Characterization of resident lymphocytes in human pancreatic islets.

The current view of type 1 diabetes (T1D) is that it is an immune-mediated disease where lymphocytes infiltrate the pancreatic islets, promote killing of beta cells and cause overt diabetes. Although tissue resident immune cells have been demonstrated in several organs, the composition of lymphocytes in human healthy pancreatic islets have been scarcely studied. Here we aimed to investigate the phenotype of immune cells associated with human islets of non-diabetic organ donors. A flow cytometry analysis of isolated islets from perfused pancreases (n = 38) was employed to identify alpha, beta, T, natural killer (NK) and B cells. Moreover, the expression of insulin and glucagon transcripts was evaluated by RNA sequencing. Up to 80% of the lymphocytes were CD3+ T cells with a remarkable bias towards CD8+ cells. Central memory and effector memory phenotypes dominated within the CD8+ and CD4+ T cells and most CD8+ T cells were positive for CD69 and up to 50-70% for CD103, both markers of resident memory cells. The frequency of B and NK cells was low in most islet preparations (12 and 3% of CD45+ cells, respectively), and the frequency of alpha and beta cells varied between donors and correlated clearly with insulin and glucagon mRNA expression. In conclusion, we demonstrated the predominance of canonical tissue resident memory CD8+ T cells associated with human islets. We believe that these results are important to understand more clearly the immunobiology of human islets and the disease-related phenotypes observed in diabetes.

Enterovirus infection of human islets of Langerhans affects ß-cell function resulting in disintegrated islets, decreased glucose stimulated insulin secretion and loss of Golgi structure.

AIMS/HYPOTHESIS: In type 1 diabetes (T1D), most insulin-producing ß cells are destroyed, but the trigger is unknown. One of the possible triggers is a virus infection and the aim of this study was to test if enterovirus infection affects glucose stimulated insulin secretion and the effect of virus replication on cellular macromolecules and organelles involved in insulin secretion. METHODS: Isolated human islets were infected with different strains of coxsackievirus B (CVB) virus and the glucose-stimulated insulin release (GSIS) was measured in a dynamic perifusion system. Classical morphological electron microscopy, large-scale electron microscopy, so-called nanotomy, and immunohistochemistry were used to study to what extent virus-infected ß cells contained insulin, and real-time PCR was used to analyze virus induced changes of islet specific genes. RESULTS: In islets infected with CVB, GSIS was reduced in correlation with the degree of virus-induced islet disintegration. The expression of the gene encoding insulin was decreased in infected islets, whereas the expression of glucagon was not affected. Also, in islets that were somewhat disintegrated, there were uninfected ß cells. Ultrastructural analysis revealed that virus particles and virus replication complexes were only present in ß cells. There was a significant number of insulin granules remaining in the virus-infected ß cells, despite decreased expression of insulin mRNA. In addition, no typical Golgi apparatus was detected in these cells. Exposure of islets to synthetic dsRNA potentiated glucose-stimulated insulin secretion. CONCLUSIONS/INTERPRETATION: Glucose-stimulated insulin secretion; organelles involved in insulin secretion and gene expression were all affected by CVB replication in ß cells.

Characterization of human organ donors testing positive for type 1 diabetes-associated autoantibodies.

In this study we aim to describe the characteristics of non-diabetic organ donors with circulating diabetes-associated autoantibodies collected within the Nordic Network for Islet Transplantation. One thousand and thirty organ donors have been screened in Uppsala for antibodies against glutamic acid decarboxylase (GADA) and islet antigen-2 (IA-2A). The 32 non-diabetic donors that tested positive for GADA (3.3% of all non-diabetic donors) were studied in more detail, together with 32 matched controls. Mean age among the autoantibody-positive donors was 52.6 (range 21-74), family history of type 1 diabetes (T1D) was unknown, and no donor was genetically predisposed for T1D regarding the human leucocyte antigen (HLA) locus. Subjects were analysed for islet cell antibodies (ICA), insulin autoantibodies (IAA) and zinc transporter 8 antibodies (ZnT8A), and pancreas morphology and clinical data were examined. Eight non-diabetic donors tested positive for two antibodies and one donor tested positive for four antibodies. No insulitis or other signs of a diabetic process were found in any of the donors. While inflammatory cells were present in all donors, subjects with high GADA titres had significantly higher CD45 cell numbers in exocrine tissue than controls. The extent of fibrosis was more pronounced in autoantibody-positive donors, even in subjects with lower GADA titres. Notably, it is possible that events not related directly to T1D (e.g. subclinical pancreatitis) may induce autoantibodies in some cases.

