Next-generation sequencing improves precision medicine in hearing loss.

Background: An early etiological diagnosis of hearing loss positively impacts children's quality of life including language and cognitive development. Even though hearing loss associates with extremely high genetic and allelic heterogeneity, several studies have proven that Next-Generation Sequencing (NGS)-based gene panel testing significantly reduces the time between onset and diagnosis. Methods: In order to assess the clinical utility of our custom NGS GHELP panel, the prevalence of pathogenic single nucleotide variants, indels or copy number variants was assessed by sequencing 171 nuclear and 8 mitochondrial genes in 155 Spanish individuals with hearing loss. Results: A genetic diagnosis of hearing loss was achieved in 34% (52/155) of the individuals (5 out of 52 were syndromic). Among the diagnosed cases, 87% (45/52) and 12% (6/52) associated with autosomal recessive and dominant inheritance patterns respectively; remarkably, 2% (1/52) associated with mitochondrial inheritance pattern. Although the most frequently mutated genes in this cohort were consistent with those described in the literature (GJB2, OTOF or MYO7A), causative variants in less frequent genes such as TMC1, FGF3 or mitCOX1 were also identified. Moreover, 5% of the diagnosed cases (3/52) were associated with pathogenic copy number variants. Conclusion: The clinical utility of NGS panels that allows identification of different types of pathogenic variants-not only single nucleotide variants/indels in both nuclear and mitochondrial genes but also copy number variants-has been demonstrated to reduce the clinical diagnostic odyssey in hearing loss. Thus, clinical implementation of genomic strategies within the regular clinical practice, and, more significantly, within the newborn screening protocols, is warranted.

Mutations in the John Cunningham virus VP1 gene could predispose to the development of progressive multifocal leukoencephalopathy in multiple sclerosis patients undergoing treatment with natalizumab.

BACKGROUND: Patients with Multiple Sclerosis (MS) undergoing treatment with natalizumab (NTZ) are at risk of developing progressive multifocal leukoencephalopathy (PML) due to the reactivation of John Cunningham (JC) virus. A relevant characteristic among PML cases is the development of single nucleotide mutations in the VP1 gene of the causal JC virus. The identification of such mutations in timely manner can provide valuable information for MS management. OBJECTIVE: To identify mutations along the JC virus VP1 gene in MS patients undergoing treatment with NTZ, and correlate them with anti-JC virus antibody index. METHODS: Eighty-eight MS patients, one hundred twenty controls, and six patients with diagnosis of Human Immunodeficiency Virus (HIV) with and without secondary PML were included. JC virus was identified in peripheral blood mononuclear cells and cerebrospinal fluid by PCR. Amplification and sequencing of the entire length of the VP1 gene were performed in all positive clinical samples. RESULTS: In MS cases no mutations were observed in the JC virus VP1 gene, but it was positive in HIV controls with PML. Interestingly, the JC virus VP1 gene sequence derived from the HIV patients exhibited a non-silent substitution in position 186 (G â†’ C), leading to an amino acid change (Lys â†’ Asp). We did not find correlation between anti-JC virus antibody index and DNA viral detection. CONCLUSIONS: . The identification of single nucleotide mutants in the JC virus VP1 gene might be an early predictive marker to PML for efficient patient treatment and follow-up.

Integrating genomic alterations in diffuse large B-cell lymphoma identifies new relevant pathways and potential therapeutic targets.

Genome studies of diffuse large B-cell lymphoma (DLBCL) have revealed a large number of somatic mutations and structural alterations. However, the clinical significance of these alterations is still not well defined. In this study, we have integrated the analysis of targeted next-generation sequencing of 106 genes and genomic copy number alterations (CNA) in 150 DLBCL. The clinically significant findings were validated in an independent cohort of 111 patients. Germinal center B-cell and activated B-cell DLBCL had a differential profile of mutations, altered pathogenic pathways and CNA. Mutations in genes of the NOTCH pathway and tumor suppressor genes (TP53/CDKN2A), but not individual genes, conferred an unfavorable prognosis, confirmed in the independent validation cohort. A gene expression profiling analysis showed that tumors with NOTCH pathway mutations had a significant modulation of downstream target genes, emphasizing the relevance of this pathway in DLBCL. An in silico drug discovery analysis recognized 69 (46%) cases carrying at least one genomic alteration considered a potential target of drug response according to early clinical trials or preclinical assays in DLBCL or other lymphomas. In conclusion, this study identifies relevant pathways and mutated genes in DLBCL and recognizes potential targets for new intervention strategies.

