From fatty liver to end-stage liver disease through type 2 diabetes

The past decades have seen a marked increase in the incidence of type 2 diabetes and nonalcoholic fatty liver disease (NAFLD). Epidemiological studies have clearly demonstrated that there is an association between type 2 diabetes and NAFLD. Further, it has been established that patients with type 2 diabetes are at an increased risk of severe liver disease. While liver biopsy remains the gold standard for diagnosing NAFLD, it is not clear how - and if - the histological features of NAFLD are associated with an increased risk of type 2 diabetes. It is unclear how to identify the subset of patients with type 2 diabetes that have the highest risk of severe liver disease. Likewise, it is not known how the currently practiced treatment strategies for type 2 diabetes affect the progression of NAFLD. Finally, the risk of cancer in the broader population of patients with NAFLD is not well known. In the first paper, we investigated the risk of type 2 diabetes in a cohort of patients with biopsy-proven NAFLD and found that higher stages of fibrosis were associated with an increased risk of type 2 diabetes. In patients with small amounts of fibrosis, the amount of steatosis on biopsy was associated with an increased risk of type 2 diabetes. These results indicate that fibrosis and simple steatosis are useful histological variables when estimating risk of type 2 diabetes in patients with NAFLD. In the second paper, we assessed the risk of severe liver disease (defined as a composite outcome of diagnoses correlated to cirrhosis) in a population-based cohort of patients with type 2 diabetes. We observed type 2 diabetes to be associated with an increased risk of severe liver disease compared to controls free of diabetes, and identified several risk factors for severe liver disease in patients with type 2 diabetes. These results motivate further studies to better characterize the patients with type 2 diabetes that are at a high risk of severe liver disease. In the third paper, we studied how a personalized 4-day treatment program for type 2 diabetes currently used in clinical practice at the Karolinska University Hospital in Stockholm affects the progression of NAFLD. Patients were examined with transient elastography at baseline and at a follow-up visit after three months. The prevalence of NAFLD and increased liver stiffness was high. Improved glycemic control seen after the treatment program was associated with a reduction in hepatic steatosis in patients with NAFLD at baseline. These results indicate that improving glycemic control in type 2 diabetes per se can also be effective in treating NAFLD. In the fourth paper, we examined the risk of cancer in a population-based cohort of patients with NAFLD compared to matched reference individuals. We observed an association between NAFLD and a slightly increased risk of any cancer. Of the specific types of cancer we investigated, the strongest association was found between NAFLD and risk of HCC. A slightly increased risk was also observed for bladder, kidney and uterine cancer. Further, male patients with NAFLD had a slightly increased risk of colorectal cancer. These results do not motivate general screening for cancer in patients with NAFLD

Human natural killer cell activation and differentiation in health and viral infection

Natural killer (NK) cells are lymphocytes that belong to the innate immune system. They are important for the early defense against viral infections and provide tumor Immune surveillance against both solid tumors and leukemias as well as in settings of hematopoietic stem cell transplantation. They also play an important role in human pregnancy via spiral artery modulation, and deliver signals that shape adaptive immune responses. However, despite these insights, several unresolved issues remain with regards to mechanisms by which NK cells respond in these and other conditions. In this thesis, NK cell activation and differentiation in healthy uninfected individuals as well as in defined acute and chronic viral infections are characterized. Via a detailed analysis of NK cell repertoires in the healthy humans and in two specific settings of immune system development, we have provided evidence that human CD56dim NK cells undergo a previously undescribed differentiation process. This differentiation process can, at steady state, be defined by analysis of expression patterns of NKG2A, KIRs, and CD57 on CD56dim NK cells. Distinct differentiation stages identified are associated with phenotypic and functional changes. This knowledge formed a platform for studies of human NK cells in settings of defined viral infections. In acute human hantavirus infection, the NK cell response encompassed a rapid and vigorous proliferation of activated NK cells followed by long-term persistence of a differentiated NKG2C+CD57+ CD56dim NK cell subset. Surprisingly, this proliferation and persistence occurred only in patients on a CMV seropositive background and was mediated by IL-15 and HLA-E, providing necessary proliferative and anti-apoptotic signals to the expanding cells. When monitoring the NK cell response to immune modulatory IFN-α treatment in the context of acute and chronic hepatitis C virus (HCV) infection, we observed that CD56bright NK cells acquired the capacity to express the apoptosis-inducing molecule TRAIL. These differentiated CD56bright‘killer’ cells efficiently inhibited HCV replication in Huh7.5 cells via TRAIL. NK cells could also utilize the activation receptor DNAM-1 to recognize Huh7.5 cells and suppress HCV replication. Chronic HCV-infection was found to cause disturbances in innate cellular immunity. One example of this was the differentiation of NK cells towards a functionally skewed CD56neg NK cell subset. Furthermore, effector CD8 T cells acquired NK cell-like properties, such as expression of CD16 and the capacity to respond independent of the TCR during chronic HCV infection. Altogether, the described model of human CD56dim NK cell differentiation may serve as a framework for studies of NK cell responses in many disease conditions, here illustrated in studies of viral infections in humans

