RSSPlasma Adrenomedullin Concentration in Dogs with Myxomatous Mitral Valvular Disease.
Source
Laboratory of Veterinary Surgery, Department of Veterinary Medicine, College of Bioresource Sciences, Nihon University.
Abstract
Adrenomedullin (AM), a peptide identified to have vasodilating and natriuretic effects, is involved in the regulation of the cardiovascular system. To evaluate plasma AM concentration in dogs with myxomatous mitral valvular disease (MMVD), and to investigate the associations between the concentrations of plasma AM and natriuretic peptides and the echocardiographic data, we evaluated plasma AM concentrations in 31 healthy control dogs and 57 dogs with MMVD. Plasma AM concentrations in dogs with MMVD were higher than that in the control subjects. Plasma AM concentration increased in population to the severity of heart failure according to the International Small Animal Cardiac Health Council (ISACHC). AM concentrations were respectively 25.1 ± 5.0 fmol/ml (ISACHC class Ia), 29.9 ± 11.0 fmol/ml (ISACHC class Ib), 43.4 ± 19.8 fmol/ml (ISACHC class II) and 73.5 ± 21.7 fmol/ml (ISACHC class III) and 7.5 ± 5.1 fmol/ml (control group). The response-operating characteristics (ROC) curve indicated an area of 0.93 (95% CI, 0.8801-0.9889; < 0.0001), a cutoff value of 30.5 fmol/ml, a sensitivity of 87.1 %, and a specificity of 82.5 % for the determination of congestive heart failure. Plasma AM concentrations correlated with atrial natriuretic peptide concentrations, LA/Ao ratio, and left ventricular diameter. In conclusion, AM may be potential diagnostic marker for canine MMVD and possibly plays a pathophysiological role in collaboration with the other neurohumoral factors such as natriuretic peptides.
- PMID:
- 22240987
- [PubMed - as supplied by publisher]
Minimal essential length of Clostridium botulinum C3 peptides to enhance neuronal regenerative growth and connectivity in a non-enzymatic mode.
Source
Center for Anatomy, Functional Cell Biology, Charité-Universitätsmedizin Berlin, Germany Department of Morphology & BIOMED Institute, Hasselt University, Belgium Université Pierre et Marie Curie, Institut de la Vision, Paris, France) Institute of Toxicology, Hannover Medical School (MHH), Germany.
Abstract
C3 ADP-ribosyltransferase is a valuable tool to study Rho-dependent cellular processes. In the current study we investigated the impact of enzyme-deficient peptides derived from Clostridium botulinum C3 transferase in the context of neuronal process elongation and branching, synaptic connectivity, and putative beneficial effects on functional outcome following traumatic injury to the CNS. By screening a range of peptidic fragments we identified three short peptides from C3bot that promoted axon and dendrite outgrowth in cultivated hippocampal neurons. Furthermore, one of these fragments, a 26-amino acid peptide covering the residues 156-181 enhanced synaptic connectivity in primary hippocampal culture. This peptide was also effective to foster axon outgrowth and re-innervation in organotypical brain slice culture. To evaluate the potential of the 26mer to foster repair mechanisms after CNS injury we applied this peptide to mice subjected to spinal cord injury by either compression impact or hemisection. A single local administration at the site of the lesion improved locomotor recovery. In addition, histological analysis revealed an increased serotonergic input to lumbar motoneurons in treated compared to control mice. Pull-down assays showed that lesion-induced up-regulation of RhoA activity within the spinal cord was largely blocked by C3bot peptides despite the lack of enzymatic activity. © 2012 The Authors Journal of Neurochemistry© 2012 International Society for Neurochemistry.
© 2012 The Authors. Journal of Neurochemistry © 2012 International Society for Neurochemistry.
- PMID:
- 22239108
- [PubMed - as supplied by publisher]
Optimization of Peptide-Based ELISA for Serological Diagnostics: A Retrospective Study of Human Monkeypox Infection.
