Vito Trinchieri

Acetyl-carnitine deficiency in Aids patients with neurotoxicity on treatment with antiretroviral nucleoside analogues

Objective:A severe dose-limiting axonal peripheral neuropathy may develop in subjects on treatment with the nucleoside analogues didanosine (ddI), zalcitabine (ddC), and stavudine (d4T). The impairment of mitrochondrial DNA synthesis is crucial to the pathogenesis of this disorder although other mechanisms have not been ruled out. The depletion of acetyl-carnitine, which regulates the metabolism and function of peripheral nerves, could contribute to the neurotoxicity of these compounds. Design:Non-randomized, cross-sectional study of selected patients. Methods:We measured the serum levels of acetyl- and total carnitine in 12 subjects with axonal peripheral neuropathy developed on treatment with different regimens of neurotoxic nucleoside analogues (ddI, ddC, d4T). Subjects who did not develop peripheral neuropathy while staying on treatment with ddI (n = 10) or zidovudine (n = 11) served as the control groups. HIV-negative subjects with axonal or demyelinating autoimmune neuropathies (n = 10) and healthy individuals (n = 13) were additional control groups. Results:Subjects experiencing axonal peripheral neuropathy on treatment with ddI, ddC and d4T had significantly reduced levels of acetyl-carnitine in comparison to the control groups. No difference was observed in the levels of total carnitine between study subjects and the control groups. Conclusions:Our results demonstrate that subjects who developed peripheral neuropathy while staying on treatment with ddI, ddC and d4T had acetyl-carnitine deficiency. The normal levels of total carnitine in the study group appear to indicate the specificity of the defect and rule out coexisting relevant nutritional problems. The critical role of acetyl-carnitine for the metabolism and function of the peripheral nerves supports the view that the acetyl-carnitine deficiency found in these subjects may contribute to the neurotoxicity of ddI, ddC and d4T, even though the interference with mitochondrial DNA synthesis is regarded as the main cause of their toxicity.

L-Carnitine Reduces Lymphocyte Apoptosis and Oxidant Stress in HIV-1-Infected Subjects Treated with Zidovudine and Didanosine

Apoptosis is critical to the progression of human immunodeficiency virus-1 (HIV-1) infection. It appears reasonable that antiretroviral therapies may not achieve a full control of the infection in the absence of an impact on apoptosis. We assigned 20 asymptomatic HIV-infected subjects with advanced immunodeficiency to receive either zidovudine (AZT), and didanosine (DDI) or the same regimen plus L-carnitine, a known antiapoptotic drug, for 7 months. Immunologic and virologic parameters were measured at baseline and after 15, 60, 120, and 210 days of treatment. We assessed on each time point the following: (a) the frequency of peripheral blood apoptotic CD4 and CD8 lymphocytes, CD4 and CD8 cells with disrupted mitochondrial membrane potential, and CD4 and CD8 cells undergoing oxidant stress; (b) the expression of the molecular markers of apoptosis Fas and caspase-1; and (c) the expression of p35/cdk-5 regulatory subunit that is involved in regulating cell survival and apoptosis. Absolute CD4 and CD8 counts and plasma viremia were also measured. Apoptotic CD4 and CD8 cells, lymphocytes with disrupted mitochondrial membrane potential, and lymphocytes undergoing oxidant stress were greatly reduced in subjects treated with AZT and DDI plus L-carnitine compared with those who did not receive L-carnitine. Fas and caspase-1 were down-expressed and p35 over-expressed in lymphocytes from patients of the L-carnitine group. No difference was found in CD4 and CD8 counts and viremia between the groups. No toxicity of L-carnitine was recognized. The addition of L-carnitine is safe and allows apoptosis and oxidant stress to be greatly reduced in lymphocytes from subjects treated with AZT and DDI.

