New Pharmacological Treatment Against Diabetic Eye Diseases Is Tested

Patients with diabetes mellitus are often affected by diseases of the eye which develop as a long-term consequence of diabetes. Regular ophthalmologic appointments for early detection and initiation of treatment are therefore important. The so called “diabetic retinopathy” and the “diabetic macular edema” are two of the most frequent ocular diseases in patients with diabetes, and both feature pathologic changes of blood vessel functions in the retina.

Experimental data and measurements in patients suggest that these changes in blood vessel functions may originate from a lack of vasoinhibin hormones in the retina. Vasoinhibin hormones can control blood vessel functions and are generated by proteolytic cleavage of their precursor hormone prolactin, also known as the “nursing hormone”.

A Mexican-German team of scientists and physicians has now initiated a clinical study in which a new pharmacological therapy is being evaluated, with which the presumptive hormonal dysregulation in the retina might be corrected. The treatment evaluates the effects of the drug Levosulpiride, which increases the pituitary secretion of prolactin. In consequence, more prolactin is available in the retina where it is converted to vasoinhibins. This might have positive effects on the blood vessels in the retina and may therefore slow down the progression of diabetic retinal diseases and preserve vision.

The treatment of study patients is being performed by ophthalmologists at the Mexican Institute for Ophthalmology (IMO) in Querétaro. The leading scientists of the study are Professor Carmen Clapp Ph.D. from the Institute of Neurobiology of the National University of Mexico (UNAM, Universidad Nacional Autónoma de México) in collaboration with principal investigator and internal medicine specialist and endocrinologist Professor Ma. Ludivina Robles-Osorio Ph.D., M.D. from the University of Queretaro (UAQ, Universidad Autónoma de Querétaro) and principal investigator, ophthalmologist and retina specialist, Dr. Renata García-Franco, M.D. (IMO).

A work group headed by Dr. Jakob Triebel from the University-Institute of Clinical Chemistry, Laboratory Medicine and Transfusion Medicine of the General Hospital Nuremberg and the Paracelsus Medical University, Head: Prof. Dr. Thomas Bertsch, is part of the team of investigators and contributes to the laboratory tests involved in the study. A description of the study, including relevant background information, has been published by the Journal Frontiers in Endocrinology – Section Diabetes as an open access article on May 29, 2018. The study is registered in the public registry for clinical trials at “” under the identification NCT03161652. The completion of the study, and information on the efficiency of the treatment, are expected in the year 2020.

Further information


Basis and Design of a Randomized Clinical Trial to Evaluate the Effect of Levosulpiride on Retinal Alterations in Patients with Diabetic Retinopathy and Diabetic Macular Edema
Ma. Ludivina Robles-Osorio, Renata García-Franco, Daniel Núñez-Amaro, Ximena Mira-Lorenzo, Paulina Ramírez-Neria, Wendy Hernández, Ellery López-Star, Thomas Bertsch, Gonzalo Martínez de la Escalera, Jakob Triebel, and Carmen Clapp



From Bench to Bedside: Translating the Prolactin/Vasoinhibin Axis
Jakob Triebel, Ludivina Robles-Osorio, Renata Garcia-Franco, Gonzalo Martínez de la Escalera, Carmen Clapp, and Thomas Bertsch


Dr. Jakob Triebel
Institut für Klinische Chemie, Laboratoriumsmedizin und Transfusionsmedizin
Klinikum Nürnberg & Paracelsus Medizinische Privatuniversität Nürnberg
Prof.-Ernst-Nathan-Str. 1
90419 Nürnberg
Tel: +49.911.398.114181

Carmen Clapp, Ph.D.
Institute of Neurobiology,
National University of Mexico (UNAM),
Queretaro, Mexico, 76230
Tel: 52-442-2381028

Dr. Renata García Franco
Instituto Mexicano de Oftalmología
Circuito Exterior Estadio Corregidora S/N
Colonia Colinas del Cimatario
76099 Querétaro, Qro, Mexico

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