Biomedical subjects

K Hellstrand

Publications and source records attributed to K Hellstrand.

At least 19 recordsLinked to original sources

PubMed2007

Impact of hepatic steatosis on viral kinetics and treatment outcome during antiviral treatment of chronic HCV infection.

Liver steatosis is highly prevalent in chronic hepatitis C virus (HCV) infection, especially in patients infected with genotype 3 virus, but its significance for the outcome of antiviral treatment is not fully understood. We have monitored steatosis in liver biopsies from 231 patients with chronic HCV infection who received pegylated recombinant interferon-alpha and ribavirin in a phase III study (DITTO trial). The degree of steatosis, along with relevant metabolic parameters, was correlated with the early disappearance of virus and with the final outcome of treatment. Our data suggest that the presence of steatosis impairs the early reduction of viral load during treatment in patients infected with HCV genotype 3 and non-3. Steatosis negatively affected the final outcome of treatment mainly in patients infected with HCV genotype non-3 virus. Based on these findings, we propose that interventions aiming at reducing hepatic steatosis prior to the onset of antiviral therapy may be of benefit to patients infected with HCV of the non-3 genotypes. Patients infected with genotype 3, on the other hand, should be offered early antiviral treatment.

Adult↗

PubMed2003

Histamine inhibits neutrophil NADPH oxidase activity triggered by the lipoxin A4 receptor-specific peptide agonist Trp-Lys-Tyr-Met-Val-Met.

The vasoactive amine histamine is found at high concentrations in the immune and inflammatory tissues. Earlier studies have revealed that histamine regulates the nicotinamide-adenine dinucleotide phosphate (NADPH) oxidase-dependent formation of oxygen radicals by phagocytic cells. However, the effects of histamine on intracellular signal transduction mechanisms of relevance to oxidase regulation remain controversial. For this study, we investigated the effects of histamine on NADPH oxidase activity in human neutrophil granulocytes triggered by a lipoxin A4 receptor agonist [the hexapeptide Trp-Lys-Tyr-Met-Val-Met (WKYMVM), a formyl peptide receptor (FPR) agonist (the chemotactic tripeptide formylmethionyl-leucyl-phenylalanine (fMLF)) and an activator of protein kinase C (phorbol myristate acetate (PMA)]. We report that histamine, acting via H2-type histamine receptors (H2R), suppresses NADPH oxidase-dependent formation of oxygen radicals induced by WKYMVM and fMLF but not that induced by PMA. Peptide-induced mobilization of granule-localized complement receptor 3 (CR3) was unaffected by histamine suggesting that the inhibition specifically affected NADPH oxidase activation. Our data suggest that histamine downregulates FPRL1- and FPR-induced NADPH oxidase activity upstream of protein kinase C (PKC) and downstream of the separation of the peptide-induced signal into granule secretion and oxidase activation.

Chemotactic Factors↗

PubMed2002

A multicentre, randomized study to evaluate the safety and efficacy of histamine dihydrochloride and interferon-alpha-2b for the treatment of chronic hepatitis C.

Interferon- (IFN-)alpha is currently the standard of care treatment for patients with chronic hepatitis C virus (HCV) infection. A significant part of the benefit of IFN-alpha in chronic hepatitis C is believed to be related to the activation of lymphocytes such as T cells and natural killer (NK) cells, which participate in the elimination of infected cells. Histamine dihydrochloride (HDC) has been shown to potentiate the IFN-alpha-induced activation of T cells and NK cells by a mechanism that involves the protection of these lymphocytes against oxygen radical-induced functional inhibition and apoptosis. This study was designed to examine the efficacy and safety of HDC in combination with IFN-alpha-2b in treatment-naïve patients with chronic HCV infection. All patients received IFN-alpha-2b, 3 MIU, three times weekly via subcutaneous injection, and were randomized to one of four HDC regimens (1 mg of either: once a day, three times a week; once a day, five times a week; twice a day, three times a week or; twice a day, five times a week). The doses of HDC in combination with IFN-alpha-2b resulted in sustained viral response rates ranging from 31% to 38%. Sustained biochemical response rates ranged from 28% to 41% across the four treatment groups. Patients infected with HCV genotype 1, and those with high baseline viral levels, which are characteristics associated with poor prognosis, had sustained virologic response rates ranging from 18% to 42% and 15% to 39%, respectively. Combination treatment was generally well tolerated. We propose that the potential benefit of HDC + IFN therapy for chronic HCV infection should be the focus of further investigation.