Source
1 Najít Technologies, Inc. , Portland, Oregon.
Abstract
Abstract Although smallpox has been eradicated, other diseases caused by virulent orthopoxviruses such as monkeypox virus (MPV) remain endemic in remote areas of western and central sub-Saharan Africa, and represent a potential biothreat due to international travel and/or inadvertent exposure. Unfortunately, extensive antigenic cross-reactivity among orthopoxviruses presents a challenge to serological diagnosis. We previously reported a 20mer peptide-based ELISA that identified recent MPV infection with >90% sensitivity and >90% specificity. However, the sensitivity of this approach was not determined with samples obtained at later time points after antibody titers had declined from their peak levels. To improve assay sensitivity for detecting MPV-specific antibodies at later time points, we compared diagnostic 20mer peptides to 30mer peptides. In addition, optimal 30mer peptides were tested in combination or after conjugating selected peptides to a carrier protein (bovine serum albumin) to further improve assay performance. An optimized combination of four unconjugated 30mer peptides provided 100% sensitivity for detecting MPV infection at 2-6 months post-infection, 45% sensitivity for detecting MPV infection at >2 years post-infection, and 99% specificity. However, an optimized combination of two peptide conjugates provided 100% sensitivity for detecting MPV infection at 2-6 months post-infection, 90% sensitivity for detecting MPV infection at >2 years post-infection, and 97% specificity. Peptide-based ELISA tests provide a relatively simple approach for serological detection of MPV infection. Moreover, the systematic approach used here to optimize diagnostic peptide reagents is applicable to developing improved diagnostics to a broad range of other viruses, and may be particularly useful for distinguishing between closely-related viruses within the same genus or family.
Fibrillar Amyloid-β1-42 Modifies Actin Organization Affecting the Cofilin Phosphorylation State: A Role for Rac1/cdc42 Effector Proteins and the Slingshot Phosphatase.
Source
Laboratory of Cellular and Molecular Neurosciences, University of Chile and International Center for Biomedicine (ICC), Santiago, Chile.
Abstract
The neuronal cytoskeleton regulates numerous processes that occur in normal homeostasis. Under pathological conditions such as those of Alzheimer's disease (AD), major alterations in cytoskeleton organization have been observed and changes in both microtubules and actin filaments have been reported. Many neurodegenerative consequences of AD are linked to the production and accumulation of amyloid peptides (Aβ) and their oligomers, produced from the internal cleavage of the amyloid-β protein precursor. We previously reported that fibrillar Aβ1-42 (fAβ) treatment of hippocampal neurons induced an increase in Rac1 and Cdc42 activities linking fAβ effects with changes in actin dynamics. Here we show fAβ-induces increased activity of PAK1 and cyclin-dependent kinase 5, and that p21-activated kinase (PAK1) activation targets the LIMK1-cofilin signaling pathway. Increased cofilin dephosphorylation under conditions of enhanced LIM-Kinase 1 (LIMK1) activity suggests that fAβ co-stimulates bifurcating pathways impacting cofilin phosphorylation. Overexpression of slingshot (SSH) prevents the augment of F-actin induced by fAβ after 24 h, suggesting that fAβ-induced changes in actin assembly involve both LIMK1 and SSH. These results suggest that fAb may alter the PAK1/LIMK1/cofilin axis and therefore actin organization in AD.
Urocontrin, a novel UT receptor ligand with a unique pharmacological profile.
Source
Laboratoire d'études moléculaires et pharmacologiques des peptides, Université du Québec, INRS - Institut Armand-Frappier, Ville de Laval, Québec, Canada; Laboratoire International Associé Samuel de Champlain (INSERM - INRS - Université de Rouen), Canada.
Abstract
In recent years, several studies have demonstrated that urotensin II (UII) and urotensin II-related peptide (URP) can exhibit differential biological activity. So far, known antagonists of the urotensin II receptor (UT) are of limited usefulness for investigating the specific pathophysiological role of UII or URP. Therefore, identification of new compounds able to discriminate UII- and URP-associated biological activities is crucially needed. In the present study, we report preliminary data regarding the pharmacological properties of a novel UT ligand termed urocontrin, i.e. [Bip(4)]URP, that is able to reduce the ex vivo efficacy of hUII- but not URP-induced vasoconstriction in rat aortic rings. In vivo studies support the pharmacological profile described above. Although urocontrin exert some residual agonist activity, this compound should be useful for the rational design of potent molecules that would allow discriminating specific biological action mediated by UII or URP.
Copyright © 2011 Elsevier Inc. All rights reserved.
Neurotherapeutics to inhibit exocytosis from sensory neurons for the control of chronic pain.
Source
International Centre for Neurotherapeutics, Dublin City University, Glasnevin, Dublin 9, Ireland.
