Support after return to alcohol use: a mixed-methods study on how abstinence motivation and app use change after return to alcohol use in an app-based aftercare intervention for individuals with alcohol use disorder

BACKGROUND

As the return to alcohol use in individuals with alcohol use disorder (AUD) is common during treatment and recovery, it is important that abstinence motivation is maintained after such critical incidences. Our study aims to explore how individuals with AUD participating in an app-based intervention with telephone coaching after inpatient treatment perceived their abstinence motivation after the return to alcohol use, whether their app use behavior was affected and to identify helpful factors to maintain abstinence motivation.

METHODS

Using a mixed-methods approach, ten participants from the intervention group of the randomized controlled trial SmartAssistEntz who returned to alcohol use and recorded this in the app Appstinence, a smartphone application with telephone coaching designed for individuals with AUD, were interviewed about their experiences. The interviews were recorded, transcribed and coded using qualitative content analysis. App use behavior was additionally examined by using log data.

RESULTS

Of the ten interviewees, seven reported their abstinence motivation increased after the return to alcohol use. Reasons included the reminder of negative consequences of drinking, the desire to regain control of their situation as well as the perceived support provided by the app. App data showed that app use remained stable after the return to alcohol use with an average of 58.70 days of active app use (SD = 25.96, Mdn = 58.50, range = 24-96, IQR = 44.25) after the return to alcohol use which was also indicated by the participants' reported use behavior.

CONCLUSIONS

The findings of the study tentatively suggest that the app can provide support to individuals after the return to alcohol use to maintain and increase motivation after the incidence. Future research should (1) focus on specifically enhancing identification of high risk situations and reach during such critical incidences, (2) actively integrate the experience of the return to alcohol use into app-based interventions to better support individuals in achieving their personal AUD behavior change goals, and (3) investigate what type of support individuals might need who drop out of the study and intervention and discontinue app use altogether.

TRIAL REGISTRATION

The primary evaluation study is registered in the German Clinical Trials Register (DRKS, registration number DRKS00017700) and received approval of the ethical committee of the Friedrich-Alexander University Erlangen-Nuremberg (193_19 B).

Attentional impulsivity accounts for the association of antisociality with craving and mental health problems in incarcerated individuals with substance dependence

PURPOSE

Prisoners with substance use disorder (SUD) are at risk of mental health problems. Given the common co-occurring of psychopathic traits with SUDs, probably because of underlying impulsive traits (Ellingson et al., 2018), this study aims to examine the relation between psychopathy (impulsive antisociality and fearless dominance) and the functioning of incarcerated individuals with SUD. The authors investigated whether impulsivity (motor, nonplanning and attentional) can account for the relationship between one psychopathy facet (impulsive antisociality) and craving and mental health problems.

DESIGN/METHODOLOGY/APPROACH

The authors assessed self-reported impulsivity, psychopathy, craving and mental health problems in 121 male incarcerated individuals with SUD and calculated cross-sectional linear regression analyses and mediation models.

FINDINGS

Impulsive antisociality was positively related to all impulsivity facets, craving and mental health problems. Attentional impulsivity mediated the relationship of impulsive antisociality with craving and mental health problems. Fearless dominance was related to lower attentional and nonplanning impulsivity, craving and mental health problems.

RESEARCH LIMITATIONS/IMPLICATIONS

Future studies should investigate these relations in longitudinal studies and evaluate tailored approaches, for example, mindfulness interventions.

PRACTICAL IMPLICATIONS

Interventions to reduce craving and improve mental health might be important for those who display self-centered, antisocial behavior but are less relevant for those with fearless, dominant interpersonal behavior. Addressing attentional impulsivity may be of special interest in this regard.

ORIGINALITY/VALUE

To the best of the authors' knowledge, this study was the first to investigate the mediating role of different impulsivity facets for the association of impulsive antisociality with craving and with mental health problems in incarcerated individuals with SUD.

Psychometrische Evaluation der deutschen Version des Substance Use Recovery Evaluator (SURE)

Zusammenfassung. Konsumvariablen und Abstinenz scheinen unzureichend zur Erfassung der Genesung bei Personen mit einer Alkoholkonsumstörung. Stattdessen rücken patientenzentrierte Indikatoren wie die Lebensqualität zunehmend in den Vordergrund. Um den Forderungen adäquater Messinstrumente gerecht zu werden, wurde der Substance Use Recovery Evaluator von Neale et al. (2016 ) übersetzt und in verschiedenen Stichproben mit Alkoholkonsumstörung nach Entzugsbehandlung psychometrisch evaluiert. In der ersten Teilstichprobe ( n = 135) wurde explorativ die Faktorenstruktur identifiziert sowie Reliabilitäts- und Validitätsmaße (Zusammenhänge mit Alkoholkonsum, Craving und gesundheitsbezogener Lebensqualität) berechnet. In der zweiten Stichprobe ( n = 120) wurde die gefundene Struktur konfirmatorisch geprüft. Das Verfahren erwies sich als reliabel und valide. Die im Original vorgeschlagene fünffaktorielle Struktur zeigte einen guten Fit, wenn auch in der vorliegenden Studie eine dreifaktorielle Struktur etwas geeigneter erschien. Diese Ergebnisse wurden in einer dritten Stichprobe ( n = 224) größtenteils gestützt. Trotz Limitationen (z. B. kleine Stichprobe) erwies sich der deutsche SURE als psychometrisch abgesicherter Indikator der Genesung von einer Alkoholkonsumstörung.