Alcohol consumption and overall accident mortality in 14 European countries.

AIMS: To evaluate the effects of changes in aggregate alcohol consumption on overall accident mortality in 14 western European countries after 1950, and to compare traditional beer, wine, and spirits countries with respect to the impact of alcohol. DESIGN, SETTING AND PARTICIPANTS: The countries were sorted into three groups--traditional spirits countries of northern Europe, traditional beer countries of central Europe and wine countries of southern Europe. Gender- and age-specific annual mortality rates were analysed in relation to per capita alcohol consumption, utilizing the Box-Jenkins technique for time series analysis. All series were different to remove long-term trends. The results of the analyses in individual countries were pooled within each group of countries to increase the statistical power. MEASUREMENTS: Overall accident mortality data for 5-year age groups were converted to gender and age specific mortality rates in the age groups 15-29, 30-49 and 50-69 years. Rates were age adjusted within groups. Data on per capita alcohol consumption were converted to consumption per inhabitant 15 years and older. FINDINGS: The analyses demonstrated a statistically significant and positive relationship between changes in aggregate alcohol consumption in all three groups of countries. The estimated effect parameter was larger in northern Europe than in central Europe, and smallest in southern Europe. CONCLUSION: The results are compatible with the hypothesis that accident mortality rates are influenced by per capita alcohol consumption in southern, central and northern Europe. However, alcohol appears to play a larger role in northern Europe than in southern Europe.

Alcohol consumption and mortality rates from traffic accidents, accidental falls, and other accidents in 14 European countries.

AIMS: To evaluate the effects of changes in aggregate alcohol consumption on fatal motor vehicle traffic accidents, accidental falls, and other accidents in 14 western European countries after 1950, and to compare traditional beer, wine and spirits countries. DESIGN, SETTING AND PARTICIPANTS: The countries were sorted into three groups. Gender-specific, age-adjusted annual mortality rates (15-69 years) were analysed in relation to per capita alcohol consumption, utilizing the Box-Jenkins technique for time series analysis. All series were different to remove long-term trends. The results of the analyses of individual countries were pooled within each group of countries to increase the statistical power. MEASUREMENTS: Overall accident mortality data for 5-year age groups were converted to age-adjusted mortality rates for the age group 15-69 years, using a European standard population. Data on per capita alcohol consumption were converted to consumption per inhabitant 15 years and older. FINDINGS: For male accidental falls, the analyses uncovered a statistically significant association with alcohol consumption in northern and central Europe, but not in southern Europe. Among females the association was insignificant in all regions. For male traffic accidents, significant relationships were uncovered in central and southern Europe, but not in northern Europe. Among females the effect was significant only in central Europe. For the remaining fatal accidents a significant relationship was found for north European males only. CONCLUSION: The association between aggregate alcohol consumption and rates of fatal accidents is mainly due to traffic accidents in central and southern Europe, and to falls and other accidents in northern Europe.

Alcohol and mortality: methodological and analytical issues in aggregate analyses.

This supplement includes a collection of papers that aim at estimating the relationship between per capita alcohol consumption and various forms of mortality, including mortality from liver cirrhosis, accidents, suicide, homicide, ischaemic heart disease, and total mortality. The papers apply a uniform methodological protocol, and they are all based on time series data covering the post-war period in the present EU countries and Norway. In this paper we discuss various methodological and analytical issues that are common to these papers. We argue that analysis of time series data is the most feasible approach for assessing the aggregate health consequences of changes in population drinking. We further discuss how aggregate data may also be useful for judging the plausibility of individual-level relationships, particularly those prone to be confounded by selection effects. The aggregation of linear and curvilinear risk curves is treated as well as various methods for dealing with the time-lag problem. With regard to estimation techniques we find country specific analyses preferable to pooled cross-sectional/time series models since the latter incorporate the dubious element of geographical co-variation, and conceal potentially interesting variations in alcohol effects. The approach taken in the papers at hand is instead to pool the country specific results into three groups of countries that represent different drinking cultures; traditional wine countries of southern Europe, beer countries of central Europe and the British Isles and spirits countries of northern Europe. The findings of the papers reinforce the central tenet of the public health perspective that overall consumption is an important determinant of alcohol-related harm rates. However, there is a variation across country groups in alcohol effects, particularly those on violent deaths, that indicates the potential importance of drinking patterns. There is no support for the notion that increases in per capita consumption have any cardioprotective effects at the population level.