Abstract
There is a pressing unmet need for long-acting and effective therapeutics to alleviate symptoms of the varied forms of chronic pain. As many sufferers do not respond satisfactorily to non-addictive anti-nociceptives, a new treatment has emerged using inhibitors for the release of pain mediators from peripheral sensory nerves to give prolonged benefit. This strategy relies on proteolytically inactivating intra-neuronal SNARE (soluble N-ethylmaleimide-sensitive-factor attachment protein receptors) proteins which are essential for regulated exocytosis of transmitters, peptides and other pain signalling molecules. Success has been achieved with botulinum neurotoxin A (BoNT/A) which targets neuronal acceptors via its heavy chain, becomes endocytosed and translocated into the cytosol where the long-lived protease of its light chain potently and specifically cleaves SNAP-25 (synaptosomal-associated protease of Mr=25k). Encouragingly, clinical trials have shown that local injections of BOTOX(®) (BoNT/A complex) reduce chronic migraine symptoms including frequency and intensity for many months. Several serotypes of the neurotoxin moiety alone have been prepared recombinantly using Escherichia coli, which exhibit optimal neuroparalysis. Moreover, an engineered chimera of BoNT/E in which its binding domain was replaced with that from /A efficaciously inhibits the TRPV1 (transient receptor potential vanilloid type 1)-triggered release of CGRP (calcitonin gene-related peptide) from cultured sensory neurons, and suppresses the resultant excitatory effects in brain slices. A longer acting composite toxin, containing the protease of type E attached to BoNT/A, displays prolonged amelioration of pain symptoms in an animal model of inflammatory pain. This provides proof of principle that therapeutically advantageous features of /E (most robust inhibitor of CGRP release) and /A (targeting to sensory neurons and dramatic extension of the longevity of E protease) can be incorporated into a single synergistically active anti-nociceptive.
Copyright © 2011 Elsevier Ltd. All rights reserved.
Conference report: the 19th international reid bioanalytical forum.
Source
Huntingdon Life Sciences, Woolley Road, Alconbury, Huntingdon, Cambridgeshire, PE16 5HS, UK. hillh@ukorg.huntingdon.com.
Abstract
The 19th International Reid Bioanalytical Forum was attended by over 120 participants. The Forum divided into approximately eight broad topics, although not always in the same session. The meeting commenced with a discussion on metabolites in safety testing, with emphasis on enabling technologies and philosophies. This was followed by a variety of regulatory-based issues initiated by Brian Booth of the US FDA. The next day started with a review of developing technologies in LC-MS and some anecdotal troubleshooting experiences. Interspersed among the sessions were experiences with bioanalysis in the discovery environment, biomarker-based topics and the rapidly developing field of the quantitation of proteins and peptides using LC-MS. The meeting finished with the best-attended session of the Forum on developing trends in using dried blood spots.
The SH2-domain of SHIP1 interacts with the SHIP1 C-terminus: Impact on SHIP1/Ig-α interaction.
Source
RWTH Aachen University, Medical Faculty, Department of Biochemistry and Molecular Immunology, Institute of Biochemistry and Molecular Biology, 52074 Aachen, Germany; International Max Planck Research School, 79108 Freiburg, Germany.
Abstract
The SH2-containing inositol 5'-phosphatase, SHIP1, negatively regulates signal transduction from the B cell antigen receptor (BCR). The mode of coupling between SHIP1 and the BCR has not been elucidated so far. In comparison to wild-type cells, B cells expressing a mutant IgD- or IgM-BCR containing a C-terminally truncated Ig-α respond to pervanadate stimulation with markedly reduced tyrosine phosphorylation of SHIP1 and augmented activation of protein kinase B. This indicates that SHIP1 is capable of interacting with the C-terminus of Ig-α. Employing a system of fluorescence resonance energy transfer in S2 cells, we can clearly demonstrate interaction between the SH2-domain of SHIP1 and Ig-α. Furthermore, a fluorescently labeled SH2-domain of SHIP1 translocates to the plasma membrane in an Ig-α-dependent manner. Interestingly, whereas the SHIP1 SH2-domain can be pulled-down with phospho-peptidescorresponding to the immunoreceptor tyrosine-based activation motif (ITAM) of Ig-α from detergent lysates, no interaction between full-length SHIP1 and the phosphorylated Ig-α ITAM can be observed. Further studies show that the SH2-domain of SHIP1 can bind to the C-terminus of the SHIP1 molecule, most probably by inter- as well as intra-molecular means, and that this interaction regulates the association between different forms of SHIP1 and Ig-α.