Adult↗

PubMed2002

Outpatient treatment with subcutaneous histamine dihydrochloride in combination with interleukin-2 and interferon-alpha in patients with metastatic renal cell carcinoma: results of an open single-armed multicentre phase II study.

OBJECTIVES: Histamine inhibits formation and release of monocyte/macrophage-derived reactive oxygen metabolites and thereby protects natural killer (NK) and T cells against oxidative inhibition. Efficacy and safety of histamine, when given in combination with interleukin-2 (IL-2) and interferon-alpha (IFN-alpha), were evaluated in patients with metastatic renal cell carcinoma (mRCC). PATIENTS AND METHODS: Forty-eight mRCC patients were included. The self-administered, outpatient regimen included IFN-alpha, 3 MIU s.c., once daily for 1 week, followed by up to nine 4 week cycles of IFN-alpha, 3 MIU s.c., days 1-7, weeks 1-4; interleukin-2, 2.4 MIU/m2 s.c., b.i.d., days 1-5, weeks 1 and 2; and histamine dihydrochloride, 1 mg s.c., b.i.d. days 1-5, weeks 1-4. RESULTS: Forty-six patients were eligible. Forty-two patients were evaluable for response with four partial responses (9% of eligible patients, 10% of evaluable patients). Fifteen patients (36%) had stable disease. After subsequent surgery of residual tumours, three patients (7%) had no evidence of disease at 14+, 21+ and 21+ months. Median survival time for all patients was 16.3 months. One grade 4 toxicity (thrombocytopenia) was observed. Most frequent grade 3 toxicities were fatigue/malaise (26%), dyspnoe (11%), nausea (9%) and stomatitis (9%). Four patients discontinued due to treatment-related toxicity. There were no treatment-related deaths. CONCLUSIONS: The present combination of histamine with IL-2 and IFN-alpha. as self-administered outpatient therapy is a safe and well-tolerated regimen. However, histamine does not appear to add efficacy with respect to response in this low-dose schedule of IL-2 and IFN-alpha. Whether histamine might improve efficacy with higher doses of IL-2 and IFN-alpha requires further investigation.

Adult↗

PubMed2001

A proinflammatory peptide from Helicobacter pylori activates monocytes to induce lymphocyte dysfunction and apoptosis.

Infection with Helicobacter pylori causes chronic gastritis, which is characterized by a dense mucosal infiltration by inflammatory cells such as monocytes/macrophages. H. pylori-induced inflammation is a risk factor for the development of gastric adenocarcinoma, but the mechanisms involved in H. pylori-associated carcinogenesis are poorly understood. A cecropin-like H. pylori peptide, Hp(2-20), was found to be a monocyte chemoattractant and activated the monocyte NADPH-oxidase to produce oxygen radicals. The receptors mediating monocyte activation were identified as FPRL1 and the monocyte-specific orphan receptor FPRL2. Hp(2-20)-activated monocytes inhibited lymphocytes with antitumor properties, such as CD56+ natural killer (NK) cells and CD3epsilon+ T cells. The changes observed in NK cells and T cells--a reduced antitumor cytotoxicity, downregulation of CD3zeta expression, and apoptosis--were mediated by Hp(2-20)-induced oxygen radicals. Histamine, a gastric mucosal constituent, rescued NK cells and T cells from inhibition and apoptosis by suppressing Hp(2-20)-induced oxygen radical formation. We conclude that H. pylori expression of this monocyte-activating peptide contributes to its ability to attract and activate monocytes and reduces the function and viability of antineoplastic lymphocytes. These novel mechanisms may be subject to local, histaminergic regulation in the gastric mucosa.

Adenocarcinoma↗

PubMed2001

Serotonin protects NK cells against oxidatively induced functional inhibition and apoptosis.