From Waldenström's macroglobulinemia to aggressive diffuse large B-cell lymphoma: a whole-exome analysis of abnormalities leading to transformation.

Transformation of Waldenström's macroglobulinemia (WM) to diffuse large B-cell lymphoma (DLBCL) occurs in up to 10% of patients and is associated with an adverse outcome. Here we performed the first whole-exome sequencing study of WM patients who evolved to DLBCL and report the genetic alterations that may drive this process. Our results demonstrate that transformation depends on the frequency and specificity of acquired variants, rather than on the duration of its evolution. We did not find a common pattern of mutations at diagnosis or transformation; however, there were certain abnormalities that were present in a high proportion of clonal tumor cells and conserved during this transition, suggesting that they have a key role as early drivers. In addition, recurrent mutations gained in some genes at transformation (for example, PIM1, FRYL and HNF1B) represent cooperating events in the selection of the clones responsible for disease progression. Detailed comparison reveals the gene abnormalities at diagnosis and transformation to be consistent with a branching model of evolution. Finally, the frequent mutation observed in the CD79B gene in this specific subset of patients implies that it is a potential biomarker predicting transformation in WM.

Exact Markovian kinetic equation for a quantum Brownian oscillator.

We derive an exact Markovian kinetic equation for an oscillator linearly coupled to a heat bath, describing quantum Brownian motion. Our work is based on the subdynamics formulation developed by Prigogine and collaborators. The space of distribution functions is decomposed into independent subspaces that remain invariant under Liouville dynamics. For integrable systems in Poincaré's sense the invariant subspaces follow the dynamics of uncoupled, renormalized particles. In contrast, for nonintegrable systems, the invariant subspaces follow a dynamics with broken time symmetry, involving generalized functions. This result indicates that irreversibility and stochasticity are exact properties of dynamics in generalized function spaces. We comment on the relation between our Markovian kinetic equation and the Hu-Paz-Zhang equation.

Augmentation of lymphokine-activated killer cell cytotoxicity by monoclonal antibodies against human small cell lung carcinoma.

This study examined the lymphokine-activated killer (LAK) cell cytotoxicity on monoclonal antibody (MoAb)-bound tumor cells from the human small cell lung carcinoma cell lines H69 and H128. LAK cells were generated from normal peripheral blood mononuclear cells by incubation with interleukin 2 for 3 or more days. Cells from the LAK culture were cytotoxic to natural killer-sensitive (K562, 84% cytotoxicity) and natural killer-resistant (Daudi, 85%; H69 and H128, 69% and 97%, respectively) cell lines, and to freshly excised human lung (49%) and breast (57%) tumors. LAK cytotoxicity to H69 or H128 cells was significantly augmented by target cell preincubation with the small cell lung carcinoma-reactive MoAbs 1096 (increases of up to 271%) or 5023 (up to 223%). SCLC 5023 or 1096 did not enhance LAK cytotoxicity to Daudi cells of lymphoblastoid origin. Pretreatment of LAK cells with an anti-Fc receptor antibody blocked MoAb augmentation by 1096 or 5023 (but not LAK cytotoxicity), suggesting that LAK-MoAb interaction may be mediated by Fc binding. LAK activity coincided with emergence of a large cell [interleukin 2-stimulated large mononuclear leukocyte (LML)] subset expressing the CD16 and NKH-1 surface determinants. Serial immunophenotyping of the LAK cell culture harvested at Days 3, 5, and 7 indicated that the level of LAK cytotoxicity, with or without MoAb augmentation, correlated with frequency of NKH-1-reactive LMLs. These observations support the hypothesis that LAK cytotoxicity is mediated by a NKH-1-reactive LML subpopulation. Antitumor cytotoxicity may be augmented by tumor-reactive MoAbs through Fc binding to this LML subset.