Copyright © 2011 Elsevier B.V. All rights reserved.
In Vivo Expression of Salmonella enterica Serotype Typhi Genes in the Blood of Patients with Typhoid Fever in Bangladesh.
Source
International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B), Dhaka, Bangladesh.
Abstract
BACKGROUND:
Salmonella enterica serotype Typhi is the cause of typhoid fever. It is a human-restricted pathogen, and few data exist on S. Typhi gene expression in humans.
METHODOLOGY/PRINCIPAL FINDINGS:
We applied an RNA capture and amplification technique, Selective Capture of Transcribed Sequences (SCOTS), and microarray hybridization to identify S. Typhi transcripts expressed in the blood of five humans infected with S. Typhi in Bangladesh. In total, we detected the expression of mRNAs for 2,046 S. Typhi genes (44% of the S. Typhi genome) in human blood; expression of 912 genes was detected in all 5 patients, and expression of 1,100 genes was detected in 4 or more patients. Identified transcripts were associated with the virulence-associated PhoP regulon, Salmonella pathogenicity islands, the use of alternative carbon and energy sources, synthesis and transport of iron, thiamine, and biotin, and resistance to antimicrobial peptides and oxidative stress. The most highly represented group were genes currently annotated as encoding proteins designated as hypothetical, unknown, or unclassified. Of the 2,046 detected transcripts, 1,320 (29% of the S. Typhi genome) had significantly different levels of detection in human blood compared to in vitro cultures; detection of 141 transcripts was significantly different in all 5 patients, and detection of 331 transcripts varied in at least 4 patients. These mRNAs encode proteins of unknown function, those involved in energy metabolism, transport and binding, cell envelope, cellular processes, and pathogenesis. We confirmed increased expression of a subset of identified mRNAs by quantitative-PCR.
CONCLUSIONS/SIGNIFICANCE:
We report the first characterization of bacterial transcriptional profiles in the blood of patients with typhoid fever. S. Typhi is an important global pathogen whose restricted host range has greatly inhibited laboratory studies. Our results suggest that S. Typhi uses a largely uncharacterized genetic repertoire to survive within cells and utilize alternate energy sources during infection.
BACE1 Trafficking and Alzheimer's Disease Pathogenesis.
Source
Department of Pathology, and Mental Health Research Institute, The University of Melbourne, Parkville VIC 3010, Australia.
Abstract
BACE1 cleaves the amyloid precursor protein (APP) at the β-secretase site to initiate the production of Aβ peptides. These accumulate to form toxic oligomers and the amyloid plaques associated with Alzheimer's disease (AD). An increase of BACE1 levels in the brain of AD patients has been mostly attributed to alterations of its intracellular trafficking. Golgi-associated adaptor proteins, GGA sort BACE1 for export to the endosomal compartment, which is its major cellular site of BACE1 activity. BACE1 undergoes recycling between endosome, trans-Golgi network (TGN), and the plasma membrane, from where it is endocytosed and either further recycled or retrieved to the endosome. Phosphorylation of Ser498 facilitates BACE1 recognition by GGA1 for retrieval to the endosome. Ubiquitination of BACE1 C-terminal Lys501 signals GGA3 for exporting BACE1 to the lysosome for degradation. In addition, the retromer mediates the retrograde transport of BACE1 from endosome to TGN. Decreased levels of GGA proteins and increased levels of retromer-associated sortilin have been associated with AD. Both would promote the co-localization of BACE1 and APP in the TGN and endosomes. Decreased levels of GGA3 also impair BACE1 degradation. Further understanding of BACE1 trafficking and its regulation may offer new therapeutic approaches for the treatment of Alzheimer's disease. © 2011 The Authors Journal of Neurochemistry© 2011 International Society for Neurochemistry.
© 2011 The Authors Journal of Neurochemistry © 2011 International Society for Neurochemistry.
Early cardiac abnormalities and serum N-terminal pro B-type natriuretic peptide levels in obese children.
Source
Department of Pediatrics, Karaelmas University, Zonguldak, Turkey.