Pilot testing of an adaptive, individualized inhibitory control training for binge drinking: first evidence on feasibility, acceptance, and efficacy

Background

Deficits in inhibitory control seem to promote habit behavior and therefore play an important role in the development and maintenance of addictive diseases. Although several training approaches have been suggested, there is a considerable lack of knowledge about the best way to improve inhibitory control. Based on a literature review regarding shortcomings of existing trainings, an individualized, adaptive inhibitory control training was developed. We aimed to assess feasibility and acceptance of this training and to provide preliminary results on its efficacy regarding inhibitory control and binge drinking.

Methods

Sixty-one individuals (30 female) with binge drinking behavior were randomly allocated to either an experimental group receiving three sessions of the inhibitory control training or a waitlist control group receiving no training. Before and after the training, the participants performed a Go/NoGo task to assess inhibitory control (commission errors and false reaction time), completed a questionnaire on drinking-related self-control, and reported drinking behavior.

Results

Although the training was feasible and accepted by participants, it did not affect self-control over drinking, inhibitory control or drinking behavior. The relationship between session number and false reaction time was linear for alcohol stimuli, but squared for neutral stimuli.

Conclusion

Although our findings have to be interpreted in the light of some shortcomings, they demonstrate that further research is needed to enhance our understanding of how to improve inhibitory control and which factors might moderate this process.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00426-022-01725-4.

App-based maintenance treatment for alcohol use disorder after acute inpatient treatment: Study protocol for a multicentre randomized controlled trial

BACKGROUND

Alcohol use disorder, a prevalent and disabling mental health problem, is often characterized by a chronic disease course. While effective inpatient and aftercare treatment options exist, the transferal of treatment success into everyday life is challenging and many patients remain without further assistance. App-based interventions with human guidance have great potential to support individuals after inpatient treatment, yet evidence on their efficacy remains scarce.

OBJECTIVES

To develop an app-based intervention with human guidance and evaluate its usability, efficacy, and cost-effectiveness.

METHODS

Individuals with alcohol use disorder (DSM-5), aged 18 or higher, without history of schizophrenia, undergoing inpatient alcohol use disorder treatment (N = 356) were recruited in eight medical centres in Bavaria, Germany, between December 2019 and August 2021. Participants were randomized in a 1:1 ratio to either receive access to treatment as usual plus an app-based intervention with human guidance (intervention group) or access to treatment as usual plus app-based intervention after the active study phase (waitlist control/TAU group). Telephone-based assessments are conducted by diagnostic interviewers three and six weeks as well as three and six months after randomization. The primary outcome is the relapse risk during the six months after randomization assessed via the Timeline Follow-Back Interview. Secondary outcomes include intervention usage, uptake of aftercare treatments, AUD-related psychopathology, general psychopathology, and quality of life.

DISCUSSION

This study will provide further insights into the use of app-based interventions with human guidance as maintenance treatment in individuals with AUD. If shown to be efficacious, the intervention may improve AUD treatment by assisting individuals in maintaining inpatient treatment success after returning into their home setting. Due to the ubiquitous use of smartphones, the intervention has the potential to become part of routine AUD care in Germany and countries with similar healthcare systems.

Association of impulsivity with quality of life and well-being after alcohol withdrawal treatment

OBJECTIVES

Impulsivity is related to a higher risk of relapse in alcohol use disorders. However, besides drinking behavior, other recovery outcomes like physical and mental health-related quality of life are at least as important. The present study aimed to fill a research gap regarding the association of different impulsivity facets with health-related quality of life and well-being in alcohol use disorder.

METHODS

Individuals with a primary alcohol use disorder diagnosis (n = 167) were interviewed with standardized self-report measures at the progressed stage of their withdrawal treatment and 6 weeks thereafter. Multiple regression models were calculated to examine the association of impulsivity, craving, and drinking patterns with health-related quality of life and well-being 6 weeks after withdrawal treatment, as well as the predictive role of impulsivity assessed during withdrawal for these two outcomes.

RESULTS

Craving was associated with health-related quality of life and well-being 6 weeks after withdrawal. Likewise, non-planning and attentional impulsivity were associated with well-being 6 weeks after withdrawal. Motor impulsivity during withdrawal treatment predicted health-related quality of life 6 weeks thereafter.

CONCLUSION

Impulsivity seems to be negatively related to health-related quality of life and well-being in the first weeks after alcohol withdrawal treatment, probably to a higher extent than drinking patterns, but differentiating between its facets seems to be important. These findings emphasize the importance of treatment approaches aiming at reduced impulsivity in the early recovery process.

