Pain assessment in chronic pancreatitis: A comparative review of methods.

BACKGROUND: Patients with chronic pancreatitis (CP) frequently report chronic abdominal pain that adversely impacts their quality of life. Assessment of pain in CP is required for clinical management and clinical studies. International consensus guidelines recognized a lack of specific and validated pain assessment tools for CP. Therefore, the aim of this systematic review is to identify and compare all clinical studies that assessed pain in the context of a treatment for pain in CP. METHODS: A systematic literature search was performed in PubMed, Cochrane Library and Ovid MEDLINE. The search identified all intervention studies for pain in CP and the pain assessment tools used based on pre-defined inclusion and exclusion criteria. RESULTS: Of 341 articles identified, 137 studies were included. Pain assessment tools were both general and CP-specific. The latter were used in only 22 (16%) studies. Despite recommendations the aspects of pain assessed were limited and variable between tools. Validation of these tools in CP patients was limited to quality of life measures. None of the pain assessment tools evaluated duration of pain and postprandial pain. CONCLUSIONS: There are no published pain assessment tools for CP that includes all relevant aspects of pain. There is the need to develop a comprehensive and validated pain assessment tool for patients with CP to standardised pain assessment, identify likely underlying pain mechanisms, help select appropriate treatments, report outcomes from interventions, improve clinical communication and aid the allocation of patients to clinical trials.

PhRMA survey of pharmacogenomic and pharmacodynamic evaluations: what next?

Interindividual variation in pharmacodynamic (PD) response to drugs is an ongoing area of research for drugs in clinical development, pre- and postapproval. To characterize how pharmacogenomic (PG ) variations can serves a predictor of differences in PD outcomes, the pharmaceutical industry has incorporated PG /PD analysis into clinical drug development. The Pharmaceutical Research and Manufacturers of America (PhRMA ) and the Industry Pharmacogenomics Working Group (I-PWG) conducted a survey of 16 pharmaceutical companies to ascertain to what extent PG/PD research is being incorporated into drug development. The survey results showed that, while the industry has made some attempt to incorporate PG/PD studies into drug development, application has been inconsistent. Nevertheless, several valid PG/PD markers have since emerged in drug labels. The I-PWG considers PG/PD research an important approach to improving success rates in drug development. This article reports the results of the survey and proposes steps toward increasing the use of PG/PD research by the industry.

Inactivation of the mouse melanocortin-3 receptor results in increased fat mass and reduced lean body mass.

Genetic and pharmacological studies have defined a role for the melanocortin-4 receptor (Mc4r) in the regulation of energy homeostasis. The physiological function of Mc3r, a melanocortin receptor expressed at high levels in the hypothalamus, has remained unknown. We evaluated the potential role of Mc3r in energy homeostasis by studying Mc3r-deficient (Mc3r(-/-)) mice and compared the functions of Mc3r and Mc4r in mice deficient for both genes. The 4-6-month Mc3r-/- mice have increased fat mass, reduced lean mass and higher feed efficiency than wild-type littermates, despite being hypophagic and maintaining normal metabolic rates. (Feed efficiency is the ratio of weight gain to food intake.) Consistent with increased fat mass, Mc3r(-/-) mice are hyperleptinaemic and male Mc3r(-/-) mice develop mild hyperinsulinaemia. Mc3r(-/-) mice did not have significantly altered corticosterone or total thyroxine (T4) levels. Mice lacking both Mc3r and Mc4r become significantly heavier than Mc4r(-/-) mice. We conclude that Mc3r and Mc4r serve non-redundant roles in the regulation of energy homeostasis.

Role of the melanocortin-4 receptor in metabolic rate and food intake in mice.

We evaluated the role of the melanocortin-4 receptor (MC-4R) in the control of metabolic rate and food intake in mice. Intraperitoneal administration of the non-selective MC-R agonist melanotan II (MT-II; a cyclic heptapeptide) increases metabolic rate in wildtype mice, while MC-4R knockout mice are insensitive to the effects of MT-II on metabolic rate. MC-4R knockout mice are also insensitive to the effects of MT-II on reducing food intake. We conclude that MC-4R can mediate control of both metabolic rate and food intake in mice. We infer that a role for MC-3R in mediating the acute effects of MT-II on basal metabolic rate and food intake in wildtype mice seems limited.

Mouse mammary tumor virus-Ki-rasB transgenic mice develop mammary carcinomas that can be growth-inhibited by a farnesyl:protein transferase inhibitor.