High concentrations of the neurotransmitter serotonin can be found in inflamed and ischemic peripheral tissues, but the role of serotonin in immunoregulation is largely unknown. Here we report that serotonin protected human natural-killer (NK) cells from oxidatively induced inhibition inflicted by autologous monocytes in vitro. Serotonin protected NK cells from monocyte-mediated apoptosis and suppression of cytotoxicity and maintained the activation of NK cells induced by interleukin-2 despite the presence of inhibitory monocytes. A detailed analysis of these protective effects revealed that serotonin scavenged reactive oxygen species (ROS) derived from the H(2)O(2)-myeloperoxidase (-MPO) system. Serotonin shared this scavenger activity with its precursor, 5-hydroxytryptophan (5-HTP); however, serotonin was >10-fold more potent than 5-HTP in protecting NK cells against functional inhibition and apoptosis. We propose that serotonin, by scavenging peroxidase-derived ROS, may serve to protect NK cells from oxidative damage at inflammatory sites.

5-Hydroxytryptophan↗

PubMed2000

Natural killer cell dysfunction and apoptosis induced by chronic myelogenous leukemia cells: role of reactive oxygen species and regulation by histamine.

Natural killer (NK) cells are deficient in patients with chronic myelogenous leukemia (CML), but the mechanisms responsible for the dysfunction are not completely understood. This study reports that CML cells effectively inhibit the baseline and interleukin-2 (IL-2)-induced NK cell cytotoxicity against a CML cell-derived line (K562). A sizable fraction of NK cells subsequently acquired features characteristic of programmed cell death/apoptosis. The CML cell-mediated inhibition of NK cells required triggering of reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-mediated formation of reactive oxygen species (ROS) and was prevented by catalase, a scavenger of ROS, and by histamine, acting via H(2)-receptor-mediated inhibition of ROS production in CML cells. In contrast, nonmalignant neutrophilic granulocytes inhibited NK cells via ROS production without the requirement of exogenous NADPH oxidase-triggering stimuli. We propose that paracrine production of ROS may contribute to the dysfunction of NK cells in CML and that histamine may serve as an autocrine inhibitor of ROS formation in leukemic granulocytes. (Blood. 2000;96:1961-1968)

Apoptosis↗

PubMed2000

Enhancement of natural immunity seen after voluntary exercise in rats. Role of central opioid receptors.

Chronic voluntary exercise in wheels for 5 weeks in spontaneously hypertensive rats (SHR) augments in vivo natural killer (NK) cell cytotoxicity. Endogenous beta-endorphin is increased in cerebrospinal fluid after voluntary exercise in rats and we have recently shown that beta-endorphin administered i.c.v. augments NK cell mediated cytotoxicity in vivo in a similar way as chronic voluntary exercise. We have now further investigated the involvement of central opioid systems in the exercise-induced augmentation in natural immunity. Exercise consisted of voluntary running in wheels for 5 weeks. In vivo cytotoxicity was measured as clearance of injected 51Cr-labeled YAC-1 lymphoma cells from the lungs. The clearance of YAC-1 cells in vivo was significantly increased in runners as compared to sedentary controls. Selective delta, kappa, or mu-opioid receptor antagonists were administered i.c.v. with osmotic minipumps during the last 6 days of the 5 weeks of running. The delta-receptor antagonist naltrindole (40-50 microg/day) significantly but not completely inhibited the enhanced NK-cell cytotoxicity seen after 5 weeks of exercise. Neither the kappa-receptor antagonist nor-BNI or the mu-receptor antagonist beta-FNA influenced the augmentation in NK cell cytotoxicity. Nor-BNI per se significantly augments in vivo cytotoxicity, indicating some inhibiting effect on natural immunity that could be mediated through the kappa-opioid receptor. Our data suggest the involvement of central delta-opioid receptors in the enhancement of natural cytotoxicity seen after chronic voluntary exercise.

Animals↗

PubMed2000

Adjuvant histamine in cancer immunotherapy.