Growth-inhibitory effects of CD40 ligand (CD154) and its endogenous expression in human breast cancer.

CD40 binding produces multifaceted growth signals in normal and malignant B cells, whereas its physiological role is less well characterized in epithelial cancers. We examined the growth outcome of CD40 ligation in human breast cancer cells, using CD40+ (T47D and BT-20) and CD40-negative (MCF-7, ZR-75-1) cell lines as defined by flow cytometric analysis, immunohistochemistry, and reverse transcription-PCR. Treatment with the soluble recombinant CD40 ligand (CD40L) molecules gp39 or CD40L-trimer significantly reduced [3H]thymidine uptake in BT-20 and T47D cells by up to 40%, but did not affect the growth of CD40-negative MCF-7 or ZR-75-1 cells. Similarly, significant growth inhibition was observed after co-incubation with CD40L-transfected murine L cells (55.0 +/- 8.9%, P < 0.001) that express membrane CD40L constitutively, or with paraformaldehyde-fixed, CD3+ CD40L+ PBLs from three different HLA-mismatched donors (39.7 +/- 3.7%, P < 0.01). Untransfected L cells and non-CD40L-expressing lymphocytes did not produce significant growth inhibition. The in vivo antitumorigenic effects of CD40L were examined using a s.c. severe combined immunodeficient-hu xenograft model. Pretreatment with two different soluble recombinant CD40L constructs (CD40L and gp39) produced similar xenograft growth-inhibitory effects [67 +/- 24% (n = 4), and 65 +/- 14% (n = 8) inhibition, respectively], which were reversed by co-treatment with the CD40L-neutralizing antibody LL48. In vitro analysis indicated that CD40L-induced growth inhibition was accompanied by apoptotic events including cell shrinkage, rounding, and detachment from the adherent T47D culture monolayer. Thirty-one and 27% of gp39-treated T47D and BT-20 cells underwent apoptosis, respectively, as compared with 56 and 65% from the same cell lines after treatment with the Fas agonistic antibody CH-11. An up-regulation of the proapoptotic protein Bax in T47D and BT-20 cells was observed, which indicated that this Bcl-2 family member may contribute to this growth-inhibitory effect. To explore the clinical relevance of CD40L-CD40 interaction, retrospective immunohistochemical analysis was carried to characterize in situ CD40- and CD40L-expression in breast cancer patient biopsies. All of the infiltrating ductal (5 of 5 cases tested) and lobular (4 of 4 cases) breast carcinomas, carcinomas in situ (6 of 6 cases), and mucinous carcinoma tested (1 case) expressed CD40. Varying proportions of tumor cells also expressed CD40L in the majority of infiltrating ductal (3 of 5 cases) and lobular (3 of 4 cases) carcinomas, and carcinomas in situ (4 of 6 cases), as determined by immunohistochemistry and validated by RT-PCR detection of the CD40L message in only CD40L positive-staining cases. Tumor infiltrating mononuclear cells from infiltrating carcinomas and carcinomas in situ expressed CD40 (10 of 10 cases), but less commonly CD40L (1 case of infiltrating lobular carcinoma, 2 cases of carcinoma in situ). Our findings indicate that the CD40 signaling pathway is active in human breast carcinoma cells. However, tumor-infiltrating lymphocytes from primary tumor tissues may be limited in their capacity to directly modulate tumor growth through the CD40L-CD40 loop.

Viral genotyping of infectious bursal disease viruses isolated from the 2002 acute outbreak in Spain and comparison with previous isolates.