For Ras oncoproteins to transform mammalian cells, they must be posttranslationally modified with a farnesyl group in a reaction catalyzed by the enzyme farnesyl:protein transferase (FPTase). Inhibitors of FPTase have therefore been developed as potential anticancer agents. These compounds reverse many of the malignant phenotypes of Ras-transformed cells in culture and inhibit the growth of tumor xenografts in nude mice. Furthermore, the FPTase inhibitor (FTI) L-744,832 causes tumor regression in mouse mammary tumor virus (MMTV)-v-Ha-ras transgenic mice and tumor stasis in MMTV-N-ras mice. Although these data support the further development of FTIs, it should be noted that Ki-ras is the ras gene most frequently mutated in human cancers. Moreover, Ki-RasB binds more tightly to FPTase than either Ha- or N-Ras, and thus higher concentrations of FTIs that are competitive with the protein substrate may be required to inhibit Ki-Ras processing. Given the unique biochemical and biological features of Ki-RasB, it is important to evaluate the efficacy of FTIs or any other modulator of oncogenic Ras function in model systems expressing this Ras oncoprotein. We have developed strains of transgenic mice carrying the human Ki-rasB cDNA with an activating mutation (G12V) under the control of the MMTV enhancer/promoter. The predominant pathological feature that develops in these mice is the stochastic appearance of mammary adenocarcinomas. High levels of the Ki-rasB transgene RNA are detected in these tumors. Treatment of MMTV-Ki-rasB mice with L-744,832 caused inhibition of tumor growth in the absence of systemic toxicity. Although FPTase activity was inhibited in tumors from the treated mice, unprocessed Ki-RasB was not detected. These results demonstrate the utility of the MMTV-Ki-rasB transgenic mice for testing potential anticancer agents. Additionally, the data suggest that although the FTI L-744,832 can inhibit tumor growth in this model, Ki-Ras may not be the sole mediator of the biological effects of the FTI.

Abnormal gene expression of cardiac fibroblasts in experimental aortic regurgitation.

Extensive primary fibrosis precedes heart failure and death in experimental chronic aortic regurgitation. To seek the molecular basis for this observation, this study analyzed the RNA pool for genes that are up-or downregulated in aortic regurgitation fibroblasts. Differential display reverse transcriptase polymerase chain reaction was used to compare RNA extracted from cardiac fibroblasts isolated from three healthy New Zealand white rabbits and from three with aortic regurgitation. Using two base anchoring oligo d(T) primers (T11VN) together with arbitrary upstream primers, numerous differences in normal versus aortic regurgitation gene expression were apparent on differential display reverse transcriptase polymerase chain reaction. The aortic regurgitation cell cultures showed numerous differentially up-and downregulated genes compared with cell cultures of normal cardiac fibroblasts. The results showed that pathologic fibrosis in chronic experimental aortic regurgitation is associated with abnormal cardiac fibroblast gene expression, which may be pathogenic for the fibrous lesion.

Activation of Proalpha2(I) collagen promoter during hepatic fibrogenesis in transgenic mice.

We previously identified the promoter sequence that is essential for basal and TGF-beta-stimulated transcription of alpha2(I) collagen gene (COL1A2). In the present study, we examined whether the promoter is activated during hepatic fibrogenesis by utilizing transgenic mice harboring the COL1A2 upstream sequence. Intraperitoneal CCl4 administration activated the -17 kb COL1A2 promoter more than 10-fold, whereas partial hepatectomy resulted in no significant change in the promoter activity. The non-parenchymal cell fraction, but not parenchymal hepatocytes, isolated from mice harboring the -313 COL1A2 promoter linked to a beta-galactosidase reporter gene contained large amounts of beta-galactosidase and endogenous COL1A2 mRNAs. beta-galactosidase activity in the cells from CCl4-treated mice was significantly higher than in those from untreated animals. These results indicated that different molecular mechanisms control COL1A2 transcription in CCl4-induced liver injury/fibrosis and physiological regeneration after partial hepatectomy, and that the -313 COL1A2 promoter is activated in a cell type-specific manner during hepatic fibrogenesis.

Calcification of elastic fibers in pseudoxanthoma elasticum.

Pseudoxanthoma elasticum is an inherited disorder of connective tissue that is characterized by calcification of elastic fibers with associated abnormalities of the skin, ocular, and cardiovascular systems. The genetic defect causing pseudoxanthoma elasticum has not been determined and the diagnosis relies on clinical recognition of skin lesions and histologic demonstration of calcification of elastic fibers that are clumped and fragmented in the dermis. The role of connective tissue components in the etiology of pseudoxanthoma elasticum is reviewed and includes changes in collagen, elastin, glycosaminoglycans, fibronectin, microfibrillar proteins, modifying enzymes of extracellular matrix proteins, fibroblasts, and fibrillins.

