Stereological investigation on the effects of metaproterenol, pilocarpine and atropine administration on the human lacrimal gland

The cytologic composition of dacryops: an immunohistochemical investigation of 15 lesions compared to the normal lacrimal gland

PURPOSE

To define the cytologic composition of the double-layered epithelial lining of dacryops (lacrimal duct cyst), improve histopathologic diagnosis, and better understand pathogenesis.

DESIGN

Clinicopathologic retrospective study with immunohistochemical studies of 15 lesions compared with normal lacrimal gland.

METHODS

Clinical data from 14 patients were reviewed and microscopy was performed with routine stains and immunohistochemical probes for epithelial membrane antigen (EMA), gross cystic disease fluid protein-15 (GCDFP-15), cytokeratin 7 (CK7), and smooth muscle actin (SMA).

RESULTS

The major lacrimal gland was involved in 13 lesions; 2 lesions arose in an accessory gland of Krause. One case was bilateral; the average age of the patients was 50.7 years. Neither visual acuity nor motility was disturbed. No lesion was discovered to have recurred after excision. Microscopically, in all dacryops specimens goblet cells and luminal pseudoapocrine apical cytoplasmic projections were identified. Lacrimal acinar cells immunoreacted with GCDFP-15 and CK7, whereas the normal ducts and the epithelium of the dacryops lesions reacted diffusely only with CK7. SMA-positive myoepithelial cells were found in the acini but not in the normal ducts or dacryops epithelium.

CONCLUSIONS

Negative GCDFP-15 staining ruled out apocrine metaplasia in dacryops. Normal ducts and dacryops showed no immunohistochemical evidence for the presence of myoepithelial cells. Pathogenetic theories of dacryops that implicate a failure of ductular "neuromuscular" contractility must therefore be revised. A dysfunction of the rich neural plexus around the ductules may play a role in the development of dacryops in conjunction with periductular inflammation and induced scarring.

Sympathomimetic protein secretion by young and aged lacrimal gland

The diminished basal tear flow in aged individuals is associated with lymphocytic infiltrations and atrophy of the lacrimal ducts and acini. We have investigated the age-related physiological changes to sympathomimetic stimulation of lacrimal tissue from F344 rats to determine if the responses are uniformly diminished as would be expected by glandular atrophy. The quantitative and temporal pattern of protein and peroxidase secretion by lacrimal gland fragments from young (4 month) and aged (24 month) F344 male rats was examined in a perifusion system. Upon stimulation of tissue from young animals with 0.01 mM phenylephrine for 40 min, secretion above baseline levels of protein was 570.8 micrograms/g tissue and of peroxidase was 45.2 delta A X min-1/g tissue. The response of the aged tissue to phenylephrine was not significantly different from that of the young tissue. beta-adrenergic stimulation by isoproterenol (0.01 mM) evoked only a modest secretion of protein and no consistently measurable peroxidase from young tissue. IBMX alone and in combination with isoproterenol (0.1 mM and 0.01 mM respectively) evoked a large secretion of protein, 1345.7 micrograms/g tissue, and a modest secretion of peroxidase, 9.5 delta A X min-1/g tissue by young tissue. The aged tissue, upon stimulation with the combination of IBMX and isoproterenol, secreted significantly less protein and peroxidase than the young tissue. In separate experiments, the production of cAMP was measured. In young tissue, isoproterenol did not cause a measurable increase of intracellular cAMP. IBMX caused a 2-3 fold increase in cellular cAMP which was not increased further by addition of isoproterenol.(ABSTRACT TRUNCATED AT 250 WORDS)