Abstract
OBJECTIVE:
The aim of this study was to evaluate early cardiac abnormalities in obese children by the conventional echocardiography and to verify whether N-terminal pro B-type natriuretic peptide (NT-proBNP) differ between obese and healthy children.
METHODS:
We started this study with 68 obese children and 35 healthy controls matched for age and sex. Body mass index (BMI) was calculated. Children with a BMI > or = 95th percentile were considered obese. Thirty children in the obese group were also diagnosed with metabolic syndrome, according to the International Diabetes Federation criteria. Standard echocardiographic study was performed on each patient and control subject. Diastolic filling parameters were evaluated using pulsed-wave tissue Doppler method. Blood samples were taken at 8 a.m. to study blood biochemistry tests, including insulin, lipids, glucose, and NT-proBNP. Serum NT-proBNP levels were measured by a solid-phase, enzyme-labeled chemiluminescent immunometric assay. Homeostasis model assessment of insulin resistance (HOMA-IR) was calculated. Children with HOMA-IR > 3.16 were considered insulin-resistant.
RESULTS:
There were diastolic filling abnormalities in obese children, as shown by a decreased mitral valve early filling (E) wave/late filling (A) ratio and a prolongation in E-wave deceleration time. The levels of NT-proBNP were not statistically different among the groups. The levels of NT-proBNP were not different between obese children with and without metabolic syndrome, those with and without hypertension, and those with and without insulin resistance, respectively.
CONCLUSION:
Although there were diastolic filling abnormalities in obese children, their NT-proBNP levels were not different from healthy controls. It seems that there is no diagnostic value in NT-proBNP levels between obese children and healthy controls.
- PMID:
- 22145463
- [PubMed - indexed for MEDLINE]
The 10th International Symposium on VIP-PACAP and Related PeptidesDecember 13-16, 2011 Eilat, Israel.
Proteogenomic Analysis of Candida glabrata using High Resolution Mass Spectrometry.
Source
Institute of Bioinformatics , International Technology Park, Bangalore -560 066, India.
Abstract
Candida glabrata is a common opportunistic human pathogen leading to significant mortality in immunosuppressed and immunodeficient individuals. We carried out proteomic analysis of C. glabrata using high resolution Fourier transform mass spectrometry with MS resolution of 60000 and MS/MS resolution of 7500. On the basis of 32453 unique peptidesidentified from 118815 peptide-spectrum matches, we validated 4421 of the 5283 predicted protein-coding genes (83%) in the C. glabrata genome. Further, searching the tandem mass spectra against a six frame translated genome database of C. glabrata resulted in identification of 11 novel protein coding genes and correction of gene boundaries for 14 predicted gene models. A subset of novel protein-coding genes and corrected gene models were validated at the transcript level by RT-PCR and sequencing. Our study illustrates how proteogenomic analysis enabled by high resolution mass spectrometry can enrich genome annotation and should be an integral part of ongoing genome sequencing and annotation efforts.
Chemical biology of homocysteine thiolactone and related metabolites.
Source
Department of Microbiology and Molecular Genetics, UMDNJ-New Jersey Medical School, International Center for Public Health, Newark, New Jersey, USA. jakubows@umdnj.edu
Abstract
Protein-related homocysteine (Hcy) metabolism produces Hcy-thiolactone, N-Hcy-protein, and N epsilon-homocysteinyl-lysine (N epsilon-Hcy-Lys). Hcy-thiolactone is generated in an error-editing reaction in protein biosynthesis when Hcy is erroneously selected in place of methionine by methionyl-tRNA synthetase. Hcy-thiolactone, an intramolecular thioester, is chemically reactive and forms isopeptide bonds with protein lysine residues in a process called N-homocysteinylation, which impairs or alters the protein's biological function. The resulting protein damage is exacerbated by a thiyl radical-mediated oxidation. N-Hcy-proteins undergo structural changes leading to aggregation and amyloid formation. These structural changes generate proteins, which are toxic and which induce an autoimmune response. Proteolytic degradation of N-Hcy-proteins generates N epsilon-Hcy-Lys. Levels of Hcy-thiolactone, N-Hcy-protein, and N epsilon-Hcy-Lys increase under pathological conditions in humans and mice and have been linked to cardiovascular and brain disorders. This chapter reviews fundamental biological chemistry of Hcy-thiolactone, N-Hcy-protein, and N epsilon-Hcy-Lys and discusses their clinical significance.