Selbstmitgefühl mediiert den Zusammenhang zwischen dysfunktionalen Persönlichkeitsstilen und der mentalen Gesundheit depressiver Patient_innen

Zusammenfassung. Theoretischer Hintergrund: Ein selbstunsicherer und Borderline-Persönlichkeitsstil scheinen positiv mit Symptomschwere und negativ mit Lebenszufriedenheit bei depressiven Personen zusammenzuhängen. Selbstmitgefühl könnte hierbei eine vermittelnde Rolle spielen. Fragestellung: Die vorliegende Studie untersuchte, ob ein geringeres Selbstmitgefühl den Zusammenhang eines selbstunsicheren bzw. Borderline-Persönlichkeitsstils mit geringerer Lebenszufriedenheit und höherer Symptomschwere vermittelt. Methode: In einer Querschnitts-Erhebung beantworteten 78 ambulante Patient_innen mit Majorer Depression Fragebögen zu Selbstmitgefühl, Lebenszufriedenheit, depressiver Symptomschwere und Persönlichkeitsstilen. Anschließend wurden Mediationsanalysen berechnet. Ergebnisse: Die Ergebnisse implizieren, dass ein geringeres Selbstmitgefühl den Zusammenhang zwischen einem selbstunsicheren Stil und depressiver Symptomschwere vermittelt. Insbesondere eine ausgeprägtere Selbstverurteilung vermittelte den Zusammenhang zwischen einem selbstunsicheren bzw. Borderline-Stil und geringerer Lebenszufriedenheit. Schlussfolgerungen: Selbstmitgefühl zu stärken und insbesondere Selbstverurteilung zu reduzieren könnte bei depressiven Patient_innen mit selbstunsicherem oder Borderline-Stil ein Ansatzpunkt zur Verbesserung der mentalen Gesundheit sein, was in Interventionsstudien untersucht werden sollte. Limitationen der Studie sind das querschnittliche Design und die geringe interne Konsistenz einzelner Selbstmitgefühls-Facetten.

Lower Emotion Regulation Competencies Mediate the Association between Impulsivity and Craving during Alcohol Withdrawal Treatment

There is evidence that craving mediates the relationship between Impulsive Personality Traits (IPTs) and relapse during the treatment of an Alcohol Use Disorder (AUD). To provide tailored interventions, a deeper understanding of the relation between IPTs and craving, namely mediating processes, is important. Based on previous literature, we proposed that lower emotion regulation competencies mediate the relation between attentional as well as non-planning IPTs and craving. To investigate these interrelations, we used data from the baseline assessment (n = 320) of the SmartAssistEntz project (pre-registered in the German Clinical Trials Register [DRKS00017700]). Inpatients with a primary AUD diagnosis were interviewed using standardized self-report measures (IPTs: BIS-15, emotion regulation competencies: ERSQ, craving: OCDS-G short version) during their withdrawal treatment. Indirect effects were calculated using the SPSS macro PROCESS v3.5. Attentional as well as non-planning, but not motor, IPTs were associated with craving. Emotion regulation competencies mediated the relationship between attentional as well as non-planning IPTs and craving. Given their mediating role in the present study, it is interesting to investigate if addressing emotion regulation competencies can mitigate the negative influences of attentional and non-planning IPTs. The direct effect of attentional IPTs implicates alternate mediating processes, which should also be investigated in future research.

Dyeless optical detection of ammonia in the gaseous phase using a pH-responsive polymer--characterization of the sorption process

pH-responsive polymers enable the dyeless optical detection of acidic or basic pollutants in air. The characterization of the sorption process and the optimization of the response time of the sensitive layers were high-lighted. The swelling of a pH-responsive polysiloxane induced by sorption of gaseous ammonia was investigated by measurement techniques such as spectroscopic ellipsometry (SE) and infrared spectroscopy (IR). Furthermore, the pH-responsive polymer was applied for the detection of gaseous ammonia using the LED-based reflectometric interference spectroscopy set-up (RIfS4lambda). A limit of detection of 0.30 mg/m3 ammonia and a response time (t90%) of 35 s could be verified. The application of pH-responsive polymers can be a powerful alternative to dye-based optical sensing, since photobleaching or leaching of the sensitive functional unit cannot occur applying this approach, and since the properties of the sensitive layer proved to be very promising.

Extravascular circulation of lipoproteins: their role in reverse transport of cholesterol

The transfer of lipoproteins out of plasma into peripheral tissues, their flow through the interstitium and their return to blood has been reviewed. In this context special emphasis has been given to reports dealing with the movement of lipoproteins into and out of the wall of arteries.

Gemfibrozil increases apolipoprotein A-I and cholesterol concentrations in human peripheral lymph

Peripheral lymph lipoproteins were studied in four hyperlipidaemic men before and after 6 weeks of treatment with gemfibrozil, a drug which is known to increase the fractional catabolic rate of very low density lipoproteins (VLDL) by raising lipoprotein lipase activity in peripheral tissues. Decreases in plasma triglycerides of 18-60% (mean, 45%) were accompanied by increases in lymph apolipoprotein (apo) A-I concentration of 30-108% (mean, 66%; P < 0.01), and in lymph cholesterol concentration of 35-100% (mean, 59%; P < 0.05). The additional lymph cholesterol was distributed over a broad range of lipoprotein particle sizes. Effects on plasma apo A-I concentration (mean, +7%) and plasma total cholesterol concentration (-7%) were not statistically significant. No changes were observed in four untreated control subjects. These findings are compatible with the hypothesis that lipolysis of VLDL at the blood-endothelium interface increases the transfer of apo A-I from plasma to interstitial fluids, and thereby promotes cholesterol efflux from cells.