Regulation of the alpha 2(I) collagen gene transcription in fat-storing cells derived from a cirrhotic liver.

Fat-storing cells (FSC) are the main producers of type I collagen in both normal and fibrotic livers. In order to elucidate the molecular mechanisms controlling collagen expression in FSC, we examined the transcription of the alpha 2(I) collagen gene (COL1A2) in two distinct FSC clones, CFSC-2G and CFSC-5H, derived from a single CCl4-induced cirrhotic liver. The phenotype of CFSC-2G resembles freshly isolated FSC, whereas that of CFSC-5H mimics activated myofibroblasts. Cell transfection experiments showed that the upstream sequence between nucleotides -378 and -183 is essential for COL1A2 transcription in both FSC clones. This is the same promoter region that is transcriptionally active and contains the binding site of a multimeric protein complex that mediates TGF-beta stimulation of COL1A2 expression in dermal fibroblasts. We therefore examined the relative levels of endogenous and transfected COL1A2 transcription and their response to TGF-beta treatment in the two FSC clones. The results showed that CFSC-5H expresses a significantly higher level of the COL1A2 mRNA than CFSC-2G. They also showed that TGF-beta treatment increases both endogenous and transfected COL1A2 transcription in CFSC-2G but not in CFSC-5H. Interestingly, nuclear proteins from both FSC clones bind to the TGF-beta-responsive element more strongly than those from dermal fibroblasts. Altogether, the data suggest that collagen production in CFSC-5H cells has been already activated by the autocrine stimulation of TGF-beta. In contrast, CFSC-2G cells are only partially activated but can be easily recruited to produce collagen when stimulated by exogenous TGF-beta.(ABSTRACT TRUNCATED AT 250 WORDS)

Overlapping pathways mediate the opposing actions of tumor necrosis factor-alpha and transforming growth factor-beta on alpha 2(I) collagen gene transcription.

Transforming growth factor-beta (TGF-beta) and tumor necrosis factor-alpha (TNF-alpha) are multifunctional peptides intimately involved in the process of extracellular matrix remodeling. We recently showed that TGF-beta stimulates the human alpha 2(I) collagen gene by increasing the affinity of an Sp1-containing transcriptional complex bound to an upstream sequence termed the TbRE (Inagaki, Y., Truter, S. and Ramirez, F. (1994) J. Biol. Chem. 269, 14828-14834). Here, we report that the TbRE-bound complex also mediates the inhibitory signal of TNF-alpha. Nuclear proteins from cells treated with TNF-alpha bind to the TbRE sequence substantially more strongly than those from untreated cells. Additionally, TNF-alpha increases binding of a second protein complex that recognizes the negatively cis-acting element located immediately next to the TbRE. Thus, we postulate that TNF-alpha counteracts the TGF-beta-elicited stimulation of collagen gene expression through overlapping nuclear signaling pathways. One modifies the TGF-beta-targeted transcriptional complex, probably by reducing its stimulatory effect on collagen transcription. The other acts on the binding of the adjacent factor, presumably by increasing its effectiveness in repressing the activity of the collagen promoter. The convergence of the TGF-beta and TNF-alpha pathways on the same sequence of the alpha 2(I) collagen promoter is yet another example of combinatorial gene regulation achieved through composite response elements.

Structural and functional analysis of the promoter of the human alpha 1(XI) collagen gene.

In order to eventually elucidate the mechanisms regulating alpha 1(XI) collagen expression in cartilaginous and non-cartilaginous tissues, we performed an initial analysis of the structural-functional features of the promoter of the human gene (COL11A1). After cloning and sequencing the 5' portion of COL11A1, primer extension and nuclease protection assays identified several minor transcriptional start sites clustered around a major one located 318 base pairs from the ATG codon. Consistent with this finding, analysis of the upstream sequence revealed the absence of a TATA motif and the presence of several GC boxes. Transient transfection experiments delineated the smallest promoter sequence directing relatively high expression of a reporter gene in a cell type-specific manner. Nine nuclear protein-bound areas were located within this promoter sequence of the COL11A1 gene. Sequence homologies suggested that the majority of the footprints correspond to potential binding sites for ubiquitous nuclear proteins, such as AP2 and Sp1. Additional experimental evidence indicated that one of the protected areas may bind a transcriptional complex that is identical or closely related to the one that regulates tissue specificity in the coordinately expressed alpha 2(V) collagen gene.