An infectious bursal disease (IBD) outbreak occurred in the east region of Spain in the spring of 2002 and rapidly spread thorough the whole country, although proper vaccination programs were applied. In this report, 33 infectious bursal disease viruses (IBDVs) isolated from this outbreak were characterized by nucleotide sequencing of the VP2 gene hypervariable region and were compared with reference IBD strains and the 1990s Spanish IBDVs in order to determine possible emergence of IBDV isolates with modified antigenic or virulent properties. Moreover, histopathologic and immunohistochemical studies of those cases where bursal tissues were available were carried out. Of the 33 isolates, 23 were identified as very virulent IBDVs (vvIBDVs), whereas the other 10 isolates were classified as attenuated or intermediate virulence classical strains and could possibly be IBDV live vaccine strains used in the immunization of these chickens. Results of this study indicate that wIBDV isolates from the 2002 Spanish outbreak are closely related with those from the 1990s outbreak. However, acute IBD cases have not been reported in Spain during these 10 yr. Genetic, management, and environmental factors likely related with IBD reemergence in Spain are discussed. Moreover, our results indicate that good correlation exists between the IBDV subtype present in the field and the degree of lesions in bursa tissue, as well as the immunohistochemistry staining.

Antibodies against fetal muscle proteins in serum from patients with amyotrophic lateral sclerosis.

The serum from 30 patients with amyotrophic lateral sclerosis and 30 controls was tested by immunoblot with protein extracts obtained from fetal muscle, adult muscle, and denervated muscle. Results with adult and denervated muscle confirm previous reports that show a lack of particular reactivity of ALS serum when compared with control serum. However, we found reacting bands 5 times more frequently with ALS than with controls in the immunoblot with protein extract from rat fetal muscle; we confirmed reactivity by immunoperoxidase staining in frozen sections of fetal muscle. Our results point to the possibility of an immune reaction in ALS patients against ephemeral proteins of muscle that are present in large quantities at early stages of muscle differentiation and innervation.

Characterization of skin-infiltrating cells during acute graft-versus-host disease following bone marrow transplantation using unrelated marrow donors.

To characterize skin-infiltrating T lymphocytes during acute GVHD, skin biopsies were obtained from two patients who received unrelated marrow matched for HLA-A, -B, -DR, and -DQ but mismatched for -DP. A total of 120 T-cell clones were generated. Phenotype analysis of the clones showed that the majority of cells were CD4+ and expressed alpha/beta TCR. HLA-DP oligonucleotide genotyping of the clones revealed the presence of lymphoid chimerism. PLT assay showed the lack of HLA specificity, including mismatched HLA-DP. However, mAb to HLA antigens blocked proliferation of the majority of the clones, indicating that the clones recognized HLA-associated molecules. Interestingly, proliferation of two CD4+ T-cell clones was inhibited by class I mAb. A few of the clones revealed augmented proliferation in the presence of CMV antigens and a few revealed cytolytic activity. The above study suggests that (a) CD4+ helper T cells may be primarily responsible for immunopathogenesis of skin manifestations during acute GVHD, (b) there is a mixed lymphoid chimerism in skin during acute GVHD, (c) HLA-DP may not be a factor contributing to the development of acute GVHD, (d) the peptide of the HLA groove or superantigen associated with HLA molecules may be the stimulatory antigen, and (e) CMV antigens appear to stimulate some of the skin-infiltrating T lymphocytes.

Evidence of rickettsial spotted fever and ehrlichial infections in a subtropical territory of Jujuy, Argentina.

Between November 1993 and March 1994, a cluster 6 pediatric patients with acute febrile illnesses associated with rashes was identified in Jujuy Province, Argentina. Immunohistochemical staining of tissues confirmed spotted fever group rickettsial infection in a patient with fatal disease, and testing of serum of a patient convalescing from the illness by using an indirect immunofluorescence assay (IFA) demonstrated antibodies reactive with spotted fever group rickettsiae. A serosurvey was conducted among 16 households in proximity to the index case. Of 105 healthy subjects evaluated by IFA, 19 (18%) demonstrated antibodies reactive with rickettsiae or ehrlichiae: 4 had antibodies reactive with Rickettsia rickettsii, 15 with Ehrlichia chaffeensis, and 1 with R. typhi. Amblyomma cajennense, a known vector of R. rickettsii in South America, was collected from pets and horses in the area. These results are the first to document rickettsial spotted fever and ehrlichial infections in Argentina.

