Investigating predictors of well-being in type 2 diabetes mellitus patients: the role of undiagnosed depression

Type 2 diabetes mellitus (T2DM) is a common metabolic disorder with various medical and psychological adverse effects. Well-being in patients with T2DM is often compromised. The aim of the present study was to investigate clinicodemographic predictors of well-being in patients with T2DM with no known psychiatric history and explore the mediatory role of undiagnosed anxiety and depression. We recruited 175 outpatients with T2DM (54.3% males, aged 34-79 (mean 59.9) years) followed-up at the Diabetes Center of the General Hospital of Nikaia-Peiraeus in Athens. Patients included had no severe diabetes-related complications or known psychiatric history. Well-being was measured with the Mental Health Continuum Short-Form (MHC-SF), a novel 14-item tool measuring the emotional (EWB), social (SWB) and psychological (PWB) dimensions of well-being, as well as a total score of well-being (WBT). Hospital Anxiety and Depression Scale (HADS) was used for screening for undiagnosed anxiety (HADS-A) and depression (HADS-D). Patients' demographics, Body Mass Index (BMI), glycemic control (HbA1c), T2DM duration, comorbid hypertension or dyslipidemia and type of antidiabetic medication were investigated as predictors of well-being or its dimensions in stepwise linear regression models, also including or excluding HADS-A and HADS-D. Mediational effects of HADS-A and HADS-D were explored in structural equation models through path analyses. Results showed that 21.1% of participants had comorbid depression (HADS-D≥11) and 5.1% comorbid anxiety disorder (HADS-A≥11). In the models without HADS, higher WBT as well as EWB and PWB were significantly predicted by lower HbA1c (all p=0.001) and lower BMI (p=0.015, 0.019 and 0.030, respectively). After being included in the model, HADS-A and HADS-D significantly predicted WBT and every dimension of well-being, but the effects of HbA1c and BMI were no longer statistically significant. In path analyses, the indirect effects of HbA1c and BMI on well-being via HADS-D were statistically significant, while the direct and indirect effects via HADS-A were not. Therefore, the effects of HbA1c and BMI on EWB, PWB and WBT were completely mediated by HADS-D. Concludingly, this is the first study using MHC-SF to measure well-being in patients with T2DM. High levels of undiagnosed depression were recorded, in agreement with other studies. Depression was predicted by HbA1c and BMI and finally predicted well-being. Undiagnosed depression fully explained the effects of HbA1c and BMI on well-being. The interplay of glycemic control and positive mental health should be further investigated.

The role of frailty among the predictors of depression on informal caregivers of older adults: a mediation analysis

BACKGROUND

Providing care for older adults has been associated with the presence of depressive symptoms among their informal caregivers. Numerous caregivers and older adults' characteristics have been mentioned as predictors of caregivers' depression. However, studies dealing with the impact of older adults' frailty status on caregivers' depression are scarce. This study was conducted to clarify the precise relationship between caregivers' depression, caregivers' burden, caregivers' characteristics and patients' characteristics, including frailty, among the variables that may have an impact on caregivers' depression.

METHODS

In this cross-sectional study, patients and caregivers' characteristics were recorded for 311 patient-caregiver dyads, when the patient was admitted to the hospital. For the purpose of the study, a mediation analysis was used with patients and caregiver characteristics considered to be predictors, subjective caregivers' burden as the mediator, and caregivers' depression as the outcome variable.

RESULTS

Only patients' frailty and caregivers' subjective burden had a direct effect on caregivers' depression. Moreover, caregivers' gender, patients' frailty status and comorbidity, duration of caregiving, and the relationship with the patient, had an indirect effect through caregivers' burden that acted as mediator. Regarding total effects, caregivers burden followed by patients' frailty status had the greater impact on caregivers' depression.

CONCLUSIONS

By organising interventions to reduce caregivers' depression, patients' frailty status could be among the targets of those interventions considering that frailty might be delayed or reversed.

Genetic Variability in Vitamin D Receptor and Migraine Susceptibility: A Southeastern European Case-Control Study

Migraine is a common primary headache disorder with both environmental and genetic inputs. Cumulative evidence indicates an association between vitamin D and headache. Unravelling the precise role of vitamin D and its receptor in the pathophysiology of migraine can eventually contribute to more efficient prevention and management of this headache disorder. The aim of the study was to investigate the relation of the three most studied VDR variants, i.e., FokI (rs2228570), TaqI (rs731236) and BsmI (rs1544410), with migraine susceptibility and distinct clinical phenotypes in a Southeastern European case-control population residing in Greece. DNA was extracted from 191 unrelated patients diagnosed with migraine and 265 headache-free controls and genotyped using real-time PCR (LightSNiP assays) followed by melting curve analysis. Genotype frequency distribution analysis of the TaqI and BsmI variants showed a statistically significant difference between migraine cases and controls. In addition, subgroup analyses revealed a significant association between all three studied VDR variants, particularly with a migraine without aura subtype. Therefore, the current study provides supporting evidence for a possible association of VDR variants with migraines, particularly migraine without aura susceptibility in Southeastern Europeans residing in Greece, further reinforcing the emerging role of vitamin D and its receptor in migraines.

Variability in oxidative stress-related genes (SOD2, CAT, GPX1, GSTP1, NOS3, NFE2L2, and UCP2) and susceptibility to migraine clinical phenotypes and features

Introduction

Migraine is a complex disorder with genetic and environmental inputs. Cumulative evidence implicates oxidative stress (OS) in migraine pathophysiology while genetic variability may influence an individuals' oxidative/antioxidant capacity. Aim of the current study was to investigate the impact of eight common OS-related genetic variants [rs4880 (SOD2), rs1001179 (CAT), rs1050450 (GPX1), rs1695 (GSTP1), rs1138272 (GSTP1), rs1799983 (NOS3), rs6721961 (NFE2L2), rs660339 (UCP2)] in migraine susceptibility and clinical features in a South-eastern European Caucasian population.

Methods

Genomic DNA samples from 221 unrelated migraineurs and 265 headache-free controls were genotyped for the selected genetic variants using real-time PCR (melting curve analysis).

Results

Although allelic and genotypic frequency distribution analysis did not support an association between migraine susceptibility and the examined variants in the overall population, subgroup analysis indicated significant correlation between NOS3 rs1799983 and migraine susceptibility in males. Furthermore, significant associations of CAT rs1001179 and GPX1 rs1050450 with disease age-at-onset and migraine attack duration, respectively, were revealed. Lastly, variability in the CAT, GSTP1 and UCP2 genes were associated with sleep/weather changes, alcohol consumption and physical exercise, respectively, as migraine triggers.

