebrovascular accidents (CEVD), myocardial infarction, and diabetes were evaluated by a questionnaire and a clinical examination. Blood pressure, and total and HDL cholesterol were measured. Current smoking status was self-reported. RESULTS: An age-associated decline in global cognitive functions, executive functions, and motor speed was observed. The decline is more apparent after the age of 85 for the MMSE, and after 75 for executive functions and motor speed. Logistic regression analysis revealed that age was independently associated with altered global cognitive functions, executive functions, and motor speed, even after adjusting for education, depression or prevalent CEVD. CONCLUSIONS: In a cohort of community-living elderly men aged 65 to 95 years, age-associated changes in mental functions are more evident after the age of 85. These changes are independent of education, depression, or prevalent CEVD.     

Targeting the minor pocket of C5aR for the rational design of an oral allosteric inhibitor for inflammatory and neuropathic pain relief

Chronic pain resulting from inflammatory and neuropathic disorders causes considerable economic and social burden. Pharmacological therapies currently available for certain types of pain are only partially effective and may cause severe adverse side effects. The C5a anaphylatoxin acting on its cognate G protein-coupled receptor (GPCR), C5aR, is a potent pronociceptive mediator in several models of inflammatory and neuropathic pain. Although there has long been interest in the identification of C5aR inhibitors, their development has been complicated, as for many peptidomimetic drugs, mostly by poor drug-like properties. Herein, we report the de novo design of a potent and selective C5aR noncompetitive allosteric inhibitor, DF2593A, guided by the hypothesis that an allosteric site, the “minor pocket,” previously characterized in CXC chemokine receptors-1 and -2, is functionally conserved in the GPCR class. In vitro, DF2593A potently inhibited C5a-induced migration of human and rodent neutrophils. In vivo, oral administration of DF2593A effectively reduced mechanical hyperalgesia in several models of acute and chronic inflammatory and neuropathic pain, without any apparent side effects. Mechanical hyperalgesia after spared nerve injury was also reduced in C5aR^−/− mice compared with WT mice. Furthermore, treatment of C5aR^−/− mice with DF2593A did not produce any further antinociceptive effect compared with C5aR^−/− mice treated with vehicle. The successful medicinal chemistry strategy confirms that a conserved minor pocket is amenable for the rational design of selective inhibitors and the pharmacological results support that the allosteric blockade of the C5aR represents a highly promising therapeutic approach to control chronic inflammatory and neuropathic pain.Inflammatory and neuropathic pain are the most prevalent types of pathological pain and represent important health problems. Whereas inflammatory pain is one of the classic symptoms of the inflammatory process, neuropathic pain arises from any of multiple nerve lesions or diseases, with symptoms including hyperalgesia or allodynia (1, 2). Some of the most powerful painkillers, including opioids and nonsteroidal anti-inflammatory drugs, are only partially effective and prolonged exposure can cause unwanted effects (3, 4). As a result, there is continuous effort to identify novel therapeutics for pain control with alternative biological mechanisms and that elicit fewer side effects.Inflammatory mediators, including cytokines/chemokines, play a critical role in the pathogenesis of inflammatory and neuropathic pain (5, 6). Emerging evidences suggest that C5a, the anaphylatoxin produced by complement activation, has potent nociceptive activity in several models of inflammatory and neuropathic pain by interacting with its selective receptor C5aR (7, 8). C5aR belongs to the class A subfamily of the seven-transmembrane (TM) G protein-coupled receptors (GPCR) (9) and is widely expressed in immune cells, including neutrophils (polymorphonuclear cells, PMN), monocytes, microglia, and in nonimmune cells, including neurons in the CNS and dorsal root ganglia (10, 11).Evidence for a role of C5a in nociception sensitization has been obtained in several models of inflammatory pain. For example, C5a was produced at the inflammatory sites and elicited mechanical hyperalgesia by activating the C5aR on infiltrated PMN (7). Direct intraplantar injection of C5a in mice elicited both heat and mechanical hyperalgesia by sensitizing primary afferent C-nociceptors (12, 13). Local activation of C5aR has been also implicated in the pathogenesis of postsurgical pain, a model of postoperative pain (13). Finally, local administration of PMX-53, a C5aR antagonist, attenuated mechanical hyperalgesia induced by carrageenan, zymosan, or lipopolysaccharide (7). In addition to the peripheral role of C5a/C5aR in inflammatory pain, up-regulated levels of C5 and C5aR have been found in spinal cord microglia in animals subjected to spared nerve injury (SNI), a model of neuropathic pain (8). Indeed, C5-null mice or the infusion of PMX-53 into the intrathecal space reduced neuropathic pain hypersensitivity in the SNI model (8). Collectively, these data suggest that a neuroimmune interaction in the periphery and spinal cord through activation of the complement cascade and the production of C5a contributes to the genesis of both inflammatory and neuropathic pain.As for other peptidergic GPCRs, the efforts to identify small molecular weight C5aR antagonists have led to a limited number of molecules, mostly lacking adequate potency and selectivity (14). The most promising candidate so far described, PMX-53, is a cyclic peptidomimetic antagonist designed to mimic the C-terminal portion of C5a (15). Despite the encouraging results obtained in preclinical studies, as for many peptide drugs, the development of PMX-53 has been limited by its short half-life and unfavorable bioavailability (16). In the present study, we report the successful design of a nonpeptidic C5a allosteric small molecular weight inhibitor driven by the structural information on a minor pocket spanning between TM1, -2, -3, -6, and -7 that is highly conserved across the GPCR family and that has been recently proposed as a key motif for the intracellular activation process. Reparixin was previously reported as a neutral allosteric inhibitor of CXCR1 and CXCR2 that binds the TM in a region that overlaps the minor pocket (17, 18). Combining the information from independent sources on structural and functional features of allosteric sites in homologous chemokine receptors, this paper intends to provide what is, to our knowledge, the first example of de novo design of a new class of allosteric small molecular weight inhibitors of a GPCR not belonging to the chemokine receptor family, C5aR. The preclinical candidate, DF2593A, is a potent and orally active C5a noncompetitive allosteric inhibitor with significant antinociceptive effects in a wide range of inflammatory and neuropathic pain models.     

