Reduction of leucocyte telomere length in radiographic hand osteoarthritis: a population-based study

Osteoarthritis in the context of ageing and evolution. Loss of chondrocyte differentiation block during ageing

Ageing is the main risk factor of primary osteoarthritis (OA) and OA is the disease most strongly correlated with ageing. Both in humans and other animals OA development appears to be not strictly time-dependent but to hold pace with ageing processes. A characteristic of OA is deviant behaviour of chondrocytes in articular cartilage. These chondrocytes resemble terminal differentiated chondrocytes in growth plates and actively produce matrix degrading enzymes. The latter results in cartilage degeneration and eventually OA. We postulate that at a young age progression of chondrocyte differentiation is actively blocked in articular cartilage. This block declines when the evolutionary pressure to maintain this block, after reproductive life, is minimized. The loss of this differentiation block, maybe as a result of changes in chondrocyte TGF beta signalling, results in combination with normal joint loading in cartilage degeneration and OA.

A systematic search and narrative review of radiographic definitions of hand osteoarthritis in population-based studies

OBJECTIVE

Currently there is no agreed "gold standard" definition of radiographic hand osteoarthritis (RHOA) for use in epidemiological studies. We therefore undertook a systematic search and narrative review of community-based epidemiological studies of hand osteoarthritis (OA) to identify (1) grading systems used, (2) definitions of radiographic OA for individual joints and (3) definitions of overall RHOA.

METHODS

The following electronic databases were searched: Medline, Embase, Science Citation Index and Ageline (inception to Dec 2006). The search strategy combined terms for "hand" and specific joint sites, OA and radiography. Inclusion and exclusion criteria were applied. Data were extracted from each paper covering: hand joints studied, grading system used, definitions applied for OA at individual joints and overall RHOA.

RESULTS

Titles and abstracts of 829 publications were reviewed and the full texts of 399 papers were obtained. One hundred fifty-two met the inclusion criteria and 24 additional papers identified from screening references. Kellgren and Lawrence (K&L) was the most frequently applied grading system used in 80% (n=141) of studies. In 71 studies defining OA at the individual joint level 69 (97%) used a definition of K&L grade > or = 2. Only 53 publications defined overall RHOA, using 21 different definitions based on five grading systems.

CONCLUSION

The K&L scheme remains the most frequently used grading system. There is a consistency in defining OA in a single hand joint as K&L grade > or = 2. However, there are substantial variations in the definitions of overall RHOA in epidemiological studies.

Nevus Size and Number Are Associated with Telomere Length and Represent Potential Markers of a Decreased Senescence In vivo

Nevus counts represent one of the strongest risk factors for melanoma. They appear in childhood and adolescence and involute from middle age onwards. Recent evidence has shown that nevus cells undergo oncogene-induced senescence involving the p16/retinoblastoma pathway. However, telomere length also influences senescence in proliferative somatic cells and varies between individuals. This study explores whether telomere length measured in white cells is associated with nevus count and size in 1,897 Caucasian women ages 18 to 79 years. Total body nevus counts were positively correlated with white cell telomere length (mean, 7.09 kbp; range, 5.09-9.37) after adjustment for age (P = 0.0001). Age-adjusted telomere length was also associated with nevus count for nevi above 5 mm in diameter (P = 0.04). Subjects in the top category for nevus count had an average age-adjusted telomere length 150 bp longer than those in the lowest category. The positive correlation between white cell telomere length and nevi number and size may reflect an increased replicative potential (reduced senescence) in individuals with longer telomeres, which may not be melanocyte specific. Understanding mechanisms influencing the induction and involution of nevi will not only help in understanding the pathophysiology of melanoma but should also shed light on the complex relationship between aging and cancer.

Telomere Shortening and Associated Chromosomal Instability in Peripheral Blood Lymphocytes of Patients With Hodgkin’s Lymphoma Prior to Any Treatment Are Predictive of Second Cancers

PURPOSE

To investigate a potential link between telomere length, chromosomal instability, and the advent of a second cancer (SC) in patients with Hodgkin's lymphoma (HL), who are known to be at risk for SCs. This study was premised on the finding that telomere dysfunction and DNA repair pathways were related to many pathologic conditions.

METHODS AND MATERIALS

Three cohorts of patients with HL were studied: 73 who were prospectively followed >5 years after diagnosis (prospective HL cohort), 28 who developed a SC (SC HL cohort), and 18 long-term survivors with no evidence of disease or complication since their initial treatment (NED HL cohort). Telomere length was analyzed by a telomeric restriction fragment assay in peripheral blood lymphocytes. Thirty healthy donors and 70 patients with a newly diagnosed solid tumor were the control population.

RESULTS

Compared with controls, patients from the prospective HL cohort, before any treatment, showed age-independent shorter telomeres (mean, 8.3 vs. 11.7 kb in healthy donors; <6 kb in 18% in HL patients), increased spontaneous chromosomal abnormalities, and increased in vitro radiation sensitivity (p < 10(-4) each). After treatment, telomere shortening was associated with cytogenetic profiles characterized by the persistence of complex chromosomal rearrangement and clonal aberrations. Moreover, the two cases of SC in the prospective HL patients had short telomeres and CCR initially. In addition, the SC HL cohort was characterized by markedly short telomeres (6.6 vs. 9.7 kb in the NED HL cohort), the presence of complex chromosome rearrangements, and increased in vitro radiation sensitivity.

CONCLUSIONS

An intimate relationship between pre-treatment telomere shortening, chromosomal instability, radiation sensitivity and occurrence of SC was found in HL patients.