Discussion

Hence, the current findings possibly indicate an association of OS-related genetic variants with migraine susceptibility and clinical features, further supporting the involvement of OS and genetic susceptibility in migraine.

Burnout Related to Diabetes Mellitus: A Critical Analysis

Background

Diabetes burnout is a condition when a patient with diabetes feels tired from his/her disease and neglects it for a certain period or continuously.

Objective

Diabetes burnout is frequent, and there is extended literature about psychosocial stress and its negative effects on health.

Methods

A search for relevant studies was conducted using PubMed, Google Scholar and ResearchGate. A systematic review was conducted on the relevant articles after critical appraisal. Only publications in English were selected. The objective of this study was to evaluate the association between burnout syndrome and diabetes mellitus.

Results

This article mainly focused on studies that evaluated the presence of burnout and diabetes mellitus effects. Diabetes can influence psychological health equally with somatic strength. Relatives can also express depression, guilt, fright, worry, rage, and burnout. Psychosocial job stress and extended working hours are linked with a higher possibility of myocardial infarction, diabetes mellitus, and hypertension.

Conclusion

Diabetes burnout is a combination of emotions and practices, ranging from tiredness to indifference, linked with a distressing sense of hopelessness. Revealing this health condition is necessary so that preventive measures can be taken.

Endothelial Dysfunction Is Associated with Decreased Nitric Oxide Bioavailability in Dysglycaemic Subjects and First-Degree Relatives of Type 2 Diabetic Patients

Oxidative stress plays an important role in the pathogenesis of diabetes. We investigated oxidative stress and nitrite/nitrate concentrations at baseline and during postprandial hyperglycaemia in 40 first-degree relatives (FDRs) of diabetic patients with normal oral glucose tolerance test (OGTT) results, 40 subjects with abnormal OGTT results (dysglycaemic) and 20 subjects with normal OGTT results (normoglycaemic). Malondialdehyde (MDA), protein carbonyls (PCs), nitrite/nitrate plasma levels, the perfused boundary region (PBR—Glycocheck) of the sublingual microvessels, a marker of glycocalyx integrity, coronary flow reserve (CFR) and left ventricular global longitudinal strain (GLS) were assessed at 0 and 120 min of the OGTT. Insulin sensitivity was evaluated using Matsuda and the insulin sensitivity index (ISI). In all subjects, there were no significant changes in MDA or PC after the OGTT (p > 0.05). Compared with normoglycaemic subjects, FDRs and dysglycaemic subjects had significantly decreased nitrite/nitrate levels (−3% vs. −24% vs. −30%, respectively), an increased PBR and reduced CFR and GLS at 120 min (p < 0.05). The percent reduction in nitrite/nitrate was associated with abnormal Matsuda and ISI results, reversely related with the percent increase in PBR (r = −0.60) and positively related with the percent decrease in CFR (r = 0.39) and GLS (r = 0.48) (p < 0.05). Insulin resistance is associated with reduced nitric oxide bioavailability and coronary and myocardial dysfunction in FDRs and dysglycaemic subjects.

Vitamin D Supplementation and Genetic Polymorphisms Impact on Weight Loss Diet Outcomes in Caucasians: A Randomized Double-Blind Placebo-Controlled Clinical Study

Vitamin D deficiency or insufficiency is common in obese people, with some studies suggesting that low vitamin D level might be an independent predictor of obesity. Thus, the purpose of the present randomized, double-blind, placebo-controlled study was to investigate the effect of oral spray vitamin D₃ 3000 IU supplementation along with personalized weight-loss diet on obesity markers in overweight and obese Caucasians with vitamin d deficiency or insufficiency. The impact of vitamin D receptor (VDR) and adrenergic receptors (ADRs) genetic variants on vitamin D levels and weight loss diet outcomes was also investigated. After signing informed consent, a total of 125 eligible volunteers were randomly assigned into vitamin D (vitamin D₃ 3000 IU/d oral spray supplementation, n = 76) or placebo (xylitol, water, mint, n = 49) group following a weight loss program (600 calories less than the total energy expenditure of each volunteer) for 3 months. Fat mass, BMI, REE and 25(OH)D serum level were monitored on baseline and each month. DNA samples were extracted from buccal swabs and genotyped for the rs2228570 (VDR), rs1544410 (VDR), rs731236 (VDR), rs1800544 (ADRA2A), rs1801252 (ADRB1), rs1042713 (ADRB2), and rs4994 (ADRB3) polymorphisms. Statistical analysis was performed using SPSS package (v.23). Between group comparisons revealed significant improvement in serum 25(OH)D level and greater reduction in weight, BMI and fat percentage in the vitamin D group compared to placebo group (p < 0.05). In the vitamin D group, carriers of the rs2228570 T allele tended to have greater vitamin D level improvement compared with the homozygous C allele (p = 0.067). Furthermore, heterozygous (CT) for the rs731236 tended to have lesser weight loss (p = 0.068) and for the rs1042713, a lower decline in fat percentage was observed for homozygous AA carriers compared to the heterozygous (p = 0.051). In the control group, differences in weight loss (p = 0.055) and BMI (p = 0.045) were observed between rs1544410 AA and GG homozygous. In conclusion, vitamin D oral spray supplementation seems to improve vitamin D status and decrease obesity markers during a weight-loss intervention in overweight/obese Caucasians with vitamin D deficiency or insufficiency. Also, the results of the present study indicate that VDR and ADRs genetic polymorphisms seem to influence vitamin D supplementation response and obesity markers.

Validity and reliability of the Greek version of Pregnancy Outcome Questionnaire (POQ)

BACKGROUND

During the last decades a considerable increase in biological and psychosocial approaches have occurred so as to enhance the study of prenatal period. This study aimed to investigate the validity and reliability of the Greek version of Pregnancy Outcome Questionnaire (POQ) in assessing pregnancy-related stress.

MATERIAL AND METHODS

The study group consisted of 135 first-time expectant women with good knowledge of the Greek language, low-risk pregnancies and a gestational age of ≥24 weeks. Questionnaires containing the POQ scale questions in addition to other questions and scaleswere distributed in printed and digital format at private gynecological clinics. The collected data were analysed using the SPSS software.

RESULTS

The POQ scale score showed satisfactory reliability (Cronbach's alpha = 0.8), while the factor analysis showed a major factor with an eigenvalue of 4.17 and an overall interpreted factor variance of 41%. The sample showed moderate intensity values on the scale. We observed that pregnancy-related characteristics affected the scale, while no significant correlations with demographic variables were recorded.

