Genetic contributions to lupus-like disease in NZB/NZW mice

TFOS DEWS II pathophysiology report

The TFOS DEWS II Pathophysiology Subcommittee reviewed the mechanisms involved in the initiation and perpetuation of dry eye disease. Its central mechanism is evaporative water loss leading to hyperosmolar tissue damage. Research in human disease and in animal models has shown that this, either directly or by inducing inflammation, causes a loss of both epithelial and goblet cells. The consequent decrease in surface wettability leads to early tear film breakup and amplifies hyperosmolarity via a Vicious Circle. Pain in dry eye is caused by tear hyperosmolarity, loss of lubrication, inflammatory mediators and neurosensory factors, while visual symptoms arise from tear and ocular surface irregularity. Increased friction targets damage to the lids and ocular surface, resulting in characteristic punctate epithelial keratitis, superior limbic keratoconjunctivitis, filamentary keratitis, lid parallel conjunctival folds, and lid wiper epitheliopathy. Hybrid dry eye disease, with features of both aqueous deficiency and increased evaporation, is common and efforts should be made to determine the relative contribution of each form to the total picture. To this end, practical methods are needed to measure tear evaporation in the clinic, and similarly, methods are needed to measure osmolarity at the tissue level across the ocular surface, to better determine the severity of dry eye. Areas for future research include the role of genetic mechanisms in non-Sjögren syndrome dry eye, the targeting of the terminal duct in meibomian gland disease and the influence of gaze dynamics and the closed eye state on tear stability and ocular surface inflammation.

Sjögren syndrome: what and where are we looking for?

PURPOSE OF REVIEW

Sjögren's syndrome affects exocrine glands leading to a dry mouth and dry eyes. Dry eye manifestations can precede the diagnosis of Sjögren's syndrome by many years. Innumerous spontaneous and inducible Sjögren's syndrome models have been used to study the pathogenesis of Sjögren's syndrome. This review focuses on recent human data, ocular and extraglandular manifestations of animal models, what is known, what is still unknown and how we need to look, and their correlation correspondence to human disease.

RECENT FINDINGS

Hallmarks of dry eye in Sjögren's syndrome include increased corneal staining, goblet cell loss and low tear volume. Confocal microscopy and impression cytology are able to clarify new markers of the ocular disease. Extraglandular manifestations should be an alert more severe complications in the eye. Some models have strong sex and exocrine gland predilection, whereas aging generally worsens the disease phenotype. Although most models do not display a significant increase in corneal staining or tear secretion impairment, conjunctival infiltration and decrease in goblet cells are frequently seen.

SUMMARY

We have seen great advances in the role of inflammation in ocular, oral and extra-glandular manifestations of Sjögren's syndrome. Several mechanisms and mediators of Sjögren's syndrome have been elucidated in animal model studies.

Plasma amylase levels as a marker of disease severity in an isogenic murine model of paracoccidioidomycosis

Survival patterns after peritoneal infection with Paracoccidioides brasiliensis vary according to the mouse strain and to the virulence of the fungal isolate. It has previously been observed that a significant increase in plasma amylase levels occurs only when susceptible mice (B10.A) were infected with a virulent isolate (Pb18). In order to verify if increased amylase levels correlate with susceptibility to P. brasiliensis infection, 12 mouse strains with different susceptibility patterns to this fungus were investigated after infection with Pb18. When compared with their respective controls, C57BI/6, B10D2/oSn, B10D2/nSn, C3H/HeJ, B10.A and BALB/c mice showed a conspicuous amylase increase and AKR, (NZB x NZW)F1, CBA/J, (A/Sn x B10.A)F1, A/Sn and DBA/2 absence of alteration. The influence of the infecting fungal isolate on this enzymatic parameter was investigated using B10.A mice and fungal isolates with diverse degrees of virulence. When compared with their non-infected controls, mice infected with Pb45 or Pb47 showed a very high amylase increase, with Pb44 or Pb18 a high one and with Pb50 or Pb265 a discrete increase. On the whole, there is an inverse correlation between survival times after infection and the increase in amylase levels. Thus, measurement of plasma amylase is a satisfactory parameter to evaluate the severity of paracoccidioidomycosis in mice.