Polyacrylamide gel disc electrophoresis of alkaline phosphatase isoenzymes in bone and liver disease

Intersecting Paths: Unraveling the Complex Journey of Cancer to Bone Metastasis

The phenomenon of bone metastases presents a significant challenge within the context of advanced cancer treatments, particularly pertaining to breast, prostate, and lung cancers. These metastatic occurrences stem from the dissemination of cancerous cells into the bone, thereby interrupting the equilibrium between osteoblasts and osteoclasts. Such disruption results in skeletal complications, adversely affecting patient morbidity and quality of life. This review discusses the intricate interplay between cancer cells and the bone microenvironment, positing the bone not merely as a passive recipient of metastatic cells but as an active contributor to cancer progression through its distinctive biochemical and cellular makeup. A thorough examination of bone structure and the dynamics of bone remodeling is undertaken, elucidating how metastatic cancer cells exploit these processes. This review explores the genetic and molecular pathways that underpin the onset and development of bone metastases. Particular emphasis is placed on the roles of cytokines and growth factors in facilitating osteoclastogenesis and influencing osteoblast activity. Additionally, this paper offers a meticulous critique of current diagnostic methodologies, ranging from conventional radiography to advanced molecular imaging techniques, and discusses the implications of a nuanced understanding of bone metastasis biology for therapeutic intervention. This includes the development of targeted therapies and strategies for managing bone pain and other skeletal-related events. Moreover, this review underscores the imperative of ongoing research efforts aimed at identifying novel therapeutic targets and refining management approaches for bone metastases. It advocates for a multidisciplinary strategy that integrates advancements in medical oncology and radiology with insights derived from molecular biology and genetics, to enhance prognostic outcomes and the quality of life for patients afflicted by this debilitating condition. In summary, bone metastases constitute a complex issue that demands a comprehensive and informed approach to treatment. This article contributes to the ongoing discourse by consolidating existing knowledge and identifying avenues for future investigation, with the overarching objective of ameliorating patient care in the domain of oncology.

Portal pressure is of significant prognostic value in primary biliary cholangitis

BACKGROUND AND AIMS

In other forms of chronic liver disease, measurement of portal pressure is of prognostic value, but this has not yet been established in primary biliary cholangitis (PBC). The aim of the study is to determine the prognostic value of hepatic venous pressure gradient (HVPG) in relation to liver-related survival outcomes, as well as to the development of hepatic decompensation, oesophageal varices and variceal bleeding.

METHODS

Baseline HVPG and liver biopsies were obtained in 86 patients followed for 10 years in a controlled trial of colchicine treatment, and subsequently in a long-term observational cohort study for a further 30 years.

RESULTS

There were 49 Hepatic deaths in addition to 10 Liver Transplants (Hepatic death/transplant; n = 59). Some of these were associated with a significant variceal bleed within 3 months of death or transplant (Portal hypertension-associated death or transplant; n = 19). There were 63 deaths from all causes. During follow-up, oesophageal varices developed in 26 patients, whilst 17 bled from varices and 32 developed hepatic decompensation over a median follow-up of 18.1 years (1.9-28.5). Baseline HVPG was highly predictive of all 6 clinical outcomes and contributed significant predictive information additional to that provided by Mayo score and Ludwig stage.

CONCLUSION

Measurement of baseline portal pressure is of significant prognostic value in primary biliary cholangitis.

Tumour markers in diagnosis and management

The 20-year period since the discovery of AFP by Abelev has seen the introduction of a wide range of new tumour markers and it is now clear that PLC is biologically heterogeneous. Hepatoblastomas, fibrolamellar carcinomas, hepatocellular carcinomas and cholangiocarcinomas may secrete a variety of distinctive markers which are predominantly glycoproteins, and may resemble those found in placenta or fetal liver. Diagnostically, AFP remains the best marker for HCC, both in sensitivity and specificity; it is known to consist of isoforms. In patients with elevated serum AFP and filling defects on liver scan, Con A reactive AFP may differentiate PLC from hepatic metastases, whilst fucosylated AFP may distinguish PLC from benign disorders when AFP is non-diagnostically elevated. With this recognition of tumour heterogeneity the value of a multiple-marker approach has become apparent. The measurement of vitamin B12 binding protein and neurotensin should lead to the detection of most patients with the fibrolamellar variant of HCC and many of these should be resectable. In patients with normal serum AFP levels, HCC-associated GGTP is of major value whilst in low-incidence areas for HCC, patients should also be screened for H-ALP; using a multiple marker approach in high-risk groups, 90% of clinically diagnosed hepatocellular carcinomas are serologically positive. The Chinese and Alaskan studies, in which small, potentially resectable tumours were detected, suggest that it is now possible to achieve 5-year survival figures of up to 60% in HCC patients detected by screening. The value of such a strategy in low-incidence countries is currently under study. In patient monitoring, as in diagnosis, AFP remains the outstanding marker. In AFP-negative patients, other markers including vitamin B12-binding protein, neurotensin, HCC-specific isoenzymes, des-gamma-carboxy-prothrombin and alpha-fucosidase, are of undoubted diagnostic value, but their value as indicants of disease progression remains to be established. In monitoring the response of hepatic metastases, CEA remains the least unsatisfactory marker but should always be used in conjunction with serial ultrasound scans. Tumour markers now play an important role in the diagnosis and monitoring of PLC but a role is also emerging in tumour imaging and drug targeting. The next 20 years should see the introduction of tumour markers of high sensitivity and specificity which make a fundamental contribution not only to detection and monitoring, but also to the effective treatment of liver cancer.