CONCLUSION

The results of the reliability and factor analyses evaluating the scale structure indicated that the tool performed well in Greek, had a compact structure with satisfying reliability, and is suitable for use in the Greek pregnant population. However, additional research is warranted to investigate the effect of various additional factors on the scale.

The combination of dulaglutide and dapagliflozin improves arterial stiffness, endothelial glycocalyx and albuminuria vs DPP-4 inhibitors independently of glycemic control

Background

Studies in recent years have shown that dulaglutide, a glucagon-like peptide-1 receptor agonist (GLP-1RA), and dapagliflozin, a sodium-glucose cotransporter-2 inhibitor (SGLT-2i), improve or prevent diabetic nephropathy and macrovascular complications in patients with type 2 diabetes mellitus (T2DM).

Purpose

The aim of this study is to determine whether the combination of dulaglutide and dapagliflozin exerts improves arterial stiffness, endothelial glycocalyx and albuminuria in T2DM compared to dipeptidyl-peptidase 4 inhibitors (DPP-4is).

Methods

Overall 37 patients with T2DM were included in our study. 21 patients were transitioned from DPP-4is to dulaglutide and dapagliflozin (treatment group) and were followed immediately prior (baseline) and 4 months after the initiation of treatment. 16 patients, matched for sex, age and glycemic control, remained on treatment with DPP-4is (control group). In each visit we measured a) Carotid-femoral PWV b) central systolic blood pressure (cSBP) c) perfused boundary region (PBR) of the sublingual arterial microvessels, d) urinary albumin-to-creatinine ratio (UACR), e) glycosylated hemoglobin (HbA1c).

Results

There were no statistically significant differences in cardiovascular markers, UACR and HbA1c at baseline (p&gt;0.05). After 4 months, patients on dulaglutide and dapagliflozin combination improved HbA1c (7.9±1.5% vs 6.59±0.6%, p&lt;0.001), PBR (2.3±0.3 vs. 2.1±0.2 μm, p&lt;0.05), PWV (11.9±0.3.5 vs. 10.9±2.2m/s, p&lt;0.05), cSBP (128.5±23.6 vs. 121.1±15.7 mmHg, p&lt;0.05) and UACR (413.66±352.57 vs. 248.06±203.5 mg/g, p&lt;0.001). There were no statistically significant differences in PBR (2.1±0.3 vs. 2.2±0.3 μm, p&gt;0.05), PWV (10.7±3.4 vs. 12±3.3m/s, p&gt;0.05), cSBP (125.4±21.2 vs. 127±20.1 mmHg, p&gt;0.05) and UACR (240.8±103.6 vs. 204.9±119.6 mg/g), in the control group, despite a statistically significant improvement of HbA1c (8.2±1.9% vs 7.3±1.3%, p&lt;0.01).

Conclusions

The combination of dulaglutide and dapagliflozin improves arterial stiffness, endothelial glycocalyx and albuminuria compared to DPP-4is in patients with T2DM.

Funding Acknowledgement

Type of funding sources: None.

VDR Gene Polymorphisms and Cluster Headache Susceptibility: Case-Control Study in a Southeastern European Caucasian Population

Cluster headache (CH) is a severe primary headache disorder with a genetic component, as indicated by family and twin studies. Diurnal and seasonal rhythmicity are key features of the disease and might be related to vitamin D, as low vitamin D levels have been observed in patients with cluster headache. In addition, the vitamin D receptor (VDR) occurs in brain areas and particularly in the hypothalamus. The aim of the present case-control study was to investigate the association of cluster headache susceptibility and clinical phenotypes with the VDR gene polymorphisms FokI, BsmI and TaqI in a Southeastern European Caucasian population. DNA was extracted from 131 unrelated CH patients and 282 non-headache controls and genotyped using real-time PCR (melting curve analysis). Linkage disequilibrium (LD) analysis confirmed that BsmI and TaqI, both located in the 3'UTR of the VDR gene, are in strong LD. Genotype and allele frequency distribution analysis of the VDR FokI, BsmI, and TaqI polymorphisms showed no statistically significant difference between cases and controls, whereas haplotype analysis indicated that the TAC haplotype might be associated with decreased cluster headache susceptibility. Intra-patient analysis according to diverse clinical phenotypes showed an association of the BsmI GG and TaqI TT genotypes with more frequent occurrence of CH attacks in this cohort. Therefore, a possible association was observed between VDR gene polymorphisms BsmI and TaqI or a linked locus and susceptibility for cluster headache development and altered clinical phenotypes in the Southeastern European Caucasian study population. Further large-scale replication studies are needed to validate these findings.

Prevalence of diabetes and pre-diabetes in Greece. Results of the First National Survey of Morbidity and Risk Factors (EMENO) study

AIMS

To report the results of the first national Health Examination Survey (HES) on the prevalence of diabetes, its pharmacologic treatment and level of control, as well as pre-diabetes in Greece.

METHODS

Data were derived from the National Survey of Morbidity and Risk Factors (EMENO), in a randomly selected, representative sample of the adult Greek population. Sampling weights were applied to adjust for study design and post-stratification weights to match sample age/sex distribution to the population. Non-response was adjusted by inverse probability weighting. Weighted prevalence estimates are provided.

RESULTS

A total of 4393 persons with HbA1c and/or fasting plasma glucose measurements were included. Total diabetes prevalence was 11.9% (95% CI: 10.9-12.9), known diabetes 10.4% (9.5-11.4), and unknown 1.5% (1.1-1.9), with considerable increase in older age groups and no difference between genders. Pre-diabetes prevalence was 12.4% (11.4-13.6). The majority of persons with known diabetes were receiving metformin. Of those with known diabetes (and measured HbA1c), 70.9% were well controlled (HbA1c <7.0%).

CONCLUSIONS

This first representative national HES showed high prevalence of diabetes in Greece, with low prevalence of unknown diabetes. Pre-diabetes prevalence is also substantial. These results will hopefully enable national authorities develop tailored and efficient strategies for disease prevention and management.

Stress Hyperglycemia in Children and Adolescents as a Prognostic Indicator for the Development of Type 1 Diabetes Mellitus

Hyperglycemia is a common manifestation in the course of severe disease and is the result of acute metabolic and hormonal changes associated with various factors such as trauma, stress, surgery, or infection. Numerous studies demonstrate the association of adverse clinical events with stress hyperglycemia. This article briefly describes the pathophysiological mechanisms which lead to hyperglycemia under stressful circumstances particularly in the pediatric and adolescent population. The importance of prevention of hyperglycemia, especially for children, is emphasized and the existing models for the prediction of diabetes are presented. The available studies on the association between stress hyperglycemia and progress to type 1 diabetes mellitus are presented, implying a possible role for stress hyperglycemia as part of a broader prognostic model for the prediction and prevention of overt disease in susceptible patients.