CD40 ligand-induced apoptosis is Fas-independent in human multiple myeloma cells.

We and others previously demonstrated that human multiple myeloma (MM) cells express CD40 and have an active CD40-growth regulatory pathway. This study characterizes the growth outcome of soluble (gp39) or membrane-bound recombinant human CD40-ligand (rCD40L) and its relationship with Fas-dependent apoptosis. Contrary to the moderate growth-stimulatory effect of the CD40-MAb G28.5, gp39 inhibited 3H-thymidine uptake of the plasma dyscrasia lines ARH-77, U266, and HS-Sultan in a dose-dependent fashion by up to 82%. By comparison, RPMI 8226 cells were resistant to CD40L-growth modulation, which may be attributable to a single base substitution (TCA-->TTA, serine-->leucine) at the 3rd cysteine-rich extramembrane region of CD40. Gp39 similarly reduced myeloma clonogenic colony (MCC) formation in patient primary bone marrow cultures by 50% (40-76%; n=6). Studies using transfectant L cells that constitutively expressed CD40L showed that membrane-bound CD40L inhibited the growth of ARH-77, U266, and HS-Sultan cells (66%, 63%, and 32%, respectively), whereas untransfected L cells did not. Growth inhibition by gp39 or CD40L+ L cells was neutralized by coincubation with the CD40L antibodies 5c8 or LL48. CD40L-treatment increased apoptotic activity of MM cells, as defined by oligonucleosomal DNA fragmentation and an increased binding to annexin V (16-28%). All three untreated CD40-responsive MM lines expressed the Fas/Apo-1/CD95 antigen (65-92% CD95+). However, only ARH-77 cells responded to the growth inhibitory effect of the CD95-agonistic antibody CH-11. CD95 expression was not affected significantly by gp39 treatment, and growth inhibition by CH-11 was additive to gp39 (from 42% to 64% decrease in 3H-thmidine uptake). Conversely, the CD95 antagonist antibody ZB4 reversed the Fas-dependent growth inhibitory process but did not significantly alter gp39-mediated growth outcome. Gp39 treatment lowered the expression of TNFR-associated factors TRAF4 and TRAF6 by 38% and 32%, respectively, whereas detectable levels of TRAF1,2,3, and 5 levels remained unchanged. Our observations indicate that the CD40L-binding inhibits human MM cell growth and increases its apoptotic activity. This growth inhibitory effect corresponds to lower levels of cytoplasmic TRAF signaling elements, and appears independent of the Fas-signaling pathway. CD40 receptor mutation may lead to unresponsiveness to CD40 growth modulation in multiple myeloma cells.

Low contents of nerve growth factor in serum and submaxillary gland of diabetic mice. A possible etiological element of diabetic neuropathy.

Insulin and nerve growth factor are peptides that share several chemical and functional properties. While the total or relative deficiency of insulin causes diabetes, the possible disorders due to deficiency of nerve growth factor have not been clearly defined. However, the intense biological actions of nerve growth factor in the maintenance and growth of several neural cells make feasible its participation in the physiopathology of some diseases of the peripheral nervous system. We measured the contents of nerve growth factor in serum, submaxillary gland and sciatic nerve of mice with streptozotocin-induced diabetes. Nerve growth factor in diabetic mice was diminished in serum and submaxillary gland when compared with matched controls (P < 0.01). This finding further supports a similar observation in diabetic patients and suggests a possible etiological involvement of neural growth factor in the development of diabetic neuropathy.

Cellular immune profile of patients with advanced cancer before and after taxane treatment.