Probiotic lactobacilli: A new perspective for the treatment of inflammatory bowel disease

Inflammatory bowel disease, such as ulcerative colitis and Crohns disease, results from an interaction between susceptibility genes, the hosts bacterial environment, gut barrier defects, and immunological factors. New management approaches have been evolved from advances in our understanding of the pathobiology of this common gut disorder In particular, the therapeutic manipulation of the bacterial microenvironment in the gut seems to offer an innovative tool for the treatment of those patients. Since the gut is a highly sensitizing organ that contributes to the systemic immune response, potent treatments need to be developed to reduce gut inflammation in this disorder. Recent studies have demonstrated that probiotic lactobacilli, and also immunostimulatory DNA sequences from those same bacteria have an important anti-inflammatory potential in this context. Future research should better define among patients with inflammatory bowel disease the various clinical phenotypes with the greatest potential of response to probiotic treatment. Identification of the genes leading to the disease and a rather better understanding of the underlying immunoregulatory abnormalities will be crucial steps to define the different profiles of interaction between endogenous digestive bacterial flora and the immune system in each individual patient. Such advances will probably lead to targeting of effective treatments, including bacteriotherapy with probiotic lactobacilli, to subsets of patients with inflammatory bowel disease.

Efficacy and Safety of a Multistrain Probiotic Formulation Depends from Manufacturing

Background Variability in probiotics manufacturing may affect their properties, with potential implications for their efficacy and safety. This is of particular concern with probiotic products destined for use in patients with serious medical conditions, including human immunodeficiency virus (HIV) infection. The purpose of the study was to carry out a series of experiments comparing the properties of the US-made probiotic formulation originally commercialized under the brand name VSL#3®, with those of the Italian-made formulation now commercialized under the same name. The US-made formulation has previously shown beneficial effects at the intestinal and neurological levels in HIV-infected subjects as well as in patients with inflammatory bowel diseases and hepatic encephalopathy. Methods Eleven subjects receiving combined antiretroviral therapy for HIV-1 were treated for 6 months with the US-made VSL#3 formulation. At baseline and 6 months, T-cells were analyzed for phenotype and activation markers, and fecal samples were analyzed for bifidobacteria, lactobacilli, and their metabolites. The fecal metabolome was assessed using 1H-NMR spectroscopy. Production of metabolites of interest by bacteria obtained from sachets of the two formulations was compared in vitro and their effects on a rat intestinal epithelial cell line (IEC-6) were assessed. Particular attention was paid to the metabolite 1,3-dihydroxyacetone (DHA). Results At 6 months, fecal samples showed a significant increase in the specific bacterial genera contained in the probiotic supplement. Immune activation was reduced as shown by a significant reduction in the percentage of CD4+CD38+HLA-DR+ T-cells at 6 months. Fecal concentrations of DHA decreased significantly. In vitro, significant differences in the production and metabolism of DHA were found between bacteria from the US-made and Italian-made formulations: the US-made formulation was able to metabolize DHA whereas the bacteria in the Italian-made formulation were producing DHA. DHA reduced the viability of Streptococcus thermophilus, reduced IEC-6 cell viability in a dose-dependent manner, and also led to a lower rate of repair to scratched IEC-6 cell monolayer. Conclusion Our data, in conjunction with previously published findings, confirm that the new Italian-made formulation of VSL#3® is different from the previous US-made VSL#3 and therefore its efficacy and safety in HIV-infected subjects is still unproven.

