Miguel Ángel Rubio

Biomarkers to predict clinical progression in small vessel disease strokes: prognostic role of albuminuria and oxidized LDL cholesterol.

OBJECTIVE Clinical progression in lacunar strokes (LS) is an unpredictable and fearful complication. Endothelial dysfunction (ED) is believed to be the first step in the pathophysiology of LS therefore we aimed to analyze the association of three markers of ED: albuminuria, von Willebrand factor (vWF), and oxidized LDL cholesterol (ox-LDL) with LS progression. METHODS From December 2007 to December 2010, 127 LS patients admitted within 6 h of symptom onset were prospectively assessed. Progression was defined as initial NIHSS score worsening ≥4 points within the first 72 h. Analysis of vWF and ox-LDL was done at admission. Albuminuria was measured in the first morning spot urine. Association between 3 biomarkers and progression was tested using logistic regression analysis. Other clinical variables of interest were also studied. Discriminative power was analyzed with a receiver operator curve. RESULTS Twenty-two patients (17.3%) progressed. Progression was associated with worse outcome at 90 days. Albuminuria and ox-LDL were associated in univariate analysis; vWF was not. Adjusted OR were: ox-LDL [OR: 1.03; 95% CI: 1.01-1.07, p=0.019], albuminuria [OR: 2.07; 95% CI: 1.04-4.13, p=0.039]. Association was linear without a cut-off point. Clinical variables were not associated with progression. The model including albuminuria and ox-LDL had a good predictive value [AUC: 0.80 [0.70-0.89)]. CONCLUSIONS Albuminuria and ox-LDL levels are independently associated with higher risk of progression in LS. The lack of reliable clinical predictors makes biomarker research a priority to improve progression detection in this subtype of ischemic strokes.

Involvement of sensory innervation in the skin of SOD1(G93A) ALS mice.

Sensory alterations have been described in both amyotrophic lateral sclerosis (ALS) patients and mouse models. While involvement of intraepidermal and subepidermal axons has been shown in skin biopsies of ALS patients, it is unclear if the SOD1G93A mouse presents similar alterations. We analyzed the epidermal and dermal innervation, based on PGP9.5 immunostaining, of SOD1G93A mice at different stages. The results showed a marked reduction of intraepidermal nerve fibers, Meissners corpuscles, and subepidermal nerve density already at 4 weeks. This loss of innervation progressed over time. Dermal axonal density decreased at a later stage of the disease. There was a gradient of axonal loss, with a more severe decline in the epidermis compared with deeper structures, indicating a distal axonal neuropathy as the mechanism of degeneration. These findings suggest that the analysis of the cutaneous sensory innervation may be an accessible and useful tool to assess the neurodegeneration process in motoneuron diseases.

Heregulin, a new regulator of telomere length in human cells

The growth factor heregulin (HRG) promotes breast cancer (BC) tumorigenesis and metastasis and differentially modulates BC cell responses to DNA-damaging agents via its dual extracellular and nuclear localization. Given the central role of telomere dysfunction to drive carcinogenesis and to alter the chemotherapeutic profile of transformed cells, we hypothesized that an unanticipated nuclear function of HRG might be to regulate telomere length. Engineered overexpression of the HRGβ2 isoform in non-aggressive, HRG-negative MCF-7 BC cells resulted in a significant shortening of telomeres (up to 1.3 kb) as measured by Southern blotting of telomere terminal restriction fragments. Conversely, antisense-mediated suppression of HRGβ2 in highly aggressive, HRG-overexpressing MDA-MB-231 and Hs578T cells increased telomere length up to 3.0 kb. HRGβ2 overexpression promoted a marked upregulation of telomere-binding protein 2 (TRF2) protein expression, whereas its knockdown profoundly decreased TRF2 expression. Double staining of endogenous HRGβ2 with telomere-specific peptide nucleic acid probe/fluorescence in situ hybridization (PNA/FISH) revealed the partial localization of HRG at the chromosome ends. Moreover, a predominantly nucleoplasmic staining pattern of endogenous HRGβ2 appeared to co-localize with TRF2 and, concomitantly with RAP1, a telomere regulator that specifically interacts with TRF2. Small interfering RNA-mediated knockdown of HRG decreased the expression of TRF2 and RAP1, decreased their presence at chromosome ends, and coincidentally resulted in the formation of longer telomeres. This study uncovers a new function for HRGβ2 in controlling telomere length, in part due to its ability to regulate and interact with the telomere-associated proteins TRF2 and RAP1.