Central cholinergic dysfunction in the adult form of Niemann Pick disease type C: a further link with Alzheimer’s disease?

Adult patients with Niemann-Pick disease type C (NPC) usually develop cognitive impairment progressing to dementia, whose pathophysiology remains still unclear. Noteworthy parallels exist in cognitive impairment and cellular pathology of NPC and Alzheimer’s disease (AD). In particular, alterations of cholinergic system, which represent one of the pathological hallmarks and contribute to cognitive deterioration in AD, have recently been demonstrated in a human brain autopsy and in an experimental model of NPC. This finding raised the issue that central cholinergic circuits dysfunction may contribute to pathophysiology of cognitive impairment in NPC as well, and prompted us to evaluate the cholinergic functional involvement in NPC patients by applying a neurophysiologic technique, named short-latency afferent inhibition (SAI). We describe clinical, biochemical, molecular and neuropsychological features, and SAI findings in three patients affected by NPC. Diagnosis of NPC was assessed by molecular analysis of the NPC1 gene in all patients. In two of them, biochemical analysis of intracellular accumulation of unesterified cholesterol was also performed. The main clinical features were cerebellar ataxia, vertical supranuclear gaze palsy and a variable degree of cognitive impairment ranging from only memory impairment to severe dementia. Electrophysiological evaluation revealed a reduced SAI in all three patients. Our SAI findings provide evidence of cholinergic dysfunction in patients with the adult form of NPC, supporting that cholinergic alterations may play a role in cognitive impairment in NPC, and strengthening the similarities between NPC and AD.     

C9ORF72 repeat expansion not detected in patients with multiple sclerosis

A hexanucleotide repeat expansion in the chromosome 9 Open Reading Frame 72 gene (C9ORF72) has recently been reported to be cause of familial amyotrophic lateral sclerosis and frontotemporal lobar degeneration. Nevertheless, in the last few years this mutation has been found to be associated with heterogeneous phenotypes, including multiple sclerosis (MS) in concurrence with amyotrophic lateral sclerosis. In this study, we sought to evaluate the presence of the C9ORF72 repeat expansion in a cohort consisting of 314 patients with MS and 222 control subjects. No pathogenic expansion was found in MS and control populations, suggesting that C9ORF72 does not play a major role in MS pathogenesis.     

Heterozygous TREM2 mutations in frontotemporal dementia

A causative association was recently demonstrated between homozygous TREM2 mutations and frontotemporal dementia (FTD)-like syndrome and between heterozygous TREM2 exon2 genetic variations and late-onset Alzheimer's disease (AD). The objective of this study was to evaluate whether heterozygous TREM2 genetic variations might be associated to the risk of FTD. TREM2 exon 2 was sequenced in a group of 1030 subjects—namely, 352 patients fulfilling clinical criteria for FTD, 484 healthy control subjects (HCs), and 194 patients with AD. The mutation frequency and the associated clinical characteristics were analyzed. We identified 8 missense and nonsense mutations in TREM2 exon 2 in 24 subjects. These mutations were more frequent in patients with FTD than in HCs (4.0% vs. 1.0%, p = 0.005). In particular, TREM2 Q33X, R47H, T66M, and S116C mutations were found in FTD and were absent in HCs. These mutations were associated with either the semantic variant of primary progressive aphasia or the behavioral variant FTD phenotypes. The FTD and AD groups were not significantly different with regard to TREM2 genetic variation frequency (AD: 2.6%, p = 0.39). Heterozygous TREM2 mutations modulate the risk of FTD in addition to increasing susceptibility to AD. Additional studies are warranted to investigate the possible role of these mutations in the pathogenesis of neurodegenerative disorders.