The purpose of this study is to determine immune recovery and function after treatment with docetaxel or paclitaxel. Peripheral blood mononuclear cells were harvested before chemotherapy and at weekly times afterwards for cycle 1. Leukocyte subsets ICD45hiCD14lo polymorphonuclear neutrophils, CD45hiCD14hi monocytes, CD45hiCD14- lymphocytes, CD3+CD4/CD8+ T cells, CD3-CD19+ B cells, CD3-CD16/CD56+ natural killer (NK) cells], and circulating cytokine levels [tumor necrosis factor-alpha, gamma-interferon (gamma-IFN), and interleukins (IL-2, IL-10, IL-12)] were followed. In addition, T-cell mitogenic function, NK function, and lymphokine activated killer (LAK) function was assessed. Ten patients were entered in the trial. T-cell frequency, B-cell frequency, and CD4/CD8 ratio did not change. IL-10 serum levels significantly decreased in paclitaxel-treated patients (4.4+/-1.3 pg/ml at week 4 versus 7.8+/-2.1 pg/ml at baseline; p < 0.05). IL-2, IL-12, and gamma-IFN levels were not detectable. NK cytotoxic activity decreased in docetaxel-treated patients. LAK cell activity was not altered. Four patients achieved a partial or complete response. They demonstrated higher than normal CD4:CD8 T-cell ratios and an improved phytohemagglutinin stimulation index (SI = 2.5). In conclusion, our findings suggest that immune function was affected more significantly after docetaxel treatment. Investigational approaches, which enhance cellular immunity, may be of greater relevance after treatment with docetaxel. Additional studies monitoring NK function after chemotherapy are recommended.

Fatty acid profiles of the total lipids and lipid oxidation in pork muscles as affected by canola oil in the animal diet and muscle location.

Twelve pigs at about 35 days of age were fed a control diet or test diets containing either 10% or 20% canola oil (CO) for 100 days. Four different muscles were excised from each carcass at 24 h post-mortem for analyses. Inclusion of 10% and 20% CO in the animal diet increased (P < 0·05) the relative amount (weight per cent) of unsaturated fatty acids in the total lipids (lipids extracted by 2:1 chloroform-methanol) by 6·7 and 15·8 percentage points, respectively, from 57·8% for the control and also increased (P < 0·05) that of polyunsaturated fatty acids by 5·5 and 9·7 percentage points, respectively, from 19·4% for the control. The 20% CO treatment increased (P < 0·05) the relative amount of monounsaturated fatty acids (primarily C18:1) by 6·1 percentage points from 38·4% for the control, while the 10% CO treatment had no significant effect. The 10% or 20% CO treatment had no significant effect on microsomal enzymic lipid peroxidation activity, heme pigment content, nonheme iron content and total lipid concentration. Overall lipid oxidation in ground muscle samples stored at 4°C tended to be higher for the 10% and 20% CO treatment groups than for the control. The tendency of increased lipid oxidation by the CO treatments apparently resulted from the increased percentages of polyunsaturated fatty acids, rather than from changes in catalytic constituents.

Fatty acid profiles and lipid oxidation in beef steer muscles from different anatomical locations.

Beef muscles at four different anatomical locations (longissimus dorsi, LD; psoas major, PM; semimembranosus, SM; semitendinosus, ST) were excised 24 h post-mortem from each of 12 steer carcasses and analyzed for total lipids, fatty acid proofiles and lipid oxidation catalysts. Also, the accumulation of thiobarbituric acid (TBA)-reactive substances in ground muscles stored at 4°C was determined. Total lipids and fatty acid composition of total lipid extracts were similar among the muscles from different locations. The microsomal enzymic lipid peroxidation activity was higher for the ST than for other muscles whereas total heme pigment was lower for the ST than for others. The nonheme iron was higher for the PM and SM than for the LD and ST. The accumulation of TBA-reactive substances in stored, raw ground muscle was highest for the PM and lowest for the LD. TBA values of ground muscle samples were positively correlated with heme pigment content and microsomal enzymic lipid peroxidation activity while not correlated with nonheme iron content. It also was positively correlated with the percentage of polyunsaturated fatty acids.