The Endothelial Glycocalyx as a Key Mediator of Albumin Handling and the Development of Diabetic Nephropathy

The endothelial glycocalyx is a complex mesh of proteoglycans, glycoproteins and other soluble components, which cover the vascular endothelium. It plays an important role in many physiological processes including vascular permeability, transduction of shear stress and interaction of blood cells and other molecules with the vascular wall. Its complex structure makes its precise assessment challenging, and many different visualization techniques have been used with varying results. Diabetes, one of the main disease models where disorders of the glycocalyx are present, causes degradation of the glycocalyx through a variety of molecular pathways and especially through oxidative stress due to the action of reactive oxygen species. As the glycocalyx has been primarily studied in the glomerular endothelium, more evidence points towards a vital role in albumin handling and, consequently, in diabetic nephropathy. Therefore, the maintenance or restoration of the integrity of the glycocalyx seems a promising therapeutic target. In this review, we consider the structural and functional capacities of the endothelial glycocalyx, the available methods for its evaluation, the mechanisms through which diabetes leads to glycocalyx degradation and albuminuria, and possible treatment options targeting the glycocalyx.

Benefits of exercise in pregnancies with gestational diabetes

A significant proportion of pregnancies are complicated by diabetes mellitus. Most of them concern women with gestational diabetes mellitus, while proportionally are presented with preexisting DM 1 and DM 2. Metabolic derangements of the diabetic syndrome are likely to generate serious complications for both the mother and the fetus with a significant impact on their later health. Undoubtedly, all appropriate interventions that will contribute to the smoothest and most uncomplicated course of pregnancy are considered essential. Healthy diet adjustments, glucose monitoring and an appropriate insulin regimen, if needed, are considered effective tools for a safe gestation. Courses with aerobic, anaerobic stretching and relaxation exercises are presented with significant benefits in the therapeutic struggle for the general public. Extended research has been conducted assessing the role of exercise incorporation in a diabetic pregnancy. As evidence would support based on recent literature, exercise is an important mean in the prevention of carbohydrate intolerance during gestation and even more facilitates a smoother management of a diabetic pregnancy. Thus, exercise poses an essential role for maternal and neonatal health.

Obesity and COVID-19: immune and metabolic derangement as a possible link to adverse clinical outcomes

Recent reports have shown a strong association between obesity and the severity of COVID-19 infection, even in the absence of other comorbidities. After infecting the host cells, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may cause a hyperinflammatory reaction through the excessive release of cytokines, a condition known as "cytokine storm," while inducing lymphopenia and a disrupted immune response. Obesity is associated with chronic low-grade inflammation and immune dysregulation, but the exact mechanisms through which it exacerbates COVID-19 infection are not fully clarified. The production of increased amounts of cytokines such as TNFα, IL-1, IL-6, and monocyte chemoattractant protein (MCP-1) lead to oxidative stress and defective function of innate and adaptive immunity, whereas the activation of NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome seems to play a crucial role in the pathogenesis of the infection. Endothelial dysfunction and arterial stiffness could favor the recently discovered infection of the endothelium by SARS-CoV-2, whereas alterations in cardiac structure and function and the prothrombotic microenvironment in obesity could provide a link for the increased cardiovascular events in these patients. The successful use of anti-inflammatory agents such as IL-1 and IL-6 blockers in similar hyperinflammatory settings, like that of rheumatoid arthritis, has triggered the discussion of whether such agents could be administrated in selected patients with COVID-19 disease.

Risk for Venous Thromboembolic Events in Patients With Advanced Urinary Tract Cancer Treated With First-Line Chemotherapy

BACKGROUND

Venous thromboembolic events (VTEs) frequently occur in cancer patients. Risk assessment models (RAMs) for cancer-associated thrombosis have been proposed. However, advanced urinary tract cancer (aUTC) was not adequately represented in these models. We studied the incidence of VTEs, the risk factors, and the applicability of recently described RAMs.

PATIENTS AND METHODS

Data from 335 patients with aUTC treated with chemotherapy between April 1995 and September 2015 in a single institution were analyzed.

RESULTS

A total of 95.2% received platinum-based first-line chemotherapy. Twenty-nine patients (8.7%) experienced VTEs. The 6-, 12-, and 24-month VTE incidence was 7.4% (95% confidence interval [CI], 4.8-10.6), 8.1% (95% CI, 5.4-11.5) and 9.4% (95% CI, 6.4-13.1), respectively. No significant association of VTE incidence with the Khorana risk score was observed. History of vascular event (VTE and/or arterial thromboembolic event) was significantly associated with the development of VTE. Patients with such history had a 6-, 12-, and 24-month VTE incidence of 16.2% (95% CI, 6.6-29.7), 19.2% (95% CI, 8.4-33.3), and 25.2% (95% CI, 12.5-40.1) compared to 6.2% (95% CI, 3.7-9.4), 6.6% (95% CI, 4.1-10), and 7.1% (95% CI, 4.4-10.6) of those who did not. The discriminatory ability of this factor adjusted for leucocyte count, sex, Eastern Cooperative Oncology Group performance status, and type of chemotherapy reached 0.79 (95% CI, 0.71-0.87) compared to the 0.58 (95% CI, 0.49-0.66) for the Khorana risk score.

CONCLUSION

Development of tumor-specific algorithms for the risk of VTEs is advisable. Patients with aUTC and a history of vascular events are at high risk for VTE development, and prophylaxis should be prospectively studied in this group.