Bone Marrow WT1 Levels in Allogeneic Hematopoietic Stem Cell Transplantation for Acute Myelogenous Leukemia and Myelodysplasia: Clinically Relevant Time Points and 100 Copies Threshold Value

The outcome of allogeneic hematopoietic stem cell transplantation (HCT) in patients with myeloid malignancies is better in those without minimal residual disease (MRD) than in those with MRD+, as assessed by multiparametric flow cytometry (MPFC). WT1 quantitation also has been used to assess the probability of relapse in acute myelogenous leukemia (AML) treated with chemotherapy. We analyzed the clinical value of normalized bone marrow WT1 levels as a measure of the expanded myeloid progenitor compartment in a consecutive series of 193 adult patients with myeloid malignancies who underwent HCT. Bone marrow WT1 levels before the HCT, at the first bone marrow aspirate after infusion, and in the follow-up samples after HCT were determined by means of real-time PCR using the European LeukemiaNet normalized method. We sought to clarify the prognostic relevance in terms of overall survival (OS), progression-free survival (PFS), and cumulative incidence of relapse (CIR). Based on earlier experience in AML, we selected a threshold of 100 copies, defining 2 groups: patients with <100 WT1 copies and those with ≥100 copies. Patients with <100 WT1 copies before HCT (median time, 36 days; range, 4 to 268 days) had a better OS, PFS, and CIR than those with ≥100 copies (40 ± 1 versus 29 ± 6 days, P = .004; 35 ± 9 versus 26 ± 6 days, P = .002; and 29 ± 7 versus 37 ± 6 days, P = .051). In the first bone marrow study after the HCT (median time, 42 days; range 14 to 157 days, respectively), patients with <100 WT1 copies also had better outcomes in terms of OS, PFS, and CIR (40 ± 7 versus 31 ± 9 days, P = .025; 36 ± 7 versus 30 ± 8 days, P = .004; and 29 ± 6 days versus 54 ± 9, P < .001, respectively). At this time point, bone marrrow samples with >100 copies also included patients who were negative for MRD as assessed by MPFC (19 of 32). During the HCT follow-up, patients with sustained WT1 levels <100 copies showed a marked benefit in terms of OS, PFS, and CIR even compared with those with only a single measurement >100 copies (mean, 68 ± 11 versus 26 ± 7 days, P < .001; 63 ± 11 versus 20 ± 8 days, P < .001; and 20 ± 8 vs. 71 ± 8 days, P < .001, respectively). Standardized bone marrow WT1 levels using a 100-copy threshold in samples obtained before HCT, at leukocyte recovery, and during follow-up provided relevant prognostic information in patients with myeloid malignacies submitted to HCT.

Adult onset Pompe disease associated with multiple sclerosis

Dear Sirs,A 27-year-old woman was referred to our center regardingprogressive lower extremity weakness. Her symptomsbegan 3 years ago with fatigue related to the exertion andmild proximal lower extremity weakness. She had nomotor development issues and she denied family history ofneurological disease. There were non ocular or sensorycomplaints. At the age of 20, a routine analysis demon-strated an increase of liver enzymes with a normalabdominal echography. She refused hepatic biopsy andhepatology follow-up visits.The force was reduced to grade 4/5 symmetrically in thehip flexion. The right knee reflex was absent and presentedleft ankle clonus. Plantar responses were extensor. Theexam of the sensory was normal except for a diminishedvibratory sensory in right leg. She was unable to walk ontip-toes and heels. Laboratory investigations showed ALT119 UI/I (7-31), AST 98 UI/I (10-38), and CK 728 UI/I(20-170). Thyroid function, vitamin B12, folate, and acomplete autoimmune profile were normal. Blood exami-nation showed no evidence of herpes virus, CMV, EBV,syphilis, borrelia, HIV-1/2, HTLV-1, or hepatotropic viru-ses. Brain MRI T2-weighted images and FLAIR revealed 8hyperintense lesions involving periventricular white matter,juxtacortical areas, and one left mesencephalic lesion,suggestive of demyelination. None of them demonstratedgadolinium enhancement. MRI of the whole spinal cord wasnormal (Fig. 1). Intrathecal IgG-oligoclonal bands werepresent in the cerebrospinal fluid examination and no ple-ocytosis. Visual-evoked potentials showed delayedresponses on both eyes. Nerve conduction studies werenormal but the results of the electromyography were con-sistent with a myopathic pattern; thus, a deltoid musclebiopsy was performed. Histopathology demonstrated thepresence of vacuoles with abnormal accumulation on peri-odic acid-Schiff (PAS) stain (Fig. 2). The enzyme activityin lymphocytes was 19.00 nmol 9 min 9 g (patient) ver-sus 614.00 nmol 9 min 9 g (controls), and was similarlylow in skin biopsy as well as in the muscle biopsy reliable toglycogen storage disease type 2. The analysis of the GAAgene found heterozygosity for IVS1-13T[G (also called c.-32-13T[G), a frequent pathogenic mutation among adultpatients with Pompe disease, as well as heterozygosity forthe unknown change M1L(1A[T), an unclassified variant.A liver biopsy confirmed the diagnosis of mild chronichepatitis. In the subsequent 2 years, the patient has suffereda progression in her symptoms. Although enzyme replace-ment therapy was started, her limb weakness has worsenedand she is able to walk with the assistance of a cane. NewsMRIs showed the presence of new T2-hyperintense whitematter lesions. According to McDonald’s criteria, a diag-nosis of primary progressive multiple sclerosis (PPMS) wasmade [1].MS and combined muscle disease has only beendescribed in a few case reports: a boy affected with cen-tronuclear myopathy who developed RRMS [2], a case ofcombined facio-scapulo-humeral muscular dystrophy [3],a case with combined myotonic dystrophy [4], and twocases of MS and mitochondrial myopathy [5]. This is thefirst report of a patient with both Pompe myopathy andmultiple sclerosis. Given the high prevalence of multiplesclerosis in our population, we consider that the associationbetween these two entities in our patient is casual. Pompe