Interleukin-2 (IL-2) is an effective activator of lymphocytes with anti-neoplastic properties such as T-cells or natural killer cells, and this property of IL-2 has formed the basis for its widespread used as an immunotherapeutic agent in human neoplastic disease. In recent years, IL-2 therapy for solid neoplastic diseases and hematopoietic cancers has been supplemented with histamine dihydrochloride with the aim of counteracting immunosuppressive signals from monocytes/macrophages. Here we review the preclinical basis for the use of histamine as an adjunct to IL-2 in cancer immunotherapy.

Animals↗

PubMed2000

Alleviating oxidative stress in cancer immunotherapy: a role for histamine?

Interleukin-2 is a remarkable activator of lymphocytes with anti-neoplastic properties such as T-cells or natural killer cells, but tumor regression only rarely occurs in interleukin-2-treated cancer patients. In this review, we focus on interactions between monocytes/macrophages and T-cells/natural killer-cells, and in particular the role of such interactions for the outcome of cancer immunotherapy with interleukin-2. We propose that interleukin-2 therapy should be supplemented with compounds that alleviate toxicity inflicted by monocyte/macrophage-derived reactive oxygen metabolites within and around tumors. The hypothesis is founded on data demonstrating that (i) functions of intratumoral lymphocytes in many human malignant tumors are inhibited by reactive oxygen metabolites, generated by neighboring monocytes/macrophages, (ii) interleukin-2 only weakly activates T-cells or natural killer cells in an environment of oxidative stress, and (iii) inhibitors of the formation of reactive oxygen metabolites or scavengers of reactive oxygen metabolites synergize with interleukin-2 to activate these lymphocyte subsets. We also review the preclinical background to the use of histamine dihydrochloride, an inhibitor of reactive oxygen metabolite formation in monocytes/macrophages, as a supplement to cancer immunotherapy with interleukin-2.

Cell Communication↗

PubMed2000

Histamine: a novel approach to cancer immunotherapy.

The functions of intratumoral lymphocytes in many human malignant tumors are inhibited by reactive oxygen species (ROS), generated by adjacent monocytes/macrophages (MO). In vitro data suggest that immunotherapeutic cytokines such as interleukin-2 (IL-2) or interferon-alpha (IFN-alpha) only weakly activate T cells or natural killer (NK) cells in a reconstituted environment of oxidative stress and that inhibitors of the formation of ROS or scavengers of ROS synergize with IL-2 and IFN-alpha to activate T cells and NK cells. In this review, we focus on the immunoenhancing properties of histamine, a biogenic amine. Histamine inhibits ROS formation in MO via H2-receptors; thereby, histamine protects NK cells from MO-mediated inhibition and synergizes with IL-2 and IFN-alpha to induce killing of NK cell-sensitive human tumor cells in vitro. Histamine also optimizes cytokine-induced activation of several subsets of T cells by affording protection against MO-inflicted oxidative inhibition. The putative clinical benefit of histamine as an adjunct to immunotherapy with IL-2 and/or IFN-alpha is currently evaluated in clinical trials in metastatic malignant melanoma and acute myelogenous leukemia.

Drug Therapy, Combination↗

PubMed1999

Validation of the internal reference technique for microdialysis measurements of interstitial histamine in the rat.

The internal reference technique (IRT) was compared with the no net flux method (NFM) as a microdialysis calibration technique for sampling of interstitial histamine in the rat. Microdialysis catheters (polyacrylonitrile, 50 kD cut off) were inserted in liver, muscle, subcutaneous tissue and in an induced adenocarcinoma. Estimated relative recovery with IRT ranged from 23+/-2% in liver to 30+/-3% in subcutaneous tissue with and without tumor (p<0.05). By using the NFM-technique we found similar recovery as compared to the IRT in all tissues studied. Interstitial histamine was up to 3-fold higher than the mean plasma histamine concentration (54+/-2 nmol/l). Subcutaneous tissue (177+/-39 nmol/l) and subcutaneous tumor (165+/-29 nmol/l) exhibited high histamine while liver (65+/-14 nmol/l) and liver tumor (75+/-7 nmol/l) had low interstitial histamine concentrations. In conclusion, the IRT was validated against the NFM as a rapid method for histamine measurements in situ in the rat.

Adipose Tissue↗

PubMed1999

Histamine protects T cells and natural killer cells against oxidative stress.