Utveckling och realisering av belysningsstyrningssystem för segelbåtar

Som uppdragsgivare för detta examensarbete fungerar Flink Engineering Ab. Arbetet har utförts som underleverantörstjänst åt Baltic Yachts Ab, som är en världsledande leverantör av skräddarsydda kolfiberyachter. Huvudsyftet med detta arbete var att tillgodose de behov som uppstod vid varvet i takt med att kundernas krav på belysningen och dess styrning ökade. Examensarbetet består av två delmoment. Båtarna vid varvet hade tidigare inte haft belysningsstyrningssystem alls, eller så var dessa begränsade och oändamålsenliga. När kundernas krav ökade uppstod ett behov av att utveckla ett ändamålsenligt system. För att erhålla ett fungerande system, behövdes först klargöras med vilken teknik detta sker, vilken leverantör som väljs samt vilka komponenter som behövs. Besvarandet av dessa frågor utgör arbetets första moment. När arbetet skulle påbörjas hade en skräddarsydd segelbåt i storleksklassen 150–200 fot, vars köpare också hade speciella önskningar beträffande belysningsstyrningen, börjat ta form. Därför ansågs det lämpligt att systemet realiseras i denna båt och detta utgör arbetets andra moment. Resultatet blev ett ändamålsenligt belysningsstyrningssystem, med tillhörande kopplingsritningar och användargränssnitt, ombord på ovannämnd segelbåt. Systemet bygger på DALI-teknik och styrs från en PLC. Systemet är ekonomiskt och prestandamässigt fördelaktigt jämfört med tidigare system och kan, tack vare sin flexibilitet, användas på flera båtar i framtiden samt utvecklas vid behov.This thesis was commissioned by Flink Engineering Ab. The work has been done as subcontractor service for Baltic Yachts Ltd, which is the world’s leading supplier of custom-built carbon fiber yachts. The main purpose of this thesis was to meet the needs that emerged at the yard as the customers’ requirements regarding the lighting and its control increased. The thesis consists of two parts. The boats at the yard had earlier not been equipped with lighting control systems at all, or these were limited and inappropriate. When the customers’ requirements increased, a need for developing an appropriate system emerged. To obtain a suitable system, one had to start with clarifying what technology to use, what supplier to choose and what components are needed. Answering these questions forms the first part of the thesis. When the work was to start, a custom-built sailing yacht in the size range of 150–200 feet, whose buyer also had special wishes regarding the lighting control, had begun to take shape. Consequently, it was considered convenient to realize the system in this yacht and this process forms the second part of the thesis. The result of the thesis is an appropriate lighting control system, together with wiring diagrams and user interface, on board the abovementioned sailing yacht. The system is based on the DALI interface and controlled from a PLC. The system is economically and functionally advantageous compared with the earlier used system and can, thanks to its flexibility, be used in other yachts in the future and be further developed as needed

Characterization of Natural Killer Cell Phenotype and Function during Recurrent Human HSV-2 Infection

Human natural killer (NK) cell differentiation, characterized by a loss of NKG2A in parallel with the acquisition of NKG2C, KIRs, and CD57 is stimulated by a number of virus infections, including infection with human cytomegalovirus (CMV), hantavirus, chikungunya virus, and HIV-1. Here, we addressed if HSV-2 infection in a similar way drives NK cell differentiation towards an NKG2A-NKG2C+KIR+CD57+ phenotype. In contrast to infection with CMV, hantavirus, chikungunya virus, and HIV-1, recurrent HSV-2 infection did not yield an accumulation of highly differentiated NK cells in human peripheral blood. This outcome indicates that human HSV-2 infection has no significant imprinting effect on the human NK cell repertoire

Irreversible impact of chronic hepatitis C virus infection on human natural killer cell diversity

Diversity is crucial for the immune system to efficiently combat infections. Natural killer (NK) cells are innate cytotoxic lymphocytes that contribute to the control of viral infections. NK cells were for long thought to be a homogeneous population of cells. However, recent work has instead revealed NK cells to represent a highly diverse population of immune cells where a vast number of subpopulations with distinct characteristics exist across tissues. However, the degree to which a chronic viral infection affects NK cell diversity remains elusive. Hepatitis C virus (HCV) is effective in establishing chronic infection in humans. During the last years, new direct-acting antiviral drugs (DAA) have revolutionized treatment of chronic hepatitis C, enabling rapid cure in the majority of patients. This allows us to study the influence of a chronic viral infection and its subsequent elimination on the NK cell compartment with a focus on NK cell diversity. In our recent study (Nat Commun, 9:2275), we show that chronic HCV infection irreversibly impacts human NK cell repertoire diversity