Variability of plasma apolipoprotein (apo) A-II levels associated with an apo A-II gene polymorphism in monozygotic twin pairs

A dimorphic MspI RFLP (alleles M1 and M2) in an Alu unit 528 base pairs downstream from the apolipoprotein A-II gene on chromosome 1 was investigated for associations with dyslipoproteinaemia or coronary atherosclerosis. No significant differences were observed between the allele frequencies in healthy random controls (M2 = 0.850, n = 70) and patients with primary hypertriglyceridaemia (M2 = 0.846, n = 52) or severe coronary atherosclerosis (M2 = 0.819, n = 47). The apolipoprotein A-II gene may also contribute to the regulation of plasma levels or composition of HDL in response to environmental changes. To study the effect upon apolipoprotein A-II variability, 42 monozygotic twin pairs were genotyped for the MspI RFLP. Pairs with the genotype M2M2 (n = 28) had significantly smaller within-pair differences in plasma apolipoprotein A-II levels (2.2 vs 5.8 mg/dl, P < 0.02; Mann-Whitney) than those with other genotypes (n = 14). The M2 allele may be in linkage disequilibrium with a functional mutation that restricts the variability of plasma apolipoprotein A-II in response to environmental conditions. This provides a new example of a 'variability' gene, one of an important group of loci which may alter responses to hypolipidaemic therapy and cardiovascular risk.

Human peripheral lymph lipoproteins are enriched in sphingomyelin

The concentrations of total choline-containing phospholipids and of sphingomyelin have been determined in peripheral lymph from six volunteers. The concentration in lymph of total phospholipids was 14.6 +/- 6.0 mg/dl and of sphingomyelin 6.1 +/- 2.7 mg/dl; the estimated concentration of phosphatidylcholine (by subtracting the concentration of sphingomyelin from that of total choline-containing lipoproteins) was 8.5 +/- 5.1 mg/dl. The concentration of free choline in lymph was less than 1 mg/dl. The ratio of the concentration in lymph to that in the subject's own plasma of sphingomyelin was 0.18 +/- 0.07 and that of (estimated) phosphatidylcholine 0.05 + 0.04; the difference between these two ratios was significant at P less than 0.002. The present data are compatible with the hypothesis that some of lipoprotein phosphatidylcholine is lost while crossing from plasma to lymph.

Lipoproteins of human peripheral lymph. Apolipoprotein AI-containing lipoprotein with alpha-2 electrophoretic mobility

Evidence from diverse sources has implicated a central role of apolipoprotein AI (apo AI), the most abundant protein of plasma high-density lipoproteins, in the transport of cholesterol from peripheral tissues to the liver (reverse cholesterol transport). Particles containing only apo AI appear to be more effective as cholesterol acceptors in tissue culture than do particles which also contain apo AII. The apo AI-containing lipoproteins of plasma have been extensively studied, but there is less information on those in tissue fluids, to which most peripheral cells are exposed. In the present study the heterogeneity of apo AI-containing particles in human peripheral lymph, collected from the dorsum of the foot, has been examined by starch block electrophoresis, exclusion chromatography and immunoelectrophoresis. The apo AI-containing particles of lymph were found to be more variable in both electrophoretic mobility and size than those of plasma from the same subjects. Of particular interest was a subpopulation which migrated on electrophoresis with the same mobility as alpha-2-macroglobulin. This fraction accounted for approximately 7% (range: 4-12%; n = 5) of lymph apo AI, contained no immunodetectable apo AII, and by exclusion chromatography was composed of particles the size of, or smaller than, albumin. Such physicochemical properties suggest that these alpha-2 migrating particles may function as the principal primary acceptors of cell cholesterol in the extracellular matrix of human peripheral tissues. By isoelectric focusing, lymph apo AI was found to contain a higher proportion of more negatively charged isoforms than the apo AI of plasma.

Lipoproteins of human peripheral lymph

The concentration of cholesterol in peripheral lymph is roughly one tenth of that in the blood plasma of the same subject. In lymph, there is virtually no very low density lipoprotein (VLDL), probably due to low permeability of the vascular endothelium for particles of this size. More than 95% of apo B-containing lipoproteins of lymph have the density of plasma low density lipoproteins (LDL). The concentration of apo A-I and apo A-II in lymph is about 15% of that in plasma; yet about 50% of the total mass of both these main HDL apoproteins is present extravascularly. High density lipoproteins (HDL) of lymph appear square-packing, and the presence of such large HDL particles is the most conspicuous difference between lipoproteins in plasma and in the extravascular fluids. It remains to be seen whether raising plasma apo A-I concentration per se will increase the initial stages of reverse cholesterol transport and also be clinically beneficial.

The concentration of apolipoprotein A-II in human peripheral lymph

The concentration of apolipoprotein A-I (apoA-I) and of apolipoprotein A-II (apoA-II) was determined immunoelectrophoretically in lymph and plasma of six subjects. The concentration in lymph of apoA-I was 20.3 +/- 3.1 mg/dl, that of apoA-II was 4.6 +/- 0.5 mg/dl. The ratio of the concentration in lymph over that in plasma (CL/CP) for apoA-I was 0.14 +/- 0.1, that for apoA-II 0.14 +/- 0.01. Lymph and plasma samples from two subjects were fractionated by exclusion chromatography and the concentration of both apolipoproteins in resulting fractions was determined immunoelectrophoretically. ApoA-I of lymph eluted with fractions spanning a wider range of particle sizes than plasma apoA-I, while lymph apoA-II eluted predominantly with fractions that contained particles corresponding in size to plasma apoA-II-containing particles. It appears that the largest and smallest lymph HDL represent subspecies of Lp(A-I without A-II). These findings are discussed in the context of their possible bearing on initial stages of reverse transport of cholesterol.