- PMID:
- 22126025
- [PubMed - indexed for MEDLINE]
In vitro antibacterial and antimalarial activity of dehydrophenylalanine-containing undecapeptides alone and in combination with drugs.
Source
International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India.
Abstract
A set of three cationic undecapeptides, analogous to the previously reported peptide VS2 (KWΔFWKΔFVKΔFVK), was created by alanine substitution in order to probe the effect of hydrophobicity on peptide activity. The activities of thesepeptides were determined against Escherichia coli, Staphylococcus aureus and the malaria parasite Plasmodium falciparum. VA1, the closest analogue of VS2, showed five-fold augmented activity [minimum inhibitory concentration (MIC)=10μM] against the Gram-positive bacterium S. aureus. The designed analogues were non-haemolytic and non-cytotoxic at their MICs and clinically relevant concentrations. By alanine substitution, it was also possible to probe the critical role of tryptophan residues in determining peptide potency. Circular dichroism studies of the peptides in a membrane-mimetic system showed a correlation between peptide helicity and antimicrobial activity. The peptides were also tested in combination with sublethal concentrations of antibiotic drugs (rifampicin and kanamycin) and the antimalarial drug chloroquine. In combination with these drugs, the effect of the peptides was synergistic or additive. These results provide insight into basic design principles for generating new clinically relevant lead peptides. It also provides an alternative strategy where a peptide and a non-peptide drug can be used in combination to battle increasingly drug-resistant microbes.
Copyright © 2011 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.
A three-hybrid system to probe in vivo protein-protein interactions: application to the essential proteins of the RD1 complex of M. tuberculosis.
Source
Recombinant Gene Products Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, India.
Abstract
BACKGROUND:
Protein-protein interactions play a crucial role in enabling a pathogen to survive within a host. In many cases the interactions involve a complex of proteins rather than just two given proteins. This is especially true for pathogens like M. tuberculosis that are able to successfully survive the inhospitable environment of the macrophage. Studying such interactions in detail may help in developing small molecules that either disrupt or augment the interactions. Here, we describe the development of an E. coli based bacterial three-hybrid system that can be used effectively to study ternary protein complexes.
METHODOLOGY/PRINCIPAL FINDINGS:
The protein-protein interactions involved in M. tuberculosis pathogenesis have been used as a model for the validation of the three-hybrid system. Using the M. tuberculosis RD1 encoded proteins CFP10, ESAT6 and Rv3871 for our proof-of-concept studies, we show that the interaction between the proteins CFP10 and Rv3871 is strengthened and stabilized in the presence of ESAT6, the known heterodimeric partner of CFP10. Isolating peptide candidates that can disrupt crucial protein-protein interactions is another application that the system offers. We demonstrate this by using CFP10 protein as a disruptor of a previously established interaction between ESAT6 and a small peptide HCL1; at the same time we also show that CFP10 is not able to disrupt the strong interaction between ESAT6 and another peptide SL3.
CONCLUSIONS/SIGNIFICANCE:
The validation of the three-hybrid system paves the way for finding new peptides that are stronger binders of ESAT6 compared even to its natural partner CFP10. Additionally, we believe that the system offers an opportunity to study tri-protein complexes and also perform a screening of protein/peptide binders to known interacting proteins so as to elucidate novel tri-protein complexes.
Dendritic SNAREs add a new twist to the old neuron theory.
Source
International Centre for Neurotherapeutics, Dublin City University, Glasnevin, Dublin 9, Ireland.
Abstract
Dendritic exocytosis underpins a broad range of integrative and homeostatic synaptic functions. Emerging data highlight the essential role of SNAREs in trafficking and fusion of secretory organelles with release of peptides and neurotransmitters from dendrites. This Perspective analyzes recent evidence inferring axo-dendritic polarization of vesicular release machinery and pinpoints progress made with existing challenges in this rapidly progressing field of dendritic research. Interpreting the relation of new molecular data to physiological results on secretion from dendrites would greatly advance our understanding of this facet of neuronal mechanisms.
New ways of insulin delivery.