Bariatric Surgery and Type 1 Diabetes: Unanswered Questions

In recent decades there has been an alarming increase in the prevalence of obesity in patients with type 1 diabetes leading to the development of insulin resistance and cardiometabolic complications, with mechanisms poorly clarified. While bariatric surgery has long been considered an effective treatment option for patients with type 2 diabetes, the evidence regarding its benefits on weight loss and the prevention of complications in T1DM patients is scarce, with controversial outcomes. Bariatric surgery has been associated with a significant reduction in daily insulin requirement, along with a considerable reduction in body mass index, results which were sustained in the long term. Furthermore, studies suggest that bariatric surgery in type 1 diabetes results in the improvement of comorbidities related to obesity including hypertension and dyslipidemia. However, regarding glycemic control, the reduction of mean glycosylated hemoglobin was modest or statistically insignificant in most studies. The reasons for these results are yet to be elucidated; possible explanations include preservation of beta cell mass and increased residual function post-surgery, improvement in insulin action, altered GLP-1 function, timing of surgery, and association with residual islet cell mass. A number of concerns regarding safety issues have arisen due to the reporting of peri-operative and post-operative adverse events. The most significant complications are metabolic and include diabetic ketoacidosis, severe hypoglycemia and glucose fluctuations. Further prospective clinical studies are required to provide evidence for the effect of bariatric surgery on T1DM patients. The results may offer a better knowledge for the selection of people living with diabetes who will benefit more from a metabolic surgery.

[Pulmonary tumour thrombotic microangiopathy associated with a gastric adenocarcinoma]

We report the case of a 67 years old patient with a history of gastric adenocarcinoma who died in a context of severe dyspnea and whose autopsy will confirm the diagnosis of a Pulmonary Tumor Thrombotic Microangiopathy (PTTM). PTTM is a fatal pulmonary complication associated to multiple cancers. It starts with an acute or subacute respiratory failure quickly evolving towards fatal thrombo-embolic pulmonary hypertension and right heart failure. Pre-mortem diagnosis is difficult and not frequent because the pathology is rare, the underlying neoplastic disease is not always known, clinical and radiological signs are not specific and progression is fast. When made soon enough, PTTM diagnosis avoids useless and sometimes harmful medication. In some cases, an improvement of patient's symptoms and comfort is observed. Some studies described several months of extended survival.

Dietary Composition and Cardiovascular Risk: A Mediator or a Bystander?

The role of nutrition in the pathogenesis of cardiovascular disease has long been debated. The established notion of the deleterious effects of fat is recently under question, with numerous studies demonstrating the benefits of low-carbohydrate, high-fat diets in terms of obesity, diabetes, dyslipidemia, and metabolic derangement. Monounsaturated and polyunsaturated fatty acids, especially n-3 PUFAs (polyunsaturated fatty acids), are the types of fat that favor metabolic markers and are key components of the Mediterranean Diet, which is considered an ideal dietary pattern with great cardioprotective effects. Except for macronutrients, however, micronutrients like polyphenols, carotenoids, and vitamins act on molecular pathways that affect oxidative stress, endothelial function, and lipid and glucose homeostasis. In relation to these metabolic markers, the human gut microbiome is constantly revealed, with its composition being altered by even small dietary changes and different microbial populations being associated with adverse cardiovascular outcomes, thus becoming the target for potential new treatment interventions. This review aims to present the most recent data concerning different dietary patterns at both the macro- and micronutrient level and their association with atherosclerosis, obesity, and other risk factors for cardiovascular disease.

Black Sea tele-diab: development and implementation of an electronic patient record for patients with diabetes

Black Sea tele-diab (BSTD) is a three-year European Union (EU)-funded International Collaboration (INCO) Telematics Application Project to develop a standardized software package (in the national languages of the partners) for the storage and transfer of medical information collected from patients with diabetes. The software utilizes an electronic medical record architecture based on the Good European Health Record, developed within the Advanced Informatics in Medicine programme. Software development is being carried out by the partners in Eastern Europe, which will help promote the development of medical informatics and communication technologies among countries of Central Europe (CCE) and newly independent states (NIS) countries. The diabetes data set is based on the WHO Europe DiabCare Basic Information Sheet; the project therefore supports the World Health Organisation (WHO) Quality Care Programme for monitoring the prevalence and incidence of diabetic complications across Europe. Diabetes is used as a model, as standards for data collection and clinical care are well developed and the concepts applied and learnt in diabetes will be generally applicable to other chronic diseases and medical disciplines.

Vitamin status as a determinant of serum homocysteine concentration in type 2 diabetic retinopathy

We investigated the association of serum homocysteine levels and vitamin status with type 2 diabetic retinopathy. This study included 65 patients with and 75 patients without diabetic retinopathy. Patients with diabetic retinopathy had significantly higher serum homocysteine levels (P < 0.001), higher prevalence of hyperhomocysteinemia (P < 0.001), lower serum folic acid (P < 0.001), and vitamin B12 (P = 0.014) levels than those without diabetic retinopathy. Regression analysis revealed that homocysteine was an independent risk factor for diabetic retinopathy and there was a threshold in its serum level (13.7  μ mol/L), above which the risk of diabetic retinopathy greatly increases (OR = 1.66, P = 0.001). Folic acid was associated with decreased odds for diabetic retinopathy (OR = 0.73, P < 0.001). There was a threshold in serum vitamin B12 level (248.4 pg/mL), below which serum homocysteine concentration significantly increases with decreasing serum vitamin B12 (P = 0.003). Our findings suggest that hyperhomocysteinemia is an independent risk factor for the development and progression of diabetic retinopathy. Decreased serum levels of folic acid and vitamin B12, through raising serum homocysteine concentrations, may also affect the diabetic retinopathy risk.

Etoposide and mitoxantrone in newly diagnosed acute myeloid leukemia patients with persistent leukemia after a course of induction therapy with cytarabine and idarubicin

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Background: The goal of induction chemotherapy in acute myeloid leukemia (AML) is complete remission with restoration of normal bone marrow. If residual leukemia is present after the first course of induction therapy, patients receive a second course identical to the first or receive a non-cross resistant antileukemic regimen. Methods: In a retrospective study of adult patients with newly-diagnosed AML treated at the University of Pittsburgh Cancer Institute between December 2002 and May 2008, we evaluated the efficacy and toxicity of mitoxantrone (10 mg/m2/d) and etoposide (100 mg/m2/d), both administered intravenously within 5 days as second course therapy of patients not responding to first-course induction therapy with cytarabine and idarubicin. Univariate and multivariate associations between patient characteristics and complete response (CR) were assessed by logistic regression, with overall- and relapse-free survival estimated by Kaplan-Meier analysis. Results: 74 AML patients (mean age 56 years, range: 18–73 years) completed treatment with etoposide and mitoxantrone; 29 (39%) achieved CR. Lower CR rate was associated with unfavorable cytogenetic risk status at diagnosis and higher percent blasts prior to treatment with mitoxantrone and etoposide. Ten (14%) patients died due to infectious complications. No grade 3 or 4 hepatic toxicities were observed. One patient developed grade 3 cardiac toxicity. Median duration of neutrophil recovery following therapy in patients achieving CR was 29 days. Median overall survival was 9.0 months (95% CI 5.8–14.9 months). The 29 patients who achieved CR received postremission therapy: 16 of these eventually relapsed, while 4 others died without evidence of relapse. Median duration of relapse-free survival in these 29 patients was 11.0 months (95% CI: 9.0–19.3 months). Conclusions: Our study suggests that the combination of etoposide and mitoxantorne is an active and well-tolerated regimen as second-course therapy in newly diagnosed AML patients who have persistent leukemia after a first course of induction therapy with cytarabine and idarubicin.