Transforming growth factor-beta stimulates alpha 2(I) collagen gene expression through a cis-acting element that contains an Sp1-binding site.

Transforming growth factor-beta 1 (TGF-beta) is a strong and rapid inducer of several genes coding for extracellular matrix components, such as type I collagen. We report here that TGF-beta stimulates transcription of the human alpha 2(I) collagen gene (COL1A2) promoter by increasing the affinity of an Sp1-containing protein complex for its cognate DNA-binding site. Cell transfection experiments mapped the TGF-beta-responsive element (TbRE) of the COL1A2 promoter to a 131 bp region that contains at least two cis-acting elements. Insertion of the TbRE upstream of the thymidine kinase promoter conferred TGF-beta inducibility to the otherwise unresponsive thymidine kinase promoter. Footprinting assays revealed that the TbRE contains two neighboring protein-bound sequences, termed Box 3A and Box B. Within Box 3A is an Sp1 recognition sequence whose structural integrity is required for nuclear protein binding in vitro, and for promoter inducibility in vivo. Gel mobility shift assays documented increased binding to the TbRE of nuclear proteins from TGF-beta-treated cells compared with those from TGF-beta-untreated fibroblasts. There was, however, no binding increase with Box 3A alone or with an Sp1 oligonucleotide. Thus, the results strongly suggest a functional interaction between Sp1 and other components of the TbRE complex in mediating TGF-beta stimulation of COL1A2 gene expression.

Protected regions in the chicken alpha 2(1) procollagen promoter in differentiated tissues.

The higher ordered structure of the chicken alpha 2(1) procollagen gene was analyzed in chromatin isolated from expressing (lung) and nonexpressing (reticulocyte and erythrocyte) tissues. Digestion of DNA with methylation sensitive restriction endonucleases revealed that this gene was methylated in all tissues examined and that no differences existed in the promoter methylation patterns between expressing and nonexpressing tissues. DNAse 1 hypersensitive sites were located between 100-300 bp upstream from the transcription initiation site and within the first intron. These sites were also hypersensitive to the single-strand specific S1 nuclease, implying that this region of the gene in the chromatin is either in an unfolded single-stranded conformation or under severe conformational stress. These differences in the alpha 2(1) chromatin structure were confirmed by the finding that the promoter was more accessible to restriction endonuclease digestion in the expressing tissues than in the nonexpressing tissues. Digestion of chromatin with Pst I and Sma I revealed that some of these sites in the promoter were differentially protected by DNA-binding proteins in the two tissue types. These protected sites were located as far upstream as -1,600 and downstream within the first intron at +800.

Pro-alpha 2(V) collagen gene; pairwise analysis of the amino-propeptide coding domain, and cross-species comparison of the promoter sequence.

Type V collagen is a minor represented and poorly characterized fibrillar collagen type. Previous cDNA cloning experiments showed that the amino-propeptide of the pro-alpha 2(V) chain shares structural features in common with pro-alpha 1(I), pro alpha 1(II) and pro-alpha 1(III) collagens. In the present paper, this analysis was extended to the gene level. Accordingly the exon/intron arrangement of the amino-propeptide coding domain was compared among pro-alpha 1(I) (COL1A1), pro alpha 1(II) (COL2A1), pro-alpha 1(III) (CO13A1) and pro-alpha 2(V) (COL5A2) collagen genes. This revealed that COL3A1 is the most closely related gene to COL5A2. Based on the assumption that critical regulatory elements might be phylogenetically conserved, we also compared the promoter sequences of the mouse and human COL5A2 genes. This revealed the highest level of sequence homology (97%) in a 52-bp segment which was previously shown to be essential in conferring cell type specificity to the human promoter.

Identification of an upstream regulatory region essential for cell type-specific transcription of the pro-alpha 2(V) collagen gene (COL5A2).

The transcriptional features of the human alpha 2(V) collagen gene (COL5A2) were examined by transfection experiments coupled to various DNA binding assays. This approach identified an upstream region essential for the cell type-specific expression of the COL5A2 promoter. Within this region are two nuclear factor-binding sites, FP-A and FP-B, responsible for the formation of distinct DNA-protein complexes. Mutations introduced across each of the two binding sites eliminated the formation of the cognate complex and decreased promoter activity by about 3-fold (FP-A) and 40-fold (FP-B) in transfection experiments. Competition experiments using recognition sequences for known transcription factors exhibiting some similarity to the FP-A- and FP-B-binding sites failed to inhibit COL5A2/protein interactions. Thus, COL5A2 expression appears to be under the positive control of a short regulatory sequence likely to harbor two novel nuclear factor-binding sites.