Rapid expansion and long-term persistence of elevated NK cell numbers in humans infected with hantavirus

Acute hantavirus infection in humans triggers a rapid expansion and long-term persistence of NK cells

Phenotypic diversity of human adipose tissue-resident NK cells in obesity

Natural killer (NK) cells have emerged as key mediators of obesity-related adipose tissue inflammation. However, the phenotype of NK cell subsets residing in human adipose tissue are poorly defined, preventing a detailed understanding of their role in metabolic disorders. In this study, we applied multicolor flow cytometry to characterize CD56bright and CD56dim NK cells in blood and adipose tissue depots in individuals with obesity and identified surface proteins enriched on adipose tissue-resident CD56bright NK cells. Particularly, we found that adipose tissue harbored clusters of tissue-resident CD56bright NK cells signatured by the expression of CD26, CCR5 and CD63, possibly reflecting an adaptation to the microenvironment. Together, our findings provide broad insights into the identity of NK cells in blood and adipose tissue in relation to obesity.publishedVersio

Skewed distribution of proinflammatory CD4+CD28null T cells in rheumatoid arthritis

Expanded populations of CD4+ T cells lacking the co-stimulatory molecule CD28 (CD4+CD28null T cells) have been reported in several inflammatory disorders. In rheumatoid arthritis, increased frequencies of CD4+CD28null T cells in peripheral blood have previously been associated with extra-articular manifestations and human cytomegalovirus (HCMV) infection, but their presence in and contribution to joint manifestations is not clear. In the present article we investigated the distribution of CD4+CD28null T cells in the synovial membrane, synovial fluid and peripheral blood of RA patients, and analysed the association with erosive disease and anti-citrullinated protein antibodies. CD4+CD28null T cells were infrequent in the synovial membrane and synovial fluid, despite significant frequencies in the circulation. Strikingly, the dominant TCR-Vβ subsets of CD4+CD28null T cells in peripheral blood were often absent in synovial fluid. CD4+CD28null T cells in blood and synovial fluid showed specificity for HCMV antigens, and their presence was clearly associated with HCMV seropositivity but not with anti-citrullinated protein antibodies in the serum or synovial fluid, nor with erosive disease. Together these data imply a primary role for CD4+CD28null T cells in manifestations elsewhere than in the joints of patients with HCMV-seropositive rheumatoid arthritis

Retained NK cell phenotype and functionality in non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD), and the progressive stage non-alcoholic steatohepatitis (NASH), is the predominant cause of chronic liver disease globally. As part of the complex pathogenesis, natural killer (NK) cells have been implicated in the development of liver inflammation in experimental murine models of NASH. However, there is a lack of knowledge on how NK cells are affected in humans with this disease. Here, we explored the presence of disease-specific changes within circulating and tissue-resident NK cell populations, as well as within other major immune cell subsets, in patients with liver biopsy-confirmed NAFLD. Using 18-color-flow cytometry, substantial changes were observed in certain myeloid populations in patients as compared to controls. NK cell numbers, on the other hand, were not altered. Furthermore, only minor differences in expression of activating and inhibitory NK cell receptors were noted, with the exception of an increased expression of NKG2D on NK cells from patients with NASH. NK cell differentiation remained constant, and NK cells from these patients retain their ability to respond adequately upon stimulation. Instead, considerable alterations were observed between liver, adipose tissue, and peripheral blood NK cells, independently of disease status. Taken together, these results increase our understanding of the importance of the local microenvironment in shaping the NK cell compartment and stress the need for further studies exploring how NASH affects intrahepatic NK cells in humans.publishedVersio

Subtype-specific surface proteins on adipose tissue macrophages and their association to obesity-induced insulin resistance

A chronic low-grade inflammation, originating in the adipose tissue, is considered a driver of obesity-associated insulin resistance. Macrophage composition in white adipose tissue is believed to contribute to the pathogenesis of metabolic diseases, but a detailed characterization of pro- and anti-inflammatory adipose tissue macrophages (ATMs) in human obesity and how they are distributed in visceral- and subcutaneous adipose depots is lacking. In this study, we performed a surface proteome screening of pro- and anti-inflammatory ATMs in both subcutaneous- (SAT) and visceral adipose tissue (VAT) and evaluated their relationship with systemic insulin resistance. From the proteomics screen we found novel surface proteins specific to M1-like- and M2-like macrophages, and we identified depot-specific immunophenotypes in SAT and VAT. Furthermore, we found that insulin resistance, assessed by HOMA-IR, was positively associated with a relative increase in pro-inflammatory M1-like macrophages in both SAT and VAT.publishedVersio