Urine concentrations of apolipoprotein AI in renal tubular proteinuria

To test the hypothesis that a significant proportion of apolipoprotein AI (apoAI) metabolism occurs through glomerular filtration of free apoAI in serum and subsequent renal tubular metabolism, we have examined the urine concentration of apoAI in three situations in which proximal tubular reabsorption of another protein metabolized in this manner and retinol-binding protein (RBP) was impaired. Following infusion of a cross-linked gelatin polymer (Haemaccel) in four normal subjects, urine RBP excretion (normally about 100 micrograms/L), was between 14 and 46 mg/L, while urine apoAI excretion was less than 0.5 mg/L. On the third day following cardiac surgery involving Haemaccel infusion, urine RBP was between 27 and 159 mg/L while urine apoAI excretion was again less than 0.5 mg/L. In 16 samples from eight patients recently transplanted with allograft kidneys, urine RBP was between 9 and 70 mg/L, whereas in only two samples was apoAI detected in the urine at 0.5 mg/L. These results have been taken to indicate that significant metabolism of apoAI through glomerular filtration and tubular absorption is unlikely to occur in humans.

Human lymphedema fluid lipoproteins: particle size, cholesterol and apolipoprotein distributions, and electron microscopic structure

The concentration of cholesterol, apolipoproteins A-I, B, and E has been determined in lymphedema fluid from nine patients with chronic primary lymphedema. The concentrations were: 38.14 +/- 21.06 mg/dl for cholesterol, 15.6 +/- 6.17 mg/dl for apolipoprotein A-I, 7.5 +/- 2.8 mg/dl for apolipoprotein B, and 1.87 +/- 0.50 mg/dl for apolipoprotein E. These values represent 23%, 12%, 6%, and 38% of plasma concentrations, respectively. The ratio of esterified to unesterified cholesterol in lymphedema fluid was 1.46 +/- 0.45. Lipoproteins of lymphedema fluid were fractionated according to particle size by gradient gel electrophoresis and by exclusion chromatography. Gradient gel electrophoresis showed that a majority of high density lipoproteins (HDL) of lymphedema fluid were larger than ferritin (mol wt 440,000) and smaller than low density lipoproteins (LDL); several discrete subpopulations could be seen with the large HDL region. Fractionation by exclusion chromatography showed that more than 25% of apolipoprotein A-I and all of apolipoprotein E in lymphedema fluid was associated with particles larger than plasma HDL2. Apolipoprotein A-I also eluted in fractions that contained particles the size of or smaller than albumin. Isolation of lipoproteins by sequential ultracentrifugation showed that less than 25% of lymphedema fluid cholesterol was associated with apolipoprotein B. The majority of apolipoprotein A-containing lipoproteins of lymphedema fluid were less dense than those in plasma. Ultracentrifugally separated fractions of lipoproteins were examined by electron microscopy. The fraction d less than 1.019 g/ml contained little material, while fraction d 1.019-1.063 g/ml contained two types of particles: round particles 17-26 nm in diameter and square-packing particles 13-17 nm on a side. Fractions d 1.063-1.085 g/ml had extensive arrays of square-packing particles 13-14 nm in size. Fractions d 1.085-1.11 g/ml and fractions d 1.11-1.21 g/ml contained round HDL, 12-13 nm diameter and 10 nm diameter, respectively. Discoidal particles were observed infrequently.

The distribution of cholesterol and apoprotein A-I between the lipoproteins in plasma and peripheral lymph from normal human subjects

The lipoproteins of peripheral lymph and plasma from normal human subjects were separated according to their density by sequential ultracentrifugation and according to their size by gradient gel electrophoresis and gel exclusion chromatography. High density lipoproteins (HDL) carried a higher proportion of the total cholesterol in lymph than in plasma. Within the HDL fraction, the less dense and more lipid-rich component (HDL2) carried a higher proportion of the total HDL cholesterol in lymph than in plasma. Gradient gel electrophoresis showed (1) a higher proportion of large to small HDL particles in lymph than in plasma and (2) the presence of at least three populations of apo A-I-containing lipoproteins with Stokes diameters larger than the Stokes diameter of HDL2. Separation by gel exclusion chromatography showed that the proportion of large HDL particles with a high cholester: apo A-I ratio was greater in lymph than in plasma. In view of the sieving effect of the blood capillaries, which favours the passage across the capillary walls of smaller vs larger particles, we suggest that the higher ratio of large to small HDL particles in lymph than in plasma is due to the conversion of small to large HDL in the interstitial fluid by incorporation of cholesterol and other lipids from extravascular cells into the smaller particles.

Comparison of apoprotein B of low density lipoproteins of human interstitial fluid and plasma

Virtually all apoprotein B (apoB)-containing lipoproteins of the peripheral interstitial fluid of subjects with primary lymphoedema float in the ultracentrifugal field in the density interval 1.019-1.063 g/ml; in this respect they are similar to plasma low-density lipoproteins (LDL). 2. Virtually all apo-B-containing lipoproteins of interstitial fluid migrate in the electrophoretic field with pre-beta mobility; in this respect they are similar to plasma very-low-density lipoproteins. 3. The apoB of lipoproteins of interstitial fluid does not differ in terms of Mr from apoB-100 of human plasma [Kane, Hardman & Paulus (1980) Proc. Natl. Acad. Sci. U.S.A. 77, 2465-2469] as determined by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. 4. Both apoB of interstitial fluid and plasma are heterogenous in terms of their charge as determined by isoelectric focusing of their complexes with the nonionic detergent Nonidet P40. ApoB of plasma LDL focuses between pH5.9 and 6.65, and that of interstitial fluid LDL between pH 5.9 and 6.1. Thus the overall charge of apoB of interstitial fluid is more negative than that of its plasma LDL counterpart.