Retinoic acid reduces chemotherapy-induced neuropathy in an animal model and patients with lung cancer.

OBJECTIVE: To evaluate the effect of all-trans retinoic acid (ATRA) as treatment for chemotherapy-induced peripheral neuropathy in an experimental animal model and in a randomized, double-blinded, controlled trial in patients with non-small-cell lung cancer (NSCLC). METHODS: Forty male Wistar rats were randomized in 5 groups: group A, control; groups B and C, treated with cisplatin; and groups D and E, treated with paclitaxel. ATRA (20 mg/kg PO) was administered for 15 days in groups C and E. We evaluated neuropathy and nerve regeneration-related morphologic changes in sciatic nerve, the concentration of nerve growth factor (NGF), and retinoic acid receptor (RAR)-α and RAR-ß expression. In addition, 95 patients with NSCLC under chemotherapy treatment were randomized to either ATRA (20 mg/m(2)/d) or placebo. Serum NGF, neurophysiologic tests, and clinical neurotoxicity were assessed. RESULTS: The experimental animals developed neuropathy and axonal degeneration, associated with decreased NGF levels in peripheral nerves. Treatment with ATRA reversed sensorial changes and nerve morphology; this was associated with increased NGF levels and RAR-ß expression. Patients treated with chemotherapy had clinical neuropathy and axonal loss assessed by neurophysiology, which was related to decreased NGF levels. ATRA reduced axonal degeneration demonstrated by nerve conduction velocity and clinical manifestations of neuropathy grades ≥2. CONCLUSIONS: ATRA reduced chemotherapy-induced experimental neuropathy, increased NGF levels, and induced RAR-ß expression in nerve. In patients, reduction of NGF in serum was associated with the severity of neuropathy; ATRA treatment reduced the electrophysiologic alterations. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that ATRA improves nerve conduction in patients with chemotherapy-induced peripheral neuropathy.

Retinoic acid increases tissue and plasma contents of nerve growth factor and prevents neuropathy in diabetic mice.

BACKGROUND: Decreased production of nerve growth factor (NGF) may contribute to diabetic neuropathy; however, exogenous administration of NGF induces only a modest benefit. Retinoic acid (RA) promotes the endogenous expression of nerve growth factor and its receptor. We studied the effects of RA on diabetic neuropathy in mice with streptozotocin-induced diabetes. MATERIAL AND METHODS: One hundred and twenty National Institutes of Health (NIH) albino mice randomly separated into three groups (A, n = 30; B, n = 30; C, n = 60). Diabetes mellitus was induced with streptozotocin in groups A and B. Animals from group A received a subcutaneous injection of 25 microl of mineral oil daily for 90 days, while those from group B received a subcutaneous injection of 20 mg kg(-1) of all trans RA. Animals from group C were taken as controls. At the end of the experiment, blood glucose and NGF levels (both in serum and sciatic nerve) were measured. Two behavioural tests were conducted in a blind fashion to detect abnormalities of thermal and nociceptive thresholds. RESULTS: Contents of NGF in healthy untreated mice were 1490 +/- 190 pg mg(-1) in nerve and 113 +/- 67 pg mg(-1) in serum; in diabetic untreated mice the values were 697 +/- 219 pg mL(-1) in nerve and 55 +/- 41 pg mL(-1) in serum; and in diabetic mice treated with RA the values were 2432 +/- 80 pg mL(-1) in nerve and 235 +/- 133 pg mg(-1) in serum (P < 0.002). Ultrastructural evidence of nerve regeneration and sensitivity tests improved in diabetic mice treated with RA as compared with nontreated diabetic mice. CONCLUSION: Our findings indicate that administration of RA increases serum and nerve contents of NGF in diabetic mice and suggest a potential therapeutic role for retinoic acid in diabetic patients.