Source
Düsseldorf, Germany. lutz.heinemann@profilinstitut.com
Abstract
The predominant number of papers published from the middle of 2009 to the middle of 2010 about alternative routes of insulin administration (ARIA) were still about inhaled insulin. Long-term experience with Exubera was the topic of a number of publications that are also of relevance for inhaled insulin in general. The clinical trials performed with AIR insulin by Eli Lilly were published in a supplement issue of one diabetes technology journal and most of these will be presented. A number of other publications (also one in a high ranked journal) about their inhaled insulin were from another company: MannKind. The driving force behind Technosphere insulin (TI) - which is the only one still in clinical development - is Al Mann; he has put a lot of his personal fortune in this development. We will know the opinion of the regulatory authorities about TI in the near future; however, I am personally relatively confident that the Food and Drug Administration will provide TI with market approval. The more critical question for me is: will diabetologists and patients jump on this product once it becomes commercially available? Will it become a commercial success? In view of many negative feelings in the scientific community about inhaled insulin, it might be of help that MannKind publish their studies with TI systematically. Acknowledging being a believer in this route of insulin administration myself, one has to state that Exubera and AIR insulin had not offered profound advantages in terms of pharmacokinetic (PK) and pharmacodynamic (PD) properties in comparison with subcutaneously (SC) applied regular human insulin (RHI) and rapid-acting insulin analogues. The time-action profiles of these inhaled insulins were more or less comparable with that of rapid-acting insulin analogues. This is clearly different with TI which exhibits a strong metabolic effect shortly after application and a rapid decline in the metabolic effect thereafter; probably the duration of action is even too short (see postprandial glycaemic excursions with test meals in the publication by Rosenstock et al. in The Lancet (1)). In the end a number of aspects are of relevance for the success of a given product; one key aspect is clearly the price. However, for patients also practical aspects (handling, need for regular pulmonary function test etc.) are of importance. We shall have to see how creatively MannKind will handle all such questions. Until now Al Mann and his colleagues were able to manage a number of challenges during the clinical development process successfully, so one can have hopes for the market success of TI. However, it is clear that at the same time, if TI fails like Exubera did before, this will be the end for pulmonary insulin in general. Not too many original publications presenting data from clinical trials were published in the last year when it comes to oral insulin (OI), nasal insulin or transdermal insulin developments; simply none with transdermal insulin. Also at the last international congresses not many studies about ARIA were presented. At least in part this might be still a reflection of the shockwaves that the failure of Exubera has sent out to pharmaceutical companies and venture capitalists; they are quite reluctant to invest in any of these developments. However, a considerable number of reviews (in some cases more than original papers!) were published about ARIA. These reviews are listed for completeness, but in most cases are not further commented. OI is still the area of research most companies are active in; however, in some cases it is not clear how active they really are (e.g. Diabetology). Nevertheless, at least some companies are quite active and progressed in their clinical development programme close to market approval, e.g. the large Indian company Biocon is in late phase 3 with IN-105 and the small Israel-based company Oramed is in phase 2b. It appears that other interesting OI developments (e.g. Diasome) were not very active in the last year; at least they have not published new study results. It is clear that for companies that produce insulin themselves (e.g. Biocon) the costs of the good are not of such relevance as for companies that have to buy it commercially. For the latter ones a low bioavailability/biopotency compared with SC insulin administration can be a real hurdle when it comes to the price of their product. Despite some publications about nasal insulin, the overall activity with this route of insulin administration appears to be low; the same holds true for transdermal insulin. Insulin pens have gained more scientific interest in recent years, which is also reflected by an increase in publications, starting from practically nil 10 years ago to a solid number of five to 10 papers per year nowadays. Besides ARIA there are also attempts to increase the speed of insulin absorption after injection into the skin by applying it not into the SC tissue but intradermally or by heating up the skin above the SC insulin depot. Reading a number of papers that were not included in this chapter because they do not present any clinical data but are novel developments tested only in animal experiments so far, the clear message is that there is definitely not a lack of creativity/imagination amongst scientists; each year a plethora of new ideas for insulin application show up. Unfortunately not too many make it towards a full clinical development. As long as there is not a single successful product on the market that is based on a given ARIA approach, this area of research will not mature. For many patients, avoiding the need for SC injections is attractive; however, as long as no clear 'advantage' can be demonstrated, reimbursement will be difficult to achieve. Living in the time of evidence-based medicine it is clear that 'relevant' clinical advantages must be proven. The question is what is relevant. Is it just an improvement in metabolic control (= decrease in HbA1c)? Can this also mean that more patients are willing to start insulin therapy earlier than with conventional SC insulin therapy? With TI we have a product that has improved pharmacological properties (also in comparison to Exubera) for coverage of prandial insulin requirements. Subsequently, in the clinical trials performed, postprandial glycaemic excursions were lower than with SC injection of RHI or rapid-acting insulin analogues. This only in part (if at all) results in an improved metabolic control in general (= lower HbA1c) (see below). The outlook for 2011 is that there are chances that we shall have an inhaled insulin product on the market. Probably also the first OI will be submitted to the regulatory authorities for market approval or will even be available in less regulated markets. In order to select all relevant publications about new ways of insulin delivery I performed a PUBMED search and also checked the table of contents of a number of journals that publish heavily in this area of research as well references in the publications I found for additional references. Selection of the manuscripts from all publications was predominately based on the fact whether they presented data from clinical studies or not. The selected studies were critically reviewed for novelty and appropriate study design etc. In some cases also reviews about a given topic were selected if they provide relevant novel insights.