Effects of starvation and plasma exchange on lecithin: cholesterol acyltransferase activity and cholesterol efflux in cholesterol-fed pigs

The effects of starvation and of plasma exchange with a cholesterol-free substitute on efflux of tissue cholesterol and on lecithin: cholesterol acyltransferase (LCAT) activity in plasma and peripheral lymph were investigated in two pigs fed a cholesterol diet for 3-4 months. The pigs were labelled with i.v. [14C]cholesterol before plasma exchange or starvation. The cholesterol diet increased plasma total cholesterol concentration and LCAT activity in plasma and lymph, but had little effect on the rate of esterification of cholesterol in plasma or lymph. During cholesterol feeding, and when the animals were fed a normal diet, cholesterol esterification rates in plasma and lymph were much lower than the maximum rates achieved when LCAT was saturated with substrate, suggesting that LCAT in normal pig plasma and lymph is not saturated with substrate. Plasma exchange, carried out when the specific activity of tissue cholesterol exceeded that of plasma cholesterol, was followed by a brief rise in the specific activity of plasma cholesterol to a maximum value between the specific activities of muscle and adipose-tissue cholesterol, reflecting the transfer of radioactive cholesterol from tissue to plasma. During the rise in plasma total cholesterol specific activity there were no differences between the specific activities of low-density lipoprotein (LDL) cholesterol and high-density lipoprotein (HDL) cholesterol in plasma or lymph. Starvation had no effect on the plasma-cholesterol specific-activity curve. From about day 14 after labelling, cholesterol-specific activity decreased in the order: tissues greater than lymph greater than plasma. This suggests that the transfer of cholesterol from tissues to plasma was mediated by lipoproteins in the interstitial fluid.

Apoprotein B of lipoprotein(a) of human plasma

Lipoprotein(a) was purified by agarose-gel chromatography from human plasma from which lipoproteins of Sf greater than 0 had been removed either by sequential or by density-gradient ultracentrifugation. After delipidation, the apoprotein B of this lipoprotein was analysed by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. It could not be distinguished from the apoprotein B of low-density lipoproteins (rho 1.019-1.063 g/ml). A significant increase in the concentration of apoprotein B in plasma from which the Sf greater than 0 lipoproteins had been removed was observed in six subjects 4 h after a fatty meal.

Further evidence for the role of high density lipoprotein in the removal of tissue cholesterol in vivo

The lipoproteins of human peripheral lymph and plasma were separated according to particle size by polyacrylamide gradient gel electrophoresis. All samples of lymph contained lipoproteins that moved to the same positions on the gel as plasma LDL and plasma HDL. Some samples of lymph also contained lipoproteins with the mobility of VLDL and IDL. The lymph lipoproteins corresponding to plasma LDL reacted with anti-LDL serum and those corresponding to plasma HDL reacted with anti-HDL serum. In the lipoprotein fraction with the mobility of HDL, the proportion of particles larger than catalase was greater in lymph than in plasma. It is suggested that the shift in size distribution towards larger HDL particles in lymph compared with plasma is due to uptake of cholesterol from extravascular tissue by HDL particles after they have reached the interstitial fluid from the plasma, rather than to preferential movement of larger particles across the capillary walls.

The concentration of apolipoprotein A-I in human peripheral lymph

The concentration of apolipoprotein A-I in peripheral lymph of eight apparently healthy subjects has been determined by quantitative immunoelectrophoresis. Under steady-state conditions the average concentration of this apolipoprotein in lymph was 15.9 +/- 3.6 mg/dl, that is 12.24 +/- 2.3% of its concentration in plasma of the corresponding subjects. Apolipoprotein A-I could not be detected immunochemically in particles smaller than haemoglobin (Mr 67 000) when lymph was subjected to gel filtration on Sephacryl S300 superfine either by thin-layer or column modification of this method. Lymph and plasma from three subjects were fractionated by column gel filtration and apolipoprotein A-I determined by quantitative immunoelectrophoresis in delipidated fractions. It was found that the distribution of apolipoprotein A-I in lymph was shifted towards larger particles when compared to its distribution in plasma.

Evidence for the presence of tissue-free cholesterol in low density and high density lipoproteins of human peripheral lymph

The specific radioactivity of free and esterified cholesterol in the lipoproteins of human peripheral lymph was measured in 4 normal human subjects at various intervals after labelling the tissue cholesterol by a single intravenous injection of [14C]cholesterol. The free : esterified cholesterol specific-activity ratios in lymph LDL and HDL at short and long intervals after labelling in vivo suggest that both lipoproteins were capable of acting as acceptors for tissue-free cholesterol, but that in 3 of the 4 subjects the predominant acceptor was HDL.