No significant financial relationships to disclose.

Adoptive immunotherapy with donor lymphocyte infusions and interleukin-2 after high-dose therapy and autologous stem cell rescue for multiple myeloma

In an attempt to induce a graft-versus-myeloma effect, we administered donor lymphocyte infusions (DLI) after high-dose therapy with autologous stem cell transplant rescue to seven patients with refractory or relapsed multiple myeloma. High-dose therapy consisted of melphalan, idarubicin and etoposide (days -9 to -6) followed by autologous stem cell infusion on day 0. DLI (five of seven donors with two or three HLA antigens mismatched) were administered on days +1, +5 and +10 along with IL-2 (from day +1 through +12). Six of the seven patients developed acute graft-versus-host disease (GVHD), which resolved spontaneously, coincidentally with autologous hematopoietic reconstitution. One patient failed to engraft and received a second autologous graft. One patient died from complications of a pulmonary hemorrhage after experiencing GVHD. With a minimum follow-up of 38 months, five patients remain without disease progression in complete remission or with minimal residual disease. In this setting, DLI/IL-2 is biologically active resulting in GVHD. A graft-versus-myeloma effect is suggested by the improved outcome of our small cohort of high-risk patients. The use of partially mismatched related donors makes this approach potentially available to nearly all patients.

A dose escalation study of topotecan in combination with epirubicin in pretreated patients with small-cell lung cancer

PURPOSE

To define the dose-limiting toxicities (DLTs) and the maximum tolerated doses (MTDs) of topotecan in combination with epirubicin in pretreated patients with small-cell lung cancer (SCLC).

PATIENTS AND METHODS

Twenty-seven SCLC patients with performance status (WHO) of 0-2 and adequate renal, hepatic, and bone marrow function who had failed EP-containing front-line chemotherapy entered the study. Patients received escalated doses of topotecan (starting dose 0.5 mg/m(2)) for 5 days and epirubicin (starting dose 40 mg/m(2)) on day 8, every 28 days.

RESULTS

All patients were assessable for toxicity and 20 for response. The MTD was topotecan 0.90 mg/m(2) and epirubicin 40 mg/m(2) with neutropenia being the most common dose-limiting event. Seventy-three courses were administered. Grade 3-4 neutropenia occurred in 22 (30%) courses, grade 3-4 anemia in 7 (10%), and grade 3-4 thrombocytopenia in 11 (15%). Seven courses were complicated with fever and one patient died of neutropenic sepsis. Grade 3-4 non-hematologic toxicity was mild and infrequent with only grade 2-3 asthenia occurring in 16 (22%) courses. Among 20 patients who were evaluable for response, 16 (80%) were refractory to prior treatment. One patient with refractory disease (5%) achieved a complete response of 14 weeks duration and four experienced stabilization of the disease.

CONCLUSIONS

The combination of topotecan 0.90 mg/m(2) on days 1-5, with epirubicin 40 mg/m(2) on day 8, administered every 28 days is a feasible outpatient regimen which merits further evaluation in patients with chemosensitive disease.

Interim analysis of the use of the anti-idiotype breast cancer vaccine 11D10 (TriAb) in conjunction with autologous stem cell transplantation in patients with metastatic breast cancer

The anti-idiotype monoclonal antibody breast cancer vaccine 11D10 (TriAb) was administered before and after autologous stem cell transplantation (ASCT) in 45 patients with metastatic breast cancer whose disease was responsive to conventional chemotherapy. Evidence of a positive anti-anti-idiotype antibody (Ab3) humoral response was noted at a median of 1.76 months post-ASCT (range, before ASCT-6 months) with this strategy. Maximal Ab3 levels and idiotype-specific T-cell proliferative responses were observed at a median of 3 and 4 months, respectively, after ASCT. The achievement of rapid immune responses after ASCT, during a known period of decreased immunoresponsiveness, opens the possibility of an additional antitumor effect at a time when the tumor burden is relatively small. Moreover, in this interim analysis, patients with the most vigorous humoral and cellular immune responses had a significant improvement in progression-free survival. Further follow-up and evaluation of this approach is warranted.

Intravesicular instillation of E-aminocaproic acid for patients with adenovirus-induced hemorrhagic cystitis

Hemorrhagic cystitis (HC) is a known complication of allogenic BMT. We report a case of a 28-year-old female with CML in chronic phase, which was treated with a matched unrelated donor (MUD) transplant, complicated by hemorrhagic cystitis on day +42 after the transplant. Adenovirus was isolated from the urine and she was treated with ribavirin, 1 g twice a day for 8 days. We report the use of Amicar (E-aminocaproic acid), 2.5 g solution as bladder instillation to treat the intractable hematuria.

High-dose corticosteroid therapy for diffuse alveolar hemorrhage in allogeneic bone marrow stem cell transplant recipients

In a series of 74 patients with hematological malignancies undergoing allogeneic bone marrow or peri- pheral blood stem cell transplants from an HLA-identical sibling donor, four developed diffuse alveolar hemorrhage (DAH) between days 0 and 23 post transplant. Diagnosis was made by the radiographic finding of diffuse bilateral lung opacities, and bloody lavage fluid on bronchoscopy. Two patients required mechanical ventilatory support. They were treated with methylprednisolone 0.25-1.5 g/day for at least 4 days with slow tapering thereafter. All patients showed an immediate response and two became long-term survivors with normal respiratory function. Two had a relapse of DAH, developed acute respiratory distress syndrome (ARDS) and died with multi-organ failure. Risk factors for DAH were one or more courses of intensive chemotherapy pretransplant vs no treatment or low-dose chemotherapy (4/4 DAH vs 23/70 no DAH; P = 0.015), and second transplants (2/2 DAH vs 1/70 with no DAH; P = 0.006). These results indicate that DAH is life-threatening but is potentially reversible by prompt treatment with high doses of steroids.