Heregulin, a new interactor of the telosome/shelterin complex in human telomeres

Telomere length, shape and function depend on a complex of six core telomere-associated proteins referred to as the telosome or shelterin complex. We here demonstrate that the isoform β2 of the heregulin family of growth factors (HRGβ2) is a novel interactor of the telosome/shelterin complex in human telomeres. Analysis of protein-protein interactions using a high-throughput yeast two-hybrid (Y2H) screen identified RAP1, the only telomere protein that is conserved from yeasts to mammals, as a novel interacting partner of HRGβ2. Deletion analysis of RAP1 revealed that the linker domain, a region previously suggested to recruit negative regulators of telomere length, interacts specifically with HRGβ2. Co-immunoprecipitation and imaging experiments demonstrated that, in addition to RAP1, HRGβ2 could associate with the RAP1-associated telomeric repeat binding factor 2 (TRF2). Deletion analysis of HRGβ2 confirmed that a putative nuclear localization signal (NLS) was necessary for nuclear HRGβ2 to exert a negative regulation of telomere length whereas the N-terminus (extracellular) amino acids of HRGβ2 were sufficient to interact with RAP1/TRF2 and promote telomere shortening. Taken together, our studies identify nuclear HRGβ2 as one of the previously unknown regulators predicted to be recruited by the RAP1 linker domain to negatively regulate telomere length in human cells. Our current findings reveal that a new, but likely not the last, unexpected visitor has arrived to the “telosome/shelterin town”.

Acute atraumatic pluriradiculopathy after heroin consumption.

To the Editor: Compressive neuropathy is the most frequent complication of the peripheral nervous system after heroin consumption. Plexopathies, radiculopathies, and neuropathies without a traumatic cause are also described but are very uncommon and their prognoses are uncertain. We present a case of an acute atraumatic pluriradiculopathy after heroin use. A 31-year-old man with regular drug abuse was admitted in the emergency department after suffering an abruptly right upper extremity weakness 2 hours after injecting intravenous heroin on his limb. The patient did not complain about pain or any sensory disorder and did not refer loss of consciousness after consumption, history of trauma, or other situations that could cause compression of the extremity. Physical examination revealed an areflectic flaccid paralysis proximally in the right upper extremity, without sensory disturbance. Creatine kinase (CK) levels were of 18,000 U/L, with a decrease to 8600 U/L a few hours later. Human immunodeficiency virus and hepatitis B virus serologies were negative, being positive for hepatitis C virus. The motor deficit still was remaining 2 weeks later, and a slight atrophy of the right infraspinatus muscle was already visible. A neurophysiological study was performed 23 days after the onset of symptoms showing fibrillation potentials and positive sharp waves in the biceps, extensor digitorum, extensor carpi radialis, palmaris longus, deltoid, and supraspinatus muscles with a neurogenic recruitment that was very poor in supraspinatus and deltoid muscles. Sensory nerve conduction studies were normal. This suggested a preganglionic involvement, affecting C5, C6, and C7 nerve roots. A magnetic resonance image of the brachial plexus and cervical spinal cord was performed, without compressive pathology at any point of the nerve pathway. Symptoms persisted for 1 month, and then progressively improved until complete recovery after 2 months. Heroin-related neuropathies without a traumatic cause are very uncommon. The clinical picture is acute, asymmetric, predominantly proximal, painful, and associated with a sensory disorder. There is no specific treatment, and the functional prognosis is variable. Symptoms appear 3–36 hours after consumption. There have been cases reported after sniffed heroin, and in cases of intravenous abuse, the affected side does not always coincide with the side of the puncture. There are very few reports described, being the largest series of 6 patients, 4 with a plexus involvement (2 brachial and 2 lumbosacral) and 2 with an acute sensorimotor axonal neuropathy. All but one of these patients had elevated levels of creatine kinase. The prognosis was variable, and 2 patients underwent nerve biopsy showing axonal loss with Wallerian degeneration. It has been proposed that there is a direct toxic effect either of the drug itself or its adulterants, as the mechanism of neurotoxicity or rhabdomyolysis. Proximal regions of peripheral nerves lack perineurium, therefore nerve fibers are in contact with blood vessels in the absence of the blood–neural barrier. This anatomical consideration favors the liability at these locations of the peripheral nervous system (ie, roots) to certain immunologic (eg, Guillain–Barré syndrome) or toxic (eg, cisplatin) phenomena. In summary, we describe a pluriradicular affectation after heroin consumption, which is very infrequent and poorly described. The reversibility of the deficit demonstrates the toxic, and sometimes transient, effect of the heroin and its adulterants in the peripheral nervous system. The peculiarity of our case is the absence of pain and sensory disorder, and the excellent and early recovery. This may suggest that in cases of heroin toxicity, the existence of a preganglionic disorder may be associated with a better prognosis.