An experimental study of a change from over-the-counter to self-service sales of alcoholic beverages in monopoly outlets.

OBJECTIVE: To evaluate if a change from over-the-counter to self-service sales of alcoholic beverages in monopoly outlets has an impact on the sales volume. METHOD: Fourteen Swedish towns were selected, each having only one state-run monopoly shop selling alcoholic beverages. Seven pairs were formed by matching towns in terms of demographic and economic criteria, and according to sales of alcoholic beverages. Within each pair, one town continued with the traditional over-the-counter sales, while the other switched to self-service sales of beer, wine and spirits. This was decided by randomization. The effect of switching to self-service was evaluated by comparing monthly sales volume of experimental and control towns over an extended period of time. In order to evaluate changes due to transfer of customers from neighboring towns, the sales statistics in these towns were analyzed. In two towns, this transfer was also evaluated with the aid of customer surveys before and after the change. RESULTS: It was found that the change produced an increase in sales volume of 17%. The increase was permanent. Approximately one half of the increase could be explained by an inflow of new customers from neighboring towns. CONCLUSIONS: The self-service shops became quite popular among the customers, and sales volume increased substantially. About one half of the increase appears to be due to new customers from neighboring towns. The remaining increase may be due to increased consumption by the local residents. Thus, the results seem to confirm the hypothesis that the physical availability of alcoholic beverages may affect consumption levels.

The prevention paradox revisited.

The contribution of heavy and moderate drinkers, respectively, to the rate of alcohol problems in society is evaluated for different types of risk functions. It is demonstrated that if the risk function is linear, the moderate drinkers will be responsible for the bulk of the problems. When the risk function is curved upwards, the heavy drinkers contribute a larger share of the problem. However, the risk function needs to be quite strongly curved before the majority of the problems can be attributed to the heavy drinkers. These calculations are based on certain empirically motivated assumptions about the distribution of the consumers along the consumption scale. The results suggest that the validity of the prevention paradox depends very much on the shape of the risk function, and hence that the role of the moderate drinkers may vary a lot across the spectrum of alcohol-related disabilities. For disabilities where the risk curve has a pronounced threshold-like form, the prevention paradox cannot be expected to apply. However, the role of the moderate drinker could be expected to be more significant for disabilities with a smoother and less convex risk curve. Accidents and social problems seem to fulfil the latter qualification, because the causal mechanism underlying such problems are connected to rates of acute intoxication, rather than to annual intake per se.

Public health consequences of the J-curve hypothesis of alcohol problems.

This paper addresses some issues related to the hypothesis that the risk for premature death is a J-shaped function of alcohol intake. The first part of the paper contains a discussion of the individual level epidemiological evidence. It is argued that the evidence is not yet good enough to allow precise statements about "safe limits", nor does it allow a precise location of the "optimum" consumption level. Measurement errors and confounding variables not yet controlled for remain substantial problems. In particular, future studies need to control for social integration, as this factor may affect both health status and alcohol consumption. The second part of the paper discusses the population level relationship. It is argued that, typically, what is optimum for an individual is too much for a population. Unintended side effects of major public health importance should be expected in this area. In the last section, a plea is made for aggregate level studies as a way of addressing the public health side of the issue.

Potential consequences from possible changes to Nordic retail alcohol monopolies resulting from European Union membership.