Fecal bacteriotherapy or probiotics for the treatment of intestinal diseases

TO THE EDITOR: Persky and Brandt (1) suggest that modulating the colonic ecosystem with nonpathogenic bacteria introduced into the bowel microenvironment with fecal bacteriotherapy may restore the balance of harmless organisms, which is a requirement for permanent eradication of Clostridium difficile. The study is very interesting, but in our opinion, it generates hypotheses rather than proving them. We have several implicit and explicit problems to discuss, despite the excellent clinical results reported in the article. One important aspect is that we do not know exactly the quantitative and qualitative composition of the endogenous digestive microflora. More than 100 different bacterial species have been identified in fecal specimens from normal individuals, but it is thought that at least 400–500 species are present in the digestive microflora (2). Furthermore, there are relevant differences among individuals, even though one of the most important features of the intestinal ecosystem is its stability over time (2). This means that each individual subject carries a unique microflora, being the intestinal colonization by bacteria affected by the net sum of such a wide spectrum of factors as age, diet, environment, immunity, and exposure to drugs and antibiotics. In other words, feces from an individual are grossly different from those from other individuals, and this implicates an extreme heterogeneity in terms of bacterial species and their concentrations but also of enzymes, bacteriocins, and other antibioticlike substances in the composition of the enemas. The logical consequence is that microbial composition and functional activities of the fecal enemas prepared from different individuals cannot be standardized, and this will hold true even in terms of clinical efficacy, as not all fecal preparations should be expected to have comparable immune and biological effects. We may reasonably expect to find that enemas from subject A will have great activity againstC. difficile colonization, whereas enemas from subject B or C will prove completely ineffective. This is disappointing, and one may suspect that fecal bacteriotherapy, as designed by Persky and Brandt, will fail in a substantial proportion of a statistically significant sample of patients. Previous studies have indeed shown a marginal effectiveness of fecal bacteriotherapy for the treatment of C. difficile colitis, and only very small samples of patients have been investigated so far (3–6). Furthermore, no data are reported in the study by Persky and Brandt on the bacterial composition of the fecal enema they used. Also, the potential for transmitting other pathogenic organisms to the recipient cannot be minimized, and this risk should not be regarded as negligible at all. It is clear that promoting the use of bacteriotherapy on this background will inevitably raise substantial concern among gastroenterologists and their patients. The conclusions in the article by Persky and Brandt and in the accompanying editorial by Borody (7) are flawed and may be misleading, as no published evidence convincingly demonstrates that fecal bacteriotherapy is better than probiotics for the treatment of intestinal diseases, including C. difficile colitis (8). The preliminary experience with high potency probiotics for the treatment of ulcerative colitis suggests an alternative and perhaps more rational approach to the problem of bacteriotherapy for intestinal diseases. Recent studies have shown that treatment with a composite mixture of a large number of probiotic lactobacilli strains could change the quantitative and qualitative composition of the gut microflora, and this was paralleled by the remission of the inflammatory activity of the disease as measured by clinical and immunological parameters (9–13). The great advantage of using such a consortium of probiotic bacteria rather than the fecal enemas proposed by Persky and Brandt is that we may dissect the metabolic, functional, enzymatic, and immunomodulating properties of the organisms we administer. If probiotic bacteria work, we may understand exactly why hey work. First principles and clinical experience tell us that this requirement does matter when investing money and effort in the design of controlled studies with the aim of establishing the ultimate role of bacteriotherapy and probiotics in the treatment of intestinal diseases.

L-carnitine: a partner between immune response and lipid metabolism ?

The authors demonstrated that in vivo administered L-carnitine strongly ameliorated the immune response in both healthy individuals receiving Intralipid and ageing subjects with cardiovascular diseases, as shown by the enhancement of mixed lymphocyte reaction. Notably, in the latter group L-carnitine treatment also resulted in a significant reduction of serum levels of both cholesterol and triglycerides. Therefore, the hypothesis is that L-carnitine supplementation could ameliorate both the dysregulated immune response and the abnormal lipid metabolism in several conditions.

L-Carnitine, a Modulator of Immunometabolic Homeostasis in Subjects Infected with the Human Immunodeficiency Virus

The inexorable decline in the numbers of CD4 T lymphocytes, which have A a central role in the immune response to pathogens, and their association with the loss of cell-mediated immunity are major hallmarks of advancing acquired immunodeficiency syndrome (AIDS).