Oxidative stress inflicted by monocytes/macrophages (MO) is recognized as an important immunosuppressive mechanism in human neoplastic disease. We report that two types of lymphocytes of relevance for protection against malignant cells, T cells and natural killer (NK) cells, became anergic to the T cell and NK cell activator interleukin-2 (IL-2) after exposure to MO-derived reactive oxygen metabolites and subsequently acquired features characteristic of apoptosis. The MO-induced anergy and apoptosis in T cells and NK cells were reversed by histamine, an inhibitor of reactive oxygen metabolite synthesis in MO. We propose that strategies to circumvent oxidative inhibition of lymphocytes may be of benefit in immunotherapy of neoplastic disease.

Antigens, CD↗

PubMed1998

The response of Dunning R3327 prostatic adenocarcinoma to IL-2, histamine and radiation.

A syngeneic, androgen-sensitive Dunning R3327 rat prostatic adenocarcinoma was transplanted bilaterally in the flanks of male Copenhagen Fisher rats. Approximately 3 months after implantation, when the tumours had a median volume of 150 mm3, one group of rats was treated with histamine alone (4 mg kg(-1) subcutaneously on week days), another group with human recombinant interleukin 2 (IL-2) alone (425 IU kg(-1) continuous infusion) and a third group with both histamine and IL-2 during 6 weeks. Tumours on one flank were irradiated (6 Gy once daily for 3 days to a total dose of 18 Gy) beginning 1 week after the onset of treatment with histamine and/or IL-2. The contralateral tumour served as the intra-animal control. The tumour volumes were determined weekly. The growth curves showed that all three drug treatments were effective in delaying growth, but when used individually did not cause tumour shrinkage. Radiation was the most effective single agent, but when used alone the shrinkage did not occur until 2 weeks after irradiation. When combined with the drugs, more rapid and extensive growth delay and/or shrinkage was seen. The growth curves showed clear differences between the different treatments. The combination of the three agents was the most effective of all. The most striking difference between radiation alone and radiation plus biotherapy was the time at which a tumour response was detectable. Thus, active biotherapy alone and especially in a combination with histamine and radiotherapy warrants further investigation as a potential therapeutic approach to prostate cancer.

Adenocarcinoma↗

PubMed1998

Histamine and cytokine therapy.

Interleukin-2 (IL-2) and interferon-alpha (IFN-alpha) are potent activators of natural killer (NK) cells and other anti-tumor effector cells, but the results obtained in clinical trials with these cytokines have proved disappointing in many forms of cancer. It may be that IL-2 and IFN-alpha are often not sufficiently effective because intratumoral monocytes/macrophages (MO) inhibit the cytokine-induced activation of cytotoxic effector lymphocytes such as NK-cells at the site of tumor growth. An essential part of this inhibitory signal is conveyed by MO-derived reactive oxygen species (ROS), which potently inhibit NK-cell-related functions, including the constitutive and cytokine-induced cytotoxicity against tumor cells. Histamine, a biogenic amine, inhibits ROS formation in MO; thereby, histamine synergizes with IL-2 and with IFN-alpha to induce killing of NK-cell-sensitive human tumor cells in vitro. Furthermore, treatment of tumor-bearing mice with histamine potentiates cytokine-induced killing of NK-cell-sensitive murine tumor cells in vivo. In ongoing clinical trials, histamine has been added to IL-2 or IFN-alpha in immunotherapy of human neoplastic disease. The results of two pilot trials in metastatic melanoma suggest that the addition of histamine to IL-2/IFN-alpha prolongs survival time and induces regression of tumors, such as liver melanoma, which are considered refractory to immunotherapy with IL-2 or IFN-alpha. In acute myelogenous leukemia (AML), histamine and IL-2 have been given in order to protect patients in remission against relapse of leukemic disease. The potential benefit of histamine therapy in melanoma and AML will be evaluated in randomized trials.

Animals↗

PubMed1998

Histamine and the response to IFN-alpha in chronic hepatitis C.