Human G-CSF-mobilized CD34-positive peripheral blood progenitor cells can stimulate allogeneic T-cell responses: implications for graft rejection in mismatched transplantation

To investigate mechanisms of stem cell graft rejection we studied the allo-stimulatory potential of G-CSF mobilized peripheral blood progenitor cells (PBPC). CD34+ cells were purified (>95%) in a two-step procedure using immunoaffinity columns for CD34 selection and T-depletion. The capacity of CD34+ cells to stimulate allogeneic T-cell responses was compared with other cells from the same individual. CD34+ cells induced potent proliferative responses at stimulator:responder ratios of 1:20, but were approximately 50-fold less efficient compared to dendritic cells. Furthermore, CD34+ cells primed responses from partially matched allogeneic T cells in bulk cultures. Dual-colour flow cytometry showed that the co-stimulatory molecules B7.1, CD40 and ICAM-1 were absent on resting CD34-positive progenitor cells, but were induced during incubation with allogeneic lymphocytes due to a cytokine-mediated effect. Up-regulation of accessory molecules on CD34+ cells was reproduced by incubation with interferon-gamma or GM-CSF which enhanced the allo-stimulatory activity of CD34+ cells. Blocking studies with inhibitory antibodies suggested co-stimulatory functions for B7.2, ICAM-3, CD40 and LFA-3. CD34+ cells were more efficient in inducing allogeneic T-cell responses when compared to the unprocessed leukapheresis products. The reduced allo-stimulatory ability of G-CSF mobilized PBPC could be explained by the presence of CD3+ 4+ and CD3+ 8+ lymphocytes with suppressor activity. We conclude that current methods of stem cell selection for transplantation do not avoid allosensitization of the recipient and that further graft manipulation with add-back of lymphocytes or selection of subsets of CD34+ cells with reduced allo-stimulatory ability may reduce graft rejection.

Donor-recipient polymorphism of the proteinase 3 gene: a potential target for T-cell alloresponses to myeloid leukemia

The curative effect of allogeneic bone marrow transplantation (BMT) is in part due to an alloresponse of donor lymphocytes against recipient leukemia termed the graft versus leukemia (GvL) effect. To identify target antigens for the GvL response on leukemia cells, we looked for polymorphism of proteinase 3, a primary granule protein overexpressed in myeloid leukemias. The study was carried out in 10 patients with hematologic diseases and their HLA-identical marrow donors. By polymerase chain reaction (PCR)-single strand conformation polymorphism assay, followed by direct sequencing of the PCR products, we found seven DNA polymorphisms. One of them encodes for either an isoleucine or a valine at position 119 of the amino acid sequence. Peptides that span the polymorphic site, at amino acids 115-124, were shown to bind in vitro to the HLA-A2 molecule. We screened 23 HLA-A2 patients with myeloid leukemia and their HLA-identical donors for this polymorphism. No relapse was found in the group of 4 evaluable patients who possessed at least one allele absent in their donor, whereas 7 of the 15 remaining evaluable patients relapsed. These data support the possibility that T-cell responses to allelic differences of proteinase 3 could be used as a basis for designing leukemia-specific adoptive T-cell therapy in acute and chronic myeloid leukemias.

Polymorphism in CD33 and CD34 genes: a source of minor histocompatibility antigens on haemopoietic progenitor cells?

Following bone marrow stem cell transplantation allo-responses against haemopoietic progenitor cells (HPC), causing graft rejection and graft-versus-leukaemia effects, can be induced by donor T cells recognizing peptides derived from polymorphic endogenous proteins present in HPC. Since CD33 and CD34 are both expressed on HPC, we looked for genetic polymorphisms that might be the source of minor histocompatibility antigens (mHA) on such cells. Bone marrow from 14 donors and their HLA-identical recipients undergoing BMT for haematological malignancies were studied. Using non-radioactive single-strand conformation polymorphism analysis (cold SSCP) of complementary DNA encoding CD33 and CD34, three DNA polymorphisms, two in CD33 and one in CD34 were found and sequenced. Two were in non-coding regions, but in CD33, ATA or ATG at codon 183 resulted in an Ile or Met in the protein sequence. Nonapeptides derived from both alleles were predicted to bind to HLA A68.1. Thus two alleles of CD33 protein exist that could be mHA. With an alternate allele frequency of < 10%, allo-responses against CD33 would be uncommon after marrow transplantation. However, donors homozygous for this allele could be used to generate cytotoxic T cells against the frequent CD33 allele, for adoptive therapy of leukaemia.

Specific depletion of alloreactive T cells in HLA-identical siblings: a method for separating graft-versus-host and graft-versus-leukaemia reactions

Accumulating evidence indicates that alloreactive donor T cells confer both graft-versus-host (GVH) and graft-versus-leukaemia (GVL) reactivity following allogeneic bone marrow transplantation. We have developed a method to deplete alloreactive donor T cells with an immunotoxin targeting the alpha chain of the IL-2 receptor. In patients with chronic myeloid leukaemia and their HLA-identical sibling donors, we measured donor helper T-lymphocyte precursor frequencies (HTLPf) against recipient peripheral blood mononuclear cells (PBMNC; donor versus host), recipient leukaemia cells (donor versus leukaemia) and third-party PBMNC, before and after the depletion. In seven pairs there was a 4.3-fold reduction of donor-versus-host HTLPf (P=0.017), without a significant change in the donor frequencies against third party (P=0.96). In eight further donor-recipient pairs, immunotoxin-depleted donor versus patient PBMNC HTLPf 4.5-fold (mean 1/155,000 before and 1/839,000 after depletion, P=0.007). There was a smaller non-significant 1.8-fold reduction in donor-versus-leukaemia HTLPf from 1/192,000 to 1/334,000 (P=0.19). These results suggest that selective T-cell depletion can significantly deplete donor anti-host reactivity while conserving anti-leukaemia reactivity in HLA-matched donor-recipient pairs.

T cell-depleted granulocyte colony-stimulating factor (G-CSF) modified allogenic bone marrow transplantation for hematological malignancy improves graft CD34+ cell content but is associated with delayed pancytopenia

To increase the stem cell content of T cell-depleted bone marrow transplants (BMT), we treated 12 patients with hematological malignancies with BMT from HLA-identical sibling donors given G-CSF 10 microg/kg/day for 5 days before marrow harvest. After CD34+ cell selection, patients received a median of 1.7 (range, 0.82-3.1) x 10(6) CD34+ cells/kg and 2.3 (range, 0.25-4.0) x 10(5) CD3+ cells/kg. All patients had initial engraftment but four developed pancytopenia between days 55-130 post-BMT. In two patients, this required a second infusion of G-CSF-mobilized donor peripheral blood progenitor cells. We observed no delayed pancytopenia in a matched historical group of 24 patients receiving T cell-depleted BMT without prior G-CSF stimulation. Compared to this control group, G-CSF-stimulated marrow recipients showed a significant decline in neutrophil and monocyte counts after 8 weeks. However, outcome after BMT was otherwise comparable, with a similar incidence of acute graft-versus-host disease and transplant-related mortality. Disease-free survival was 63 vs 67% for controls matched for CD34+ cell dose (P = NS). These results indicate that G-CSF stimulation can increase the CD34+ cell content of T cell-depleted marrow but carries a risk of late graft failure.