This paper projects the consequences of modifying or eliminating the current national alcohol retail monopolies in Sweden, Norway and Finland as a possible result of those countries' membership in the European Union (EU). First, the authors project absolute alcohol consumption in each country based on different possible changes in alcohol price and availability. Then they predict the future levels of alcohol-related problems likely to result from increased per capita alcohol consumption (Sweden and Norway only). All of the scenarios examined in this paper are expected to lead to increases in per capita alcohol consumption. The smallest increase in consumption would result from a partial elimination of the current monopoly and a modest reduction in alcohol prices. In that case, projected per capita consumption in Sweden for inhabitants 15 years and older would rise from 6.3 to 9.3 litres; in Norway, from 4.7 to 6.7 litres; and in Finland, from 8.4 to 11.1 litres. The greatest projected increase in consumption would result from a complete elimination of the state monopolies such that all beer, wine and spirits were sold in food shops, grocery stores and gasoline stations, along with a substantial drop in alcohol prices as a result of private competition within each country and increased cross-border alcohol purchases. That scenario would result in projected per capita consumption of 12.7 litres in Sweden, 11.1 litres in Norway and 13.7 litres in Finland. The authors project that a 1-litre increase in consumption would result in a 9.5% increase in total alcohol-related mortality in Sweden and a 9.7% increase in Norway. Further, alcohol-related assaults would increase by 9% in Sweden and 9.6% in Norway. A 5-litre increase in consumption would result in a 62% increase in alcohol-related mortality in Sweden and a 60% increase in Norway, and a 57% increase in alcohol-involved assaults in both countries.

Alcohol and suicide--the Portuguese experience.

An analysis of regional (18 regions) and temporal (1931-89) covariation of suicide rates and indicators of alcohol use and abuse in Portugal is reported. In the time series analysis, a positive relationship was found. An increase in per capita alcohol consumption of one litre is accompanied by a simultaneous increase in the male suicide rate of 1.9 per cent. This is comparable to what has been reported for France and Denmark, but considerably less than that found in Norway, Sweden and Hungary. In the regional data, there was a substantial negative correlation between the variables. However, after controlling for religious and family integration, the latter correlation became small and insignificant but still negative. A possible explanation is suggested for the different outcomes of the two analyses.

Alcohol and suicide in Denmark 1911-24--experiences from a 'natural experiment'.

In 1916-17, prices of alcoholic beverages increased dramatically in Denmark, and alcohol consumption decreased strongly. On the basis of this 'natural experiment', the effect of variations in per capita alcohol consumption on suicide rates is estimated, and compared to Norström's analysis of Danish data from the period 1931-80, as well as similar analyses from other countries. It is concluded that per capita alcohol consumption is probably related to the suicide rate in Denmark, but to a less extent than in some other countries.

The tail of the alcohol consumption distribution.

The consumption containment rate (CCR), proposed by Taylor as a way of characterizing the upper tail of the alcohol consumption distribution, is analyzed and estimated from a collection of data sets from different countries. It is found that CCR curves for different countries are highly different at low consumption levels. However, at high consumption levels, they are remarkably similar across cultures. It is proposed that this may be due to cross-cultural similarities in heavy drinking careers.

The development of alcoholics' and heavy drinkers' consumption: a longitudinal study.

Results are reported from two prospective longitudinal studies of heavy drinkers and alcoholics who have received treatment. The present study focuses on the drinking habits of subjects who have been interviewed four times after the end of treatment. The data uncover substantial changes in heavy drinkers' and alcoholics' consumption level over time, and these observed changes are only partly explainable in terms of measurement error and short-term fluctuations. Changes show signs of accumulation over time. This suggests that heavy drinkers' and alcoholics' consumption level is very unstable over longer periods. The signs of systematic progression are weak. No convincing evidence for loss of control is found, and neither is there convincing evidence for a strong and persistent progression towards heavier drinking. At all levels substantial changes are found, and these are nearly equally strong in both directions. It is concluded that the observed pattern of change more resembles an indeterministic (or stochastic) process than a systematic natural history of a disease.

The validity of self-reported drug use.

Response errors in self-reported drug questionnaires are evaluated, with particular reference to incidence and prevalence estimates. A simple model of response errors is defined, and some analytical results are obtained from this model. By assuming independence of response errors at different points in time, estimates for response errors are obtained from panel data. The results suggest that while the frequency of false negatives may be larger than the frequency of false positives, the latter error may nevertheless produce large errors in prevalence estimates, particularly if the prevalence rate is small.