Whole blood concentrations of histamine were examined in 20 patients with chronic hepatitis C after longterm treatment with interferon-alpha (IFN-alpha). In 13 of these patients, a transient (n = 5) or sustained (n = 8) normalization of liver enzymes and elimination of viral RNA were noted at the end of therapy. Seven patients did not respond to IFN-alpha. Nonresponding patients had significantly lower histamine levels in blood than transient (p = 0.0005) or sustained (p = 0.04) responders. Histamine levels were not different in patients with a sustained vs. a transient IFN response. Confounding factors, such as ongoing viral replication or liver cirrhosis, did not account for the differences in histamine levels. Our data suggest that hypohistaminism in peripheral blood may determine a poor response to IFN-alpha in chronic hepatitis C.

Adult↗

PubMed1997

Duration and mechanisms of the increased natural cytotoxicity seen after chronic voluntary exercise in rats.

We have recently shown that in vivo natural cytotoxicity is enhanced after chronic exercise in spontaneously hypertensive rats (SHRs). In the present report, we have studied the duration of this augmentation and some possible mechanisms involved. Exercise consisted of voluntary running for 4-5 weeks, with the running distance ranging from 2.7-15.6 km day(-1) during the last week of running. In vivo cytotoxicity was measured as clearance of injected 51Cr-labelled YAC-1 lymphoma cells from the lungs. The in vivo natural cytotoxicity was increased in running SHRs, and also in SHRs that had their running wheel locked for 24 and 48 h prior to the experiment, and was still present after 96 h. The enhancement of in vivo cytotoxicity after 5 weeks of exercise was abolished after an acute injection of the beta-adrenergic receptor antagonist timolol (0.5 mg kg(-1) i.v.), indicating that catecholamines are involved in this augmentation. Interestingly, 24 h after the last exercise bout, the increased natural cytotoxicity could be blocked by timolol. The opioid receptor antagonist naloxone given subcutaneously for 7 days by osmotic pumps (6 mg kg(-1) h(-1)) could not reverse the increased in vivo cytotoxicity seen in the running SHRs, suggesting that opioid receptor mechanisms are not involved, or at least not the naloxone-sensitive mu-receptor. Natural immunity was not influenced by the histamine H2 receptor antagonist ranitidine, either in controls or in runners, indicating that the natural killer cell-regulatory effect of histamine is not present in SHRs and does not seem to be involved in the exercise-induced changes in natural immune function. We conclude that the augmentation of in vivo natural cytotoxicity after voluntary chronic exercise in rats is long-lasting and that the augmentation is partly mediated by beta-adrenergic receptors.

Adrenergic beta-Antagonists↗

PubMed1997

Histamine in cancer immunotherapy.

A novel strategy for enhancing the efficacy of immunotherapy with interleukin-2 (IL-2) and interferon-alpha (IFN-alpha) in human neoplasia is presented. IL-2 and IFN-alpha are potent activators of the antitumour activity of natural killer (NK) cells but only rarely reduce the tumour burden in treated patients. Recent studies suggest that a reason why these cytokines are insufficiently effective in human cancer is that phagocytes inhibit the tumour-killing activity of NK cells at the site of the tumour. Histamine prevents the phagocyte-induced, NK cell-inhibiting signal; thus, histamine and IL-2 or histamine and IFN-alpha synergize to induce NK cell-mediated killing of human tumour cells in vitro. Further, treatment of tumour-bearing mice with histamine enhances IL-2- and IFN-alpha-induced destruction of NK cell-sensitive tumour cells in vivo. More than 50 patients with neoplastic disease have been treated with histamine, given in subcutaneous injections, together with IL-2 or IFN-alpha. The results of two pilot trials in metastatic melanoma suggest that the addition of histamine to IL-2 and IFN-alpha prolongs survival time and induces regression of tumours, such as liver melanoma, which are otherwise considered refractory to immunotherapy. The results of a trial in acute myelogenous leukaemia (AML) suggest that histamine and IL-2 protects AML patients against relapse of leukaemic disease. Histamine is well tolerated: for example, AML patients in remission have treated themselves with histamine at home without supervision for a total of > 300 weeks with only a handful of therapy-related hospital contacts. Controlled trials in melanoma and AML are under way to further investigate the putative benefit of histamine in neoplastic disease.

Animals↗