Surface binding and catabolism of low-density lipoprotein by circulating lymphocytes from patients with abetalipoproteinaemia, with observations on sterol synthesis in lymphocytes from one patient

Surface binding of low-density lipoprotein (LDL), degradation of LDL protein and sterol synthesis were investigated in freshly isolated lymphocytes from normal and abetalipoproteinamic human subjects. LDL binding as a function of LDL concentration showed no evidence of the presence of high-affinity binding sites in fresh lymphocytes from either group of subjects. The rate of degradation of LDL protein by lymphocytes from the patients was no greater than that from the normal subjects and, in the fresh lymphocytes of the one patient studied, sterol synthesis was not increased. We conclude that the formation of LDL receptors and the synthesis of sterol in circulating lymphocytes are largely suppressed and that in normal subjects this may be due to the presence of some plasma constituent other than LDL, possibly the apoE protein. This conclusion is discussed in relation to the possible contribution of LDL receptors to the degradation of LDL protein in vivo.

Sterol balance in a patient with abetalipoproteinaemia

Total-body cholesterol synthesis was measured in a woman with abetalipoproteinaemia and in a normal woman of similar age. The rate of synthesis of cholesterol was 15.4 +/- 4.1 mg/kg/day in the patient and 14.3 +/- 2.6 mg/kg/day in the control subject, indicating that cholesterol synthesis in the whole body is not increased in the complete absence of plasma low density lipoprotein.

Biologically active low density lipoprotein in human peripheral lymph

We have compared the ability of human serum and peripheral lymph to suppress the activity of 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMG-CoA reductase), to activate cholesteryl ester synthesis, and to compete with 125I-labeled low density lipoprotein (LDL) for binding to LDL receptors in cultured human fibroblasts. Whole lymph was active in all three tests and the activity per unit volume in lymph was approximately equal to 1/10th that in serum. All three biologic activities in lymph were confined to the d less than 1.063 g/ml fraction. Whole lymph had no significant effect on HMG-CoA reductase activity in fibroblasts from a patient with homozygous familial hypercholesterolemia, whose cells lack LDL receptors. The LDL-like biologic activity per unit mass of immunologically active apoprotein B was approximately the same in lymph as in serum. The current data indicate that functionally active LDL is present in lymph and that the concentration of this lipoprotein is approximately equal to 1/10th that in serum.

Concentration of lipoproteins containing apolipoprotein B in human peripheral lymph

The concentration of apolipoprotein B (apoB) in human serum and peripheral lymph was measured by quantitative immunoelectrophoresis with anti-serum to human low-density lipoprotein. In four normal and six hyperlipidaemic subjects, total lymph apob/ml was 5-10% of total serum apoB/ml in the same subject. These ratios were equivalent to lymph apob concentrations of 60-120 microgram/ml. When the assays were carried out under conditions in which unmasking of immunoreactive sites on lymph and serum apoB was assumed to be maximal (delipidation with Nonidet P40), the lymph/serum apoB concentration ratios in three normal subjects were similar to those obtained with untreated lymph and serum.

The passage of apoproteins from plasma lipoproteins into the lipoproteins of peripheral lymph in man

1. The transport of apoprotein B from the lipoprotein of plasma into the lipoproteins of lymph draining the foot has been studied in four men with type III hyperlipoproteinaemia. 2. Three subjects were given autologous 125I-labelled very-low-density lipoprotein (VLDL) and 131I-labelled low-density lipoprotein (LDL) by intravenous injection; the fourth was given autologous 125I-labelled VLDL and 131I-labelled intermediate-density lipoprotein (IDL) plus LDL. 3. The 125I/131I ratios in serum and lymph apoprotein B, and the 125I and 131I specific radioactivities of apoprotein B in VLDL, IDL and LDL from serum and lymph, indicate that apoprotein B in the circulating VLDL can reach peripherallymph without the intermediacy of circulating LDL.

The metabolism in vivo and in vitro of plasma low-density lipoprotein from a subject with inherited hypercholesterolaemia

1. The metabolism in vivo and in vitro of an abnormal low-density lipoprotein (LDL) obtained from a patient with an inherited form of hypercholesterolaemia was compared with that of LDL obtained from a normal subject. 2. The rates of turnover of the apoprotein of the two types of LDL in a normal subject, and their uptake and catabolism by normal lymphocytes in vitro, were similar. 3. It is concluded that the abnormal behaviour of the patient's LDL may not be due to an abnormality in the apoprotein component.

The effect of ventromedial hypothalamic lesions on metabolism and insulin secretion in rats on a controlled feeding regimen

The metabolic effect of ventromedial hypothalamic (VMH) lesions, which are known to cause hyperphagia and obesity, has been studied in rats kept on a controlled light and food regimen. The animals were sacrificed at 4 different times during the second postoperative day. A feeding-induced hypersecretion of insulin was found to the VMH-lesioned animals. It was accompanied by a marked hypoglycemia as compared to the control groups during the feeding period. The glycogen content of liver and diaphragm in the lesioned groups is increased as compared to the controls during the same period. The VMH-lesioned animals showed hypertriglyceridemia both in the fed and fasted state, whereas the postabsorptive plasma levels of free fatty acids and glycerol were decreased. An increased level of urea was observed in all lesioned groups. This is in accordance with the demonstrated protein catabolism which follows VMH lesions.