© 2011 Blackwell Publishing Ltd.
- PMID:
- 21323811
- [PubMed - indexed for MEDLINE]
New insulins and insulin therapy.
Source
Diabetes-Zentrum für Kinder and Jugendliche, Kinderkrankenhaus auf der Bult, Hannover, Germany. danne@hka.de
Abstract
The introduction of the so-called 'designer' insulins, the insulin analogues, has offered new opportunities in the clinical management of diabetes. Two additional new entities are close to reaching clinical practice. Linjeta™ (formally called VIAject) is not an analogue but rather a different formulation of human insulin which may give it a more rapid onset of action, potentially even faster than the currently available rapid-acting insulin analogues. Degludec™, on the other hand, is an insulin analogue molecule with an ultra-long clinical profile derived from the soluble multi-hexamer formation, resulting in a continuous slow and stable release of insulin degludec monomers which may last longer than currently available long-acting analogues. As with any new type of drug, the safety of the 'designer' insulins has to be closely scrutinised. Last year the increased cancer risk in diabetes entered the spotlight and the potential role of insulin analogues led to controversial discussions. In spite of recent new in vitro and observational data no new conclusive evidence became available. The need for multiple well-conducted and appropriately designed prospective observational studies to follow up the effectiveness and safety of the new insulins and the new insulin treatment regimens remains. In this chapter it was our mission to chose articles published about "new insulins" over the last year that have the most important contribution for the on-going development of ultra-fast- and ultra-long-acting insulin analogs and preparations and their potential side-effects, particularly cancer. This has been done by means of PubMed searches as well as a review of abstracts of the recent large international diabetes meetings such as ADA, EASD and ISPAD.
© 2011 Blackwell Publishing Ltd.
- PMID:
- 21323810
- [PubMed - indexed for MEDLINE]
A heme peroxidase of the ascomyceteous lichen Leptogium saturninum oxidizes high-redox potential substrates.
Source
Unit of Environmental Biotechnology, International Graduate School of Zittau, Markt 23, 02763 Zittau, Germany. liers@ihi-zittau.de
Abstract
Lichens belonging to the order Peltigerales display strong activity of multi-copper oxidases (e.g. tyrosinase) as well as heme-containing peroxidases. The lichen peroxidase was purified to homogeneity from the thallus of Leptogium saturninum (LsaPOX) by fast protein liquid chromatography and then partially characterized. The oligomeric protein occurs as both 79 kDa dimeric and 42 kDa monomeric forms, and displayed broad substrate specificity. In addition to an ability to oxidize classic peroxidase substrates (e.g. 2,6-dimethoxyphenol), the enzyme could convert recalcitrant compounds such as synthetic dyes (e.g. Azure B and Reactive Blue 5), 4-nitrophenol and non-phenolic methoxylated aromatics (e.g. veratryl alcohol). Comparing LsaPOX with a basidiomycete dye-decolorizing (DyP)-type peroxidase from Auricularia auricula-judae showed that the lichen enzyme has a high-redox potential, with oxidation capabilities ranging between those of known plant and fungal peroxidases. Internal peptide fragments show homology (up to 60%) with putative proteins from free-living ascomycetes (e.g. Penicillium marneffei and Neosartorya fischeri), but not to sequences of algal or cyanobacterial peptides or to known fungal, bacterial or plant peroxidases. LsaPOX is the first heme peroxidase purified from an ascomyceteous lichen that may help the organism to successfully exploit the extreme micro-environments in which they often grow.
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