Cytotoxic T lymphocytes specific for a nonpolymorphic proteinase 3 peptide preferentially inhibit chronic myeloid leukemia colony-forming units

We previously showed that a peptide (PR1) derived from the primary granule enzyme proteinase 3 induced peptide specific cytotoxic T lymphocytes (CTL) in a normal HLA-A2.1+ individual. These CTL showed HLA-restricted cytotoxicity to myeloid leukemias (which overexpress proteinase 3). To further investigate their antileukemic potential, we studied the ability of PR1-specific CTL, derived from two HLA-A2.1+ normal individuals, to inhibit colony-forming unit granulocyte-macrophage (CFU-GM) from normal and leukemic individuals. CTL from 20 day PR1 peptide-pulsed lymphocyte cultures showed 89% to 98% HLA-A2.1-restricted colony inhibition of chronic myeloid leukemia targets. Colony formation in normal HLA-A2.1+ bone marrow or HLA-A2.1- CML cells was not inhibited. Sequencing of the exon encoding PR1 showed that colony inhibition was not caused by polymorphic differences in proteinase 3 between effectors and targets. Analysis by flow cytometry showed that proteinase 3 was overexpressed in the leukemia targets compared with normal marrow targets (median channel fluorescence 1,399 v 298, P = .009). These results show that PR1-specific allogeneic T cells preferentially inhibit leukemic CFU-GM based on overexpression of proteinase 3, and that proteinase 3-specific CTL could be used for leukemia-specific adoptive immunotherapy.

Negative transcriptional regulation of human interleukin 2 (IL-2) gene by glucocorticoids through interference with nuclear transcription factors AP-1 and NF-AT

IL-2 gene transcription is affected by several nuclear proteins. We asked whether dexamethasone (Dex) and cyclosporin A (CsA) inhibit IL-2 gene transcription by interfering with the activity of nuclear proteins that bind to the IL-2 promoter. Nuclear extracts from primary human T lymphocytes were analyzed by electrophoretic DNA mobility shift assays. Both Dex and CsA inhibited the binding of transcription factors AP-1 and NF-AT, but not of NF-kB and OCT-1/OAF, to their corresponding sites on the IL-2 gene promoter. To correlate changes in nuclear factor binding in vitro with transcriptional activity in vivo and define the structural requirements for IL-2 promoter repression, we used transient DNA transfections. Jurkat cells were transfected with plasmids containing either the intact IL-2 promoter or its AP-1, NF-AT, and NF-kB motifs. Dex inhibited the IL-2 promoter and the AP-1, but not the NF-AT and NF-kB plasmids. In contrast, CsA inhibited the IL-2 promoter and the NF-AT, but not the AP-1 and NF-kB plasmids. These results suggest that in human T lymphocytes both Dex and CsA inhibited IL-2 gene transcription through interference with transcription factors AP-1 and NF-AT. We propose that, while maximum inhibition may involve interaction with both transcription factors, AP-1 is the primary target of Dex.

Dissociation of catalytic and invasive activities of Bordetella pertussis adenylate cyclase

Bordetella pertussis organisms secrete adenylate cyclase, at least one form of which can invade host cells and appears to be a virulence factor. Treatment of urea extracts containing invasive cyclase of B. pertussis with trypsin, chymotrypsin, or subtilisin abolishes the ability to increase intracellular cyclic AMP levels in CHO cells (invasiveness) at concentrations that have minimal or no effects on adenylate cyclase activity. Higher protease concentrations can inhibit catalytic activity, and 1 microM calmodulin protects this catalytic activity, but not invasiveness, against proteolytic inhibition. Rabbit immunoglobulin G (IgG) fractions from antisera prepared against urea extracts inhibited invasiveness at 10-fold-lower concentrations than inhibited catalytic activity. One IgG from a rabbit immunized against a partially purified, noninvasive form of the B. pertussis adenylate cyclase inhibited catalytic activity but was ineffective against invasiveness. We conclude that these two properties of the adenylate cyclase are independent functions that reside on different domains of the same protein or on different proteins.

Modulation of invasiveness and catalytic activity of Bordetella pertussis adenylate cyclase by polycations

Penetration of Bordetella pertussis adenylate cyclase into CHO cells was monotonically inhibited by polylysines, with a minimum degree of polymerization of greater than 6 and less than or equal to 9 to 10. Above this level, inhibitory potency per lysyl residue was independent of polymer length; 50% inhibition was obtained with 60 microM lysine monomer. Other polycations were also potent inhibitors. The adenylate cyclase itself showed a biphasic (stimulation-inhibition) response, with a similar independence of polymer length above a certain minimum. Half-maximal inhibitory concentrations for cyclic AMP accumulation corresponded to half-maximal stimulatory concentrations of poly-L-lysine for the cyclase. The inhibitory effect of polylysines on cyclic AMP accumulation was not reversed by washing or enzymatic removal of neuraminic acid. We conclude that charge-charge interactions play an important role in the penetration of B. pertussis adenylate cyclase into host cells.

Extracellular cAMP formation from host cell ATP by Bordetella pertussis adenylate cyclase

The effect of exogenously added adenylate cyclase from Bordetella pertussis (strain 114) has been investigated in Y-1 mouse adrenal tumor, chinese hamster ovary (CHO) and several other cells. A partially purified adenylate cyclase was found not to enter cells but, nevertheless, produced large amounts of cAMP in the medium. We could show that this resulted from release of ATP (and not larger molecules). The ATP released by the cells could be (1) directly measured and was replenished after each change of medium; (2) was reciprocally related to the cAMP produced; and (3) was competed for by ATPases present in added serum or by hexokinase and, less effectively, by exoenzymes on the cell surface. The extent of ATP leakage varied widely between different cell lines, being marked in CHO and Y-1 adrenal cells but negligible in transformed lymphocyte lines. The uncertainty of the origin of cAMP found in media of cultured cells requires separate analysis of cell and medium cAMP and an assessment of ATP leakage.