Observations on the passage of apoproteins from plasma lipoproteins into peripheral lymph in two men

1. The passage of radioactive apolipoproteins into lymph draining the foot was investigated in two men, each given a single intravenous injection of low-density lipoprotein containing 131I-labelled apoprotein B and of very-low-density lipoprotein containing 125I-labelled apoprotein A and apoprotein C. 2. Protein-bound 125I and 131I appeared in the lymph of both subjects. Immunoelectrophoresis of lymph lipoproteins against anti-(high-density lipoprotein) and anti-(low-density lipoprotein) showed the presence of apo-high-density lipoprotein and apo-low-density lipoprotein with faster mobilities than plasma high-density and low-density lipoprotein respectively. Most of the protein-bound 131I in lymph was recovered in the precipitin line formed by the apoprotein B-containing lipoprotein after immunoelectrophoresis. Polyacrylamide gel electrophoresis of the lymph lipoprotein fraction showed the presence of 125I-containing bands with mobilities similar to those of the apoprotein A of high-density lipoprotein and of three of the fast-moving C apoproteins. 3. These results suggest that most, if not all, of the apoproteins of plasma lipoproteins reach the interstitial fluids and that some lipoproteins undergo modification during their passage into peripheral lymph.

The effect of nicotinic acid on the metabolism of the plasma lipoproteins of rhesus monkeys

The effect of nicotinic acid was investigated in Rhesus monkeys. Subcutaneous injections of nicotinic acid lower the plasma very low density lipoprotein (VVLDL) and low density lipoprotein (HDL) concentration. The fall in LDL concentration is not accompained by any change in the lipid or protein composition of either lipoprotein. Analysis by Sephadex gel chromatography and polyacrylamide-gel electrophoresis showed that the proteins of monkey VLDL and LDL are qualitatively similar to those of human VLDL and LDL, although there are differences in the proportions of the various proteins present in the two species. Subcutaneous injections of nicotinic acid diminish the maximum incorporation of 14C from [14C]threonine into VLDL and LDL apoproteins, but have no effect on incorporation into albumin or HDL apoprotein. Peak incorporations into the apo-B and apo-C of VLDL are diminished to about equal extents by nicotinic acid. Comparison of the amount of 14C lost from apo-B of VLDL after the peak of incorporation, with that gained by apo-B of LDL during the same period, suggests that some of the circulating apo-B of LDL IS DERIVED FROM SOURCES OTHER THAN CIRCULATING VLDL.

The metabolism of low-density lipoprotein in a patient with familial hyperbetalipoproteinaemia

1. Plasma low-density lipoprotein (LDL) from a patient with homozygous familial hyperbetalipoproteinaemia was labelled with 125I and LDL from a matched normal subject was labelled with 131I. The two samples of LDL were injected simultaneously into the patient and into a second normal subject.

2. In each subject the fractional rate of turnover of the two LDL samples was the same, but the fractional rate in the patient was less than half that in the normal subject.

3. It is concluded that the hyperbetalipoproteinaemia in the patient was not due to an abnormality in her LDL protein recognizable by her own body or by that of the normal recipient.

The lipids and lipoproteins of human peripheral lymph, with observations on the transport of cholesterol from plasma and tissues into lymph

1. The lipids and lipoproteins of lymph obtained from the dorsum of the foot were examined in seven human subjects.

2. The concentration of total cholesterol in lymph was about one-tenth that in plasma and was significantly correlated with the plasma total cholesterol concentration. The ratio of esterified to total cholesterol in lymph was similar to that in plasma.

3. Triglyceride was detectable in lymph, but the concentration was less than one-tenth that in plasma and was unrelated to the plasma triglyceride concentration.

4. No lipase activity was detectable in lymph, either before or after intravenous injection of heparin.

5. Cholesterol-esterifying activity was detected in four samples of lymph.

6. The major lipoprotein antigens of human plasma (apo-A, apo-B and apo-C) were present in whole lymph, but their distribution in fractions of different density was different from that in plasma.

7. [14C]Cholesterol, injected intravenously, appeared in lymph within 30 min of the injection, indicating that some of the cholesterol in lymph is derived directly from plasma.

8. At intervals greater than 29 days after a single intravenous injection of [14C]-cholesterol, the specific radioactivity of lymph cholesterol was greater than that of plasma cholesterol, indicating that some of the cholesterol in lymph is derived from tissue pools of cholesterol with slow turnover.

Lipoprotein lipase activity in the adipose tissue of rats adapted to controlled feeding schedules

1. The relationships between nutritional state, lipoprotein lipase activity in epididymal fat-pads, and the concentrations of glucose, insulin and unesterified fatty acids in the plasma were studied in rats that had been adapted for 3 weeks to one of two controlled feeding schedules. In one of these, rats had access to food for 14h during each 24h period, and in the other, they had access to food for 14h during each 48h period. Groups of animals were killed at different times during the 14h when they had access to food and during the following period when they were deprived of food. 2. Low lipoprotein lipase activity, low concentrations of plasma glucose and insulin and high concentrations of plasma unesterified fatty acids were found in rats deprived of food for 34h. Feeding resulted in increases in lipoprotein lipase activity and in the concentrations of glucose and insulin in the plasma. Enzyme activity continued to increase during the first 6-9h of the feeding period. 3. After adapted rats had been deprived of food for 12-16h there was a marked and unexpected increase in lipoprotein lipase activity; this occurred even when the rats were kept in an isolated environment. 4. The findings suggest that factors other than the absolute concentrations of insulin and glucose in the blood can exert a considerable influence on lipoprotein lipase activity in the epididymal fat-pad of a rat.