Alkaline phosphatase and cholestasis

The process of cholestasis in both man and rat leads in the majority of cases to the appearance of a biliary band in the electrophoresis of alkaline phosphatase isoenzymes. In this article, the biochemical nature and mode of formation of the biliary band is discussed, with reference to its appearance in cholestasis and other hepatobiliary diseases.

Biochemistry of alkaline phosphatase isoenzymes

The review discusses the similarities and differences between the common isoenzymatic forms of ALP. Methods for separating, measuring, and purifying the isoenzymes on the basis of these differing properties are described. The evidence is reviewed for the existence of different genes coding for different isoenzymes, and the current state of knowledge is surveyed concerning the location, development, function, and regulation of the isoenzymes. Finally, some unusual forms of ALP which may appear in the circulation are described.

Intestinal alkaline phosphatase in bile: evidence for an enterohepatic circulation

The isoenzyme characteristics of alkaline phosphatase in human bile obtained from patients with gallstones have been determined by means of electrophoresis on polyacrylamide gel, both before and after preincubation with neuraminidase, and also by means of inhibition tests with heat, urea, and L-phenylalanine. Bile alkaline phosphatase is shown to be partly secreted by the liver cell, but partly derived from the small intestine. The presence of small-intestinal alkaline phosphatase in bile implies an enterohepatic circulation of this high molecular weight glycoprotein. The significance of this finding is discussed in relation to the mechanism whereby large protein molecules may pass across the plasma membrane of the liver cell.

Electrophoretic separation of alkaline phosphatase isoenzymes compared with alkaline phosphatase and gamma-glutamyltransferase in hepatobiliary diseases

Electrophoretic separation of serum alkaline phosphatase fractions and measurement of serum alkaline phosphatase and serum gamma-glutamyltransferase were carried out in 82 consecutive patients with suspected hepatobiliary disease to investigate the usefulness of the three tests in distinguishing between parenchymatous hepatic disease and occlusive hepatobiliary disease. It was concluded that measurement of total serum alkaline phosphatase was superior to the two other tests.

Indian childhood cirrhosis in the United Kingdom

Two young brothers with cirrhosis are reported. They are the issue of a first-cousin marriage between Bangladeshi parents. The older boy was born in Bangladesh, the younger in England. A diagnosis of Indian childhood cirrhosis (ICC) was made on the basis of the clinical features and the liver histology. The younger brother represents the first example of this disease in a patient born in the United Kingdom.

Studies on the frequency and pathogenesis of liver involvement in rheumatoid arthritis

A systematic prospective survey of 100 outpatients with rheumatoid arthritis revealed that 45 had biochemical evidence of liver disease. In most cases this was due to increases in total serum alkaline phosphatase (ALP) and/or gammaglutamyl transpeptidase (GGT). Examination of serum ALP isoenzyme profiles in 50 of the patients showed that the liver isoenzyme was the sole or major component in 44 patients, including many with normal total ALP levels. 18% had raised serum liver ALP together with raised GGT, suggestive of an underlying hepatobiliary lesion. No correlation could be detected between raised serum levels of liver enzymes and the age or sex of the patient, duration or severity of arthritis, and drug or alcohol history. However, there was a significant correlation between raised serum ALP and lacrimal or salivary gland dysfunction. It is suggested that immunological mechanisms may be involved in the development of hepatic abnormalities in rheumatoid arthritis.

Intestinal alkaline phosphatase in the diagnosis of liver disease

Alkaline phosphatase isoenzymes have been studied by acrylamide gel disc electrophoresis in 76 patients with liver disorders comprising 15 with an extrahepatic lesion, 53 with an intrahepatic lesion, and eight patients who had features of both intra- and extrahepatic disease. No intestinal band was found in the 15 cases of extrahepatic liver disease, in marked contrast to the patients with intrahepatic lesions in whom an intestinal band was found in 45% of cases. The intrahepatic group was heterogeneous, a high incidence of intestinal bands being found in patients with cirrhosis of the liver. It is concluded that where a raised serum alkaline phosphatase is found in a patient with jaundice, and a gut band is present on electrophoresis, the lesion is likely to be intrahepatic.